Cooperation: The Engineer and the Architect 9783034610551, 9783034607940

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Aita Flury (Ed.)

Cooperation The Engineer and the Architect

05  Andrea Wiegelmann  Preface 07  Elisabeth Boesch  Foreword 09  Aita Flury  Inquisitive Openness

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  Theory 19 Marco Pogacnik 

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Research 75 Jürg Conzett 

Technology as a Means of Expression in the Nineteenth Century – Architects and Engineers in Dialogue

The Interplay of Technical and Architectural Aspects in the Palazzo della Regione in Trento by the Architect Adalberto Libera and the Engineer Sergio Musmeci

33 Christoph Wieser

Pioneer and Projection: The Misappropriation of the Engineer in Modernist Architecture

91 Yves Weinand New Structural Potential of Wood: the IBOIS Research Laboratory at EPF Lausanne

41 Christian Penzel The Culture of Construction: Examples from the Last Fifty Years of a Remarkable Development

57  Christoph Baumberger Structural Concepts and Spatial Design: On the Relationship Between Architect and Engineer

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103 Aita Flury and Jürg Conzett Tetto gigantesco – a diverse huge roof Foils of a Research

114 Model Photos

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  Practice

208 Meta-Dialogue

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  Teaching

133 Markus Peter

243 Joseph Schwartz 

Deviations



139 Andreas Hagmann

249 Christoph Wieser





Structure and Space

Structural Theory and Structural Design

Art and Science

147 Mike Schlaich 

257 Mario Monotti





Each His Own

153 Roger Boltshauser, Aita Flury and Jürg Conzett

Constructing as a Science

263 Paul Kahlfeldt

Construction Transforms Material into Space

A Process of Rapprochement

161 Stefan Polónyi

269 Roger Boltshauser, Aita Flury und Jürg Conzett  





On Designing Structures

169 Renato Salvi The A16 Transjurane Highway: Architectural Acupuncture

175 Elisabeth und Martin Boesch, Carlo Galmarini, Urs B. Roth und Judit Solt  Rules to Play By and Play With

Program and Structure

274 Authors and Interview Partners 277 Literature 279 Image Credits 283 Acknowledgements 284 Imprint



185 Adolf Krischanitz und Aita Flury Mutual Frankness and Self-Reassurance

193 Heinrich Schnetzer, Aurelio Muttoni, Joseph Schwartz und Aita Flury  Strong Structures

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Preface Andrea Wiegelmann

“We have a fundamentally mistaken understanding of roles if we define the professional profiles of architects and civil engineers in the usual way, making the former responsible for design (and construction) and the latter for structural analysis (and technology). ... What demarcates their areas of responsibility is the task in hand, the diverse natures of ‘their’ buildings. The architect shapes objects that aim to satisfy a complex of human needs directly, and are therefore multifunctional. He creates spaces that are used by people. ... The engineer, in contrast, forms objects whose relationship to people is ‘only’ indirect. They serve individual, highly specific purposes and are relatively large or slender, as their form or shape is derived from the requirement to withstand stresses. The objects of the engineer in the strict sense are load-bearing structures. ... ”1 This apt description of—and distinction between—the professional scopes of the engineer and the architect was formulated by Jörg Schlaich.2 Although both work on the same building, their points of view are different. Curiosity about each other’s profession, interest in each other’s work and way of thinking, and a readiness to understand each other’s language are all required if mere coexistence is to be transformed into fruitful and lasting cooperation. That cooperation, as the essays contained in this book reflect, is crucial—not least to the integrated conception and realization of buildings. If the architect’s enthusiasm for the design, composed in terms of form and space, could be linked successfully to the engineer’s enthusiasm for the structure, they might produce buildings that would cause us to rethink the way in which we build. As Aita Flury suggests in her introduction and as Christoph Baumberger, among others, points out in his essay, collaboration between the engineer and the architect can in itself be understood as a contribution to the culture of building. Peter Rice 3 goes further by raising the potential for innovation that is inherent in this coexistence to the status of a humanist principle. This book not only provides an insight into the complex relationship between the two professions, it also covers historical analysis and theoretical approaches to the investigation of specific aspects, such as the relation of structure to space, or the process of designing and building as reflected upon by its proponents, as well as presenting new attempts to equip students of architecture with the tools needed for cooperation in future. This book gives a comprehensive picture of just how diverse and complex, how trying and yet inspiring the process of collaboration between the architect and the engineer can be. If it encourages more members of the two professions to make the effort nevertheless, then much will have been achieved.

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1

Jörg Schlaich in: KlausDieter Weiß et al, Von Gerkan Marg und Partner. Unter grossen Dächern [Under large roofs], Wiesbaden: Vieweg, 1995

2 Jörg Schlaich, emeritus professor at the University of Stuttgart and partner in the engineering practice of Schlaich Bergermann & Partner

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Peter Rice (1935–1992), Irish engineer, founded L'Atelier Piano & Rice with Renzo Piano in 1977

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Foreword Elisabeth Boesch

In 2006, the Zurich Architectural Forum, then still accommodated in the basement of a building in the old town center, showed a small, but impressive, exhibition, which questioned a number of Swiss architects and engineers about their experiences of interdisciplinary cooperation. This exhibition, with the refreshingly unconceited title of Constructors’ Dialogue, concentrated on statements by engineers and architects in the form of drawings, models, photographs, and words, without any kind of spectacular presentation that would have given a distorted view of the content. In my position as vice president of the Federation of Swiss Architects (BSA), I was delegated to sit on the executive committee responsible for proposing exhibitions and events for the Architecture in Dialogue series, initiated by the Swiss embassy in Berlin, and for supervising their organization. After many years of involvement with the Zurich Architectural Forum, it was logical for me to suggest the Constructors’ Dialogue exhibition for this series, with the intention of recreating it in an expanded form. Dialogue—present in the title of both the exhibition and the series—was to take place at various levels: within each of the disciplines, between the two disciplines, between students, specialists, and members of the public, between professional bodies, and in other countries. The exhibition, held at the German Center for Architecture (DAZ) in Berlin in the spring of 2010, was a great success, not least on account of two high-level symposia, which resulted in a small publication. This is now being republished in an expanded form, appearing in the autumn of 2011 to coincide with a further symposium on cooperation between architects and engineers, held at ETH Zurich. I would like to express my gratitude to Aita Flury, without whose persistence and considerable commitment this book would not exist, to my colleagues on the central committee of the BSA, and to the Society for the Art of Civil Engineering and the Department of Architecture of ETH Zurich for their encouragement and their financial support of this project.

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Inquisitive Openness Aita Flury

And on the sphere of the architect there appears a reflection of engineering: the reflection of the laws of physics. And on the sphere of the engineer there appears, from the other side, a reflection of architecture: the reflection of human problems.

Le Corbusier

Antagonism is the form of force.

Nietzsche

In Andrew Saint’s book, Architect and Engineer. A Study in Sibling Rivalry 1 the author, after five hundred pages of meticulous historical research into the relationship between the architect and the engineer, constructs his conclusion around three issues. He affirms that the two disciplines were indistinguishable from one another from 1400 to 1750: in these years, the title of architect or engineer depended mainly on the type of project in question, as well as on its associated hierarchy and institutions (king, military, church, etc.). This distinction, however, reflected neither different construction techniques nor different design capabilities. The when and why of the professions’ subsequent separation is placed by Saint, as by others, in the period from 1750 to 1900: the continual demand for new types of building and construction during the nineteenth century; the emergence of new materials and a newly scientific basis for calculations inevitably led to the emergence of different sets of skills and thus to specialization. According to the author, this development should be dated earlier within the said period rather than later. He then identifies a reunification of the professions during the twentieth century, based on a need to counteract the spread of fragmentation within the professions and their consequent lack of unity and comprehensiveness—something for which the nineteenth century is often criticized. In the twentieth century, the engineer and the architect, equipped with different skills, worked together on the same projects. The most popular model to establish itself was a form of collaboration in which the consulting engineer answered the architect’s questions at a time chosen by the latter. Now, at the beginning of the twenty-first century, Saint argues, this thoroughly dialectical relationship hangs in the balance. He sees the engineer disappearing in a throng of equally important consultants, specialists, and subcontractors, and/ or—in a world dominated by art objects and medial symbolism—letting himself be dragged out of the temple of reason for exploitation by the architect in the service of a predetermined form. To put the conclusion of another publication at the beginning of this book may seem unusual, but that brief summary provides the ideal context for this collection

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Andrew Saint, Architect and Engineer. A Study in Sibling Rivalry, New Haven and London: Yale University Press, 2007

of material on the current state of collaboration between the engineer and the architect. In the last two hundred years of building, the many aspects of the relationship between the two professions and their mutual influence have always been the subject of lively debate. Today we seem to have reached the point at which the ‘informing idea’ has little to do with structure, with spaces being composed without any concern for the reality of the structure. As a result, the architect-as-artist often really sees the engineer as a pure service-provider who delivers the computational tools; as a means to an end who is able to implement an aesthetic concept, to render it buildable. In the face of this widespread view, the Zurich Architectural Forum launched the Constructors’ Dialogue exhibition in 2006, with the intention of showing that architects and engineers could easily take a more inspired approach to their roles. This hypothesis drew its conviction from a number of buildings that had been completed in Switzerland during the previous fifteen years—or were in the process of being built—and which seemed to draw their power precisely from the affirmation of a close design relationship between the architect and the engineer. Curating this exhibition was a leap into the dark for me, and my approach to the subject was rather intuitive and autobiographical—based less, at that time, on theoretical studies of the subject than on my own experience of the limitations and the potential of cooperation in practice, through my work as an architect. Influenced by years of ‘apprenticeship’ with some of the participants in the exhibition and collaborating with others, my view of the subject undoubtedly had its own particular focus. The exhibition seemed to me an opportunity to show, on the basis of several more-or-less well-known buildings, that the effort put into productive collaboration between architects and engineers often passes unnoticed and that intellectual recognition of their added value requires a kind of ‘second sight.’ These were projects whose authors (architects and engineers) discussed technology during the design process in a way different to that which they presented for public view. Their strategies were based on structural subtlety and saw no need to reveal everything at once—and for exactly this reason, they had a lasting effect on our ‘sensual intelligence.’ Emanating from these projects was the sense of a balance between the possibilities of structural discovery on one hand, and assured handling of space on the other. The resulting designs were the visible evidence of dialogical relationships between the two professions and of a new culture of constructing, based on impressive tenacity and skill in jointly developing ideas. It emerged that this depended greatly on the engineer and the architect interpreting the brief in terms of a jointly formulated understanding of the problem, as it were a voluntary commitment to accept common interfaces. This was most clearly evident in the case of shear wall/floor slab structures, because they define space more immediately than any other, i.e. the primary structure and the resulting space are inseparable. Back in the 1960s, German architect Fred Angerer had examined the structural nature of continuous solid surfaces in his remarkable publication Bauen mit tragenden Flächen [Surface Structures in Building. Structure and Form]. Angerer was convinced of the great creative possibilities of such surfaces

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Inquisitive Openness

as systems and he investigated the correct design of such buildings in its various aspects by analyzing the systems’ structural parameters. Using simple examples of the basic positioning of shear walls, he showed how they function structurally in combination—as long as they are touching—and then proceeded to address the resulting design issues: “The lack of sides to a space has serious architectural consequences. In place of a room enclosed on all sides there appears an intimation of space; rather than individual spaces being strictly delimited, they flow into each other. The sense of space changes.”2 This type of structure leads, then, to a new spatial distribution of ‘open’ and ‘closed,’ ‘heavy’ and ‘light’. Such systems become spatially and structurally interesting when they are applied over several stories: if developed as bridge-like structures (the upper floors spanning the ground floor, for instance, without intermediate columns) they can be suitable for large-span volumes combined with floors divided into small rooms above them. The structural behavior of the various elements remains open to interpretation and is not obvious at first glance, so that the systems acquire multiple layers of meaning. This apparent ambiguity oscillates between an engineering and an architectural character, as the ample amount of material to be found on both sides perfectly illustrates. Because this border area between architecture and structural theory perfectly illustrated ‘intimate’ collaboration on equal terms, it became an important starting point and cornerstone of the exhibition. The search for the conditions, possibilities, and limits of this dialogue naturally led to structures that are more resolved, i.e. more hybrid, and to relationships of cooperation that are more hierarchical: models in which the engineer affects the architectural idea by reinterpreting or transforming the architect’s original inspiration, or by ‘incorporating’ the structure into an architectural image. Overall, the exhibition was conceived as a platform for dialogue,

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Fred Angerer, Bauen mit tragenden Flächen. Konstruktion und Gestaltung [Surface Structures in Building. Structure and Form], London: A. Tiranti, 1961], Munich: Georg D. W. Callwey, 1960, p. 61

Cover and page 57 from Fred Angerer, Bauen mit tragenden Flächen. Konstruktion und Gestaltung [Surface Structures in Building. Structure and Form], Munich: Georg D. W. Callwey, 1960

3 Aita Flury, Dialog der Konstrukteure [Constructors’ Dialogue], Sulgen: Niggli Verlag, 2010

so that in describing different styles of dialogue, it included this possibility of continuing them. Dietmar Steiner, the director of the Architecture Center in Vienna, attested to “unfashionable tenacity” of this format in his speech at the exhibition opening. This turned out to be especially true in the sense that the display panels and models subsequently went on an exhaustive tour of Switzerland’s universities, in the course of which countless related events took place, including lectures and panel discussions involving members of both professions. The texts written for the exhibition were made available to the public in the publication Dialog der Konstrukteure,3 beginning a chain reaction of events. In the end, it was the Federation of Swiss Architects (BSA) that decided to provide long-term support for this move to foster public discussion between the two professions and to give it new impetus. Thanks to personal involvement by its vice president, Elisabeth Boesch, an expanded version of the “Constructors’ Dialogue” exhibition was shown at the German Center for Architecture (DAZ) in Berlin as the final event in the “Architecture in Dialogue” series during the spring of 2010. Two international symposia were organized to accompany it, to which a number of new essays and interviews were contributed; these contemporary position papers and general papers were compiled, to start with, in a self-published catalogue. These essays, lectures, and conversations, too, comprehensively covered the subject of practical cooperation, whether in competition entries or built projects. The range was extended by contributions that described educational concepts at various universities, and research topics. This publication is essentially based on the texts presented in Berlin, supplemented once more by several essays with historical and theoretical perspectives. These essays, which illuminate the relationship between the professions at specific times during the not-so-distant past, provide a historical context for reflection upon contemporary practice. All of the articles have been written by practitioners (architects and engineers), or teachers involved in both disciplines, with the exception of Christoph Baumberger, who is a philosopher. This compilation of material remains true to the initial idea of leaving the stage to the practitioners themselves, above all, and letting them talk about the subject in the light of their different experiences, in order to arrive at a stimulating blend of different perspectives. The circle of those involved has been widened by encounters with new people, and even more so by the participation of further associations and institutions, but the initial principle has nevertheless remained: that each text be written specifically in connection with the “Constructors’ Dialogue” with the aim of arriving at statements on cooperation between the professions. The compilation is not a reappraisal of the history of construction, but rather a reader that, by virtue of the material selected for it, aims to provide inspiration for productive collaboration and thereby have an effect that reaches further than a mere survey of the current situation could achieve. The exhibition had already shown that no one seriously calls the separation of the two professions into question. Accordingly, the premises of productive collaboration include no shifts of responsibility from one to the other, being based instead

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Le Corbusier’s sketch “Les Constructeurs,” which he explained as follows: “In the diagram, the domain of the engineer is shown as a hatched area, whereas the domain of the architect is dotted. Beneath this symbolic sign of synthesis are two hands interlocking ten fingers horizontally at the same level, fraternally, both working in solidarity on equipping the Machine Age. This is the sign of the constructors.” From: Science et Vie, 1960

on the notion of ‘close co-existence.’ Productive work in neighboring areas is, however, only possible if they share a common language, which in turn requires mutual interest (followed by knowledge) and empathy for the problems of others. Real curiosity about how things are made is lacking in many architects today. It may also be the case that familiarity with ‘making’ is not necessarily beneficial, given that a genius such as Le Corbusier, who vocally proclaimed and publicized the takeover of architecture by engineers, was ultimately more interested in engineering as an idea than in the reality of construction itself—because to follow the ‘path of technology’ could, if taken to the extreme, mean the loss of architectural freedom. For architects with an interest transcending their own borders, however, talking to an engineer with a sense for both structure and space can broaden their awareness of ideas and extend their patterns of thought. In doing so, each attains greater understanding of the other side’s position— for instance, of their respective enthusiasms, which may be imagined as follows: while the architect is interested, first and foremost, in the visible and directly experienced aspects of the finished work, the engineer is equally passionate about the hidden aspects, those that cannot be perceived directly. Engineers look forward to the finished building—to put it provocatively—no more than to the intelligent process of production and construction, to the acrobatic conditions of work on the site itself. They are inspired by organizing the construction schedule, by plotting out the phases of a building or edifice or, to phrase it poetically: the technical and structural narration of the construction process. 4 For them, it is therefore ultimately of secondary importance if the engineering input and the structural beauty remain concealed in the completed building, as the Reformed Church in Wädenswil (1764–1767), by the Grubenmann brothers, illustrates: outwardly the building is simple and unassuming; inside it is impres-

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Bruno Reichlin, “Technisches Denken, Denktechniken” [Technical thinking, thinking techniques], in: Alexander von Vegesack (ed.), Jean Prouvé. Die Poetik des technischen Objekts [Jean Prouvé. The Poetics of the Technical Object, Weil am Rhein: Vitra Design Stiftung GmbH, 2006], Weil am Rhein: Vitra Design Stiftung GmbH, 2006, p. 32

sive, using space to its full effect. A single, high hall of 20 m length x 38 m width is spanned without columns by a flat, white ceiling that is enlivened by applied stucco reliefs. Their patterns are abstract and atectonic. The ceiling as a whole gives no hint of the complex construction needed to support it, which develops for several levels above, out of sight. The audacity of that structure, based on the principles of bridge-building (of which the Grubenmann brothers were acknowledged masters), is completely hidden from church-goers—the engineer’s heaven-on-earth is to be found among the timbers of the roof! The fragmentation of experience, the disintegration of knowledge into many independent specialisms, each with its own language—specifically, in this context, the

Roof structure of the Reformed Church, Wädenswil . (1764–1767) by the Grubenmann brothers. Bold as a bridge, the roof trusses span an auditorium of 38 m x 20 m

Interior of the Reformed Church in Wädenswil. The structure through which they achieved this spatial effect is completely covered up

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separation of design from technically-driven structural planning—are now given facts that diminish our sense of the whole more and more. The promotion of active cooperation and teamwork, and the cultivation of a harmonious combination of various skills are therefore of the utmost importance. The prerequisite for this is an attentive, inquisitive almost Faustian readiness to cross borders: architects can find the key to a fruitful dialogue if they rediscover the master builder in themselves, the building designer with a keen understanding of structure. The engineers, on the other hand, would refresh their approach if they combined ‘sensibilità statica’ (Pier Luigi Nervi) with a spatial sensibility: this would allow them to approach the architects’ apparently subjective choices with self-confidence as engineers, and to question or even improve their proposals. The engineer would become an author, like the architect, which would shift the focus of attention and redefine their relationship.

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Theory Marco Pogacnik takes a lively debate sparked off by Richard Lucae, a nineteenthcentury architect, and a visual theory developed by Franz Reuleaux, an engineer, as starting points for refuting the misconception that the historicist components of engineering structures were no more than eclecticism and a hollow mask. The fact that these buildings were designed with their spatial effect in mind rather permits the conclusion that the engineer’s visual culture had deep roots in a classical and historical education. Christoph Wieser explores the question of the engineer as a role model for Modernist architecture in Germany, Neues Bauen, in the 1920s. Contrary to current theories of architecture, most of which emphasize the predominance of visual rhetoric over a supposedly minimal contribution by construction technology, he explains, using selected examples, the relevance of functional Modernism as a laboratory for issues of structural design in relation to the building process. Christian Penzel makes use of selected examples from the twentieth century to illuminate different strategies for the interplay of formal issues and construction techniques, and distills these into paradigmatic lines of development. He demonstrates how changing architectural interests generate new structural design approaches and how these gain importance within the engineering sciences themselves, from where they subsequently affect approaches to space. Christoph Baumberger takes a philosophical approach to the different forms of communication between the engineer and the architect. He compares the modes of cooperation using three models: monologue, soliloquy, and dialogue. He identifies the latter as an essential prerequisite for a building culture that sees itself neither as an art of packaging nor as an excessive display of the art of structural design, but which rather seeks to intertwine, so to speak, space and structure.

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Technology as a Means of Expression in the Nineteenth Century – Architects and Engineers in Dialogue Marco Pogacnik

In the late 1860s, a new generation of railway termini was built in Berlin within the space of a few years. This sparked a lively debate among the members of the city’s architects’ association.1 At that time, architects and engineers did not yet form two separate entities, so the discussion took place among experts who saw themselves as colleagues, belonging to the same club. A close look at issues of the building trade journals Deutsche Bauzeitung and Zeitschrift für Bauwesen 2 from the 1860s reveals how diverse and stimulating debate was at the association. The same attention was paid to technical details as to fundamental historical questions, and every topic was discussed with the same care. Lectures were given on Roman buildings in Trier, waterways in France, hot-water heating systems, the arrangement of riveted joints, and on murals in Pompeii. Questions were answered too, for example on the non-uniform loading of shallow-arched bridges, protecting the walls of a weir from being undermined during a flood, and whether dry docks were preferable to floating ones in the Baltic ports. Architects and engineers joined in the discussion of these subjects with equal interest, with the last word on formal matters usually going to the architects, and on technical matters to the engineers. Among the former, Richard Lucae, Hermann Blankenstein, Martin Gropius, Carl Schwatlo, August Orth, Friedrich Hitzig, and Friedrich Adler should be mentioned, while Johann Wilhelm Schwedler was a frequent speaker among the latter. Berlin’s architectural scene still gave a very consistent impression and was united in maintaining the legacy of Karl Friedrich Schinkel. Karl Bötticher’s book, Die Tektonik der Hellenen,3 provided a language, a system of classification, that gave the generation of architects after Schinkel the impression of being on the right track in order to bridge the apparently deep divide between technology and design.

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1

For the stations analyzed here, see Ulrich Krings, Bahnhofsarchitektur (Railway station architecture), 1985

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Both journals were published in cooperation with the architects’ association of Berlin

3 Karl Bötticher, Die Tektonik der Hellenen (Tectonics of the Hellenes), Potsdam, 1852

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Martin Gropius, “Die Provinzial-Irren-Anstalt in Eberswalde” [The Provincial Lunatic Asylum in Eberswalde], in Zeitschrift für Bauwesen XIX 1869, p. 185

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Richard Lucae, “Ueber die Macht des Raumes in der Baukunst” [On the power of space in architecture], in Zeitschrift für Bauwesen XIX 1869, pp. 294–306; Id, “Über die ästhetische Ausbildung der Eisen-Constructionen, besonders in ihrer Anwendung bei Räumen von bedeutender Spannweite” [On the aesthetic formation of iron structures, especially those used in spaces of a significant span], in Zeitschrift für Bauwesen XX 1870, pp. 532–546

As Martin Gropius – the architect of the famous Museum of Decorative Arts in Berlin – noted in an essay published in 1869, the architects of the time felt “dependent on foreign assistance” when it came to finding a shapely solution to technical problems. Gropius drew a very original distinction between the mathematician and the technician, attributing the ability to express an idea in a unified way to the former, but not to the latter. Technology as such would always mean imperfection in building: “If we call for the involvement of art in important buildings at all now, we must also grant it the same right that it has exercised in all the great ages of art, namely the right to reshape functionally necessary forms in an artistic way, or, if this is impossible, to disguise them with expressive artistic forms.”4 Here, Gropius took a decisive step. On the one hand, he drew a distinction between engineering science and technology, while on the other hand, he saw disguise as a legitimate means of achieving the necessary consistency of composition. So according to Gropius, the architect and the engineer both face the same problem: of giving a consistent appearance to technical imperfection. The architect, he postulates, tries to achieve this objective through recourse to the long tradition of his discipline (the orders of architecture, Classical ornamentation etc.), the engineer with the aid of mathematics. As Gropius aptly remarked, architects were increasingly aware of being “dependent on foreign assistance” in the nineteenth century. Once they began dispensing with the theoretical construct of the Classical orders, on which they had relied for centuries, their knowledge was no longer adequate for the task. Karl Bötticher, Gottfried Semper, and Heinrich Hübsch were among the most important theorists to attempt to establish a new doctrine that would meet the challenge of technology. Their system was not put to the test until the 1860s – and it is to this chapter of history that the aforementioned debate on the Berlin railway buildings belongs. The conflict was triggered by two lectures given by Richard Lucae, a Berlin-based architect, in 1869: “On the power of space” and “On the aesthetic formation of iron structures, especially those used in spaces of a significant span”.5 Richard Lucae was an important figure on the Berlin architectural scene after Schinkel’s death: he was the director of the Bauakademie [Building Academy] for many years and he built the educational institution that succeeded it, the Technische Hochschule in Charlottenburg (now the Technische Universität Berlin). Lucae’s main concern was to appreciate the structural boldness and artistic grandeur of the new stations, and he wanted to persuade his audience (and the public in general) to see, in these works, the seeds of a new kind of beauty. In his view, the spatial impression ought to be considered before anything else. Lucae writes that the factors on whose effect “the power of space in architecture” depends are as follows: “... form and light. Form … together with scale, and light accompanied by ... color. I have deliberately not mentioned style, because in my opinion it only influences the spatial effect insofar as it can shift the predominance of the four aforementioned forces relative to each other.” The architect, says Lucae, should start with the definition of space: whether it is intended to convey domesticity,

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ceremonial, seriousness, or merriment. The question of style (i.e. the historical architectural dress) is of secondary importance in this scenario. Only after the spatial effect has been determined should the structural framework be devised. This principle, that of Bekleidung [clothing, or dressing – to translate it as “cladding” lacks the historical association with textiles] reigned supreme from Gottfried Semper to Adolf Loos. But just how should a structure be dressed, or disguised? Or does this constitute a crime, a violation of the principles of construction? Even today, no account is taken of the fact that two opposing views on construction held sway in the nineteenth century: Bötticher versus Semper. Bötticher defined the relationship between what he called the “artistic form” and the “core form” as mutual reflection. The decorative “shell” should be the analogue of the structural framework. Semper, in contrast, spoke of this clothing as a mask, stating that the frame and the clothing did not have a direct relationship. Lucae, like Martin Gropius, shared the latter view, writing in his essay: "However paradoxical it may seem at first, the ceiling can only be shown when it is more or less hidden. Take the space-enclosing wall, which like the ceiling should appear as a whole, and consider how the individual stones, from which we have to assemble it, are concealed from view by colored plaster: so the ceiling, likewise, becomes an ever more perfect ceiling, the more that it appears to us as a whole. Moreover, tectonics certainly does not proclaim it as a principle that the structure and its material should be shown; it knows nothing of this.”6 “The purely mathematical structure is no more a finished product of art than the human body with its exposed muscles and ligaments, no more than the human skeleton alone is a living creature of Nature ...”7 We may consider these principles of Lucae’s to be embodied in a well-known contemporary work by the architect Friedrich Hitzig (a student of Schinkel’s): the Berlin Stock Exchange. The main hall of the building was covered by a shallow, vaulted ceiling. The detail drawings allow us to reconstruct accurately the architect’s method of working: first he defined the spatial effect, a function that is performed here by the beautiful decorative ribs and the coffered ceiling elements lying between the trusses. After that, he resolved the question of how the ceiling as a whole should be supported. This step is documented in the left half of the drawing of the crescent truss. A closer analysis of the detail drawings soon reveals that the iron crescent truss, pictured on the left, is not viable in itself. The upper chord appears to be very slender and the lower chord is set relatively high, with the result that the connection to the joint seems not to be fully formed. This design suggests that the decorative rib-like cladding was not just applied, but was also intended to make an important contribution to the stability of the structure as a whole. Without the attached decorative elements, the crescent truss would not have been adequate for its load-bearing function. This principle was described in great depth by Semper in his book Der Stil in den

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Lucae, “Über die ästhetische Ausbildung der Eisen-Constructionen”, p. 539

7

Ibid., p. 533

Berlin Stock Exchange by Friedrich Hitzig

technischen und tektonischen Künsten, oder praktische Ästhetik, in the section in which he discusses hollow bodies. Semper proposes that the hollow body—or tubular system—is the oldest principle available to the architect to construct forms (wheel, chair, beam, or pillar). He documents it with reference to the principle of corrugation, i.e. the folding of a sheet metal surface. A very efficient construction method developed along these lines, making it possible to achieve a very high load-bearing capacity with a very low mass. Although Semper does not say so, it seems quite clear that behind his examination of hollow body construction in the Assyrian and other Mesopotamian cultures lay an interest in the achievements of architecture and engineering in his own time, such as Robert Stephenson’s Britannia railway bridge across the Menai Strait in Wales, opened in 1850. The icon of nineteenth-century architecture is the cast column, itself a hollow body. The lower chord of our crescent truss is constructed as just such a hollow body, and in Semper’s terms this means a dissolution of the core and a predominance of the shell. The ornament does not need to follow the form of the structure, or to imitate it. The ornament itself becomes the structure. Lucae’s second lecture was on the design of bridges and railway stations. It paid particular attention to three station buildings in Berlin, which were built almost simultaneously from 1866 to 1869: Görlitzer Bahnhof, Ostbahnhof, and Niederschlesisch-Märkischer Bahnhof. Their halls spanned 36–37 meters over the tracks

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and were supported without intermediate columns, either by crescent trusses or three-jointed trussed arches. Only a few years later, in the early 1870s, the first solid-side, sheet-metal trusses were introduced in the form of two- or three-hinged arches in, for example, Berlin's Potsdamer Bahnhof. Two of these station buildings were created in collaboration with the engineer Johann Wilhelm Schwedler. Whereas crescent trusses were used at Görlitzer Bahnhof and Niederschlesischer Bahnhof, Schwedler introduced a three-hinged trussed arch at Ostbahnhof. This structural innovation led the way for a third generation of stations, epitomized by Anhalter Bahnhof with a hall span of 62.5 meters. The structures used in the stations considered here could be modeled fairly well using methods formulated both graphically and analytically a few years previously, which belonged to the infant discipline of structural analysis.8 In contrast, the first – often very daring – iron structures had been designed only thirty years earlier by architects without proven methods of calculation to rely on. Noteworthy in this respect are works by the architect Heinrich Hübsch (his iron roof for a theater), Georg Moller and his dome for Mainz Cathedral, and the bridges of Georg Ludwig Friedrich Laves. What interested Lucae in our railway stations, however, were not the technical achievements of engineering, but the possibility of analyzing such important buildings formally with regard to the most advanced aesthetic standards. The attitude towards such works at that time was not really very favorable. We need to bear in mind that an important volume on Berlin and its buildings, published by the Berlin architects’ association in 1877, dealt with the station buildings in the chapter on railways, while churches and monumental structures in general came under the heading of building. It is Lucae who we have to thank for giving the stations the architectural status that they deserve. That also meant appreciating them particularly in respect of the silhouette, lighting, roof structure, and spatial effect. The architects of Görlitzer Bahnhof were August Orth and the works department of the Görlitz railway company. The roof structure was characterized by wroughtiron crescent trusses with one fixed and one movable roller bearing, as we shall see later. The shallow, barrel-vaulted roof opened at the crown into a continuous lantern of 7.5 meters in width, with two narrow strips of glazing, each 1.5 meters wide, immediately above the impost zone. Lucae judged the distribution of light to be particularly unfortunate, because it was split into three strips. Niederschlesischer Bahnhof was designed by the architect Eduard Römer in collaboration with Schwedler as an engineer. Each crescent truss consisted of a deeper, polygonal, top chord, composed of individual lattice members, and a similarly polygonal bottom chord that resembled a tie-bar. The fifty-four roof trusses were supported at a height of 15.8 meters. One bearing was fixed and the other was designed as a movable roller bearing; the spacing was 3.77 meters. The uniform central skylight consisted of blank glass panes laid in stepped rows. The lighting was thus kept very consistent, but the crescent ties, which were formed of very slender members, appeared even thinner against the backlight. Foreshortening

23

8

Johann Wilhelm Schwedler, “Theorie der Brueckenbalkensysteme” [Theory of bridge girder systems] in: Zeitschrift für Bauwesen I 1851, pp. 114 ff; 162ff; 265ff

Görlitzer Bahnhof by August Orth Görlitzer Bahnhof, view of the platform hall from the inner courtyard

24

Architects and Engineers in Dialogue  A

meant that anyone not standing in the middle of the space saw them as a tangle of lines, which Lucae felt to be unsatisfactory. According to him, in the case of these three stations, we are broadly “dealing less with a ceiling than with a roof. A roof is still far from being a ceiling.” From an architectural viewpoint, he said, space ought to be defined by the ceiling, rather than the roof. Moreover, its elements should symbolically interpret the theme of floating: like a carpet suspended and stretched from wall to wall. In this regard, he stated, a better effect was achieved at Ostbahnhof, built by Schwedler with Adolf Lohse, because its trusses were coupled. There not just the bearing points, but also the crown were formed as joints. It was here that Schwedler employed his pioneering structural form, the three-hinged trussed arch, for the first time. Lucae rated the spatial effect of such trusses very positively, as their repetition could create a rhythm. The reactions of the architects concerned (August Orth, Carl Schwatlo, Eduard Römer, and Hermann Ende) were not positive, and even Schwedler showed no sympathy toward the problems of better cooperation between architects and engineers. He made a categorical statement: “The structural form is superior to the art form ... The structural form is the result of science, it is the truth in built objects. The power of imagination may not tamper with this truth.”9 Lucae’s attempt to bring the architect and the engineer closer together therefore seemed to have failed. A closer look at the various arguments nevertheless reveals that contemporary engineers possessed a not inconsiderable visual culture themselves. This is evident, for example, in the detail sheet for the crescent truss at Görlitzer Bahnhof. What this sheet and its accompanying text tell us about the technical details is that, for contemporary architects, tectonics functioned as a kind of semiology of structural design: the load-bearing structure was seen as a comprehensible and communicative architectural element. What the French had called “architecture parlante” in the eighteenth century could now have been termed a kind of “construction parlante”.10 On the sheet referred to, the details numbered 17–26 were originally intended for production, but in order to speed up construction, the details to their right were ultimately used. They are all discussed in a report by August Orth, the job architect: “In the original design for the structure ... the upper chord consisted of cast-iron struts with an elliptical cross-section at the middle. ... The construction is identical for both projects, except that in the former it was necessary, owing to the differing rates of thermal expansion of cast iron and wrought iron, to connect the structural components using hinged joints. This was made possible without danger by diagonally bracing one truss of each pair, and furthermore it is extremely simple to assemble such a truss, because the individual joints are connected using cast-iron hinge bolts with push-on caps fixed with cotter pins. ... Fig 23 [in the drawing] shows a member of the top chord, with the longitudinal dashes representing the internal compression lines for the dead load of the structure alone, and when fully loaded.”11 A key feature of the design of the structure is the great extent to which the various

25

9

J.W. Schwedler, speaking at a meeting of Berlin's architects' association on December 16, 1869,quoted in: Zeitschrift für Bauwesen XX 1870, p. 545

10

A good example can be found in: Carl Schwatlo, “Eisen-Konstruktion. Über die Anwendung, die baukünstlerische Berechtigung und Ausbildungsfähigkeit der Eisen-Konstruktionen in Bezug auf den Baustyl der Gegenwart”, in: Romberg’s Zeitschrift für praktische Baukunst 30 1870, pp. 19–34

11 August Orth, “Der Bahnhof der Berlin-Görlitzer Eisenbahn zu Berlin” [The station of the BerlinGörlitz railway in Berlin], in Zeitschrift für Bauwesen XXII 1872, pp. 547–552

Niederschlesisch-Märkischer Bahnhof by Eduard Römer and Johann Wilhelm Schwedler Niederschlesisch-Märkischer Bahnhof, view from the railway lines

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Architects and Engineers in Dialogue  A

Ostbahnhof by Adolf Lohse and Johann Wilhelm Schwedler, three-hinged trussed arch Ostbahnhof, view of the platform hall

27

12

August Orth, “Der Bahnhof der Berlin-Görlitzer Eisenbahn zu Berlin” [The station of the Berlin-Görlitz railway in Berlin], in: Zeitschrift für Bauwesen XXII 1872, pp. 547–552

parts that make up the entire ‘organism’ are differentiated. Taking into consideration not only their shape, but also their material (distinguishing between wrought and cast iron, sheet metal and hollow bodies, steel rods and wire cables), the various elements are formed in such a way that their structural function is not only fulfilled, but is also expressed effectively. August Orth summed up his skepticism about Lucae’s attempt to reconcile the architect and the engineer in the following words: “The hall of the Berlin-Görlitz station has provided an opportunity to discuss the question of the ideal, monumental design of such halls ... in the proceedings of the architects’ association, and owes its origin to an essay by Lucae .... These [proceedings] have had little positive result. In the judgment of the present author, even the halls constructed later, like almost all the existing halls, fall far short in this respect of what could be achieved technically and artistically. The present author did not set himself this task at the Berlin-Görlitz station hall ... because the architect cannot simply dispose of the client’s funds without the knowledge and consent of the same.”12 Rather than continuing the discussion started by Lucae on an abstract level, Orth, as a pragmatist, wanted to set it in the context of the prevailing economic conditions. In any case, he was not suggesting opposing or contradictory positions for the architect and engineer, but—on the contrary—referring to their shared responsibilities towards the client. The relationship between structure and form seems to diverge less in reality than it does when the question is analyzed solely at a theoretical level. Consequently, we need to stop regarding the architecture of the nineteenth century as historicist froth, perpetrated by clueless architects for a hollow gimmick. We also need to rid ourselves of the prejudice that the engineers were unimaginative calculating machines who did not consider the visual and formal aspects of the structures that they designed. A good example of those who did is the engineer Franz Reuleaux, who established the study of technical kinematics in Berlin. He first worked in Zurich at the ETH, then in Berlin at the Gewerbeakademie [Industrial Academy] and at the Königliche Technische Hochschule [Royal Technical College]. What interests me in the theoretical work of this engineer is a small manual, which was published by Vieweg in 1862. The book’s title translates as: “On mechanical engineering style: A contribution to the creation of a theory of forms for mechanical engineering”. Reuleaux recognized “the spiritual essence of the forms was to be chosen freely according to the feelings or taste of the designer,” and accordingly he sought to develop a theory for the design of technical devices, to which no attention had been paid until then, because they were mere utensils. Therein lies the germ of the idea to reform industrial products as undertaken subsequently by the Werkbund and, later, the Bauhaus. “In many cases, the independent mechanical engineer designs completely freely, indeed he cannot escape this creative urge and its consequences at all, because he has to make a choice countless times between the curved and the straight line, the hollow body and the solid piece, the rotatable body and the prism, where both would serve his purpose equally well, and thus each involuntar-

28

Architects and Engineers in Dialogue  A

ily gives his constructions a certain expression, a certain stamp, which betrays the mindset of the designer.”13 Reuleaux also cites Semper and his concept of style, as an example of a theory of form that was understood as ‘practical aesthetics’ at the time. He reflected: “Architecture, however, remains extremely instructive for engineering. It sometimes provides us with forms ready-made for our purposes in the form of entablatures,

13

Franz Reuleaux, Über den Maschinenbaustil. Ein Beitrag zur Begründung einer Formenlehre für den Maschinenbau, Braunschweig: Vieweg, 1862

Franz Reuleaux, from: Über den Maschinenbaustil [On mechanical engineering style]

29

beams, columns, etc. ... which we must not, however, apply blindly. ... The base and the capital heighten our understanding of the column as an upright and loadbearing structural member.” According to Reuleaux, the mechanical engineer should pay attention to the task of design, in which he proceeds not much differently to the architect: how to shape a starting point or a base; how to form a transition; how to subdivide or structure a particular element; how to connect and finally terminate an element or an object. Reuleaux’s manual contains a wealth of tables, by which means he expresses this close relationship between mechanical engineering and architecture. A function of this kind is fulfilled by architecture itself in the solution for the design of a rib, whose line Reuleaux defined as a parabolic envelope line and which he recognized in the profile of the echinus of a Doric capital and the trochilus of an Attic base in Greek architecture. In the twentieth century, architects such as Le Corbusier and Walter Gropius, along with art historians such as Sigfried Giedion, declared the engineers of the nineteenth century to be the real pioneers of modernity, who had succeeded in banishing tradition and history from the art of building. The works of the engineers were taken as models and sources for a design approach that took only material, function, and economy into consideration. We now know that this idea is false and deceptive. If the visual culture of nineteenth-century engineers had not been so deeply rooted in a classical and historical education, then recognition of their magnificent achievements would be unthinkable, even today.

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Architects and Engineers in Dialogue  A

31

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Pioneer and Projection: The Misappropriation of the Engineer in Modernist Architecture Christoph Wieser

Objectivity was the intellectual tool with which the pioneers of Modernism hoped to triumph over the historicist architecture of the nineteenth century and its emphasis on matters of style. Hermann Muthesius, one of the first to use the term objectivity in connection with architecture, wrote as early as 1902 that “aesthetic progress ... [could] only be sought in a move towards the strictly factual: in dispensing with merely applied ornamental shapes and in creating form according to the requirements of the function on each occasion.”1 This was accompanied by a conviction that when designing, priority must once again be given to the floor plan, rather than to the composition of the facades. Questions of style should be replaced by factual questions: “Instead of external formulation, an internal definition of the new architectural problem is needed: the spirit in place of the formula, an artistic deliberation over the basic form from the outset, no subsequent decorating,” as Walter Gropius put it in 1913.2 This quotation makes it clear that objectivity did not remain limited to an aesthetic imperative, but presupposed a particular mindset that ought to distinguish the modern architect, the modern man par excellence. Objectivity versus exuberance 3 was the maxim in the 1920s; it left its mark on architecture just as much as on other arts and areas of life, from sport to the way of speaking: “We expect communication to be succinct and expressed vividly, without sentiment. A string of good observations, seeming like the product of an outdated education, are not acceptable. We reject the laborious nature of the words and demand that thought be structured, wanting not talk, but simplicity.” 4 That is how the German philosopher Karl Jaspers described the prevailing spirit of “this technical world” at the time. It is no wonder that the architects who adopted Neues Bauen [literally: New Building], as the Modern Movement was known in Germany, took as their model the engineer, who constructs his thoughts just as much as he does machinery and buildings. One consequence of this way of thinking was a radical change in their

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1

Hermann Muthesius, Stilarchitektur und Baukunst. Wandlungen der Architektur im XIX. Jahrhundert und ihr heutiger Standpunkt, Mülheim-Ruhr: K. Schimmelpfeng, 1902, p. 51 [Style-architecture and Building-art: Transformations of Architecture in the Nineteenth Century and its Present Condition, tr. Stanford Anderson, Santa Monica: Getty Center, 1994]

2

Walter Gropius, “Die Entwicklung moderner Industriebaukunst” [The development of modern industrial architecture], in: Deutscher Werkbund (pub.), Die Kunst in Industrie und Handel (Deutscher Werkbund Jahrbuch 1913), Jena: Eugen Diderichs, 1913, p. 19

3 “Sachlichkeit versus Überschwang” is a chapter heading in: Hans Ulrich Gumbrecht, 1926, Ein Jahr am Rand der Zeit [A year at the edge of time], Frankfurt am Main: Suhrkamp Verlag, 2001, pp. 337–344 4

Karl Jaspers, Die geistige Situation der Zeit, Leipzig: Walter de Gruyter & Co., 1932, p. 26 [Man in the Modern Age, tr. Eden and Cedar Paul, London: Routledge, 1933]

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Pioneer and Projection  A

professional identity: the artist-architect of the nineteenth century was to give way to an organizer who worked entirely rationally, like an engineer, giving reason and objectivity greater weight than subjective feelings. This focus on construction aspects was also associated with a desire to bring art and science closer together, as they had been before 1800. Functional Buildings Belong to Architecture   The concept of Neues Bauen, which was introduced in Germany around 1920, needs to be understood as a program: the ballast of architectural styles was to be dropped in favor of a fundamental renewal of architecture. The return to the roots of the profession—which is why Bauen [building] was used instead of Architektur [architecture]—was to turn the focus of attention back to the essence, which was now supposed to reside in the most expedient organization of the floor plan and no longer in the application of ornament in historical styles. Therefore the protagonists of the new architecture sought—and found—the models for their vision in the engineering structures and commercial buildings that until then had not counted as architecture, because they generally needed to satisfy functional criteria without any representational purpose. Typical of this was the title given by Adolf Behne in 1926 to his perceptive survey of the new movement, Der Moderne Zweckbau [The Modern Functional Building]. In the eyes of architects, the seemingly unconscious forms of civil engineering, derived solely from their functions, also ennobled their creators: the engineer was portrayed as the quintessential New Man, a man of action who reached his decisions objectively, soberly, and perfectly rationally, and who had mastered technology and knew how to use it for his purposes. Free of the cultural constraints of traditional stylistic conventions, which the architects had yet to shake off laboriously, he was instinctively acting correctly: “The engineers are healthy and virile, active and useful, moral and happy. The architects are frustrated and idle, garrulous or grouchy. Why? Because soon they will have nothing more to do. We have no money left for warming up historical memories. We must urgently cleanse ourselves of it all. The engineers will make sure of it; they will build.”5 These sentences from Le Corbusier’s Vers une architecture of 1923 are symptomatic of the contemporary glorification of the engineer, whose one-sided characterization reveals more about architects’ own yearnings than it corresponds to reality. Muthesius had already debunked the myth of the “unconsciously” creative engineer in 1913: “For the engineer, too, many roads lead to Rome; the directions in which he pursues a task, even purely mathematically, can be many and varied right from the start. It is natural to choose the one that satisfies the eye as well as the structural calculations.”6 In the yearbook of the Deutscher Werkbund that contains this quotation, there is an article by Walter Gropius, one of the first attempts to place modern architecture in a historical context with reference to civil engineering structures and other works of the “functional tradition.” After World War II, J.M. Richards took up this theme again in the Architectural Review, identifying English industrial buildings of the eighteenth century as the earliest examples of the kind,

35

Exemplary elegance of engineering structures: Sigfried Giedion published this picture of the Galerie des Machines, from the 1889 Paris World Expo, in Building in France (1928) and again in Space, Time and Architecture (1941) Engineer Victor Contamin Architect Charles-LouisFerdinand Dutert

5

Le Corbusier, Vers une architecture, 1923. op. cit.: idem, Ausblick auf eine Architektur (Bauwelt Fundamente Band 2), Braunschweig: Friedrich Vieweg & Sohn, reprint of the 4th ed., 1985, p. 31

6

Hermann Muthesius, Das Formproblem im Ingenieurbau [The problem of form in civil engineering], in: Deutscher Werkbund (pub.), Die Kunst in Industrie und Handel (Deutscher Werkbund Jahrbuch 1913), Jena: Eugen Diderichs, 1913, p. 31

Boat house with cast-iron frame, dating from 1861, in the Naval Dockyard, Sheerness, Kent

for instance prototypes of frame structures with strip windows. Unlike the situation in the 1920s, the debate now took place in a calmer tone, as no one any longer had to be convinced of the value of these buildings to architecture.

7 Hannes Meyer, “Bauen” [Building], in: bauhaus, 1928, No. 2, p. 13

The Rationalization of Building  Order was another central concept of Neues Bauen that reflected the desired closeness to the technical thinking of the engineer. This did not just mean creating architectural order by, for example, simply structuring the building or laying out the floor plans on a functional basis, as such characteristics are by no means limited to modern buildings. Rather, even the design, production, and construction processes were to be subject to a rational and systematic methodology. It was hoped that these measures would, in particular, lower the cost of building, which had the highest priority, given the housing shortage that prevailed after World War I. The aim was to rationalize construction comprehensively; architecture was to surrender its artistic and individualistic pretensions and be transformed into an exact science. This brought about, as I mentioned earlier, a redefinition of the profession’s role: “the architect? ... was an artist and will be a specialist in organization!” wrote Hannes Meyer in 1928. 7 This intention confronted a construction sector with a very broad handcraft base and which, with the help of Taylorism, was supposed to become industrialized. In 1910, Frederick Winslow Taylor had developed a system of scientific production management, in which the manufacturing stages were analyzed as a preliminary to optimizing not only the workflow, but also the workers’ movements and the tools needed, without straining them physically. Henry Ford applied this method to car production, which is why the architect J.J.P. Oud invoked him in describing his own Kiefhoek housing estate in Rotterdam (1925–30): “We tried to find a solution

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Pioneer and Projection  A

Walter Gropius, Bauhaus housing estate at Törten in Dessau, 1926. Axonometric projection of standard houses, on-site production of cinder blocks, plan for site facilities

Alexander Klein, diagram for systematically producing floor plans for small apartments, c. 1928

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8

J.J.P. Oud, “Siedlung ‘Kiefhoek’ in Rotterdam” [The ‘Kiefkhoek’ estate in Rotterdam], in: Zentralblatt der Bauverwaltung, No. 10, Berlin, March 11, 1931, p. 149

9 Sigfried Giedion, Space, Time and Architecture, 1941. op. cit.: idem, Space, Time and Architecture—The Growth of a New Tradition, Harvard University Press, reprint of 5th ed., 1982, p. 218

to the brief that resembled the way in which Ford makes his cars cheap and good: utilizing space and material as economically as possible; practical construction and operation. A Ford for living in.”8 Walter Gropius went a step further, applying Taylor’s system and Ford’s method of assembly line production in an almost literal way to his housing estate at Törten in Dessau (1926–28): firstly, he moved the factory that fabricated the structural units onto the site and, secondly, he erected the terraced houses in stages, arranging them in two parallel rows, divided into different construction phases. The project was planned in advance, down to the smallest detail, in a meticulously prepared construction schedule. The materials were located on site in accordance with the construction process, not without a symbolic effect, which reveals Gropius’s intention to illustrate the rational ethos of his architecture even during construction. Mathematical and scientific methodologies (and above all their modes of representation, such as tables, diagrams and lists) were also utilized by Hannes Meyer—for instance in his competition entry of 1926 for the Petersschule in Basel. Like Rem Koolhaas today, for example, he used such elements as graphic devices, as well as evidence of analytical and deliberate design work. Comprehensive rationalization did not prevail at the time and moreover it failed to address the essence of architecture. Sigfried Giedion, however, concluded that “contemporary architects have succeeded at the end of a century of struggle in drawing abreast of construction”. The sentences that follow it, which reflect upon the progress of Neues Bauen from its beginnings up to 1941, when the manuscript of Space, Time and Architecture was completed, are still applicable today: “New tasks await architecture today. It must now meet needs other than the strictly rational, other than those which are pragmatically determined. A living architecture must also succeed in satisfying those subrational, emotional demands, which are deeply rooted in our age.” 9 Thus the engineer, too, lost his function as a role model for Modernism as it developed. Postscript  Looking back, it is striking how heavily the technical side of architecture was emphasized by leading exponents of Neues Bauen, while the formal aspects, in contrast, were pushed aside as unimportant. This observation is based primarily on the written sources, which despite their claim to be factual often contain an unmistakable undertone of propaganda. The buildings, as is well known, speak a different language; examining them, it becomes clear how important the introduction of a new formal vocabulary was. It would, however, be short-sighted to think of the borrowing of forms from civil engineering and technical objects (the widespread use of ship and machinery metaphors comes to mind) as being solely creatively motivated. The symbolism of such forms was also deliberately exploited as an expression of the machine age. At the same time, it indicates the great efforts that were then being taken to modernize architecture with regard to planning and fabrication. The stock market crash of October 1929 and the ensuing global economic crisis put an abrupt end to such ideas. After World War II, they were revived and—with consequences that are known to all—implemented on a large scale.

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The Culture of Construction: Examples from the Last Fifty Years of a Remarkable Development Christian Penzel

Technology does not primarily ask what is, but what can be. In this spirit, any truly technical achievement has the character of the discovery as revelation: an existing fact per se is thus extracted, as it were, from the region of the possible and transplanted into that of the real.

Ernst Cassirer, Form und Technik, [Form and technology] 1930

Collaborations between architect and engineer always appear interesting at first glance if a design makes use of exceptional structural means or methods. Development of the technical prerequisites is above all incumbent upon the engineer, who devises the structural systems—supposedly independent of design influence— from the inherent necessity of material and purpose, and brings these into view in independent, engineered structures. Inspired by these buildings, architects seek to use the opportunities they generate in structure and appearance, appropriating them for their own purposes. Since the beginning of industrialization, since the impressive appearance of the first large industrial structures, our concept of that which is built has been repeatedly modified by that which is technically feasible, in a continuous process of acquisition and reshaping. New positions in architecture are generated by the driving force of technical progress, in the constant search for cultural appropriation of the formal potential contained therein.1 Upon closer inspection, however, this self-evident observation could perhaps be turned around, the consequence then being the unexpected assumption that certain achievements in the field of construction and technology will not be conceivable without first changing the cultural context. The technical achievement would also consequently always be based on a creative stance, without which it could not become reality. A look back at some of these vicissitudes might illuminate some of

41

1 Diverse publications, beginning with: Le Corbusier, Vers une architecture, Paris: Crès, 1923; Werner Lindner, Die Ingenieurbauten in ihrer guten Gestaltung, Berlin: Wasmuth, 1923; Erich Mendelsohn, Amerika— Bilderbuch eines Architekten, Berlin: Rudolf Mosse, 1926.

today’s issues and reveal a few basic patterns in the relationship between engineer and architect.

2

On the genesis of the Miesian grammar, see: Colin Rowe, “Neoclassicism and Modern Architecture,” in: The Mathematics of the Ideal Villa and Other Essays, Cambridge, MA: MIT Press, 1998; Phyllis Lambert, “Learning a Language,” in: Phyllis Lambert, Mies in America, New York: Abrams, 2001 3 On recent reception to Mies’s Minimalism, see: Detlef Mertins, The Presence of Mies, New York: Princeton Architectural Press, 1994 4

Stanley Tigerman, “Mies Van der Rohe and His Disciples, or The American Architectural Text and its Reading,” in: John Zukowsky, Mies Reconsidered: His Career, Legacy, and Disciples, New York: Rizzoli, 1986

Universal Systems – Mies van der Rohe, Fazlur Khan, and the Regime of the Grid  The work of Skidmore, Owings & Merrill (SOM), unlike that of almost any other architectural firm, represents the development of American and international corporate architecture of the post-war era. Highly successful in economic terms, they adapted the fundamental principles of the International Style and the achievements of some important Bauhaus members who emigrated to the USA, such as Gropius, Hilberseimer, and Mies van der Rohe, and translated these precepts into built works on a large scale. The great homogeneity of design accompanying this period of growth was based on the binding force of a modern canon that was formed to a significant degree by these architects. The combined phenomena of rationalization and reproduction that accompanied the onset of mass production were declared an expression of their time and were artistically interpreted using the principles of formal abstraction. The aesthetics of modern technology were symbolically elevated and adapted in the form of a seemingly classic purity and order. One of the most important and arguably most influential structural innovations of this period was the introduction of skeleton construction and with it, the differentiation between load-bearing elements and those dividing space. Above all others, Mies van der Rohe exhaustively explored the architectural potential of this new construction technique with his sustained work on the appearance of load-bearing frameworks, on the form of their structural members, on their disposition within the whole, and on their relationship to the outer skin. With his formal adoption of the double-T profile, he also ultimately supplied the decisive evidence that products of industrial technology—the steel products coming from the rolling mills—are thoroughly suited for an architectural language that is contemporary but nevertheless remains connected with architecture’s Classical heritage.2 The Minimalism practiced by Mies—as seen in mature form in the high-rise buildings in Chicago and New York—manifests itself, along with the meticulous details and the precise proportions, primarily in the multiplication of identical elements in the rhythm of the structure.3 These skeleton structures constitute simple prisms extruded over the entire height without projections or setbacks. The grid, which appears on the facade either directly or in the form of subdivisions, represents the internal structure. The structural necessity that is put on view, in other words, therefore becomes a superordinate symbol of rational architecture. In such a form it was outstandingly suitable—with some simplifications and by not adhering too closely to ancient rules that Mies regarded as compulsory—for duplication and for coping with the wide-scale production of buildings.4 Yet despite their structural simplicity, technologically these skeletons were only ostensibly optimized and, for their part, they now offered freedom for some exceptional structural developments. In a series of projects at SOM, the engineer Fazlur Khan worked on an array of new

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Lake Shore Drive Apartments by Mies van der Rohe Lake Shore Drive Apartments. Detail of the curtain wall facade

building types that were intended to respond to the demands for increased height and greater efficiency. Their systems are identified according to their structural behavior: outrigger, tube, tube-in-tube, and diagonalized tube.5 They are innovative in how the facade is utilized for stiffening the building—a task that had previously been assumed by the internal cores and floor framing, and which had physically and economically restricted building heights to approximately fifty stories. With the tube systems, this threshold can now be raised to a height of up to 250 meters. This decisive step forward was achieved merely through a slight modification of the already existing facade system: the grid of relatively closely-spaced columns and spandrel elements is now rigidly constructed, so the facade thereby functions over the entire height as one vast shear wall. Connected together, the four sides of the building constitute a tube that can counteract the horizontal loads as a large cantilever. The first building of this type is the DeWitt-Chestnut Apartment Building (1961–64) by SOM under the technical direction of Fazlur Khan. Here, the structural action of a tube is ensured through a lattice made of reinforced concrete, which stiffens the

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5

On tube systems, see: Werner Sobek, Fazlur Khan in: Beiträge zur Geschichte des Ingenieurwesens 9, Lehrstuhl Prof. Eberhard Schunck, TU München, WS97/98 and Mir M. Ali, Art of the Skyscraper: The Genius of Fazlur Khan, New York: Rizzoli, 2001

Heights for structural systems built of steel (above) and concrete (below)

Development of the tube concept from a solid outer wall to a framed composite of columns and beams

forty-three-story building without the aid of internal cores. With conventional construction, only about twenty-eight stories would have been possible—as high as the adjacent Lake Shore Drive Apartments (1949–51). In these first high-rise buildings conceived by Mies, the outer part of the structure is also located in the plane of the facade. The load-bearing steel sections must nevertheless be encased for fire safety and the relatively wide column spacing requires an additional construction plane for affixing the surrounding glazing. The primary structural grid is vertically subdivided and set behind the renowned double-T beams that serve as mullions and representatives of the genuine load-bearing structure, which is unseen due to the fireproof cladding. The remarkable thing, of course, is that Khan does not use the narrow grid as an illustration and abstraction of the technical reality behind—as was intended by Mies—but instead he retransforms it and thereby establishes a real function on a technical level. The window division is simply brought into the same plane as the structure and structurally activated. How much the language and grammar—Mies’s legacy—remains as a formal reflex can be seen in the design of the building corners. Through the negative form, they repeat Mies’s renowned solution, although here the structural conditions are exactly reversed. It is not a curtain-wall facade whose corners are connected to the load-bearing structure behind on the grid—as Mies sought to depict—but instead it is a tube, whose corner rightly must have been positive, especially since they are disproportionately strained due to the so-called shear lag effect. This small difference, however, conversely also manifests the high degree of correlation with the formal means that links the buildings to one another despite a complete metamorphosis of the structural system. In both cases, the grid appears as the primary, formative element; with Mies, it emerges from subdividing the main axes

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so the theme of the curtain wall facade can be played out with the help of applied profiles; with Khan, in turn, it again receives a meaningful structural role. Only one detail nevertheless makes the DeWitt-Chestnut Building recognizable as a work of engineering: the thickness of the posts and rails diminishes moving upwards and thus makes explicit that the building shaft functions as a cantilevered beam. This ultimately also demonstrates the modified logic of such buildings, whose systems now are no longer oriented toward reducing the vertical loads in terms of Classical tectonics—like the Miesian skeleton—but, above all, to reduce the wind loads that increase greatly with increasing height. The development of tube structures is in this regard a decisive prerequisite for the push to previously unthinkable building heights.6 That revolutionizing an entire building typology does not in the process entail greater creative consequences is mainly due to the mutual interests of architects and engineers, which have common ground in the primacy of rationality and economy. Even formally significant changes like the exterior diagonal bracing of the diagonalized tube that appears for the first time in the John Hancock Center (1970), are integrated into the canon of the modern grid and the elegant form.

6

A good summary is found in: “The Structural Architecture of Chicago,” Process Architecture, no. 102, 1992

DeWitt-Chestnut Apartment Building by SOM. Depiction of the shear lag effect

DeWitt-Chestnut Apartment Building

45

7

Paul Valéry, Eupalinos oder der Architekt, Frankfurt am Main: Suhrkamp, 1973 (Original: Eupalinos ou l’Architecte, 1924)

8

Buckminster Fuller, quoted in Reyner Banham, Theory and Design in the First Machine Age, Cambridge, MA: MIT Press, 1964, p. 274

9

A synopsis of Buckminster Fuller’s influence on the English technology movement is found in: Carsten Krohn, Buckminster Fuller und die Architekten, Berlin: Dietrich Reimer, 2004 10

On design and structure of the Centre Pompidou, see: Renzo Piano, The Renzo Piano Logbook, London: Thames and Hudson, 1997; and Peter Rice, “Beaubourg,” in: Peter Rice, An Engineer Imagines, London: Artemis, 1994

The methodology used at the architectural and structural level thereby remains primarily deductive: from abstract analysis of a generally understood problem, the form nearly emerges as a universal derivative. As types, the results lay claim to a more or less universal validity that is understood as a response to the challenges of our time and should be suitable in manifold repetition for building up the modern world. Despite the existence of variations, the built expression remains abstractmodern, to some extent overly individualized, and thereby presents itself as being associated with the anonymity of a science based on physical laws. In the background, the architect appears as creator, one who—as Valéry characterizes him— as a demiurge, conveys the world to a higher order with his grids and systems.7 The formal canon—and that needs to go on record here—thereby precedes the structural development: the structural elements of the Second Chicago School are developed before the engineers take possession of theirs, and with them, erect the most modern and highest buildings of the day. Individual Orchestration – Renzo Piano, Richard Rogers, Peter Rice, and the Drama of Construction  With his polemics on contemporary building culture, the American engineer and innovator Buckminster Fuller now explicitly opposes this outlined process of coalescence, in which modern technology is to be integrated in an established architectural canon and thereby loses its autonomy.8 All efforts to that effect taken by architects are seen by him as attempts to uphold a traditional system of form and design and to deny acknowledgement of the real power of technology based on constant mutation and renewal. This criticism is taken up and translated to good effect by the technology movement of the 1960s, most notably by architects like Cedric Price and the Archigram group, who, with their visions of technologically determined building structures in a state of constant change, fundamentally call into question the image of a completed form in the Classical sense.9 The most important built manifesto that emerged from this euphoria is the Pompidou Center, (1971–77) by Renzo Piano and Richard Rogers. The machine for culture, located in the center of Paris, is a multifunctional building that derives its outward appearance above all from the architects’ idea of creating a completely flexible building, a kind of freely usable framework.10 At any point in the building, each one of the diverse uses should be conceivable, so that one can imagine the building’s inner life in constant flux. The consequence of this is the accumulation of maximum requirements: an enormous multi-level building that doesn’t have a single column inside—to be able to install large exhibitions unhindered—and whose load-bearing structure must be capable, at every point, of taking the heavy load of a library. This stipulation ultimately leads to a complete inversion of the building, in which all the customary ‘innards’ are exposed on the outside—from the structure to the mechanical system and the pedestrian circulation—to obtain a completely purified footprint, free of any built limitations. The span needed for this purpose— nearly 45 meters—is surmounted by a series of trusses 3 meters high, hung from

46

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an exterior structural framework. As a representative of the idea, this framework of course expresses the intrinsic visual message of the building. Its effectiveness comes from the complete fragmentation of the structure into discrete elements, each of which fulfills a very specific function. Tubes as columns for the compressive forces, vertical and diagonal rods for the tensile forces, and as the most prominent structural element, the so-called gerberettes, specially formed members for transmitting loads. The gerberettes (they owe their name to Gerber beams) direct the internal loads from the trusses, thanks to their hinged support condition, without transmitting any bending moments into the very slender columns, which are themselves not in the plane of the facade, but are instead in front of it to maintain the purity of the concept—a quite elaborate solution to a self-made problem. For ordinary load transfers and bracing of the prismatic building form, something that can usually be managed in one plane, the architects thus establish a construct several meters high. At the center of this arrangement is precisely that cast-iron gerberette, an invention of the engineer Peter Rice. The artistically designed chunk of steel, needed for conveying loads from truss to column and external tension bracing, enables customized detail connections and can be adapted to the expected flow of forces. The didactic content of this visualization finds its counterpart in the expressive use of materials. Here, for the first time since the advent of rolled sections, cast steel is again employed at a large scale for building construction. In so doing, Rice seeks an explicit connection to the historical works of engineering from the nineteenth century.11 With the notion of the tactile in construction, however, Rice is not only concerned with the material expression, but in essence about individualization of the form, which represents the spirit of its creator like a signature.12 The recognizable hallmark of the designer is meant to make the machine-made components accessible to the attentive viewer. Whereas Mies’s efforts would have been precisely to extract cultural significance from the anonymous industrial product, Rice eschews standardized common products such as the continuous profiles of double-T beams, and insists on the individual form of the cast part. The engineer takes a stance against the dictate of using industrially premanufactured components through a masterly exploitation of building materials; his formative idea represents human appropriation of material with the help of technology. Innovation is thus elevated to a humanistic principle. The repetitive use of visibly pinned and bolted components does not lack a certain irony, yet it is also reminiscent of Joseph Paxton’s Crystal Palace, a key building of Modernism that, like no other, forced architecture to engage with the new possibilities presented by functional buildings. Over a hundred years later, it seems, the time has now come in which its technological, non-tectonic expression—albeit now equipped with a touch of romance and yearning for simple mechanics—is suitable for representing one of the most important cultural buildings of the twentieth century. Contrasted with the Miesian order, the decisive shift now no longer lies in representing the technology with genuine architectural means, but in bringing the

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Pompidou Center, Renzo Piano, Richard Rogers and Peter Rice

11

Peter Rice, “Beaubourg,” in: Peter Rice, An Engineer Imagines, p. 29f.

12

Peter Rice, “The Role of the Engineer,” in: Peter Rice, An Engineer Imagines, p. 78f.

Pompidou Center Structural layers

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Pompidou Centre, relationship of gerberette, pivot bearing, column, and tension and bracing elements Pompidou Center, cast gerberettes

Pompidou Centre, relationship of truss, gerberette, column, and tie rod

untransformed technology into view as directly as possible. With this in mind, the gerberette is no longer necessarily understood as a tectonic element obligated to provide stability; instead, it has much more the character of a machine component. With its dynamic form, milled-out joints, and pinned axes, it can be associated more with the image of a rocker arm, and in fact, a considerable degree of its effectiveness is based on the possible movement, which is prevented, however, by various precautions and which allows an optically precarious balance to emerge. Using these means, Piano and Rogers orchestrate the drama of a structure as a balancing act—the glorification and exploitation of technology as image. This, conversely, is consistent with Rice’s intention to exaggerate the structural circumstances enough for a spectacle of the lines of force to emerge from them—a performance for the amusement of the viewer. Like theater directors, the designers thereby highlight certain details and connections and de-emphasize others, in order to create a precisely calculated image on the edge of instability.13 The skillful hallmark of the engineer plays a decisive role in the process. His suggestive power and individuality contributes significantly to an architecture that, as High-Tech and recently also as Bio-Tech, to this day operates formally by always transforming new building technologies into brands. But even more important than elevating technology to a fetish is no doubt the accompanying dissolution of customary tectonic relationships. The classic aspiration toward repose and strength as resistance to gravity, only briefly interrupted in the early Modernist era by experiments in their symbolic conquest, is now replaced by the precisely constructed game for the amusement or irritation of the viewer. In the battle for attention, the temptation to orchestrate such a spectacle and to refine it with the art of the engineer, now belongs to the fixed repertoire of architecture.

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13

Peter Rice, “Instabile Strukturen,” in: Arch+, no. 124/125, 1994

14

Cecil Balmond, Informal, London: Prestel, 2002

15 For design and structure of the ZKM, see: Rem Koolhaas, Bruce Mau, S,M,L,XL, New York: Monacelli Press, 1995, p. 666ff

Partial Collages – Rem Koolhaas, Cecil Balmond, and the Informal Patchwork With various innovations in connection technology and the use of materials, including his research on structural glazing, among other things, Peter Rice has subsequently significantly broadened the scope of the constructible. Despite an obvious tendency toward orchestration, Rice nevertheless remains tied to the engineering tradition that is committed to optimizing the means and which sees the beauty of a thought represented in the form of a closed and harmonious system. With the strategy of the informal, Cecil Balmond—who follows shortly after Rice as directing engineer at Ove Arup—now puts up for negotiation exactly that very core of the engineering tradition.14 Similarly to Rem Koolhaas on a formal level, Balmond is concerned with fundamental revision of the rationalist reflection of Modernism with regard to structural design. In the designs for the libraries in Paris (1992–93) and for the ZKM media center in Karlsruhe (1989), they experiment together with the goal of overcoming the constraints of regular and ostensibly optimized systems and freeing themselves from the logic of grids and repetition. Thus the ZKM, a stacked hybrid with different uses, is to be understood as a polemical reckoning with the Pompidou Center.15 The building typology is nevertheless by and large identical: an outer layer, which serves as a circulation zone and carries the vertical loads, encompasses the large, internal spaces with the main uses. The enormous trusses from the Pompidou Center, which take up a proportionately large amount of space in each of the levels, are in this case, however, replaced with the much more efficient, story-high Vierendeel trusses, allowing every other level to function as a beam thanks to vertical, rigid connections between floor and ceiling slabs. In this way, even though only half of the levels are in fact column-free, the volume can be used without restrictions.

ZKM Karlsruhe, Rem Koolhaas-OMA, sectional model, schematic section

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The Culture of Construction  A

But efficiency constitutes merely the ostensible goal. Koolhaas and Balmond are concerned above all about eliminating a recognizable and dominant structure. To avoid the idea of uniformity, the Vierendeel trusses are replaced to some extent by trusses, reinforced in other locations by individual columns, and the individual elements of each of these structural members are formed differently—from dissolved bracing structure to double-T sections and solid-walled tubular sections. These elements are combined with exhilaration, and in so doing, the readability of their precise function—upon which Rice was absolutely dependent—is intentionally undermined. The artistically formed detail, which is meant to give a visual impression, in sinewy or beefy form, of the nature and strength of the acting forces, is replaced here by a series of ad-hoc solutions. In so doing, Balmond explicitly distinguishes his attitude from High-Tech architecture inasmuch as he recognizes the elegance of their elaborated details, but declares the essence of the repetition and the multitude of structural elements as being a formal problem.16 In place of the closed system, a discernible order of parts corresponding to one another, he uses an open collage of loosely connected structural fragments. In one fell swoop, not only is the didactic communication of stability rejected, but at the same time, the regulatory effect of a building structure based on proportion is also eliminated. The dismissal, in other words, is not only ostensibly directed against High-Tech architecture, but in fact against the cumulative modern canon of an abstract rationale that expresses itself in geometric orders and structural hierarchies, and which found its culmination with Mies. The concept of the informal, in contrast, follows a series of vaguely defined generators—local, hybrid, and juxtaposition—that are meant to lead to the dissolution of an unequivocal order, beginning at the structural level. Accordingly, the local event has primacy over the universal solution (local), the overlap over clarity (hybrid) and the parallelism of orders over the singularity of one system (juxtaposition).17 In the first step, this methodology enables the relatively free combination of structural interventions. For example, the Kunsthal in Rotterdam (1987–92), one of the early projects done in collaboration with Rem Koolhaas, has individual segments utilizing different load-bearing structures that correspond to distinctions in the program and which often appear to be pieced together without a clear system.18 Columns of different shapes and dimensions, walls, sloped floors, and trusses are structurally connected to one another, without resulting in an overall system. In contrast, the

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ZKM Karlsruhe Difference between truss (Pompidou) and Vierendeel system (ZKM) Sketch of irregular Vierendeel system (ZKM) Sketch of an impure Vierendeel system with a combination of solid walls, triangulated diagonals, and variation of the vertical struts (ZKM)

16

“Musik als Quelle der In spiration—ein Gespräch mit Cecil Balmond,” in: Detail, no. 12, 2005

17

Cecil Balmond, Informal, p. 109f.

18

Cecil Balmond, “Informelles Konstruieren,” in: Arch+, no. 117, 1993

19

Claude Lévi-Strauss, The Savage Mind, Chicago: University of Chicago Press, 1968

20 Peter Rice, “Glass and Polycarbonate,” in: Peter Rice, An Engineer Imagines, London: Artemis, 1994

sub-orders constitute something like a pluralism of disparate elements, which constantly produce new irregularities in zones of transition. As with a collage, the fragments of the structure, such as the large, arched lateral bracing in the roof, always remain as discrete interventions within the state of tension between autonomy and integration in the whole. In the manner of the bricoleur, who Claude Lévi-Strauss established as a counterpart to the engineer,19 the structural elements are taken like found objects from an imaginary repertoire, selected according to the task, and then assembled. Balmond does not meet structural challenges with inventions— specifically developed solutions like in the case of the gerberette—but with more or less existing and generally well-known means. The structural fragments thus represent neither a particular innovation, nor do they intend to didactically communicate their precise function. Balmond breaks with the obligation to legibility as well as with the optimization logic of an engineering ethic that directs its ambition toward reducing dimensions and minimizing the use of materials. In reaction to the elegance of Rice’s hybrid structures, such as the one he developed for the IBM Pavilion (1980–84)—delicately machined and tapered wooden struts, which are connected together with elaborately formed, polished steel nodes and deep-drawn polycarbonate pyramids into a self-supporting, barrel-shaped building shell 20—Balmond responds with the ad-hoc system of boards, bent rebars, rolled sections, and metal decking as the roof structure for the Congrexpo in Lille

Kunsthal, Rem Koolhaas-OMA Lower exhibition space with irregularly placed ‘tree-trunk columns’ Diagram of the various structural systems

Auditorium and cafeteria with inclined columns

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The Culture of Construction  A

(1990–94).21 At the scale of the systems as well as at the level of detailing, Balmond succeeds, in a very pragmatic and direct way, at responding to the varied circumstances and requirements. In other words, the real achievement is paradoxically in abandoning the search for an optimal solution, in order to begin a process of finding that ends with partial solutions of limited consequence. Instead of an elaborated tracery—Rice continually identified the Gothic as a reference 22—the integration of disturbances, randomness, and dissonant elements then produce more a kind of artistic patchwork. As opposed to exaggerated eloquence, Balmond relies on the formal exploitation of his pragmatism, a disinterest in the ‘good form’ in favor of using found elements and systems. The compulsion to practice formative design, as is ostensibly the case with Rice, admittedly appears at first glance to be clearly mitigated, but upon closer inspection it reappears at another level and to a vastly greater extent: inasmuch as the regime of the grid is eliminated and a superordinate organizing structure is thereby destroyed, the entire process of design gains an increasing dynamic in which architectural and structural elements are decreasingly distinguishable from one another. The formation of load-bearing structures in the form of local centers, their rhythmization into partial orders, and the orchestration of overlapping zones are operations of great consequence, in spatial as well as conceptual terms. By eschewing the overly explicit perceptibility of his computational actions and thereby camouflaging his instruments, the engineer, beneath the cloak of the bricoleur, thus succeeds in substantially expanding his influence far into the architect’s area of expertise.23 Not unexpectedly, the question of authorship between engineer and architect can, in this case, only be answered very imprecisely. What SOM achieved with speculative jumps in height and dimension, Piano and Rogers opened up with their focus on the technology, and Koolhaas continues with his manner of surrealistic assembly: they all open up possibilities at the architectural level that literally appear to provoke a complementary reaction in structural thinking—congenial responses that coalesce to yield an independent reality and the autonomy of the engineer. Epilogue  The three cases presented here may be viewed as paradigms for developments in architecture in which the formal expression and the structural form coalesce in an exceptional way. An initial conjecture would be that the contributions in both of their disciplines—the artistic as well as the technical—each constitute an autonomous achievement that would also be measured in their respective categories. Developing an architectural concept is something fundamentally different than working out techniques and methods for construction. Even so, it appears that crucial developmental steps take place in both disciplines in a similar manner, following cycles of rejection and reinterpretation. A consequence of this observation is that the art of engineering, contrary to all expectations, does not develop in the scientific sense of a linear and constant increase in knowledge, but is instead equally subject to the changing positions of its protagonists and the conditions of a

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21

Cecil Balmond, “Congrexpo—oder ‘das Ei’ in Lille,” in: Arch+ no. 124/125, 1994

22

Peter Rice, “Sydney,” in: Peter Rice, An Engineer Imagines, London, 1994, p. 63

23

Some issues in the controversy over authorship are addressed in: Jennifer Kabat, “The Informalist,” Wired, no. 9.04, 2001

IBM Pavilion, Peter Rice, Relationship between tension and compression elements made of wood and the structural polycarbonate panels between them Congrexpo Lille, Cecil Balmond Assembly of rolled steel, reinforcing bars, and glued boards to form composite unit Cecil Balmond, Informal, Munich: Prestel, 2002, p. 286

cultural setting. Accordingly, it would in no way be like what is commonly assumed, that the engineer merely places the tools at the architect’s disposal. Rather, certain shifts in the architectural culture evidently first lead to new approaches in the art of thinking about a structure, and thereby to achievements that ultimately achieve independent significance in the field of technology. From there, they subsequently have a reflexive effect on architecture, which, for its part, is always prepared to seize the formal potential of new insights. Thus progress in the applied sciences appears less autonomous than commonly presumed and the interdependency of both disciplines seems considerably more complex than expected.

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A

Structural Concepts and Spatial Design: On the Relationship Between Architect and Engineer Christoph Baumberger

The profession of the master builder has become differentiated in the course of the technological developments stemming from industrialization, separating into the professional disciplines of the architect (in the modern sense) and the structural engineer. Ever since, the question has been about the relationship between architect and structural engineer and the nature of their collaboration. Differing responses have been propagated in architectural theory and exemplified by building practice. In this essay, I distinguish between the models of the monologue by an architect or engineer, the soliloquy of the engineer-architect, and the dialogue between architect and engineer as equal partners. For the third model, upon which we will focus our attention, I characterize more precisely the method of collaboration and discuss two construction methods—shear wall-slab systems (also known as deep-beam/slab structures) and truss structures—that call for the method presented. Beginning with a clarification of the concept of tectonics, I conclude by examining whether, with regard to the discussed structures, one can speak of a “new tectonic culture.” Monologue – The Engineer in the Service of the Architect and the Engineer Who Behaves Like an Architect  The first model is seldom postulated, yet it is practiced more frequently. Depending on who has the say, there are two manifestations. According to the first, the domains of the architect and the structural engineer are separated as cleanly as possible; the interfaces in their cooperative effort are clearly defined and reduced to a minimum. The architect designs the building, the engineer calculates the planned structure. The engineer’s work is limited to working out some technical aspects of the architectural design. He is thereby sim-

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ply one of the ever-growing number of specialists with increasing differentiation who are drawn upon for the realization of a project. His approach is essentially deductive: the application of a known structural system yields its dimensions and reinforcement. The conceptual part of his work is restricted to dimensioning elements so they are as delicate and cost-effective as possible, and helping to realize the architect’s formal and spatial concepts without asking too many questions. This subordinative differentiation between calculating engineer and designing architect is typically accompanied by distinctions between the engineer as technician and the architect as artist, as well as between the engineer as constructor and the architect as designer. The work of the engineer or constructor, it is said, is only subject to functional and purposively rational terms, whereas that of the artist or designer also underlies aesthetic and symbolic terms. Because the art of construction is not a liberal art, it must take into account the terms of structural engineering and construction (as well as those of function and materials). But as the idea goes, these only serve to restrict the creative will or the will to art. The typical situation is easily recognized in this model of collaboration between architect and engineer. Not only the vast amount of that which is built, but also those broad portions of progressive architecture, in which the form is developed without regard to—or even against—the constructive logic, are attributable to the delineated model. This is reinforced by the fact that, with the introduction of skeleton construction, load-bearing structures and facade design have developed asunder. Conversely, the delineated model in turn fosters this divergent development, since it allows the domains of the architect and the engineer to be correlated with various components of the building. While the engineer works on the structure according to purely functional and purposively rational criteria, the architect tends to focus his design—as does Jean Nouvel with his tower in Cologne—on the cladding, which must primarily satisfy aesthetic and symbolic criteria. Indifference between the structure and cladding according to the model set forth by Robert Venturi’s concept of the decorated shed is just the paradigmatic case. The cladding can also make reference to the structure by allowing it to partly appear through the curtain wall, by exhibiting an analogous structure, or by suggesting, simulating, or masking it. Of course, engineers do not limit themselves to merely carrying out calculations for architectural designs; rather, they also develop new design concepts. Yet their collaboration with architects falls under the first model as long as their technical innovations do not actively affect the architect’s design of form and space, whether it is because they limit themselves to addressing the structure hidden behind the architectural form, or—as with the Actelion headquarters in Allschwil by Herzog & de Meuron with WGG Schnetzer Puskas Ingenieure—because they are acting solely in the service of realizing the architects’ expressive gestures. In this case, the form does not result from engaging with the logic of the structure. Rather, structural possibilities are sought to realize an independently conceived form. As long as that is the case, we are dealing with a monologue by the architect.

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Actelion Headquarters, Allschwil, 2007–2010 Architect Herzog & de Meuron, Basel Engineer WGG Schnetzer Puskas Ingenieure, Basel

Rather than an equal discussion partner for the design process, the structural engineer is a specialist whose services are called upon for a well-defined area within the entire planning and construction process, in order to enable the architect to hold a monologue. Such a separation is not conducive to making use of the architectural potential of new structural concepts nor to the optimization of these concepts in terms of their architectural opportunities. It may indeed reduce the planning effort and make fewer demands on the engineer in particular. But precisely in that way, a potential for optimization is wasted, which can have a negative impact on both the construction costs and the quality. The situation is similar with the second manifestation of the delineated model: the monologue of the engineer, which is hardly less common and is the usual case in civil and underground engineering. But while in the first manifestation, the architect consults the engineer as a specialist—and these days must do so—in the second manifestation, the engineer does entirely without the architect. If he means to develop the form alone on the basis of structural, economic, and use requirements, in other words he intends to develop it solely according to purposively rational and functional criteria, he is succumbing to an illusion, since design leeway always exists. And when he actively seeks to use it by incorporating aesthetic and symbolic criteria into the development process and tries to act as an architect himself, the results are often enough naive. Soliloquy – The Exceptional Engineer-Architects  In a few cases, the engineer and the architect are united in one person. The monologues of the technician and the artist, of the constructor and the designer, are interwoven with the great engineer-architects such as Pier Luigi Nervi, Félix Candela, Eduardo Torroja, Frei Otto, and Santiago Calatrava. Their act of designing is one of constructing: the architectural form is developed from the principles of structure and construction, and in paradigmatic works, it exists in the structure itself. As a result, however, not only must the form also meet criteria of purposive rationality, but the structure must also meet aesthetic and symbolic ones. Thus their act of constructing is conversely also a matter of design: formal concepts guide the development of structure, and

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Palazzetto dello Sport, Rome 1956–58 Architect Marcello Piacentini Engineer Pier Luigi Nervi Section Elevation 1 Stefan Polónyi: “Die Tragkonstruktion als architektonische Dominante,” in: Hans Kollhoff (ed.), Über Tektonik in der Baukunst, Braunschweig: Vieweg, 1993, pp. 26–37, here p. 31

2 For this obsession, but above all for more on the search for the remains of the weighty, see Joseph Hanimann, Vom Schweren: Ein geheimes Thema der Moderne, Munich: Hanser, 1999

3

Cited in Fritz Neumeyer (ed.), Quellentexte zur Architekturtheorie, Munich: Prestel, 2002, pp. 349–359, here p. 355

generally this is carried beyond the constructional necessities (and often beyond the economically beneficial and functionally required), in order to generate a spectacular figure, which orchestrates the flow of forces with expressive exaggeration and often takes on an ornamental or decorative character. With the great engineerarchitects, this tendency toward exaggerating the structure in the service of artistic expression generally only goes far enough to ensure that the structural behavior still remains interpretable (even if not necessarily directly discernible). For example, the buttresses of Nervi’s Palazzetto dello Sport in Rome can be interpreted structurally even though, as Stefan Polónyi notes, they could have been omitted if a tension ring had been used at the top.1 The exaggerated representation of structural behavior often accompanies a penchant for organic forms. With some of Calatrava’s built works, they are distorted in surrealist manner and transformed into zoomorphic figures. Both in the tradition of those architects who argued for the primacy of structure and who, like Eugène-Emmanuel Viollet-le-Duc, typically cited the Gothic, as well as in the spirit of the engineers whose ambition was always directed, with the aid of the science of statics, toward minimizing the use of materials for the structure while maximizing the dimensions spanned, the typical buildings of engineer-architects also display a tendency toward dissolution of the mass, and increasingly delicate structures. In so doing, they are following an ancient obsession: to have the object appear lighter than it actually is.2 If this position is pushed to an extreme, it can come into conflict with the intrinsic objective of architecture: design of forms and the enclosure of space. Dialogue – Architect and Engineer as Equal Partners in Discussion  In the wake of increasing specialization, engineer-architects must remain the exception, regardless of how their individual works may be judged. The separation of architect and engineer, by contrast, offers the possibility of cross-fertilization. Thus a close collaboration between architect and engineer as two equal partners was called for, even early on. For instance, Peter Behrens wrote in his lecture “Art and Technology” from 1910: “It is unlikely that a special profession which could be called engineer-architect will develop. Instead, I believe that the future will make a close coexistence of artist and engineer necessary. Neither the architect nor the engineer should be subordinate to the other.”3 Neither a monologue by one or the other,

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nor a soliloquy of the engineer-architect is sought in this third model, but instead a dialogue between two specialists with different perspectives on the same: building. In the dialogic design process, both perspectives, which in the architect’s case might focus on spatial design, and in the engineer’s case on the structural concept, are combined, and brought into—possibly exciting—harmony with one another. The architect’s spatial ideas and material concepts provide the engineer with starting points and useful information for conceiving and elaborating the load-bearing structure; and the engineer’s three-dimensionally conceived structural concept affects the architect’s spatial design and choice of materials. The dialogue between architect and engineer often builds upon a building structure proposed by the architect. A convincing example of how such a structure can be implemented in various structural concepts that, in turn, conversely alter the spatial composition of the building and the associated spatial perception, is provided by the engineering competition organized by the architects Jüngling & Hagmann for the administration building for Würth International in Chur. Jürg Conzett’s proposal, which is based on the idea of a suspended truss, results in an emphasis on the vertical articulation and thus produces an almost Gothic sense of space. The realized proposal by Hans Rigendinger, which operates with frames arranged floorby-floor, results in a horizontally articulated composition and thus a more classicistic sense of space. Such engineering competitions could be a means to break the established pattern of commissioning work on the principle of seeking to minimize planning fees, and to give a chance to the design-intensive form of collaboration between architect and engineer in the service of quality. 4 A Logic for Developing Structural Hypotheses  Whereas the engineer’s process is a deductive one for the first model in the paradigmatic case, that can no longer apply for the third model. In the delineated design process, the engineer is not merely responsible for calculating the dimensions, reinforcement, etc., by applying a structural system to the planned load-bearing structure. Rather, it is a matter of developing the structure itself. The process for doing so can be described as a modified form of the reasoning of abduction. An “abduction” denotes a conclusion identifying the best explanation for the ex-

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4

Cf. Andreas Hagmann: “Struktur und Raum,” in the same volume, (pp. 143-45)

Conzett and Rigendinger proposals. Engineering competition for the administration building for Würth International, Chur, 2002 Architect Jüngling & Hagmann Architekten, Chur Engineer Jürg Conzett, Chur, suspended truss Engineer Hans Rigendinger, Chur, frames located at each floor (realized)

5

The abduction, or the conclusion identifying the best explanation, plays an important role in contemporary epistemology and philosophy of science; cf. e.g. Thomas Bartelborth, Begründungsstrategien: Ein Weg durch die analytische Erkenntnistheorie, Berlin: Akademie Verlag, 1996, pp. 138–148

6

For clarification of the functional concept (using the example of museum architecture) cf. Christoph Baumberger, “Kunst aktiviert Kunst: Ein Framework für eine funktionale Analyse der Museumsarchitektur,” in: Julian Nida-Rümelin, Jakob Steinbrenner (eds.), Kontextarchitektur, Ostfildern: Hatje Cantz, 2010, pp. 49–76 7

In the case of the mixed-use building on Ottoplatz and with the Volta school, this stipulation appears sensible: with the first, the user needs for the ground floor were still unknown in the design phase, and sports halls should not be interrupted by columns. With the Kerez building, in contrast, it comes dangerously close to simply being an ambitious target 8 Jürg Conzett presents the idea of such structures, which he attributes to Robert Maillart, in “Tragende Scheiben im Hochbau” (Werk, Bauen + Wohnen, 9 (1997), pp. 34–39) and in “Bemerkungen zu räumlichen Scheibensystemen” (Schweizer Ingenieur und Architekt, 26 (2000), pp. 4–8)

istence of certain circumstances. Assuming that a hypothesis best explains the circumstances, one presumes the truth of this hypothesis. 5 A detective concludes that the butler is the murderer because that is best explained by the evidence; a doctor diagnoses the disease that best explains the patient’s symptoms. Since the conclusion of an abduction goes beyond what is contained in the premise, it follows only with probability. That the butler is the murderer can be the best available explanation for the evidence and still be wrong; the doctor’s diagnosis can be wrong even if it is the best available explanation of the symptoms. Abduction is therefore an insight-expanding, non-deductive conclusion. Together with induction, it belongs to the logic of discovery. But while inductions typically provide generalizations, abductions provide explanations. In the first case, the instruction is “collect as many observations and then generalize!”; in the second case, it is “think about what could explain the known circumstances, compare the explanations, and choose the best one!” According to the dialogic model, the engineer’s process is a modified form of abduction, because its contribution to the planning is less a matter of explaining certain data, but more one of developing structural hypotheses under certain conditions that result, among other things, from the architect’s spatial ideas and material concepts, and from user requirements and functions. 6 Beginning with such conditions, the engineer concludes a structural hypothesis (structural concept) by showing that it best enables fulfillment of the initial conditions upon application of a suitable structural system. The structural hypothesis then affects the architect’s spatial design, which can lead to modifications of the initial conditions, which could, in turn, require the structural design to be adapted. The engineer’s structural concept fulfills the initial conditions best when it combines with the architect’s spatial concepts into a homogeneous whole. The load-bearing structure now supports the architectural idea, and the architectural form displays the load-bearing structure to its advantage, which however must by no means imply straightforward presentation of the structure. For a simplified example, the call for a large, column-free space beneath floors with smaller rooms can be examined as the initial condition. With the residential and office building on Ottoplatz in Chur by Jüngling & Hagmann Architekten with the engineer Jürg Conzett, the required column-free space is a public ground-floor zone, in the Volta school building in Basel by Miller & Maranta Architekten, likewise with Jürg Conzett it is a gym, and with the Forsterstrasse apartment building in Zurich by Christian Kerez with the engineer Joseph Schwartz, it is an underground garage. 7 The stipulation can of course be ideally met, through the application of structural systems known from bridge construction, if the structure is designed as a box-like system of prestressed concrete slabs and walls. 8 The example is simplified, because of course in every case many more—and in the three projects, different—initial conditions were to be taken into account and because the structural proposal is only the first step in a complex mutual coordination of structural concept and architectural idea, which has yielded very different results in each of the three projects.

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Shear-Wall/Slab Systems and Truss Structures  Many of the contemporary buildings that result from close collaboration between architects and engineers as equal partners continue the tendency toward the dissolution of the mass—toward lighter structures, more transparency, and more flexibility—and therefore employ delicate forms of construction, typically making use of the skeleton system. Often they also continue the tendency toward decorating buildings with superfluous constructs (supplemented by over-dimensioned mechanical equipment) and radicalizing them insofar as, in contrast to buildings by engineer-architects, the individual elements of these structures can often no longer be interpreted as load-bearing. One can recall works by Renzo Piano with the engineer Peter Rice (discussed by Christian Penzel in his essay) as well as examples of so-called light-tech architecture. Buildings such as the residential and office building on Ottoplatz, and the Kerez building follow neither of these two tendencies. They are distinguished precisely because their massive structures based on pre-tensioned horizontal and vertical concrete slabs demonstrate an alternative to the skeleton system of construction. Firstly, this alternative leads to abolition of the separation between load-bearing structure and space-articulating elements. The structure acts not as decoration meant to give the buildings a constructional or technical appearance, but as a space-defining system. Thus unlike with skeleton construction, with the structural principle of vertical and horizontal slabs, a clear interface between the work of architect and engineer is not possible. Secondly, the alternative yields a different kind of flexibility. Whereas the skeleton specifies the same grid system for all stories, the slab system enables different layouts on each floor, whose degree of flexibility can be adapted to different uses. Thus it allows the bridge-like structure of both buildings, where the upper floors span above the ground-floor level or the parking garage like a bridge, in order to accommodate small-scale space above large, column-free areas. Since their walls are parts of the structure, however, in these stories the flexibility—in the sense of the possibility to relocate the partition walls—is relinquished in favor of clearly defined spaces. Moreover, in neither building is the idea of different layouts on each story translated to the section or developed further in the direction of spatial

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Volta school building, Basel 1997–2000 Architect Miller & Maranta, Basel Engineer Jürg Conzett, Chur

Forsterstrasse apartments, Zurich, 2003 Architect Christian Kerez, Zurich Engineer Joseph Schwartz, Zug Structural model Exterior view

planning. The floors cantilevering around the Kerez building make this limitation more conspicuous. Thirdly, the structural behavior of the various elements of the structure, as will be shown, can without exception be interpreted, even though it is not discernible at first glance. Finally, the structure of horizontal and vertical slabs also counteracts the tendency toward ever more delicate and transparent structures and fosters a more suspenseful relationship between weight and lightness, between open and closed. For instance, the mass of the upper floors of the residential and office building on Ottoplatz bears unsettlingly upon the open, column-free ground floor, whose glazing is slightly recessed, intensifying the effect even more. And with the Kerez building, the weight of the load-bearing concrete walls and slabs is in harsh contrast to the lightness and transparency of the nearly circumferential story-high window surfaces, which are recessed behind the front edges of the slabs and thus recede behind the concrete structure. Through them, the composition of heavy concrete slabs inside can also be seen in outline form, overlaid by the dancing green reflections of leaves on the glass. In recent years, interest has shifted from the massive, shear-wall/slab construction method to lighter truss structures. Both with the extension of the Graubünden

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Cantonal Bank in Chur by Jüngling & Hagmann with Hans Rigendinger (see p. 144) and the Leutschenbach school building in Zurich by Christian Kerez with Joseph Schwartz (see p. 194 –197), the structure is built partly of multistory trusses. These trusses, which span over the ground-floor banking hall of the Cantonal Bank and are stacked above each other in the Leutschenbach school building, like the concrete slabs in the building on Ottoplatz, form a bridge-like and space-enclosing structure. As with the preceding buildings, there is no strict separation between the load-bearing structure and space-articulating elements. But since the massive shear walls have been resolved into a series of lattice struts, the ratio of wall to opening within the load-bearing elements as well as the resulting relationship between structure and space are more ambiguous than in the earlier buildings. The dissolution of the shear walls is emphasized, because at the Leutschenbach school the interior walls are built of Profilit (profiled glass elements) and at the Graubünden Cantonal Bank, the glazing plane is separated from the truss. Structurally, the trusses in both buildings function as walls; visually, however, they are simultaneously openings. Thereby, the pendulum has not only swung back toward more delicate and transparent structures. At least at the Leutschenbach school, where some of the trusses were moved—with great technical effort—to the exterior, the tendency of utilizing the structure as ornamentation is again noticeable, giving the building a structural expression; one in which, however, the structural elements can be interpreted structurally, as is the case with buildings by engineerarchitects.

Ottoplatz apartment and office building, Chur, 1999 Architect Jüngling & Hagmann Architekten, Chur Engineer Conzett Bronzini Gartmann, Chur

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9 For example, Ulrich Pfammatter, Building the Future: Building Technology and Cultural History from the Industrial Revolution until Today, Munich: Prestel, 2005, p. 152 10

Cf. Nikolaus Pevsner et al. (eds.), Dictionary of World Architecture, Munich: Prestel, 1992, p. 630. Kenneth Frampton sometimes has a much broader (and arguably too broad) concept in mind, whereby the tectonic—as the “poetics of construction”— generally involves the poetical “expressive potential” of structure and construction (Studies in Tectonic Culture: The Poetics of Construction in Nineteenth and Twentieth Century Architecture, Cambridge, MA: MIT Press, 2001, p. 2) 11 Hans Kollhoff, “Der Mythos der Konstruktion und das Architektonische,” in: idem, Über Tektonik in der Baukunst (note 1), pp. 9–25; here p. 17 12

Key texts on this debate, about whether coursed masonry is still an architectural criterion and whether it can be real or merely in the form of facade cladding, are to be found in Gert Kähler (ed.), Einfach schwierig: Eine deutsche Architekturdebatte, Braunschweig: Vieweg, 1995 13 Hans Kollhoff, “Der Mythos der Konstruktion” (note 11), p. 11 14

“Diskussion,” in: Kollhoff (ed.), Über Tektonik in der Baukunst (note 1), pp. 126–135, here p. 130

15

Stefan Polónyi, “Die Tragkonstruktion” (note 1), p. 26

Tectonics – A Distinction from the Neotektoniker  When it comes to the correspondence of structure and form as well as the interpretability of the structural behavior, the notion of tectonics is often brought into play. Probably because the discussed buildings are distinguished by such correspondence and interpretability, one speaks of a “new tectonic culture” in connection with them, and especially with regard to shear-wall/slab structures. 9 The expression ‘tectonics,’ which—like almost every basic term used in architectural theory—usually serves more to propagate certain architectural positions than to describe buildings, comes from the art of carpentry. This is still evident with Gottfried Semper, who used ‘tectonics’ for wood constructions and ‘stereotomy’ for stone constructions in his book Style in the Technical and Tectonic Arts. The term has subsequently sometimes been reserved for delicate or skeleton-framed structures as opposed to solid structures (even though solidly constructed wooden structures exist, such as log cabins). As a rule, however, following Bötticher’s Tektonik der Hellenen [The Tectonics of the Hellenes], it is applied to building in general. According to a standard definition that picks up on Bötticher’s ideas, tectonics identifies the science of assembling rigid individual parts into a building that aims for a correspondence of form and structure. 10 He thus unites, as Hans Kollhoff observes, “the seemingly contradictory pairs of appearance and construction, art and technology.”11 A building is thus recognized as tectonic when its individual parts are assembled together, and it must be in such a manner that the form and structure correspond. I call the first stipulation the ‘assembly requirement’ and the second one the ‘correspondence requirement.’ Of course, everything depends on how the two conditions are understood. In order to clarify whether a “new tectonic culture” can be spoken of in connection with buildings like those discussed with shear-wall/slab structures, a final distinction will be attempted: that of the advocates of a rehabilitation of the tectonic in the 1990s dispute over principles centered in Berlin.12 The Structure Hidden Behind its Descriptive Image  The Neotektoniker [adherents of Neotectonic architecture] start from the premise that with the establishment of the skeleton construction method, the separation of structure and cladding has been irrevocably consummated. “The architecture of cladding,” writes Hans Kollhoff, “is simply a fact.”13 But of course, as Fritz Neumeyer says, “structure is by tendency non-tectonic. The structures of modern engineers have led to the abrogation of the tectonic; they irritate our senses.”14 This assessment is not surprising if one adheres to the assembly requirement in some form or another. Because monolithic reinforced concrete structures, at the least, are not assembled; at most, as Stefan Polónyi notes,15 non-structural parts are attached to it. The soughtafter rehabilitation of the tectonic thus does not take place at the level of the structure, but at the level of the cladding. To soothe the irritated senses, it is typically structured (as in Hans Kollhoff’s high-rise on Potsdamer Platz) according to the model that supplies a paradigm for the architectural assembly of parts: the joining together of blocks into solid masonry (which, according to Semper, is not precisely

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tectonic, but stereotomic). The concept of the tectonic thereby focuses not on the “structure itself as a technical reality,” but instead on a descriptive “image of the structure”;16 its “goal is not the visualization of the structure itself, but their recollection.”17 The image is usually a fictive one and the recollection (despite the metaphor, going back to Adolf Loos, of clothing as a skin that the structure neither exhibits nor cloaks) is one not of the structure behind the cladding, but of structures as they once were. Because the actual structure, in the case of monolithic concrete construction, is not at all assembled—or, as is the case with steel construction, it is assembled differently than the cladding. Moreover, these attempts at rehabilitating the tectonic feign solidity more than they actually create it, because behind the ‘stone wallpaper,’ whose joints very often imitate the pattern of load-bearing stone construction, minimally dimensioned concrete or steel skeletons carry the whole building [see overleaf: high-rise on Potsdamer Platz]. There is, in other words, a curious reversal of the old obsession: instead of lighter, the object suddenly appears heavier than it is. All this simulation, however, apparently does no harm to the tectonic character of such buildings. On the contrary, because “architecture must,” according to Fritz Neumeyer, “not be honest in terms of its construction, but it must instead create an appearance of the honestly constructed. The magic necessary for this characterizes the art of tectonics.”18 What, of course, does this mean for the correspondence of form and structure, to which the assembly of individual parts according to the standard definition of “tectonic”aims? With the separation between structure and cladding, construction and form have grown apart. Their correspondence lies in the form acting as a descriptive image of the structure or as a recollection of it. But since the image is fictional and the recollection is one not of the structure hidden behind the cladding, the correspondence turns out to be illusory. The buildings in question thus do not satisfy the correspondence requirement. That probably explains why Hans Kollhoff and Fritz Neumeyer omit this stipulation in their conditions for tectonics. At least the second appears to be replaced with something like a “descriptiveness requirement.” 19 Furthermore, they relate the assembly requirement to the structuring of the outer form, which to them means: the cladding. A building is considered tectonic if its cladding at least appears to be assembled from individual parts, 20 and indeed in such a manner that it produces a descriptive image of a structure, which can also be fictional. 21 Like the correspondence of construction and form, the unity of technology and art sought after, at least by Hans Kollhoff, also proves to be virtual: whereas the load-bearing structure is essentially the prerogative of the engineer and can be attributed to construction technology since it must only satisfy functional and purposively rational criteria, the cladding—which is primarily intended to meet aesthetic and symbolic criteria—is, as the domain of the architect, at the heart of architecture. The delineated understanding of tectonics, which underlies much of what the advocates of the rehabilitation of the tectonic propagated in the dispute over principles and have also realized, thus falls under the first model of the relationship between architect and engineer. The intended dialogue turns out to be a monologue.

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16

Fritz Neumeyer, “Tektonik: Das Schauspiel der Objektivität und die Wahrheit des Architekturschauspiels,” in: Kollhoff (ed.), Über Tektonik in der Baukunst (note 2), pp. 55–77; here p. 62. In the following, I use Neumeyer’s expression “image of the structure,”even though what it denotes is naturally not a matter of images in the proper sense

17

Hans Kollhoff, “Der Mythos der Konstruktion” (note 11), p. 15

18 Fritz Neumeyer, “Tektonik” (note 16), p. 63 19

Another notion of tectonics, one used by Eduard Sekler, incorporates the descriptiveness or expression requirement into the correspondence requirement. A building is accordingly considered tectonic if it is assembled from individual parts and if the structure and its flow of forces is descriptively expressed (“Structure, Construction, Tectonics” in: Gyorgy Kepes, Structure in Art and Science, New York: George Braziller, 1966, p. 89ff)

20

The facade of Kollhoff’s high-rise building on Potsdamer Platz is precisely not assembled of blocks, but constructed of precast facade elements with inset clinker bricks. The building attempts, however, to avoid this impression and suggests that the facade is assembled from individual bricks

21

Fritz Neumeyer remains vague in his stipulation: “ The core of the notion of tectonics refers to the mysterious relationship between a thing’s ability to be assembled and its descriptiveness, and concerns the relationship between the order of something built and the structure of our perception” (“Tektonik” (note 16), p. 55). But the further remarks referenced above appear to justify my interpretation

High-rise building on Potsdamer Platz, Berlin, 1998–2000, by Hans Kollhoff

The Structure Concealed by Our Viewing Habits  The collaboration between architect and engineer that underlies buildings like the residential and office building on Ottoplatz or the Kerez building, in contrast, belongs to the third model. The separation of structure and cladding presumed by the Neotektoniker is reversed in these buildings. Their form is like the paradigmatic works of engineer-architects in the structure itself, or it at least comprises a substantial part of their form. But unlike the works of engineer-architects, they renounce a spectacular display of the flow of forces. Neither an expressively exaggerated staging of the structural behavior nor a clear image of the structure is sought. The relationship between the structural characteristics affecting the structural behavior and their perceptibility is more complicated. Consider again the residential and office building on Ottoplatz. On the one hand, the load-bearing structure is not cloaked by cladding. The elements that appear to be load-bearing—and only those—actually carry loads (the built-in elements are inserted into the primary structure like large pieces of furniture with round edges); and the load-bearing elements are as a basic principle visible. On the other hand, the structural behavior of the visible structure is not easy to recognize. In the lapidary way in which the building stands, the clever and ambitious structural concept is not showcased. The use of horizontal and vertical prestressed concrete slabs supports this ambivalence, because the walls and slabs may be visible, but the prestressing tendons that are crucial for their structural function remain hidden like the ordinary reinforcing as well. So one will hardly be able to immediately recognize that the offset, slender concrete walls (deep beams) constitute a kind of lattice girder, inasmuch as they are connected diagonally by means of prestressing tendons arranged in a diamond-like pattern. Without even giving it further attention, one will notice that the openings between the concrete walls are a result of the crossed tendons. But perhaps one wonders how this column-free, glass-enclosed ground floor is possible; and perhaps one will notice that the vertical concrete slabs are staggered from floor to floor, so the strong vertical accent is overlaid with a diagonal orientation. Such clues can stir silent amazement that affects our experience of the building, and they can persuade us to concern ourselves more precisely with the underlying structural concept and to investigate its hidden elements.

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So is the building on Ottoplatz a tectonic structure? Can it serve as evidence of a “new tectonic culture”? The following considerations speak against it. Even though it satisfies the correspondence requirement because the form consists substantially of the structure itself, it firstly violates the standard definition’s assembly requirement, and therefore behaves downright contrary to typical buildings of the Neotektoniker. Whereas the building’s facade, for which the prefabricated concrete slabs are used, can perhaps be described as being assembled from individual parts, it appears that is no longer the case for the rest of the structure, which (like the entire structure of the Kerez building) is constructed of monolithic reinforced concrete. Secondly, the structure violates the Neotektoniker’s descriptiveness  requirement, because its form does not especially produce a descriptive image of the structure. Of course, one could attempt to expand the concept of assembly so much that all types of structures, even monolithic reinforced concrete ones, are included. In so doing, one would consummate the complementary strategy providing an alternative to Hans Kollhoff and Fritz Neumeyer: the correspondence requirement is retained and the assembly requirement would be forsaken de facto. But whereas the result of their strategy is still a tectonic concept because the descriptiveness requirement takes the place of the correspondence requirement, with this second strategy the question of the tectonic would be replaced by the more general question of the relationship between construction and form. If, in contrast, one holds fast to the assembly requirement and combines it with the descriptiveness requirement, what becomes clear is: it cannot be understood so broadly that our building satisfies it. Because, since the descriptiveness or “legibility” of the image is considered more important for a building’s tectonic character than is its correspondence to the actual structure, the joints relevant to this image are typically oriented to the paradigmatic assembly of blocks into a wall. This is descriptive, and “readable”: we are familiar with it. But precisely this familiarity could be a factor in why we are only able to “read” with difficulty the behavior of structures comprising prestressed deep beams and slabs. The load-bearing structure of the residential and office building on Ottoplatz is admittedly not hidden behind cladding, but the perceptibility of the structural behavior is concealed by our viewing habits. And buildings that are identified as “typically tectonic” especially appear to perpetuate these viewing habits. Constructors’ Dialogue  The structures discussed—and of course not these alone—reveal, on the one hand, alternatives to the art of the architect’s monologue; whether it is the decorative art of packaging, which in the service of branding, often relies on an appealing or communicative envelope, or whether it is the conservative art of disguise (cladding) that, in the service of a stone-like city and the legibility of its facades, aims for a descriptive image of the structure. On the other hand, they reveal alternatives to the excessive constructional art of engineerarchitects, which is often also in the service of demonstrating technical possibilities in an expressively exaggerated staging of the structural behavior. The alternatives

69

Ottoplatz apartment and office building, Chur, 1999 Architect Jüngling & Hagmann Architekten, Chur Engineer Conzett Bronzini Gartmann, Chur Architect and engineer's concept sketch Stress fields

build upon a close partnership between architect and engineer. Massive shearwall/slab structures differ from other efforts in the same direction in that they do not continue the trend to ever-more-delicate load-bearing systems and increasing transparency and flexibility, nor do they continue the tendency toward decorating buildings with superfluous constructs. Rather, they stage an exciting game between the light and transparent, on one side, and the heavy and opaque on the other, enable customized flexibility with comfortably defined spaces, and conceive of the structure as a space-defining system. Trussed structures, as currently in vogue, by contrast, partly follow the first tendency again; and at least some of them utilize the structure as ornamentation. But even with these, there is no strict separation between load-bearing structure and space-articulating elements. The development of the load-bearing structure and the spatial design thereby conflate, and the domains of the structural engineer and the architect are no longer cleanly separated from one another. Both work on the structure, one primarily from the viewpoint of the structural concept, the other primarily from the viewpoint of spatial formation. Theirs is a constructors’ dialogue.

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71

72

B

Research Jürg Conzett investigates the interplay of technical and architectural aspects in the case of the Palazzo della Regione in Trento, by the architect Adalberto Libera and the engineer Sergio Musmeci. He attempts to unscramble the mixture of different influences from the two sides in their design collaboration— hardly a reversible process—by addressing the various design steps through creative structural hypotheses. Yves Weinand describes how the potential of the neglected properties of wood as a material is being explored at the IBOIS Research Laboratory at EPF Lausanne in order to develop new, space-defining structural systems. In a tightly-knit research and education program, experiments are performed on large-scale structures made of small, repetitive units and the use of textile-like (woven) timber techniques. The stated goal is to expand the repertoire of freer forms without losing sight of the traditional values of timber structures. As part of a research project on The Pitched Roof, Aita Flury examines the interaction of structure and space in the headquarters of the Società Ippica Torinese (S.I.T.) in Nichelino, Turin (1958/59), by the architects Gabetti & Isola and the engineer Giuseppe Raineri. A dialogue in the form of an ‘uncut’ exchange of e-mails, in which the architect turns to the engineer Jürg Conzett for his opinion during her research, illustrates how this led to the analysis ending up not only more profound structurally, but also “much more amusing.”

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B

The Interplay of Technical and Architectural Aspects in the Palazzo della Regione in Trento by the Architect Adalberto Libera and the Engineer Sergio Musmeci Jürg Conzett

This is the summary of a talk given on December 2, 2005 at a symposium about the Palazzo della Regione. The contributions to this symposium were published in Italian in the book Il Palazzo della Regione a Trento di Adalberto Libera e Sergio Musmeci, ed. Marco Pogacnik, Trento: Nicolodi, 2007. I am grateful to Marco Pogacnik for his kind permission to use various original documents from the Libera archive for this article.

The Palazzo della Regione, completed in 1964, consists of three wings, namely the Edificio Assessorati with its characteristic ‘tree columns’, the Sala Consiliare as a functionally justified conical shell, and the Giunta with its huge roof span. Common to all three parts of the building is the elementary, almost tangible expression of the structural forces. This does not necessarily reflect the true situation, however; rather than taking a didactic approach, Libera and Musmeci have sought to exaggerate the real statics. There are two issues with this building that interest me: firstly, the relationship between “computational stability” and “represented stability” (as Gropius phrased it) and secondly, the influence of Musmecis’ work on the form of the Palazzo.

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Aerial view of the Palazzo della Regione in Trento. On the left is the Edificio Assessorati, along the front is the Giunta, behind it the Sala Consiliare. To their right is an older building, the Grand Hotel Trento.

Edificio Assessorati: Structural Drama  The Edificio Assessorati is a concrete frame structure. The upper floors have a rhomboid grid of about 6 x 6 m. The column spacing on the ground floor is double that. Out of each ground-floor column rise four struts (inclined at an angle of 25 to 30 degrees to the horizontal), each of which, in turn, bears the load transmitted by a column on the first floor. This is the first situation in which a kind of deliberate deception of the viewer by the designer is evident. The elevation (see plan 106) of the longitudinal facade shows ground-floor columns that are tapered, becoming narrower towards the base. A vertical structural element whose cross-section diminishes towards its lower bearing point only makes structural sense as part of a frame: as a component that has to accommodate a horizontal force at its foot (among other places), whereby this force produces a bending moment in it which increases with height. This kind of structural component, which appears unstable at first sight and needs to be made of rigid material, became a hallmark of engineering during the second half of the nineteenth century (the arch of the Garabit viaduct, the hinged bearings of the Galerie des Machines at the 1889 Paris Expo, the truss bearings of the AEG Turbine Hall at a later date, still later Maillart's three-pin box-girder bridges, and finally a great many works by Prouvé). The main point is that such elements can only ever be part of a structure; they depend for their stability on other structural parts, which are often arranged symmetrically (as in an arch), but which can also have a completely different form (such as a pin-ended column under a half frame). In other words, the upright of a frame never stands by itself. Now, if Libera and Musmeci form the main column with a taper as the upright of a frame, they have to connect that part (the main column and the four attached struts) to the adjacent column struts in some way. This makes ribs necessary in the structural slab above the ground floor, or at least an increase in its thickness (see sketch 1). Once we understand what is happening in this structure, the struts suddenly lose a large part of their visual effect. The designers’ treatment of the floor slab as a smooth, continuous element ignores its structural function (namely, of tying together the upper ends of the struts), and gives the misleading impression that the

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The Interplay of Technical and Architectural Aspects   B

columns of the upper floors stand on cantilevers—in which case, the struts would be subjected mainly to bending forces and not, as they actually are, to compression. On closer inspection, we discover that the slab does indeed possess ribs, but as upstands, concealed in the floor depth above (see plan 110). This arrangement, rather awkward for the flooring contractor, must have been chosen deliberately in spite of its disadvantages—and the only credible reason for that is to achieve a smooth surface for the underside of the slab. If the main columns were tapered as shown, then the masking of the slab’s structural contribution to stability would be partly neutralized, because this unmistakable sign of instability in the uprights of a frame means that a stabilizing element—if not in the slab, then above it—must be connecting the individual columns via their struts. This knowledge, in turn, would undo the impression (an intentional and calculated misapprehension) created by the cantilever arms. Although, from a purely formal point of view, it would have been a plausible motif (the elegant taper of the four struts/arms recurring, inverted, in the main column), it would also have weakened the structural drama, which is why, I think, the designers ultimately chose to form the vertical members as cylinders with a constant cross-section. Sala Consiliare: The Logic of Form  The Sala Consiliare rests on four columns, which transmit the loads to pile foundations. At basement level, a circular drum

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Interior of the Edificio Assessorati. The smooth, continuous floor slab does not seem to be part of the primary structure and thus gives the impression that the diagonal struts are cantilevered brackets

Plan 103: ground floor of the Edificio Assessorati. The column grid of the upper floors is double-spaced here Plan 106: earlier elevation of the Edificio Assessorati. Here the ground floor columns are tapered Sketch 1: Structural effect of tapering a column towards the base: This only makes sense as part of a frame Sketch 2: Column with a constant cross-section

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Plan 110: later cross-section through the Edificio Assessorati. The columns now have a constant cross-section, making them more effective as independent elements. The slabs contain beams, which tie the inclined struts together. These beams are concealed in the depth of the floor above, as shallow upstands

spans between these supports, from which it is suspended because of the soft subsoil. In the top third of the drum’s beam are regularly spaced openings with triangular reinforcement in their corners, in the manner of a Vierendeel girder. The floor levels around the central chamber are formed by concrete slabs, cantilevered outward over the columns. The longest cantilevers, in the two corners towards the Giunta, are reinforced by ribs, which span diagonally from the columns to the corners and become shallower towards their tips. The council chamber itself consists of a truncated conical shell, 300 mm thick; this is suspended from the four main columns and a ring beam serving as a wall. Two bridge-like slabs provide access to the hall of the Giunta via openings that are sections cut out of the conical shell. The way in which these cut-out sections are dealt with is an example of good coordination between the spatial composition and the structure, and it demonstrates the quality of the collaboration between Libera and Musmeci. In particular, we see this in the treatment of the ribs that frame the cut-outs. The uppermost slab, which surrounds the top edge of the conical shell, serves as a roof for the adjoining rooms. Here, upstands are used, rather than the downstand beams that support the corners of the lower floors, thus changing the position of the ribs relative to the floor slab. These upstands continue inside the building, running downwards alongside each section cut of the bowl, serving both as parapets and as edge reinforcement.

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Plan 304: section through the Sala Consiliare

Structural shell of the Sala Consiliare Structural principle of the Sala Consiliare

The building of the Sala Consiliare possesses a structural logic that is immediately obvious and unambiguous. Therein lies its high quality. The reason why the Assessorati and the Giunta require a longer and more intense examination is due to the fact that they raise more questions, that they are more problematic. Giunta: The Difficulties of Interpretation Spina Centrale  In structural terms, the Giunta is a simple beam with cantilevers at both ends. Two piers under the central, longitudinal axis support the building. The middle span is 40 meters, with the two cantilevers each measuring 14 meters along this axis. The most important load-bearing element is the Spina Centrale, the only internal wall, which runs the entire length of the building and rests directly on the two piers. In an early design draft, it is perforated by two apertures in each bay, forming a two-story Vierendeel girder. At that stage, the supports between ground level and the underside of the lower slab still consist of very strong longitudinal shear walls, flanked by two slightly oblique round columns, which run through to the roof and stabilize the building against horizontal or asymmetric forces.

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In this two-story Vierendeel form, the Spina Centrale would have caused significant structural problems, with the horizontal parts of the frame needing very strong reinforcement at the supports. It is likely that Libera and Musmeci discussed the arrangement of the openings intensively in the next few stages of the project. In the search for a solution, Musmeci plotted the principal stress trajectories of the ‘spine’, given the assumption of a solid wall with no openings. We should ask, though, whether this diagram shows what there is, or whether it represents what there should be. Admittedly, the sheet has the character of a free-hand drawing and it would not be appropriate to analyze its correctness too stringently, but it is still the case that with the trajectories of an I-beam, as represented by the Spina Centrale, we could expect a field of distribution that would be inclined across the whole of the wall at less than approximately 45 degrees to the horizontal. It is therefore quite possible that here we see the influence of what Musmeci had absorbed from A.G.M. Michell (1870–1959): the methodical search for a structure with minimal weight. For a finite rectangular field that bears a uniformly distributed load and is cantilevered, the Michell figure is equivalent to an intersecting group of cycloids. In fact, Musmeci’s drawing of the stress trajectories recalls this Michell figure much more strongly than it does the ‘correct’ picture of the trajectories of the I-beam. So we may assume that this is an illustration of an ideal state, a distribution of forces that should be preserved as far as possible. The openings in the wall are subsequently positioned in this flow of forces like islands, streamlined so as to create minimal disturbance, as is clear to see in the longitudinal section. The position and shape of the openings are directly influenced by Musmeci’s way of thinking, which owed much to Michell’s figures. Another engineer, for instance, beginning with the 45° trajectories, would have ended up with an arrangement of openings that was closer to that of a truss (cf. the facades of the building on Ottoplatz in the chapter by A. Hagmann, pp. 139–145). Musmeci’s structures, in contrast, often display broad, sweeping lines that also satisfy the search for minimal weight from a technical viewpoint, even when this involves considerable effort (Ponte sul Basento in Potenza, design for a spiral skyscraper). That said, the two-story Vierendeel girder of the 1956 draft is much more closely related to a trussed structure, because a Vierendeel girder, like a truss, involves the addition of similar elements, being a construction system that was developed mainly in the search to rationalize construction processes. End facade   Looking at the north facade of the Assessorati, we seem to encounter a kind of insect: the end of the Giunta building (see diagram 106). It presents us with a variety of curved shapes and structured (hatched) surfaces. One striking motif is the ‘belly’ of the first floor: a line that will remain unchanged right through to the finished building. This downward curve leads us to suppose, at first, that the first floor is suspended from a T-shaped frame (see top sketch, p. 87). The gently reentrant inner haunches of the ‘hangers’, the chamfered outer corners, the slightly curved edges of the six window openings: all support the idea of an elastic mem-

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Early plan of the second floor of the Giunta. The Spina Centrale is clearly recognizable

Early longitudinal section through the Giunta. The Spina Centrale is a kind of Vierendeel girder

Cross-section corresponding the above

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Musmeci’s drawing of the principal stress trajectories in the Spina Centrale

“Michell figure” for a finite, rectangular, uniformly loaded field that is constrained along its right edge

Principal stress trajectories in the web of an I-beam, plotted with a slice program

Plan 208: revised longitudinal section (part) through the Giunta

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brane in tension. Even the suggestion of horizontal layering in the facade of the first floor could be interpreted in this way, with the masonry as structurally inactive units, loosely laid on a sagging cable. In contrast, the vertical board-marking of the T-shaped element above suggests resistance and tension, similar to the radially aligned stones of an arch, or the soldier course of a lintel. In this interpretation, the T-element is borne by a central column, which in turn transmits its forces right through the first floor (or bypasses it) to the central part of the base structure; into a support whose middle part is stabilized effectively by oblique lateral struts, connected as in a frame. Doubts soon arise, however: isn’t the shape of the upper cross-beam wrong for this purpose? Shouldn’t it at least have a straight bottom edge, so that the beam height would correspond to the distribution of bending moments under a load concentrated at each end? So is the cross-beam too straight, too flat, for the first floor to be suspended from it? Let’s reverse the situation, let’s assume that the cross-beam is resting on its ends: The ‘hangers’ become ‘horns’ growing up from the first floor, with the beam ‘stuck’ between them—an interpretation that is supported by the clearly drawn, inset joint at each end (see middle sketch, p. 87). In this situation, the horns support the roof beam and restrain it laterally, above all against any tilting of the central column, which now seems relatively wobbly (if seen as columns in compression, the lower part of the horns appears to have a greater cross-section than the central column). In this reversal of the first interpretation, the first floor structure becomes a girder, cantilevered in both directions and supporting the roof at three points. The basic structural concept for the Giunta would therefore have it consist of just three overlaid elements: base, first floor, roof. The expressive function of the ‘masonry’ surface of the first floor structure would also be transformed: instead of being structurally inactive, it would now really embody strength and resistance, much as the traditional rusticated plinth of facades lends buildings a kind of armorplating. Even this second interpretation raises doubts, however. Aren’t the forms of the first floor a bit too rounded for that? And doesn’t the haunch of the roof beam seem rather too big now? The contours of a reinforced concrete beam bearing on three points are well known: it is normally thickened less and for a shorter length. The designers, too, seem to have been dissatisfied with these contradictions, because they later transformed key parts of the facade. The final version of the Giunta’s structure is to be found in the construction drawings of 1960. Here, the aforementioned ambiguity of the end facade has been cleared up: almost floating above the rest is a roof beam cantilevered in both directions. The way in which the curving underside of the beam is squared off at its middle indicates the presence of a load-bearing rectangular beam running the length of the building, a kind of spine for the ribs of the roof. This central support is able neither to prevent the roof from twisting, nor to secure it against lateral displacement (assuming that the roof surface is not considered to be a structurally active plate, analogous to the first-floor slab of the Assessorati). Vertical and horizontal stabilization is instead provided by the single ‘horn’ growing out of the first floor (see bottom sketch, p. 87). Usually,

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under a symmetrically distributed roof load, the horn is not subjected to any forces, as is indicated by the symmetrical form of the roof beam, whose form now completely corresponds to the effective distribution of moments. The horn’s stabilizing effect comes into play only when the symmetrical equilibrium is disturbed. The stabilizers can be given a slender and seemingly elastic form, because the forces involved in performing this function are small. These small horizontal forces do nonetheless justify thickening the horn lower down at first floor level, because here the bending moments are greatest. The first floor is a rigid box, supporting itself independently of the roof. Its connection to the roof is, again, purely stabilizing and—as far as the size of the forces is concerned—secondary. The first floor facade is rusticated. The elliptical paraboloid of the pier, two bays in from the end, is also rusticated. The two components do not directly touch each other, but their similar surface treatment suggests that they are closely related. The curving surface of the paraboloid implies the presence of hidden structural components that—extrapolating the sweep of its contours, so to speak—connect the pier and the box to each other. So the box is somehow borne by the two piers of this kind along the central axis. What is the roof borne by? Two smooth round columns stand at the sides of each pier, pointing exactly at the center of gravity of the longitudinal spine that is concealed within the roof structure. The roof rests on these inclined columns, says the end facade. The lower load of the roof means that these columns can have a smaller diameter. Thus far, this explanation of the form of the individual parts is consistently logical. The exterior of the building does not give any sign of the existence of the two-story Spina Centrale, as this would weaken its visual effect. Under the rusticated zone on the end facade, there is a smooth, recessed surface. Viewed obliquely, this turns out to be a beam: a beam with a curving lower edge. Since we have just interpreted the outline of the roof beam as a clear indication of the stresses occurring in it, we must, if we are to be consistent, assume that this beam spans from end to end. The first-floor slab rests on this support, which is suspended from the box formed by the rusticated outer walls at first-floor level. This view is supported by the fact that the beam under the end facade is clearly separated from the longitudinal thickening under the floor slab. A look at the rear longitudinal facade of the Giunta confirms this interpretation: the rusticated surface spans the entire length by itself. The treatment of the two openings to the Sala Consiliare likewise shows that rustication is being used to indicate a structurally active element. Returning to Piazza Dante, we are able to see this visually striking structural composition as a whole: a self-supporting box, connected internally with the parabolic piers. This concealed connection is hinted at by the panel-like formation of the slab underside, which encompasses the two pier-and-column groups, but never extends to form a tight connection with the outer walls. The floor beams are hung from the box, spanning the entire width of the floor slab (the forces are transmitted from the slab through the beams to the exterior walls and from there to the paraboloid pier, describing a kind of vortex). On the side facing Piazza Dante,

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the stabilizers of the roof ride on the upper edge of the box. Being limited to what is necessary for their function, they stop just short of the lower edge of the box. This runs uninterruptedly along the entire 72 m-long facade, thus emphasizing once more that the box is a single, strong entity. Above it the roof structure soars from its longitudinal spine, which is supported by the two pairs of oblique columns as a kind of A-frame (see sketch, p. 88). That is one possible interpretation, but it is not the only one. After looking inside the building, we recognize the functional importance of the first-floor Vierendeel frames projecting at right-angles to the spine. The beams beneath the slab and the stabilizers projecting through the facade onto Piazza Dante are now revealed to us as the edges of load-bearing wall panels. The design detail at the lower edge of the box, where the stabilizers are chamfered so as to end flush with the beams, has already hinted at this connection from outside. The fact that the structural ‘truth’ could have been expressed much more simply, with an all-round projecting wall, shows that this was not what the designers were aiming for. Instead, what they lead us to see as the building’s structural behavior becomes superimposed on what we know of its real structural behavior. The interplay of these different perceptions creates a kind of polyphony, with fascinating overtones.

Palazzo della Regione in Trento, site photo: the Giunta in the foreground, with the Edificio Assessorati to its left

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Three different structural interpretations of the end facade of the Giunta

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Interpretation attempting to summarize the ‘represented stability’ of the Giunta

Translator’s note: We have decided to follow British rather than American usage when numbering the floor levels, as this matches European usage, including that of the plans shown in this book. Thus the ground floor equates to the US ‘first floor’, the first (upper) floor to the US ‘second floor’ and so on. In other chapters, where such references are infrequent, we have endeavored to use phrasing that is intuitively understandable in either context.

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New Structural Potential of Wood: the IBOIS Research Laboratory at EPF Lausanne Yves Weinand

The IBOIS  The predominance of steel and later reinforced concrete in practical applications and research within the fields of structural engineering and materials science over the last two centuries has created a huge gap of missing research on timber as an engineered structural material. The intuitive knowledge of carpenters and our professional predecessors has been lost since the eighteenth-century rise of the Ingénieur des Ponts et Chaussées (Engineer of Bridges and Roads), who does not take advantage of timber as a construction material, having a priori accorded it a lower level of importance than steel and concrete. My dual profile of architect and civil engineer allows me to focus on the interdisciplinary aspects of construction design in a synergistic way. Having conducted pioneering research work in both structural design and construction, my perspective on various phenomena differs significantly from that applied by most theoreticians or by practitioners specializing in only one of those specific areas. Uniquely positioned as an active practitioner, researcher, and teacher of both, my broad experience has established a balance in which the subjectivity and even aesthetic aspects required by architects is counterbalanced by a deep structural and technical understanding that reinforces rather than compromises these values. My research focuses on the technical, constructional, material, and structural aspects—which, with few exceptions since the time of Leonardo da Vinci, have been overly neglected or delegated away by architects driven by the search for aesthetic appeal. It takes account of myriad underlying links between art and science as well as the specific constraints of observed phenomena and their physical realization. Implications of the concept of scale are often simply ignored in the field of structural analysis for building construction. My approach perceives the mechanical requirements of form/structure as attributes that can only have full meaning and sense within the

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framework of the geometrically scaled phenomena upon which they depend. I see the rise of digital architectural representations as an invaluable tool, but as one that can only be exploited to strengthen the integration of structure, form, and material within our concept of design if the physical reality of every observed phenomenon is treated as a consideration of major importance, thus linking the production of form and space with that of structure. Research in Architecture and Structural Engineering  Architectural research, composition, production, and even construction processes remain closely linked to the personal design processes of the individual architect, while the architect’s freedom of expression as an artist is, by definition, respected as being inherent to the creative process. This epistemological framework makes research in architecture different and also difficult to accept for disciplines primarily rooted in the cultures of either technology or the social sciences. In general, research in architecture is not primarily intended to give importance to the applied technique. Truly interdisciplinary research approaches that link architecture with civil and structural engineering remain uncommon. Technical considerations are very often considered as comprising an almost neutral set of knowledge that does not, or should not, affect the initial creative design process of a given architect in a determinate manner. Technique, construction methods, and ultimately considerations of structural design and engineering are seen as almost unwelcome factors in certain cases. More often than not, these supposedly neutral technical considerations are tacked on at a later stage in the design process, compromising the truly interdisciplinary and fundamental quality to which such research approaches could aspire. Even certain very celebrated iconic buildings—such as the Guggenheim Museum in Bilbao by Frank O. Gehry, or the Olympic Stadium in Beijing by Herzog & de Meuron— illustrate how formalism has pushed back the structural approach to the status of a secondary issue. First and foremost, engineered structures must adequately serve as robust systems—beams, columns, and construction elements that are constituent parts of larger integral units—in order to achieve their bearing quality. Our society does not presently associate major works of civil and structural engineering with expressions like ‘textile’ or ‘timber’. For most people, ‘textile’ has a connotation of softness that seems incompatible with the general context of engineering structures. Although the term ‘textile’ has a large range of applications and interpretations, to date there have been no attempts to employ its qualities and production technologies at the scale of timber construction. Yet the strategy of devising textile-like (woven) timber surfaces can exploit wood’s fibrous, inherently flexible nature and turn this feature of the raw material, which has been perceived over the last two centuries as a limitation, into a structural advantage. The invention of structural timber fabric embodies both a vision of the future and an understanding of the past. It is inspired by the vision of building as an integrated planning process, where aspects of craft, technique, aesthetics, and structural engineering converge as they did just before

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the revolutionary “Age of Enlightenment”—but this time using contemporary engineering methods and tools. The raw material resource in question has innate qualities (such as smoothness) that can also provide the aesthetic and conceptual qualities sought by architects. The emerging tools of digital architecture, design software, and the way digital drawing tools are now seen as instruments for conceiving architecture have opened the way for broader applications of digital technology, including those of a technical nature. Technical advances that now lie within reach render feasible the integration of textile principles, textile technologies, and fabrication systems in ways that were unthinkable only a few years ago. The environmental arguments in favor of increasing the possible uses of (renewable) timber resources are undeniable. Society’s burgeoning awareness of the urgent need to identify building materials that are sustainable has become an important influence in timber construction’s renewed economic importance in recent years. Environmental considerations are helping to restore or establish the legitimate use of timber in the built fabric of our cities on a scale unprecedented for many centuries. We are only now discovering that techniques ranging from friction-welding to knitting, weaving, and even origami can be applied to timber at the building scale. My own group’s work is already demonstrating that the application of such techniques can radically expand timber’s range of technical and aesthetic attributes. Such techniques allow us to invent timber products fit for novel purposes because society is both culturally and economically ready to accept timber as a construction material that is no longer marginalized. We foresee significant advantages to the application of such techniques because they should facilitate the creation of largescale, free-form structures from small repeating units—and this opens the way to expanded use of both timber off-cuts and post-consumer recycled wood products as high-quality construction materials. The gradual replacement of timber by steel and concrete over the last two hundred years has not helped to improve new and contemporary applications of timber construction from an architectural and engineering point of view. Only when examined at a closer perspective than the one traditionally associated with its present day uses in construction does timber reveal its surprisingly close connection to textiles and its vast potential for the application of textile techniques: timber can be classified as both a soft and a viscous material with smooth properties. It is subject to ‘creep,’ almost like a liquid material. All timber is basically composed of multitudinous cellulose fibers. These smooth fibers are flexible, allowing curvature. Such properties suggest that woven, flexible timber structures of a building scale should offer exceptional performance in resisting seismic instability as well as extreme wind or snow loads. To date, the potential that building-scale woven structures have for significantly reducing the risk of structural collapse in the face of such challenges has not been systematically explored. On a wider level, the investigations made by the IBOIS laboratory will contribute to a more profound understanding of spatial structures in general and set new prec-

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The development of woven structures is a field of research at IBOIS. Beginning with existing principles of weaving, a jump in scale is made to implement these same principles at the scale of buildings or load-bearing structures. For this purpose, the specification of global geometric patterns is necessary. Markus Hudert depicts such possible geometries using drawings The process of joining the textile module as depicted here creates a mechanically complex condition. The module possesses internal stresses that result from the juncture and are relieved in part by themselves (relaxation). The structural system reacts to the application of external loads through deformation, thereby functioning as an interactive system inasmuch as it adjusts its inherent stiffness in real time. The raw material, wood, appears particularly well-suited due to its deformability (we work with large deformations)

edents for cooperative interaction between the architects and engineers analyzing those structures. Case Study 1: Textile Module Applications  The empirical models shown here have been developed by Markus Hudert at IBOIS. In this case, the initial drawings have given birth to an exciting structural module. Even though this first approach controls geometrical aspects, it revealed astonishing structural aspects in addition to its formal qualities. This structure gains static height when it is loaded. Thus it is a self-reacting structure and the very essential question becomes: Since we have observed that this specific structure gains static height when it is deformed under experimental conditions of increasing loads, can we assume that in the case of extreme loads—such as storms and earthquakes—it might also sufficiently adapt its disposition and strength to resist such extreme loads? In particular, research needs to be undertaken on initial stress analysis of large deformations and non-linear behavior. Case Study 2: Experimental Vault with Overlap  Based on those geometries, a vault structure made of planar elements was defined digitally. This vault, initially composed of a wide range of elements of different sizes, was then redesigned in such a way that it now uses only two different overlapping basic elements. This work appears promising since it opens the way to approaching the following more detailed questions: How should the overlapping connections be built at a large scale? A deeper underlying question regarding this woven structure is: Since the global model depends directly on the local behavior and mechanical model of that connection, how should this structure be dimensioned? Ultimately it is the interaction between the global and the local that will lead (or not) to issues of feasibility for such large-scale structures and their potential application. It has also become clear that the relationship between the global and the local can only be successfully controlled through the design of the connection details. Thus the col-

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The textile module in this form was also developed by Markus Hudert, and poses a two-pronged question: What mechanical traits does this module have and what sculptural and space-defining qualities can it yield? The combination results in a fundamentally innovative, complex, and promising approach that can be studied from the viewpoints of both structural engineering and architecture

Repetition of the basic module creates arched or domed structures of a new character. From a mechanical viewpoint, what develop are hybrid structures that remain partly subjected to internal stresses. The study of these structures with regard to large deformations and non-linear systems is currently being pursued at the IBOIS laboratory

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The two elements along the weave’s primary axis are made from timber sheets of different lengths. The continuity of these sheets can be ensured in assembled systems. We are especially interested in the geometric condition at the points of overlap. At these junctures, there is also an opportunity to establish a third structural axis, which helps connect the panels to one another and also helps to achieve spatial rigidity

The proportions of the panels play a significant role in developing the textile module. A slender form is tested here in EPFL’s test facility. Numerical findings and test results are compared

The contact points and constraints of the structure need to be captured geometrically and mechanically. Differing support and connection conditions are designed and built for the individual prototypes. The construction details directly determine the internal stress condition, but also the manner in which the woven object can be extended

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laboration between architects and engineers discussed here also becomes crucial, as they must interact in defining the connection details. Case Study 3: Building Fabric Lookout Tower  Steve Cherpillod has developed a tower made of a singular and highly specific timber module. His control of the general geometry and the global form of that tower enabled him to ‘reduce’ this complexity and define that basic module. Again, his initial input is a geometrical understanding of the interaction between stairs and towers, which is a very old and seductive theme. Having understood the spatial and functional requirements of a stair and successfully relating them to the structural requirements of a tower, the synthesis of those two main aspects of design that is shown here is achieved by controlling that basic module. Further structural analysis showed that this module will be the subject of intense discussions regarding its stability and further development of the tower as a whole. Conclusion  This research is not subjected to the constraints of immediate practical applications. The IBOIS laboratory takes time and energy to explore unknown paths that do not directly confront the needs of application or efficiency, as do the engineering sciences. We do not expose our research to the real constraints or demands that a building must respond to. The research work shown here should be understood as potentially applicable for architecture and structural engineering.

The principle of weaving was applied to an arched bridge with a span of 85 m. Four arched sections made of laminated wood overlap and thus mutually support each other. The buckling length of each individual arch is thereby greatly reduced. This unusual geometric disposition defines a space on the bridge

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Taking into account the consequential high deformations, Masoud Sistaninia models the geometry with the aid of the finite element analysis program Abaqus. Since the deformed state differs geometrically to a significant degree from the non-deformed state, a fundamental condition of structural analysis is no longer respected

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Drawings—such as elevations, sections, and axonometric views—as well as digital and physical models are important in the development of the geometries

Model view of a parametric arched structure consisting of many facets. The insertion angle between one facet and the next can be adjusted as desired. This angle governs the global geometry, but also the way the local joint is formed. Bastien Thorel developed this structure as part of an exercise in the Weinand studio

Another version constructed as a cardboard model. The design process is guided iteratively

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Tetto gigantesco – a Diverse Huge Roof Foils of a Research Aita Flury and Jürg Conzett

The following exchange of e-mails took place in the course of writing an article for a research project on “The Pitched Roof” at the ZHAW [Zurich University of Applied Sciences] in Winterthur. 1

From: Aita Flury [mailto:[email protected]] Sent: Wednesday, 8 August 2007 12:15 To: Conzett Bronzini Gartmann AG; Jürg Conzett [mailto: j.conzett @ cbg-ing.ch] Subject: “gusci” [shells] etc. Dear Jürg, In the attachment, I am sending you the text that the engineer Giuseppe Raineri wrote on the load-bearing structure and the construction of the riding school building for the Società Ippica Torinese (S.I.T.) in Nichelino, Turin, in 1958. As I said, I am examining the building in connection with a research project on “The Pitched Roof” at the ZHAW [Centre of Structural Design] in Winterthur. My translation has the air of a Latin exercise; I ask you to ignore the ‘poetic, syntactic’ aspects and rather to examine the text in respect of its statements and meaning. The architectural show-stealer is the gigantic, interconnecting canopy that unites everything under one roof—I find Raineri’s text very cryptic, however, and I think that is not just due to my translation .... Can you help me to understand what the main aims for the load-bearing structure and the construction could have been here? Much obliged! Aita

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The final text by Aita Flury: “Tetto gigantesco–andersgroßes Dach. Der neue Sitz der Società Ippica Torinese (S.I.T.) in Nichelino/Turin, 1958/59 von Gabetti & Isola, Architetti, und Giuseppe Raineri, Ingegnere” [Tetto gigantesco–gigantic roof. The new headquarters of the Società Ippica Torinese (S.I.T.) in Nichelino/ Turin, 1958/59 by Gabetti & Isola, Architetti, and Giuseppe Raineri, Ingegnere] is published in: Barbara Burren, Martin Tschanz, Christa Vogt (eds.)/ZHAW Zentrum Konstruktives Entwerfen, Das schräge Dach. Ein Architekturhandbuch [The pitched roof. Architectural manual], Sulgen, 2008

German translation (by Aita Flury with corrections by Jürg Conzett) of the Italian text by engineer Giuseppe Raineri on the structure of the new headquarters of the Società Ippica Torinese (S.I.T.) in Nichelino/Turin, 1958

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On 09.08.2007 at 22:22 Jürg Conzett wrote: Dear Aita, the text is already rather ‘free’ in the original—should it be translated including blur or not? I advise you to free yourself to a large extent from the original, because in this case, precision is not very much use, to summarize the whole thing if need be and possibly even to omit parts that are difficult to understand. In principle, he is saying: the folded plate using the Hourdis system with screed on top is not much heavier than a pure (continuously curved) concrete shell, but it is stiffer, so it functions just as well in spite of the angular shapes. In comparison with the shell, the folded structure of plates is easier to manufacture and can possibly be supplemented by prestressed reinforcement or cables running in its ribs, so it can be dimensioned economically for the minimum necessary strength and still not deform much. I hope this was more understandable ... Good night Jürg From: Aita Flury [mailto: [email protected]] Sent: Friday, 10 August 2007 15:49 To: Conzett Bronzini Gartmann AG; Jürg Conzett [mailto: j.conzett @ cbg-ing.ch] Subject: Re: Re: “gusci” etc. Dear Jürg, thank you very much—I do appreciate it and imagine that it was time consuming! I see that I suffered a few avoidable ‘lapsi’ in translating the text (I hope my maestro d’Italiano will forgive me ...), which certainly contributed to a lack of clarity—but for the greater part of your structural interpretation and translation, I am eternally grateful. It would have been impossible for me to summarize exactly what this is about. The following questions remain open for me: Dear Aita, I will simply write directly in your text: 1. Page 1, 2nd paragraph, last sentence: Does this really refer to the building industry in general and not to the actual building by G&I? [Gabetti & Isola] Or does it mean that conventional construction methods are designed for short spans, but then where would the connection to the preceding sentence be? “The structures used by the building industry in general (the usual structures, the conventional structures) were, however, used for those parts of the building that have short spans.” That way, it seems logical, as a contrast to the newly conceived large-scale forms. That’s the really interesting thing about this building: that the unconventional large-scale form is constructed of a plate structure using ‘normal’ building systems such as Hourdis slabs—and that is

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inexpensive, which makes sense to me. 2. Page 2, 2nd line: “The truss is constructed in the simplest way, by making the lower nodes of the truss (or rather: the bottom chord nodes) of perforated metallic cylinders, in which (through which) the iron rods of the bottom chord and the diagonals run (are pushed).” What does that mean? 3. On the folded plate: it is not clear to me how this system of ribs between the Hourdis slabs works. Is it a kind of frame structure, which is polygonally inclined? Yes! Where do these ribs occur and where not? They result naturally, so to speak, from the changes of geometry. In the places where the plates butt against each other, there is simply more concrete = a ‘rib.’ In one crosssection (the one that is garnished with details), these chords appear as black patches. 4. On the relationship between columns and their different axial dimensions (approx. 6.75 m lengthways and 4.75 m crossways). Is it only the supports that have a load-bearing function, or the walls too (I think that the outer walls are not loadbearing, but probably the inner walls at the two ends are, right?). The difference in axial dimensions must have come about somehow on geometrical grounds and this is only structurally relevant in so far as the force per support will be correspondingly less at shorter intervals. I reckon that here, this decision was not taken for structural reasons. It is not evident whether the walls are load-bearing or not. Looking at the detail section with the reinforcement, I get the feeling that they are not—so logically they should be masonry—do you recognize that anywhere? The hypothesis of non-load-bearing walls is also backed up by the horizontal beams along the end wall, halfway up— otherwise, why would they be needed? (The architect isn’t Adalberto Libera, after all ...). 5. Also: Why are there only two such ‘tie frameworks’? And above all, how could they have been avoided? That is the big question. I think, a prima vista, they would have been avoidable if the central part of the roof had been treated as a ‘polygonal barrel vault’ and its horizontal thrust taken up by the roofs at the side of the hall. But then it would have been necessary for the end walls to absorb the entire horizontal thrust, because the roofs are not supported by buttresses bearing on the subsoil—the two roof surfaces would have had to be ‘tied together’ around the outside of the hall. The tying together is done here in a more direct way and is certainly a pragmatic solution. But not the only one of all the possibilities. Does the division of the groin into a triangle of elements make sense to you (from a structural point of view), or is it purely formal in your opinion? Both. Basically, each new edge makes a folded plate stiffer, but on the other hand it adds a complication. What does

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eliminating the “angular edge disturbances” mean? That is slang. In the first approximation, we assume the slices to be infinitely thin, i.e. without plate bending moments (moments arising from loads perpendicular to the plane of the plate, which deform the element out of that plane). At discontinuities in shells or at edges in folded plates, bending moments occur locally (a graphic way of understanding it would be to picture the plates as being connected with hinges, but since this is not the case, bending moments occur instead—close to the edges, especially) and these bending moments are called ‘edge disturbances.’ So omit ‘angular’ before edges. The claim that the smusso [chamfer] reduces the edge disturbance may well be justified (the proof would take some time ...), I just don’t know exactly. The determination of the edge disturbance is a task for a mathematical virtuoso, which I don’t think can ever really be checked properly. 6. The external struts, which are intended to counteract a possible push-out—could this point have been solved any differently? I wonder, namely, whether this actually has an architectural intent. Could they be interpreted as a ‘gothic’ element? Yes. For the rest, see above. It is an idiosyncratic combination of struts that do not continue down to the ground (but which are stabilized by the lower roof areas and their ties along the adjacent edge (it is plausible that they are tied together, as you can see on the large reinforcement plan, where the 6 d=14 rebars restrain the roof areas diagonally)) and a more conventional truss system. This means that with regard to the statics, the main columns might just as well have continued up vertically in one scenario, or else the whole thing could have functioned purely as a folded plate without trusses, although then the reinforcement would have had to be considerably thicker and would have caused problems by occupying too much space. Shall we take the truss as being a compromise? On the other hand, it brings a certain fragile touch to the whole interior, it hints, so to speak, at the problem of horizontal thrust. As I basically find layered systems exciting, I’m beginning to like the interior now, just as it is. What I could imagine in terms of space is that they wanted to exaggerate the ‘groins’ further, to emphasize them, and have made use of these struts to do so. 7. What are “single-axis curved glide planes”? Kimbell Art Museum: take a cycloidal curve and shift it out of its plane, this creates the shell as a glide plane. If the shift is linear, the shell is curved along a single axis, i.e. you can unroll it. 8. What’s the deal with this perimeter beam, what’s the problem with its bending lines, Any perimeter beams must logically deform the same as the shells adjoining them. This, again, causes an ‘edge disturbance,’ as the case may be. In the ‘pregnant oyster’ [Congress Hall] by [Hugh A.] Stubbins, in Berlin,

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these edge disturbances caused cracking, which led to corrosion and ultimately to the collapse of the shell. Perimeter beams can be prestressed to deform them so that they ‘fit’ better and thus reduce the extent of edge disturbances. It’s all a matter for specialists! where they are located in the S.I.T., on the outermost row of supports? Yes, for instance. In principle, each ‘rib’ in the roof structure is also a perimeter beam. The text is virtually propaganda here and claims wonderful things that it would be nice to see quantified in diagrams and so on. Without that, a clear relationship to the S.I.T. building itself cannot be established. What is the “limitation of the projecting members” when they no, the perimeter beams must have the same deflection curve? It means, in plain language, that not everything goes. I suppose that then has an influence on the spans? Of course. 9. How is an “area-producing radius” defined? Cannot every radius produce surfaces, some steeper, some more level? Yes, but the larger the radius (the flatter the arc), the higher the tensions, and the greater the danger of bending or buckling. Here, the Hourdis slab system with its hidden ribs and correspondingly greater stiffness would actually be cheaper. Otherwise normal ribs, or a scalloped profile in the case of a shell (UNESCO Paris by [Nicolas] Esquillan), would be needed to overcome the bending forces. The variability of the radius would not have to be specially mentioned. 10. Could it be said that this is a very hybrid design? Not incredibly ‘hybrid,’ but a little bit, certainly. What does that mean anyway? It roughly amounts to compensating for the edge disturbance .... I would formulate the really interesting feature in this way: it is 1. A combination of a folded plate with two trusses; 2. The construction of the flat sections as Hourdis slabs. They seem to want to make so much allowance for the building process and the “lack of intelligence” of the construction workers, but as an overall package the structure seems to be very delicate and dependent on being constructed with precision, doesn’t it? To me, the Hourdis slabs seem to be easily built. And as for the interplay of forces, you can at least ‘fiddle around’ with trusses. The structure is adjustable, which does make sense. 11. How would you assess the relationship between the design intention and the structural and technical input? A fairly high standard of coordination. 12. I am not planning to reproduce the text—at most, some excerpts—what’s important to me above all is to get an idea of how much the design as a whole was revolutionary for the time, or innovative, or simply clever. In that respect, I would of course like to hear your opinion. I assume that your earlier summary of the structural idea still basically stands as you formulated it, even after my round of questions? Yes. What does a line of reasoning like this one neglect at best? The unknown

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problems that might have occurred over time (cracks? deformations?). How does the whole thing fit in to the ‘gusci story,’ perhaps in comparison to a Nervi? The structure is unique in this form, as far as I know. New and ingenious at the same time, in its “formation of a space truss with simple means.” A government official in Trento said, at the time, that Nervi and his Italian colleagues were world leaders in theoretical work as engineers, yet worked with comparatively simple construction processes. The text, as I have said, simply lacks the specific illustration of its static and structural assertions, which gives rise to a degree of suspicion. The point of the fundamental considerations quickly becomes clear. The parts about edge disturbances and glide planes, in contrast, are rather hard to pin down. I would translate those in quotes at most, along the lines of “... the authors claim.” 13. You write that a folded plate structure consisting of Hourdis slabs and concrete, despite its angular form, works just as well as a shell—should I then conclude that the architect first had the ‘polished’ image in mind, and only then did Raineri consider what the best way to construct an angular folded plate would be? No, in terms of statics alone, the ideal shape with a minimum of material is the continuously curved surface (Musmeci). Expensive to build, in practice. The ‘message’ of the S.I.T. building: a polygonal shape needs little more material than a shell does, if it is ribbed. The ribbing is very easy to accomplish with the Hourdis system (given cheap Hourdis-layers in Italy—so the economies made at S.I.T. were somewhat dependent on the circumstances). I imagine the design process as similar to that of the Volta school; at some point, engineer Raineri will have said: assemble the roof from flat elements! Or else Raineri developed the internal geometry of the central section fairly independently and G&I looked over his shoulder in fascination ... It could well have been an engineering response to a spatial composition. Spatially, it is also interesting that the interior geometry and the articulation of the building don’t match up externally. Moreover, the most striking thing for me is the vault-like feel of the arena: the difference in inclination from one plane to the next is so slight that the spatial impression really is just like a shell. The nice thing about that is that the space is thus bounded on all sides. The combined system and the “smussi” allow quite a lot of freedom, I would say, so G&I might perhaps have fiddled around with them for quite a long time. OK!–I won’t ask any more now, otherwise it will get too much for you at some point ... Actually I did not mean to write this much, but it is indeed a most exciting ‘piece of work’—and I am rather dismayed that I hadn’t heard of something like this before—so by all means get in touch again if you discover more things like this (in the postcards, too, by the way—thank you again!). I do believe, however, that this construction can be described in terms of very basic principles and that this would really suffice (for lack of

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exact performance data). Perhaps this observation will help you to relax over the weekend. Per il momento– ti ringrazio tanto! Aita Warmest regards Jürg

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All plans and images on these pages: the headquarters of the Società Ippica Torinese (S.I.T.) in Nichelino, Turin, 1958/1959 Architect Gabetti & Isola Architetti, Turin Engineer Giuseppe Raineri, Turin

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Apartment building, Forsterstrasse, Zurich 2003 Architect  Christian Kerez, Zurich Engineer  Dr. Schwartz Consulting, Zug Model  Dr. Schwartz Consulting

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Boots factory, Beeston/Nottingham 1932 Engineer and architect Sir Owen William, London Model HTW Chur, 2009 Students: Michael Krähenmann, Lukas Mürner

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Elbphilharmonie concert hall, Hamburg, under construction Architect Herzog & de Meuron, Basel Engineer WGG Schnetzer Puskas Ingenieure, Basel Model WGG Schnetzer Puskas

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Graubünden Cantonal Bank, Chur 2006 Architect Jüngling & Hagmann Architekten, Chur Engineeer Hans Rigendinger, Chur Model Jüngling & Hagmann Architekten

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Detail of the corner of the Hardturm Stadium, Zurich, Project Architect Meili Peter Architekten, Zurich Eingineer Conzett Bronzini Gartmann, Chur Model Conzett Bronzini Gartmann

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Residential and office building Ottoplatz, Chur 1999 Architect Jüngling & Hagmann Architekten, Chur Engineer Conzett Bronzini Gartmann, Chur Model HTW Chur, 2009 Studenten: Valentin Alig, Davide Fogliada

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Georges Pompidou Center, Paris 1976 Architect Renzo Piano, Richard Rogers Engineer Peter Rice Model HTW Chur, 2009 Student: Beni Signer

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Sports hall Mülimatt, Brugg 2010 Architect Livio and Eloisa Vacchini, Locarno Engineer Fürst Laffranchi Ingenieure, Wolfswil Model Studio Vacchini

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Practice The architect Markus Peter argues that the specialization of thought should not be condemned out of hand—as a logical consequence, he has himself adopted the engineering mindset, as the linguistic coloration of his essay shows beautifully. Andreas Hagmann demonstrates how, even on smaller construction projects, the architectural concept can provide opportunity enough for ingenious exploration in the fields of structure and construction. Mike Schlaich considers every design to be a prototype that requires the engineer to work as a generalist, acting competently and responsibly with regard to the whole, across the entire range of buildings and materials. Jürg Conzett, Roger Boltshauser and Aita Flury discuss a small project to illustrate a process of rapprochement, in which the interplay of load transfer and intended perception is negotiated. Stefan Polónyi, with his typical generosity toward the artistic form, gives an insight into the practice of bridge building and presents us some surprising formal gestures. Renato Salvi, talking of his work on the A16 Transjurane, reports on the spatial problems associated with integrating a highway and its constituent elements into a hilly landscape. In three interviews, Adolf Krischanitz and Heinrich Schnetzer/Aurelio Muttoni/Joseph Schwartz, along with Carlo Galmarini/Urs B. Roth/Martin and Elisabeth Boesch give their opinions on the topic of cooperation.

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Deviations Markus Peter

The dialogue between structural engineers and architects is based in no small part on mutually ascribed behavior and perception of roles. But it is not so much the dichotomy between aesthetics and engineered structures, as it was expressed in the debates at the end of the nineteenth century, nor the expulsion of engineers by the adherents of Neotectonic architecture, that is currently a cause for concern. Rather, concern lies increasingly in the knowledge that the pursuit of one’s own interests within the two disciplines does not necessarily coincide, and that an innovation in one medium does not inevitably and simultaneously reveal something in the other. The resulting call for dialogue, for a common education, criticizes the high degree of specialization. Indeed, it condemns the monological dimension of the engineering sciences. Yet since even the specialization of scientific thought necessarily builds upon a solid general academic education, which is contingent precisely upon specialization, it is surprising that scientific specialization is so readily, so persistently, condemned as a corruption of thought. Such judgments, whether they are expressed by a great thinker, like Goethe, or by lesser mortals, must at the very least astound us with their inefficacy. Science, to paraphrase Gaston Bachelard, goes its way unchallenged.1 1. In the works of the 1990s, our design strategy focused on establishing a relationship between structure and space. Grid, repetition, and order were less the goal than was the search for conveying tension from the load-bearing structure to the enveloping and pervasive space itself. Thus in Murau (Austria), for example, we treated the wood structure as a monolithic element—almost like a self-supporting car body—whose upper and lower chord bracing carry the roof and floor of the bridge. In close proximity to the structural design, the actual space of the bridge was created by manipulating the structural elements of the horizontal and vertical slabs. The structure is not located, as Hermann Czech describes it, 2 under or next to the circulation space that guides the user over the river, but actually in this space. The structural principle of the single-span Vierendeel truss, a structural frame without diagonals, enables both the horizontal opening in the middle as well as the staggered disposition of the planes at the sides. The truss itself is assembled from two vertical, plate-like box beams—the ‘shear walls’ made of three-ply plywood—and solid upper and lower chords made of laminated wood that are subsumed only by the overall form, such that the bridge constitutes a sculpturally formed, homogeneous and space-defining element of wood. This simple and experimental architectural scheme, however, can only be properly conceived in the

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1

Gaston Bachelard, Epistemologie [Epistemology], Frankfurt am Main, 1993, p. 162

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Hermann Czech, “Ungefähre Hauptrichtung,” in: Marcel Meili/Markus Peter 1987–2008, Zurich: Scheidegger & Spiess, 2009 p. 435

Mursteg footbridge, Murau, 1993–95 Architect Meili Peter Architekten, Zurich Engineer Branger, Conzett & Partner, Chur

technical sense provided that it is in itself the product of a simplification process. In contrast to the Cartesian illusion of initially clear and distinctive ideas, the simple is necessarily the product of a purification process in the face of structural ambiguities. Only the simple and efficient connections made with ductile steel dowels and threaded rods, which transmit enormous shear forces between the chords and shear walls, permitted the conceptual supposition of a largely homogeneous transmission of force. Due to the rabbets along the chords, this simple connection technology resulted in a large bearing surface over the abutments, which proved helpful in stabilizing the single-span frame against overturning. On the other hand, the structural decision to use a single central girder required torsion-resistant chords, which inevitably turned out to be bulky. The beefy dimensions of the chords thus resulted from the shape of the bridge cross-section; of course it was now also capable, without additional measures, of absorbing considerable bending stresses in the longitudinal direction, enabling the central opening of the gigantic window. The staggered shear walls at the sides, due to their diagonal positioning, delimit the space together with the horizontal surfaces of the floor and ceiling slabs, and they evoke minimalist spatial experiments of the early Modern era. The experiments of that time, which took place predominantly in new areas of application and adapted material technologies, avoided using rodlike steel, which in no way defines space. The roofs over the platforms of Zurich’s main train station are constructed in this spirit: the delicate steel construction of the roof trusses is concealed from below by wooden latticework. Alone architecture and technology themselves are capable of drawing their own boundaries. For the field of engineering sciences, however, drawing a boundary already means crossing it. The scientific boundary is not so much a barrier as it is an area of particularly active thoughts, a zone of assimilation. 2. Our interest in the power of large forms and the inescapable ruthlessness of the programs changed our designs and shifted the experiments to areas of heterogeneous and also partly hybrid structural forms. The fact that the geometry of football stadiums is determined to a large extent by the logics of grandstand ge-

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ometry and roof structure effects the orderliness established by the multifunctional conglomerates, which is something characteristic of nearly all the new stadium projects in Switzerland. The dimension of the large-scale form, which emerged from the urban topography, no longer follows standard radial principles of ordinary stadium designs. The intended nakedness of the grandstand element is admittedly reminiscent of large stadiums in which the formal gesture presents itself as a direct indication of its contents, but its origin is a very different one. The form, with its enormous cantilevers, approaches that of an ideal pentagon. The bridge-like cantilevered beams of this grandstand are placed next to and within a conventional slab and column structure. They in fact come into contact with each other, even penetrate one another and transmit forces to one another, but remain autonomous in their composition and computational modeling. The actual structure of the Zurich stadium’s crown consists of individual beamcolumns, laid out in a rectilinear plan, that stand like balance beams on the crown’s piers, yet due to the differing lengths of their cantilevers, cannot be brought into balance on their own. Overturning of the truss elements is prevented by the loads of the adjoining ones, which push down on the short lever arms and thus establish a state of equilibrium. The crown rests secondarily on the inclined columns that constitute elements of the grandstand trusses. Due to their inclination, even though the bending moments of the vertical plane are greatly reduced, bending occurs in the horizontal plane of the crown. The hollow box construction, which permits the incorporation of a number of functions such as loges and sky boxes, can accommodate this flexure considerably more easily than it could cope with the solely vertical bending that would have occurred if the inclined columns had been omitted. The enormous torsional stiffness of this traversable box profile enables

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Zurich stadium, unbuilt project, 2000–2009 Architect Meili Peter Architekten, Zurich Engineer Conzett Bronzini Gartmann, Chur/Basler & Hofmann AG, Basel

3

What is meant is the computational effort for the hybrid structure, which was influenced by highly diverse forces and hence also by varied techniques for analyzing forces. This necessitated a huge effort in conducting CAD modeling. The consequences of even a very small change, such as the widening of a stair into a pier, were not foreseeable even by the engineers and involved week-long computerized calculations. Apart from that effort, the internal stability of the modeling system itself is also affected— it always had a somewhat precarious status, as opposed to a simple, or at least simpler, computer model of a Vierendeel truss.

supplemental restraint of the steel roof trusses, which counteract the moments that emerge due to the oblique columns and the corner bearing points. The immensely elaborate computational modeling for dimensioning this hybrid structure demanded maximum discipline with regard to changes and suppression of one’s own ‘original’ contributions: we were confronted with an engineering-oriented way of thinking that would not have easily found the stability and coherence of a secure existence.3 3. The design for a panorama restaurant on a site of spectacular beauty required an even more profound alteration of the epistemological field of engineering science. Far beyond the technological, such a mechanical complex is a significant step in the alteration of the mountains: it replaces the idea of the mountain lodge, which seeks to merge with the landscape, with a panorama-perception machine. We were fascinated by the sublime Villa Girasole by Angelo Invernizzi, in which the rotating, angular building cinematically orchestrates the view of the Veronese landscape and the guise of the building itself is animated within the landscape. Because the restaurant is supported off-center, the rotational movement projects the figure into the surrounding countryside to varying extremes. In the opposite direction, seen from the landscape, the mountain guesthouse is perceived as a mechanical sculpture that continually changes shape. Perhaps this project demonstrates one of the strengths of the much-criticized deductive theoretical construction in the engineering sciences—that all those technological objects whose physical behavior is primarily determined by the laws of

Revolving restaurant on the Hoher Kasten, Appenzell, 2004–2005 Architect Meili Peter Architekten, Zurich Engineer Conzett Bronzini Gartmann, Chur

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mechanics are fundamentally controllable with the system of theoretical mechanics that unfolded in the eighteenth century. The actual rotary mechanism was to be positioned inside, on top of the cylindrical tower housing the vertical circulation. It was imperative that the design of the structure assumed a stabilizing effect on the acting forces in order to impart a uniform capability for propulsion. In addition to the unequally distributed wind loads, live loads, and snow loads, the asymmetry—vis-à-vis the rotational axis—of the uppermost restaurant level also needed to be accommodated in establishing the equilibrium. For this reason, the rotating bearing seat has the largest possible diameter and is located as high as possible. Conversely, the center of gravity for the rotating mass needed to be situated as low as possible. Only after a prolonged study of variants did a solution appear for guaranteeing stabilization of the movable part by using the structure’s dead load, thus sparing costly efforts to safeguard the movable bearing against suction forces from wind. The boldly cantilevered roof, from which the restaurant floor is suspended, is supported by a host of radial, oblique wooden struts, which are held together at the periphery with a kind of tension ring. The roof itself is a thin, pretensioned concrete slab that absorbs the tensile forces as a membrane. The actual rotary mechanism is located on top of the concrete cylinder and as a result, only needed lateral guidance from rollers to maintain proper clearance at the sides. After initial attempts at constructing the rotating framework in the old tradition of the mechanics of railroad cars and other moving machinery like hoisting devices made from steel, a solution of different components assembled from various materials proved to be more efficient. To this end, the preconceived notion of fashioning the structure from a single material and, above all, of using lightweight construction, had to be overcome. In this case it turned out that, as Georges Canguilhem unremittingly emphasized, problems do not necessarily emerge on the terrain where they find their solution.

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Structure and Space Andreas Hagmann

An initial approach to the subject can be aptly made by examining a column in the living quarters of the apartments built in 1936 by the architects Alfred Roth, Emil Roth, and Marcel Breuer in Doldertal (Zurich). In the living room, a solitary column located directly next to a thick wall defining the space is a source of irritation. In a building of solid masonry or concrete construction—which is doubtless how the building initially appears—the forces could easily be carried by this wall. Yet the column does not seem superfluous. It provides spatial articulation and, together with the massive wall and the bay-like projecting glass front, generates tension in the room and gives it support. Horizontally, the column together with the lobby establishes a spatially tangible axis extending lengthwise through the entire building; vertically, it also makes the transition to the exposed pilotis at the ground level. When you finally discover that the structure of the apartment building is constructed as a steel frame, a relevance that is not only spatial, but also structural, is revealed. The example confirms, on the one hand, the notion of the building as an ‘artistically’ assembled organism of material, construction engineering, and spacedefining structure. But at the same time, it also demonstrates that the “constructors’ dialogue” pays off not only with long-span structures. The dialogue between the disciplines can certainly be profitable in a more humble context—for smaller building tasks or even individual construction elements, like a facade. Mutual Interest as a Prerequisite  We gained our first experience with close conceptual collaboration in 1990 together with the engineer Jürg Conzett: for the new building at the University of Applied Sciences HTW Chur, a multifunctional, flexibly subdividable auditorium (approx. 900 m2) was traversed with a one story high, prestressed and space-defining girder grid. In the process, it quickly became Doldertal Apartments in Zurich, living area The Doldertal Apartments are comprehensively documented in: Arthur Rüegg, Ein Hauptwerk des Neuen Bauens in Zürich: Die Doldertalhäuser 1932–1936 [A major work of New Building in Zurich], catalog gta, 1996

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University of Applied Sciences HTW, Chur 1993 A story-high girder grid spans over the freely subdividable auditorium Architect Jüngling & mann Architekten, Chur Engineer Conzett Bronzini Gartmann, Chur

evident that a “dialogue” is fruitful if there is mutual interest in each wanting to understand the project’s spatial and technical requirements from the other side. For example, on this project we learned to understand that with long-span structures, structural deformations can arise that can impact progress on the construction site and have severe consequences for the interior finish work. In a sustained group effort, we came to realize that the work of engineering is not only informed by socalled functional aspects, but can also be a central design factor in the formation of space. In such a strategy, the structural concept combines with the architectural notions into a homogeneous entity. Simultaneously, however, the architectural concept allows the characteristics of the structure to have their freedom and respects the engineer’s inherent boundaries and fields of research. Reference Systems for Engineers, too  Another example that originated from such an attitude is the school complex in Mastrils, which is anchored along the slope of a steep mountainside as a cascading building form. With terraced buildings, floor slabs naturally merge into roofs, and it seemed logical to construct these of the same material and to be able to simultaneously use them as a principle of articulation and connection across the entire complex. The roofs of each story are therefore made of shallowly inclined concrete panels. The gym’s asymmetric gabled roof results from the common ridge of the building form, but also from the logic of the interior spatial development: the asymmetry made it practically impossible to use a conventional structure with tie rods at the bottom, and several unsuccessful attempts showed that their placement in the form of beams would have also led to a disruption of the interior spatial development of the entire complex. Gradually, the concept of a prestressed folded structure was developed, which,

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despite the shallow slope, led to an astonishingly efficient and low-cost structure. Each half of the roof has guided, parabolic tensioning cables that, during the prestressing process, produce deflection forces which are directed diagonally upward. These forces prevent the roof slabs from shifting in their plane and thereby support the ridge. Consequently, the entire structure can be set as an independent rigid body upon conventional brick masonry walls. Interestingly, Jürg Conzett sees the starting point for such a structure in a historical analogy, namely in a Grubenmann church from the eighteenth century. Not only architects, it seems, but also engineers can be influenced by a historical background and its chain of associations! Whereas the sequence of spaces inside are developed as exposed brickwork, it seemed logical to construct the outer shell in concrete because of the complicated junctures at the base and the adjacent terrain of the mountainside. For this purpose, a tactually ‘softer’ surface appearance was sought from porous tamped concrete. Since this concrete—slightly water-permeable—could not be reinforced, the slab stratification was extended to become an outer girdle, which thematizes the stepped layering of the building stories and simultaneously also ensures the structural stability of the tamped concrete fill. Thus a dialogue between the disciplines can indeed be suitable for everyday use and can consequently be profitable not only when constructing ‘strong’ structures with long spans, but also in the ‘narrative’ context of a placid rural schoolhouse. Potentials and Shortcomings of Slab-Wall, Trussed, and Framed Structures   In what follows, another three projects will be discussed, whose loadbearing structures were developed together with different engineers. 1 That of the administration building in Würth was developed in a competition between three engineers. Design approaches were proposed that—in spatial and constructional terms—were in part diametrically opposed. In our office, engineers are usually only marginally included in architectural competitions. This reflects a pragmatic attitude; for many competitions these days, no guarantee of followup work is given for the planners consulted. For this reason, the engineer is not included until the subsequent preliminary design phase. As a result, the dialogue

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1

The structural concept for Ottoplatz was created together with the engineers Conzett Bronzini Gartmann in Chur; the structures for Würth International and the Graubünden Cantonal Bank were developed with the engineering firm of Hans Rigendinger in Chur

School building, Mastrils 1995. Concrete girdle as facade articulation. A shallow, asymmetrically folded structure spans over the gym. Architect Jüngling & Hagmann Architekten, Chur Engineer Conzett Bronzini Gartmann, Chur

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is based on a building structure proposed in advance by the architects. Of course, such a structure can often be implemented using various structural concepts that, in turn, conversely change the spatial composition of the building. This collaboration can work, provided that both the architects and the engineers understand the development of structure and space as a joint advancement of the design and not merely as the mechanical implementation of a given design concept. But unfortunately the reality is also that in the face of unmitigated fee competition, the collaboration—in the sense of teams of engineers and architects who regularly work together—degenerates into a luxury, which in turn results in their innovative strength being decisively weakened in the common practice of the free market. The engineering competition can be a valuable instrument for breaking through the pattern of awarding work according to the precept of the lowest fee and, in that way, giving the “constructors’ dialogue” a chance. The three comparably illustrated structures for the office building on Ottoplatz, the administration building in Würth and the Graubündner Kantonalbank [Graubünden Cantonal Bank] point out the typical problems of commercial and administration buildings: a complex spatial program with highly diverse requirements for room sizes and the desire for flexibility. At the same time, the mostly public ground floor is interpreted as a floor level that is as open as possible, but must simultaneously establish a transition to the strongly defined structure of the underground parking levels. The structure of the building on Ottoplatz comprises a box-like composite of prestressed concrete slabs and walls, thereby providing an alternative to the common skeleton construction system: the ground floor is traversed as if by a bridge with an exciting ratio between solid mass and openings. There is no separation between load-bearing structure and space-defining floors, walls, and ceilings. As a result, a clear interface between the work of architect and engineer can no longer be identified. The checkerboard-like disposition of the openings is not ornamentation, but is instead determined by the structural behavior—which admittedly cannot be seen at first glance, but can be understood by thinking of a diamond-shaped truss pattern in the solid parts of the wall. The expansion of the Graubünden Cantonal Bank is spatially and structurally determined by similar issues: visually, however, the building form uses the theme of stepped greenhouses, which establishes a connection at the urban design level with the neighboring Baroque park. Therefore an intense dissolution of the spatial structure was pursued inside as well: the ground floor was traversed using trusses that are partly multistoried, so the banking hall is spatially related to the park through multiple structural layers. As with the office building on Ottoplatz, it is a space-enclosing, bridge-like construction. Yet the relationship between structure and space is more ambivalent, as is apparent, among other ways, in the separation of the glazing pane from the trusses. The solid spandrel bands along the galleries represent an attempt to counteract the potential risk of the space otherwise becoming too agitated. The load-bearing structure, which partly consists of multistory trusses, proved to be extremely adaptable for construction in both the horizontal

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Ottoplatz mixed-use residential and office building, Chur 1999 The upper floors are rigid boxes acting as a multistoried wall-slab system that span 20–30 m over the openings on the ground floor Architect Jüngling & Hagmann Architekten, Chur Engineer Conzett Bronzini Gartmann Ingenieure, Chur

Administration building for Würth International, Chur 2002 Frames located on each floor establish a horizontally subdivided spatial structure. Architect Jüngling & Hagmann Architekten, Chur Engineer Hans Rigendinger, Chur

Graubünden Cantonal Bank, Chur 2006 A multilevel truss spans over the customer service lobby on the ground floor. Architect Jüngling & Hagmann Architekten, Chur Engineer Hans Rigendinger, Chur

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and vertical directions, and it is also very efficient in terms of construction sequencing and costs. In contrast to the wall and slab system, lengthy shoring times that, depending on the situation, could severely interfere with the subsequent progress of construction are avoided. For the administration building in Würth, what initially seemed like a rather conventional solution of multiple prestressed frames arranged floor-by-floor, eventually prevailed in the aforementioned engineering competition. The proposal for a more expressive structural system, which would have consisted of an upward-thrusting suspended truss that strongly articulated the space, was rejected. This decision was reached in favor of a much calmer and more composed sense of space, which develops from the horizontal articulation of the long-span frame. In this case, it surprisingly turned out that, depending on the situation, the floor-by-floor integration of these frames in an overall structure can be spatially and constructionally as good as a single girder incorporating multiple levels. Moreover, in this way prestressing could be reduced to a few components of the individual girders—where they can be understood as self-evident. To us, the often intensive use of prestressing appears to be the Achilles’ heel of wall-slab constructions. It is hard to imagine how incomplete the documentation of buildings is, frequently even a generation later. This can hamper the flexibility in subsequent renovations and alterations to the building, and with regard to heavily prestressed, will concern us more in the future.

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Each His Own Mike Schlaich

The history of progress in construction is also the history of materials. Iron, steel, and reinforced concrete have each sparked revolutions with entirely new loadbearing structures. But inherent in this is also the history of the development of new technologies. For example, discovery of the principle of prestressing is what first made possible prestressed concrete, high-strength bolted connections, and complex cable and membrane structures. The same applies to the development of new joining techniques that led to the composite materials that are so widespread today. Ever since digital data processing entered the construction industry, the influence of new technologies has become perfectly obvious. Many load-bearing structures were not possible until this ‘watershed in construction’ was reached— these days we design, calculate, construct, manufacture, and install in a closed process chain with the aid of computers. Responsibility and Limitations  To begin with, the structural engineer is solely responsible for built structures in which the load-bearing structure comprises a significant portion of the whole—typically bridges and long-span roofs. The profession of structural engineering is exceptional because, like few others, it closely combines technical and scientific skills with creative work, and because practically every design remains a prototype, much unlike other engineering disciplines. The structural engineer shoulders a great responsibility, because even a single oversight can have catastrophic implications. As a civil engineer, he is also responsible for the entire built infrastructure, the energy and water supply, and traffic on our roads, railways, and rivers, and along our tunnels, bridges, and canals. For ‘his’ projects, the structural engineer is of course responsible for the design. He who is most capable should lead the team. It is a gross misunderstanding to presume that the architect is always responsible for the form and the engineer is only responsible for the structure. Each is fully responsible within their field—also for the design. Structural engineers must therefore learn to recognize, expand, and transcend their limitations. When creative matters become too demanding, they must obtain support for the team in a timely manner. They must receive early training in conceptual design, not only in calculating and dimensioning. Otherwise, they won’t free themselves from the negative image—which, incidentally, is not so bad outside Germany—of being unimaginative structural analysts. In Spain, for instance, the ingeniero de canales y puertos is esteemed, much like doctors or lawyers in our country. But meanwhile, there is much also happening in Germany. From Stuttgart

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to Dortmund, and from Berlin to Hamburg, conceptual design is now taught to structural engineers. Creative minds—serious partners in the planning team—are being trained. We must also be aware that in addition to the architects, the building physicists and MEP engineers are becoming increasingly important in building construction. To achieve overall quality, they must also be integrated into the planning team from the beginning.

1 Compare Alfred Messel’s Wertheim department store in Berlin with the new shopping mall recently built on Alexanderplatz

Sunderland Strategic Transport Corridor, New Wear Bridge, 2003 Single-pylon, self-anchored suspension bridge with glass sculpture on the backstay cables Architect Gehry Partners LLP, Los Angeles Engineer Schlaich Bergermann & Partner, Stuttgart

Loss of Responsibility  We engineers crave architects who share these goals. Unfortunately, however, one repeatedly encounters architects who, since they have ceded too many responsibilities, no longer have much in common with earlier, multifaceted master builders. That doesn’t imply a lack of understanding about just load-bearing structures and their construction: ‘acoustics, heat, and humidity’ are also delegated to building physics, the building services are handled by MEP engineers, the interiors are designed by a scenographer, there are project managers for administering design and construction schedules, and quantity surveyors prepare bills of quantities for invitations to bid. What remains, drifts helplessly in a cloud of 3D bubbles. The architect is at risk of degenerating into the maker of cute images for investors. Wertheim becomes Alexa.1 Fortunately that’s not the general rule, and working in a team, we occasionally get close to a synthesis of the arts. Whether the result is of lightweight or solid construction depends on the context, which itself depends on the local constraints, and of course also on the design wishes of the client and the planner. When acoustic insulation needs dominate, lightweight construction makes no sense, and for long spans, solid construction would be the wrong approach. The Search for the New  In our engineering firm, we are always searching for something new. With each project, we try to take a small step forward, to develop things further. That way, the tasks remain interesting and we stay involved with

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progress being made in the building industry. We work on building design projects and bridges, on long-span roofs and facilities for producing solar energy. We try to be generalists. For instance, it could be that an engineer who has just finished working on a cable-stayed bridge is given a glass roof as the next assignment. That is admittedly demanding, because one needs to become acquainted with new subject matter, but on the other hand, there are no repetitive tasks to cause boredom or a lack of motivation. The loss in efficiency remains slight, because within the team there is always at least one person with the necessary experience. Our working method, which spans across building types and construction materials, liberates valuable synergies. Thus, for example, today we also regularly employ the collective experience in steel casting, which we originally gained in building construction, for bridge construction, in the same manner that we design cable-stayed roofs that support like bridges. Lightweight Construction—Active and Adaptable  Even when the results of our design process are not always lightweight constructions, they’re still quite common in our work. This is not surprising, since we structural engineers fundamentally try to achieve maximum effect with a minimum of material, and because lightweight constructions are compellingly contemporary for aesthetic and ecological reasons: lightweight constructions manifest the load transfer in a natural way—we like things we understand. Lightness is associated with elegance, and the lighter and more transparent a structure is, the less it blocks the view—we don’t feel threatened. Light structures are labor-intensive and, by definition, resource-saving. Building with skilled labor and low material consumption facilitates sustainability. Lightweight construction is nothing new, and we ask ourselves: how and where will it progress? One direction is certainly that of active and adaptable structures, because other industries show that in this way, security, comfort, and energy consumption can be improved. New (micro-system) technologies, such as those already successfully introduced into the automotive industry, and bionic principles, like those

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Sunderland Strategic Transport Corridor, New Wear Bridge, 2003 View of the ‘loop cables’ and the glass sculpture Architect Gehry Partners LLP, Los Angeles Engineer Schlaich Bergermann & Partner, Stuttgart

we know from nanosurfaces, for instance, will certainly also generate advances in light construction and ensure that our structures become active, adaptable, smart, intelligent, autonomous, or adaptive. In this way, the demand for sustainability and a reduction in consumption in construction will hopefully also become less of an issue. Instead of thick-walled ‘boxes’ with windows the size of crenelated openings prescribed by building physics, new and interesting things can develop. Competitions offer a good opportunity for sounding out this potential for progress, and for collaborating in teams of architects and engineers. Examples include the currently ongoing competitions for IBA Hamburg on the topics of “smart material” and “smart houses,” in which the team is specifically called upon to deal with these questions of new materials and new technologies. Landmarks and Efficiency  I also remember a bridge competition that we had the honor of doing in 2003–2004 with Frank O. Gehry as being very stimulating and instructive. We met for a two-day workshop in Gehry’s office in Santa Monica, California, to design the bridge in Sunderland in northern England. The clash of different worlds—we sketched and Gehry folded, we focused on an efficient structure for the bridge and Gehry thought about designing a landmark—led to an exceptionally fruitful dialogue and a result that, although it was never built, is quite impressive. A single-pylon, self-anchored suspension bridge spans approximately 300 meters over the River Wear. The loop cables are innovative: they are guided to the superstructure near the mast, consequently resulting in short hanger cables and an efficient load-bearing structure. The backstay cables that stabilize the mast landward simultaneously constitute the supporting structure for a glass sculpture approximately 100 meters high, which makes the river crossing recognizable from

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afar and is meant to be a symbol of the glass manufacturing tradition in Sunderland. For this competition, the constructors’ dialogue resulted in a formally and technologically ambitious design. We must cultivate the culture of dialogue—it is both sensible and promising when it is characterized by curiosity, respect, and a willingness for discussion.

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A Process of Rapprochement Roger Boltshauser, Aita Flury and Jürg Conzett

Project for a new spa house at the Tamina Hotel in Bad Ragaz, 2009 This case study shows the dialogue between the architect and the engineer as two disciplines joining in a process of mutual rapprochement. The assumption is that the dominance of one discipline over the other is usually detrimental to a building as a whole. The aim is rather to achieve the best match between programmatic, functional requirements, along with structural and technical constraints and potential, on the one hand, and design objectives regarding space and atmosphere on the other. This journey of discovery would seem to be best illustrated with reference to a small, easily understandable, project such as the new spa house at the Tamina Hotel, Bad Ragaz. Perceptual Statics  Let us begin with the premise that soundness and stability expressed visually need not necessarily coincide with soundness and stability demonstrated by calculations. For example, the slenderest possible cross-section of a column is not always the optimal choice in terms of the spatial impression. Nowadays, the transmission of loads from columns to slabs is often concealed within the slab depth by means of elaborate reinforcement. If the proportions of the columns make them appear too thin, this can give rise to the awkward impression that they are punching through the slab. The rows of columns in Greek temples, for instance, are not the result of purely structural considerations for transferring loads. They should rather be seen as the synthesis of an exploration of statics, proportions, and spatial effect overall. Such structures seem to mirror a “constructors’ dialogue” at the highest level; they reveal that only the mutual consideration of effective (calculated) statics and space can lead to a convincing whole. Spatial Atmospheric Report  When designing the new Tamina spa house and hamam in Bad Ragaz, there was no initial focus on a particular structural concept. The starting point was rather a spatial idea, with the aim of creating a certain atmosphere in the baths complex. The precursors and reference systems under consideration were all archaic—or at least historic—structures, many of them vernacular architecture, built anonymously without an architect and without an engineer (cf. Bernard Rudofsky, Architecture without Architects). It soon seemed clear that this should be a simple building with solid walls and open-topped segmental domes. During the design process, however, the spatial and architectural ideas became increasingly

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sophisticated as they took shape, which presented structural challenges, especially with regard to the structure of the roof and dome. The planning regulations provided an interesting starting point for the design, insofar as they limited—without any possibility of an exemption—the extent of the building outline above ground level, which meant that a significant proportion of the baths complex would have to be located in the basement. In response, the design concept was eventually refined into a sequence of rooms that become more spacious and brightly lit towards the top of the building. Bathers are led through a subterranean hamam environment up to the light in the pool hall on the first floor. Once up there, they find themselves in a space made sublime by virtue of its shape, height, and quality of light: the thermal bath itself, which forms the highlight of the complex. The solid walls that shelter it on three sides guarantee sufficient tranquillity and intimacy for it to be opened up along the entire length of the remaining side. At this stage, the design included full-height glazing to give bathers the feeling of floating among the treetops; the glazing could be lowered in the summer months to create an open loggia that would enhance this impression. To counter possible glare and the perceived flow of space out through the glazing, the room was kept 'in equilibrium' by openings in the hall roof. These star-shaped, dome-like structures were designed to provide diaphanous, atmospheric natural lighting and thus decelerate the flow of space. These requirements for the uppermost room generated a new structural challenge. That the building should basically be a structure of solid walls was not in question, but with regard to the statics, a star-shaped double dome in combination with a broad, movable window structure could barely be supported without an elaborate arrangement of beams. In addition, ventilation would be required and the roof glazing would have problems with condensation, not to mention the expense of it all. Structural Concept   The succinct and ingenious structural solution to this problem was to introduce two pairs of diagonally arranged cross beams. The intriguing thing about these is that towards the glazed side of the hall, the middle beams are in fact cantilevered from points along the central axis where they are supported by the other beams, which span diagonally from wall to wall. This diagrid system allows the window area to be spanned without columns, in line with the design goal of an uninterrupted opening. The criss-cross arrangement of beams is also an efficient way of reducing the spans of the glass-block elements. Large ventilation ducts are integrated in cavities within the beams, which naturally requires them to have a greater overall cross-section. The diagonals thus appear more massive, which nicely suits the design concept: their structurally oversized crosses impose equilibrium on the room and create a sense of place in the manner of “here and there” (cf. Wolfgang Meisenheimer, Das Denken des Leibes und der Architektonische Raum [Reflections on the body and architectural space). It is precisely these qualities of centering and repose that are intrinsic to the domes of the “anonymous architecture” mentioned earlier. In spite of the ‘modern’ structural flattening of the

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ceiling here, a gestural, abstract image of the referenced buildings is transposed, without becoming stuck in an outmoded analogy. Structural Report   The following engineer’s report gives a matter-of-fact description of the structural results of the intensive dialogue: “The structure of the underground rooms leading to the new spa house consists of walls and ceilings of reinforced concrete. A bottom slab serves as the foundation. The absorption of vertical and horizontal influences (earthquake) represents no particular problems, thanks to the small spans and a sufficient number of shear walls. The roof slab has larger spans over the window opening, as these are to be executed without columns. Here, the glass-block/concrete elements are reinforced by diagonal ribs. The girders b-b and c-c are simple beams and each rests at both ends on bearing walls. The girders a-a and d-d are balanced on the other two girders. They bear at points B and C and cantilever towards point A. There is therefore no need for a support at point A. The wall bearings receive only small upward or downward forces from the girders a-a and d-d when the girders are loaded asymmetrically. These ribs are also able to accommodate the ventilation system: the ducts are simply cast in the concrete and the outlets pierce the walls of the ribs only at points. The diagonal arrangement of the ribs saves material, because it allows the overlying glass-block/concrete elements to be made less thick.” Epilogue  This example shows that the “constructors’ dialogue,” without clinging to a preconceived strategy, can deliver solutions to smaller tasks that are both structurally and spatially productive. The pragmatic structural analysis report at the end almost leads one to forget what a demanding process of refinement, of giveand-take, the partners go through together. It also reflects their different scopes of interest, without losing sight of the fact that the fruitfulness of this dialogue depends, to a certain extent, on a fundamental consensus. The “constructors’ dialogue” is a joint effort and although it cannot be taken for granted nowadays, to do without it would be inconceivable.

Reference images for the spa house of the Tamina Hotel, Bad Ragaz, project 2009

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Spa house for Tamina Hotel, Bad Ragaz, project 2009 Architect ARGE Boltshauser & Flury Architects, Zurich Engineer Conzett Bronzini Gartmann, Chur

The girders b-b and c-c are simple beams and each rests at both ends on bearing walls. The girders a-a and d-d are balanced on the other two girders. They bear at points B and C and cantilever towards point A. There is therefore no need for a support at point A. The wall bearings receive only small upward or downward forces from the girders a-a and d-d when the girders are loaded asymmetrically.

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All illustrations on these pages: New spa house for the Tamina Hotel, Bad Ragaz, project 2009 Architect ARGE Boltshauser & Flury Architekten, Zurich Engineer Conzett Bronzini Gartmann, Chur

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On Designing Structures Stefan Polónyi

Architecture generally emerges with the assistance of the structural engineer— the structural designer. He enables realization of the architect’s ideas, he refines the architectural concept by assuring systematic structural behavior of the built work, and he develops the art object together with the architect. The following text chronicles this collaboration between architect and structural engineer. In so doing, it would be wrong to speak about areas of expertise; rather, it is a matter of different points of view that do not form antitheses, but instead complement one another. Furthermore, when devising a built structure, the fields of activity are not delimited; they are not separated until the task of documentation begins. The most flourishing collaboration has taken place when, in the end, one has no idea who contributed which thoughts to the design—and one simply doesn’t ask. It is a joint composition. The subsequent observations give some examples in order to facilitate such compositions. Structural engineering does not consist of adapting systems learned in lessons on statics. Since we can analyze the structural behavior of all forms with the aid of computer programs, we don’t need to restrict ourselves to known structural systems. They merely serve as guidance for us. By logically guiding the inner forces, we are capable of developing new compositions and forms yet unknown. The objective is not the load-bearing structure itself, but rather the space-defining surface or the platform for carrying traffic. Which raises the question: How does the surface need to be designed/constructed, what exists and what must be added so it is capable of carrying the forces/loads acting upon it? It is understood that the form must correspond to the functional requirements and the architectural ideas. Defining Space1  Structure and spatial definition are one: on this premise, forms are chosen preferably from the repertoire of geometric surfaces. Spherical shells lend themselves to serving as domes, and cylindrical shells can be beam-like shells (old market hall in Frankfurt) or even glazed lattice shells, like the Galleria at Messe Frankfurt. Here, O. M. Ungers wanted a coffered pattern, so the arches and longitudinal bars are made of laminated wood and the diagonals, which provide the lattice shell effect, are steel rods. Ruled surfaces generated by straight lines, such as hyperbolic paraboloids, are advantageous structurally as well as in terms of production, and they offer interesting creative opportunities. The form is admittedly always dependent on the properties of the building materials and construction methods used.

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1

Reference literature on this subject is listed in: S. Polónyi/W. Walochnik, Architektur und Tragwerk [Architecture and structure], Berlin: Ernst & Sohn, 2003

St. Suitbert Church, Essen-Überruhr 1965 J. Lehmbrock/S. Polónyi St. Pius X Church, Krefeld-Gartenstadt 1967 J. Lehmbrock/S. Polónyi/ R. v. Kalmar

The shell of St. Suitbert Church in Essen-Überruhr is five centimeters thick (six at the periphery) and spans thirty-eight meters. It is constructed using shotcrete on formwork boards. In the 1960s, hyperbolic paraboloid shells were popular, not least due to the influence of Felix Candela. They can also be formed of planks, whereby they are not laid along the generators, but rather along the lines of principal curvature. The roof of the St. Pius X Church in Krefeld-Gartenstadt is assembled from four three-ply formwork boards. Using single- or double-layered ruled ribbed metal decking, ruled surfaces, hyperbolic paraboloids, or conoids, like the roof of the Nederlands Dans Theater in The Hague, can be formed. Here, Rem Koolhaas stipulated the floor plan and the room heights. For the auditorium roof, he wanted an animated form. My suggestion was the conoid, with reference to the roof of the rectory and kindergarten of the Sagrada Família in Barcelona by Antonio Gaudí. Only this time made not of flat tiles, but of warped metal decking, which he accepted. In the quest for new, interesting and logical forms, one can seek these by minimizing the material costs. That can be achieved by avoiding bending stresses as much as possible. Here, soap bubbles provide us with an example. Translated into the language of structural design: for the given constraints, one must determine the form in which, under dominant loading, the stress is constant at every point and in every direction. This requirement is fulfilled by skin-like shells, in which the form is determined experimentally and/or mathematically.

Nederlands Dans Theater The Hague 1987 Rem Koolhaas-OMA/ S. Polónyi and H. Fink

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St. Paulus Church, NeussWeckhoven 1967 Fritz and Christian Schaller/ S. Polónyi/R. v. Kalmar

With the Keramion in Frechen, Peter Neufert wanted a form reflecting pottery for the ceramic museum. I showed him a study depicting a skin-like shell of 120-meter diameter that we had created for a flight departure hall. He immediately picked up on the idea and designated the points of support, the position of the outer edge, and the point of intersection for the skylight. The design was finished in half an hour. We computed the vertical coordinates of the surface from the ‘ideal’ stress condition. Circumferential prestressing of the edge ensured that only compressive stresses occur in the shell (a skin-like shell with only tensile loads is a membrane). As St. Paulus Church in Neuss-Weckhoven shows, the surface can also be stabilized with folds. The pastor wanted a long church of fixed size, and this time Fritz Schaller wanted to build a high church. As a result, the overall form was defined and the question became how to stabilize the surface. The answer was by means of folding, by forming the surface out of triangles. Working on the appearance and inserting the indirect skylights demanded an intensive collaboration with Fritz and Christian Schaller. In the process, perhaps we were inspired by some of Lyonel Feininger’s images. The thickness of the reinforced concrete slab is seven centimeters. For the central glass hall of the new Leipzig Trade Fair, the initial concept for a construction with trussed arches and purlins was not convincing despite the structure’s elegant formation. With the involvement of Ian Ritchie, a cylindrical lattice shell with an eighty-meter span was developed, which was stabilized against buckling every twenty-five meters with cable-braced struts. This restraint against buckling is the dominant architectural feature of the hall. A spatially defining surface can be stabilized against buckling with ribs that are necessary for assembling elements of the greatest transportable size. The globes of the 1971 German industrial exhibition in São Paulo, Brazil, were assembled from

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Keramion Frechen [Frechen Historical Museum for Ceramics], 1971 P. Neufert/S. Polónyi/ R. v. Kalmar

three-millimeter-thick shell elements made of fiberglass reinforced polyester. The upstands of the metal sheets covering the curved translational shell of the St. Antony Ironworks in Oberhausen form ribs that provide stiffening on the bottom and top surfaces. In answer to the earlier question “What exists?,” elements of the mechanical systems can also be factored in, as with the ventilation ducts in the banking hall of the Dresdner Bank in Düsseldorf. The architects had initially envisaged a space truss. As the size and extent of the air conditioning ducts to be accommodated in the truss became clear, I suggested omitting the space truss. The air conditioning ducts were oriented in the direction of the shorter spans, given thicker walls, and where needed, received cable-trussing below. Platforms for Traffic—Bridges   Bridges are art objects in the landscape, in the town, in the city; they are landmarks—points of orientation—comparable to churches. A bridge is a spatial object and not simply the addition of planar systems. In designing bridges, the principle also holds that the goal is not the load-bearing structure itself, but the surface for traffic. The question is: How must the roadway deck be constructed—or rather, what must be added to bridge over the span? The answer can, for example, be a pipe arch, from which the walkway is suspended. I was invited by the State Development Corporation (LEG) in Dortmund to consult on a bridge for Erin Park in Castrop-Rauxel. About ten people took part in the discussions. On sketch paper, I systematically drew about thirty different solutions right there: first for wood, then reinforced concrete, and finally steel. We were all in agreement that a bridge in the Ruhr area needs to be made from steel. Reinforced concrete is not generally an option for pedestrian bridges due to the unfavorable Pavilion for German industrial exhibition, São Paulo 1971 G. Lippsmeier/S. Polónyi/ R. v. Kalmar

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relationship between imposed and dead loads. I thought about elements that are characteristic for the industrial landscape. I came up with a pipe. What if we were to bend the pipe, like Norbert Kricke and Ursula Sax do with their sculptures, and used that to form the main supporting structure? The architect Peter Freudenthal took up the idea drawn in one of my sketches, and together we bent the pipe further in new sketches. Over the large span we suspended the walkway from the arch, and at other places we supported it on top of the serpentine pipe. Peter Freudenthal became bold: What if the serpentine pipe were also to run over the walkway? Why not? The enthusiasm of everyone involved was palpable. Only one woman—who had just designed the neighboring office building—labeled our proposal a “sick worm.” Since then, that’s what we call the bridge. A new bridge type was born: a calligraphic form of minimal art. A narrow footbridge should not be hung by two arches; they would be too close to each other. With the Erin Bridge, there is one arch in the middle of the walkway. That looks quite interesting, but is also slightly disturbing. For the bridges over both Terneddenstraße and the Emscher River, we placed the arch in a skewed plane, meaning it is at an oblique angle to the main bridge axis. What results is an interesting spatial object. For the 1997 Federal Horticultural Show in Gelsenkirchen, the landscape architect Wedig Pridik had designed the path’s main axis to be at 45° to the axis of the Rhine-Herne Canal. The length of the bridge is 110 meters. It is suspended from two asymmetric arches that run perpendicular to the channel axis. The arches each span a length of seventy-nine meters and they are thirty-two meters apart. The apex of each arch is located directly above the walkway. The arch axis is selected in such a way that the arch incurs no bending moments under full loading. Over the curved walkway across Mülheimer Straße in Oberhausen, a steel pipe arch spans along the vertical plane, changing sides laterally in relation to the walkway. The suspension rods are not parallel; their axes share a common transversal above the apex. The arch’s form is a result of the requirement that it should be free of bending stress under dominant loading. The suspension bars are set higher to allow for the necessary clearance height at the walkway. The arch appears more dynamic than a parabola or an arc.

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Banking hall of the Dresdner Bank, Düsseldorf 1985 Kraemer, Sieverts & Partner/ Schiel Possekel/ S. Polónyi and H. Fink Roof shelter for St. Antony Ironworks [Rhenish Museum of Industry], Oberhausen 2010 F. Ahlbrecht/Schülke Wiesmann

Erin-Bridge, Castrop-Rauxel 1995 LEG, P. Freudenthal/ Polónyi & Partner

Eastern bridge over the Emscher River, Nordsternpark Gelsenkirchen 1996 Feldmeier + Wrede/ Polónyi & Partner

Bridge over Mülheimer Straße, Oberhausen 1998 Polónyi & Partner

Tiergarten Bridge over the Mulde River, Dessau 2000 Kister Scheithauer Gross/ S. Polónyi

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In Dessau, the walkway leads to the Tiergarten along a circular arc over the Mulde River. The arch inclines in a diagonal plane over the footbridge. The walkway is suspended from the arch and simultaneously stabilizes it. The girder beneath the walkway is a wing-shaped box beam that is rigidly fixed at both ends; the temperature deformation thus takes place in the radius of the curvature. With all of these bridges, my sketches were put forward as the basis for design. We discussed proportions, details, formation of the bearing seats, the abutments, and the railings with the architects, as well as the color scheme and lighting. The two sinusoidal steel pipes, on the other hand, running parallel with the Ripshorster Straße Bridge in Oberhausen—which symbolize movement along the bridge and carry a fifty-centimeter-thick reinforced concrete roadway—came about without dialogue with an architect.

Ripshorster Straße Bridge, Oberhausen 2006 S. Polónyi with Schülke Wiesmann

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The A16 Transjurane Highway: Architectural Acupuncture Renato Salvi

The A16 highway, the Transjurane, is one of the last sections of the road network that still needs to be planned and built in Switzerland. It leads from Choindez near Moutier to the French border at Boncourt, and arose from the political desire to connect the canton of Jura, newly established in 1979, with the rest of Switzerland. With the 1988 competition open to all architects in Switzerland, a decision was made to take a novel approach. Following the example of the canton of Ticino, which in the 1970s entrusted its highway structures to the architect Rino Tami, an architect was sought who knew how to integrate the fifty kilometer highway with its numerous highway structures and tunnel portals into the landscape. More than forty percent of this route runs underground. As winners of the competition together with Flora Ruchat-Roncati, we have worked on sections 4, 5, and 6 between Delémont and Porrentruy (1988–98), and I am still occupied with the project on a daily basis. A Highway as Contemporary Trump  In our societies, art has only concerned itself with the landscape for about two hundred years. A relatively brief time compared with countries like China, which in its painting, seeks to express and reveal the inner forces of a landscape and not its actual appearance. The notion of landscape is primarily a cultural one. It is interesting to note that the engineer practically Highway A16, section 2, Grands Champs overpass Architect Renato Salvi, Delémont Engineer IJA, M. Jobin SA, Delémont

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never speaks about landscape, but solely about environment. He has, in other words, a purely quantitative notion (for example: type of flora and fauna, air quality, various compensations) that is close to his Cartesian thinking. Architects and engineers need to grapple with the landscape in which they build, however, whether it is rural, peripheral, or urban. With which instruments, what technical knowledge, which cultural baggage, and with what emotions will they confront it? Every act of creation does violence to an existing condition (Denis de Rougemont), and at least in terms of this force, engineers and architects are alike.

Highway A16, sections 4, 5, and 6, Vieilles Forges, retaining walls Architect Renato Salvi/ Flora Ruchat-Roncati, Delémont/Zurich Engineer GGT, Porrentruy

Road Alignment From the outset, the dealings between the engineers and the architect proved to be difficult and tense. The road alignment defined by the engineer could not be called into question. As a result, some possibilities remained beyond consideration, which led in part to unfortunate, inappropriate solutions. The establishment of the highway’s course is in fact crucial; it is decisive for the impact the highway has on the landscape. A lateral shift of a few meters at the foot of a slope, for example, would have spared retaining walls visible from afar, which can only be integrated into the landscape with difficulty because they are only embellished very rudimentarily. Their incidental geometry and their means of construction make them objects whose appearance is not controllable and which, consequently, do not do justice to the place. By shifting the lanes in cross-section, it would have been possible to integrate them more subtly in the hillside. Wounds Of course the design for a ventilation facility or a highway structure is decisive, but the huge wounds left by their construction often appear in the background of the initial studies, even though only the precise positioning of the work

Impact of the road alignment on the landscape

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Highway A16, sections 4, 5, and 6, Mont Russelin Nord (Les Gripons) Architect Renato Salvi/ Flora Ruchat-Roncati, Delémont/Zurich Engineer GGT, Porrentruy Highway A16, sections 4, 5, and 6, Mont Terri Sud (Les Gripons) Architect Renato Salvi/ Flora Ruchat-Roncati, Delémont Engineer IJA, Delémont/ Porrentruy

(a tunnel portal, bridge, retaining wall, embankment, etc.) in the terrain in which it is to stand provides information about its compatibility with the site. This moment, in which the initial hypothesis is verified on location, is the absolute moment of truth. Backfilling of the built structures, which fuses the work with the adjacent landscape, should be an integral part of the deliberations. Far too often, this point is left open and not resolved until the work is completed. This leads to unforeseen, poorly controlled solutions that are often unacceptable with regard to integration. Through very careful selection of the planting, the wounds in the landscape can be healed over time. Reflections on Four Portals  Over time, the partnership with the engineer enabled development of solutions that approached the structural essence ever closer, without losing sight of the aesthetic aspects in the process. The Portals of Les Gripons  Two tunnel portals augment the junction at Les Gripons near Saint-Ursanne. Conceived as a succession of built planes, fronts, and layers more or less markedly offset and patterned, the central ventilation stations for the tunnels at Mont Terri Sud and Russelin Nord bear witness above all to the mind-set of an architect. The entirely closed nature of the rectangular, subterranean equipment spaces, which had already been designed in basic terms by the engineer, do not match the appearance sought in the final state. The world beneath the terrain belongs to the engineer, and the visible to the architects. L’Oiselier Portal  The L’Oiselier tunnel portal, in the western part of Porrentruy, is emphatically volumetric, its expressive power is stronger and it is more closely connected with the mind-set of the engineer. The structurally required wall thicknesses are an integral part of the design, of the basic concept, and through the

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materiality, they confer a stronger, less fragile presence to this built structure as opposed to the earlier portals. Numerous problems were solved with a single form that is also coherent thanks to its functionality. The offset replaces the classic partition wall between the tunnels. The retaining walls at the sides not only fulfill their structural role, holding back the earth, but they also establish a flowing transition at the entrance and exit of the tunnel. Courrendlin Nord Portal  With this portal, still under design, the connection between engineer and architect is even closer. The section through the tunnel itself is characterized by the chamfered vaulting, which absorbs the axial and lateral forces that develop from the weight of the surrounding earth. This theme is also incorporated in the portal and developed further as a logical consequence, so that, for the first time along the A16, the geometric form of the portal results directly from the tunnel’s cross-section (which in this case is not round). From engineering rigor and formal continuity, a built form emerges, a portal, in complete accord with the world of the engineer and that of the architect. In the Highway A16, section 3, Banné Ouest (L’Oiselier) Architect Renato Salvi, Delémont Engineer IJA, M. Jobin SA, Delémont

Highway A16, section 8, Choindez Nord portal Architect Renato Salvi, Delémont Engineer GETUC (Groupe d’étude Tunnel de Choindez), Delémont/Porrentruy

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earlier works, only the cast shadows—in itself a simple device—concealed the difficult transition between the round section through the tunnel and the straight geometry of the portals. Voyeboeuf Portal  The search for a shared language suitable for both parties manifested itself in a patient design process, using cardboard, papier-mâché, and lots of perseverance. Over time, the rigorous engineering side also became part and parcel of the process. But that was not all, because the engineer had to put aside his habits and understand that every detail, even the absolutely smallest one, is an integral part of the work. Given the complex geometry of the Voyeboeuf portal, the supports for the viaduct, which feeds directly into the portal, must also be studied.

Highway A16, section 3, Voyeboeuf portal Architect Renato Salvi, Delémont Engineer IJA, M. Jobin SA, Delémont

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Rules to Play By and Play With Elisabeth and Martin Boesch, Carlo Galmarini, Urs B. Roth and Judit Solt

Judit Solt interviewed the architects Elisabeth and Martin Boesch, the structural engineer Carlo Galmarini, and the geometric engineer Urs B. Roth on May 13, 2011.

Judit Solt  A team consisting of architects, a structural engineer, and a geometric engineer is unusual—simply because “geometric engineer” is not a common profession, but an activity that concentrates on solving mathematical and in particular geometric problems.1 You are now working in this constellation for the second time. How did this come about? Architects  We got to know Carlo Galmarini when we were designing the “OUI!” pavilion at Expo.02. Urs Roth was not yet involved in the project, but we were already puzzling over the unusual geometry of one part of the building. There was a forest of columns, which supported a thin roof. The appearance of disorder was deceptive; in fact, the layout and color of the columns obeyed a system which, although it didn’t follow mathematical rules, was governed by a specific geometry. The columns were arranged according to spatial, empirically developed parameters. In the first section, they were quite openly spaced, after which they became ever denser, creating a visually impenetrable forest. There were probably many other positions that would have met our criteria equally well, but yet more that would not have met them. The engineer was not deterred by the lack of a grid. He acquainted himself with our seemingly random forest of columns, subjected it to his own criteria, informed us of his rules, and corrected us when a column needed to be positioned differently, or to be thicker, for structural reasons. This cooperation to ascertain the spatial and structural interaction was very productive. Afterwards, we were often asked whether we had designed the pavilion together with an artist. Structural Engineer  “Form follows function”: we’ve all heard that thousands of times—but really to grasp one task means looking at it from all sides and understanding all of its functions, including the supporting function. In the Expo pavilion, nine-meter columns were supposed to support a roof that was as thin as possible, while the building on the shore of Lake Neuchâtel had to withstand strong winds from time to time. The load-bearing function, therefore, had a variety of implications. There was a relationship between the strength of the roof and the rhythm

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Judit Solt: “Kein Mensch wartete auf mich!” [No one was waiting for me!], in: TEC21 – Zeitschrift für Architektur, Ingenieurwesen und Umwelt, 7/2010, Zurich, 2010, pp. 12–13

Expo.02, “OUI!” pavilion, 2002 Architect M. & E. Boesch Architekten, Zurich Engineer Walt+Galmarini Bauingenieure, Zurich

of the columns: the broader the clearings in the forest of supports became, the thicker the roof had to be. But there was also an interaction between the different thicknesses of the ‘tree trunks,’ because they had to withstand the sum of the wind stresses. The various columns performed different tasks: under wind stresses, the thick ones restrained the roof, whereas the thin ones were merely appended to it. The thick ones were like tree trunks, rooted only in the soil, the thin ones had to be stabilized at the top as well as the bottom. js  You worked together for a second time on a competition entry for the extension of the Institute of Oriental Studies and the Department of Comparative Indo-European Linguistics (Indology) at the University of Zurich. Again, it was necessary to give an apparently chaotic form some structural and formal order—this time with the assistance of Urs B. Roth. Architects  Besides minor works to strengthen the old building, a villa probably built by Leonard Zeugheer in 1863, an underground library was to be built. Contrary to the requirements in the competition brief, we located it under the drive on the side facing the mountain. This had the advantage of preserving the garden, while allowing the inner circulation to be resolved logically. It also meant, however, that the new building had to resist pressure from the weight of sloping ground, as well as avoiding the roots of two old trees. Our response to the conditions imposed by the terrain is reflected in the floor plan. The idea of giving the ceiling a relief pattern came to us early on, at the competition stage. We also wanted it to be omnidirectional, free of columns, and to float like the heavens above the room, with a form that referred to the Orient and Islam. Our vision of a geometric, three-dimensional treatment of the ceiling was inspired by a drawing by Sol LeWitt. Because the room was fairly large and located under the drive, which was used by trucks, the ceiling had to be prestressed. We decided to integrate the runs of the prestressing tendons, the cables, in the relief, with the proviso that its overall shape should be justified in structural terms. We didn’t want a random pattern, but a true geometry, in which all of our requirements—omnidirectionality, freedom from columns, topographical and formal references, statics—would merge as one.

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Continuous Forms and Color, 1988 Gouache on Paper, Sol LeWitt Conversion of a villa at 66, Rämistrasse, for the Institute of Islamic Studies, University of Zurich, Project 2004 Architect M. & E. Boesch Architekten, Zurich Engineer Walt+Galmarini Bauingenieure, Zurich Geometric Engineer Urs B. Roth, Zurich Ceiling relief in the underground library Axonometric Projection of the underground library Basement floor plan

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This brought us up against our limits and so we called in the geometric engineer. Geometric Engineer   An incredibly beautiful task: a column-free, structured ceiling, under which historical Islamic manuscripts are stored! Anyone who has an interest in geometry knows the refinement of Oriental patterns. It was, however, out of the question for me to borrow from this cultural sphere for the relief. I rather wanted, as a western European who works with geometry, to create something new that would reflect the Oriental canopy in spirit. When the architects showed me the floor plan, my first question was: “Does it have to have exactly this shape?” I knew that the outer wall had to run around the tree roots, I just wanted some leeway to develop the pattern so that it rises at the edges. The architects agreed on the condition that the deviation remained small. My first suggestion, which I called “mountain and valley,” was made up of shallow, concealed pyramids, overlapping one another, with deep valleys in-between. The structural engineer took one look and immediately said no. The prestressing cables would have had to zigzag, which is not possible. Architects   Prestressing cables are usually straight ... Structural Engineer  ... to put it more precisely, they are usually bent only in the vertical plane. Geometric Engineer  But a pattern that adopted the straight lines of the prestressing cables would have been directional. The engineer proposed a solution in which the prestressing cables were bent slightly in the horizontal plane, like a flat S. A very small degree of bending seems to be possible, but without sharp kinks, and especially not in the middle of the room, where the prestressing cables hang the lowest. Then I realized that I needed to consider the problem from the other end, and start with the flat S of the prestressing cable in order to find the pattern for the relief. The architects didn’t want people to see masses of wavy lines when they look at it, and so I came up with the polyhedron pattern. It still contains the snaking lines, but the trick is that you don’t really notice them. The eye is distracted, it focuses on the fields instead of on the edges. To check whether the ridges were thick enough to take the prestressing cables, I drew a horizontal section through the formwork. The image is reminiscent of a river bed, from which large stones protrude, with water flowing between them—the spaces would indeed have been large enough to accommodate the prestressing cables. Structural Engineer  The geometric engineer understood that it makes sense for a long-span roof that has to carry high loads to be resolved into components. For a rectangular floor plan, a hollow block or concrete beam construction would have been chosen. In this case, the shape of the room means that the forces flow more dynamically. In order to achieve a really good solution, the structural functions

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had to be clear. The architects and geometry specialist wanted to understand the details of the load-bearing function. Ultimately, the form followed the load-bearing function: it makes sense to thin out the weight between the ribs of the ceiling— only these are no ordinary ribs ... Architects  The pattern created by the polyhedra does have an approximate orientation, but it contains no straight lines or beams. The ridges, where most of the mass is concentrated, contain the prestressing cables. In addition to these, the rest of the reinforcement had to be accommodated. The idea that someone should have to prepare a reinforcement drawing for this complicated form and lay the rebars accordingly on site, seemed rather awkward to us. Many things are possible, but was that really necessary? Then the structural engineer proposed using steel-fiber reinforced concrete, completing a solution that would have been very elegant, right through from the drawing board to the building site. js  You are now working as a team again, on new stairs for the freshly renovated Hardbrücke viaduct in Zurich. This project brings together two very different geometric systems and some very special structural requirements ... Architects  We imagined elegantly styled flights of concrete stairs, which would descend from the tower in a dynamic curve. They were not supposed to be spiral staircases, on which people move in circles: at the base, they open out invitingly into the city, while as they rise towards the bridge, their radius narrows and they cling to the elevator tower. To start with, the structural engineers working with us at the time claimed that it was impossible to build the design in that form. It seemed inevitable that columns would be needed under the stairs, or suspended beams to absorb the movements of the bridge. Then another structural engineer joined the project, and he suggested constructing the stairs as cantilevers. So the structural principle was decided. Now we had to sort out the form—a kind of spiral that also developed along the axis in the third dimension, as it were. The traffic engineers mentioned clothoid curves to us. We had never even heard of them ... There were two main difficulties. Firstly, the staircase stood in public space, so it had to meet high standards of design, in addition to all the safety requirements. Because it had no landings, it had to be as comfortable to use as the main staircase of a palace; not to mention being fun, robust, and durable. Nothing less than the perfect staircase! Secondly, how does one describe these clothoids, and how do you build them? Geometric Engineer  A clothoid is a curve whose radius increases and decreases linearly. It is often used in road construction, but for a stairway there is something better. The logarithmic spiral, which occurs naturally—in nautilus shells, for example—has all the necessary characteristics. Not only does its radius change constantly, it also has an inner logic that permits a nice solution to the problem of the

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stairs. Each radial that you draw from the center of a logarithmic spiral intersects the curve at the same angle. This constant angle determines the form of the spiral, while the spiral itself always grows by the same factor, according to a geometric progression. I chose a very special one, a self-generating logarithmic spiral. It is the one logarithmic spiral whose tangent intersects the next turn of the spiral orthogonally. The radials dictate the direction of formwork on the underside of the stair. This basic geometry had to have a second geometry superimposed on it. The pitch of the stair necessarily requires regularity, not a progression. This combination led to an antilogarithmic, linear division of the curve. Architects  Lots of identical, narrow boards were used as shuttering for the underside, so as to illustrate how the stair is built up from layer upon layer. The formwork contractor would certainly have been able to produce a smooth, continuous surface, but we wanted the material to express the geometry behind it. Geometric Engineer  The superposition of two sets of directions for the top side and the underside of the stairs has a further consequence: in section it produces a taper towards the outer edge. That makes sense structurally, because the steps are cantilevers and so the greatest torques are on the inside. And it makes sense aesthetically, too, because the stairs should appear as lightweight as possible. The logic underlying the chosen geometry is consistent with that of the staircase. Structural Engineer  From the architects’ design sketches it was clear that the stairs should bear like a spring and would require torsional rigidity. The steps form projecting angles and are therefore strongest at the inner stringer. The architectural idea, the structural function, and the mathematical form are congruent. js  You have the objective of dovetailing the various aspects of a project in such a way that they are inconceivable without each other. This correspondence is recognizable in both the library and the staircase. Nevertheless, you avoid making any kind of didactic gesture. For example, visitors can follow the distribution of forces in the library ceiling, if they so wish, but the knowledge is not imposed on them. And as for the nautilus shell ... Architects  We are not interested in obvious representations; relationships should be evident in a subtle way. After all, buildings have to communicate without being explained by their authors—subcutaneously, as it were—and to reveal their secrets by themselves to anyone who takes a close look. Geometric Engineer  Some things naturally remain invisible. The prestressing cables in the library ceiling are not visible in the finished building; you only see where they ought logically to run. The mathematical laws of the ceiling relief are of no interest to the majority of visitors, but a mathematician can reconstruct them,

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Hardbrücke stairs, Zurich Plan view with steps and underside board pattern overlaid Each radial drawn from the center of a logarithmic spiral intersects the curve at the same angle. In the selfgenerating logarithmic spiral, this angle is orthogonal

Example of a natural logarithmic spiral: a nautilus shell Logarithmic spiral k = 4,78936902918 × 10-3 Antilogarithmic division 17 / 26 / 40 Good approximation to a = 1,53886204679

Hardbrücke stairs, Zurich 2011 Architect M. & E. Boesch Architekten, Zurich Engineer Walt+Galmarini Bauingenieure, Zurich Geometric Engineer Urs B. Roth, Zurich

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Hardbrücke stairs, Zurich Cross-section

including the system of proportion, from the evidence available. js  In hindsight, it all sounds very natural. That the library responds to the pressure of sloping ground and the trees in the park; that the construction of the ceiling obeys structural laws; that the pattern has to do with the contents of the library; and that the ridges match the lines of the prestressing cables—of course. That a flight of stairs in public space is inviting, safe and comfortable; that the production of the shuttering and the arrangement of the steps obey the same geometric principle—how could it be otherwise? But a great deal of intellectual effort has gone into achieving this simplicity. The projects are incredibly concentrated; every single particular is filled with multiple significance and functions. Architects  The word ‘concentration’ is apt. What we are looking for together is the “solution élégante.” Or as Le Corbusier put it: “très difficile, mais satisfaction de l’esprit.” That makes us happy; the difficulty must not be visible in the end. Geometric Engineer  The stairs’ two overlapping geometric systems cost us a substantial amount of work. How many passers-by notice them? If the result seems so much a matter of course, that’s perfect. We know the secret, we don’t have to broadcast it ... Structural Engineer  Beautiful projects always come about in the same way: you try to comprehend a brief with all its functions and to develop rules that perform as many of these functions at once. js  This concentration requires collaboration between architects and engineers as equal partners. You look for “judicious intervention” as you call it, in your respective areas of expertise. How would you describe your collaboration? Is it as free of conflict as the result? Architects  Working in this constellation is inspiring. Although the responsibility

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lies with us as architects, we are open to any clever input. And if one of us explains why something will not work, then we won’t attempt to enforce the impossible. Stubbornness blocks. Geometric Engineer  It is important that everyone has their own area of responsibility. We complement each other well. Structural Engineer  Freedom from conflict is important. When working in a team is enjoyable, people’s interaction functions and everyone responds to each other. Then it doesn’t matter who put forward which argument—usually no one has the final idea at an early stage, anyway. Sometimes this joint work produces a feeling of conspiratorial fun. In the Hardbrücke stairs, for example, the walkway leading from the stairs to the bridge cantilevers out seven meters, like a diving board. It must be elastic enough to adapt to the not-inconsiderable movements of the bridge. We find it particularly nice that our walkway, our thin little cantilever, also makes a tiny contribution toward stabilizing the bridge itself: if the bridge settles, the walkway pulls it up a little bit; if the bridge rises, the walkway pushes it down a little bit. Architects  One has to be careful with idealizations, but it’s an extremely satisfying and efficient way of working!

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Mutual Frankness and Self-Reassurance Adolf Krischanitz and Aita Flury

With his extension to the Rietberg Museum in Zurich and his laboratory building on the Novartis Campus in Basel, Swiss architect Adolf Krischanitz has designed two buildings that are remarkable for their powerful structural elements.

Aita Flury (af) In connection with the exhibition “Constructors’ Dialogue” I would be interested to hear your comments, from an architect’s point of view, on the interaction between form and structure, as well as on the concepts of innovation and risk. Adolf Krischanitz (ak)  The interaction between form and structure is—to take it to an extreme—just as difficult to diagnose as the interaction between form and function. Structure disconnected from form probably does not exist as such: even the choice of structure involves a decision on form. In three-dimensional spatial concepts, the generation of space jointly via form and structure produces entities that are even more integrated, and which it is virtually impossible to resolve into categories of formal and/or structural components. The relationship between the ‘structural’ and the ‘formal’ is neither clear nor consistent. A certain “relationship to the [human] body” (Wolfgang Meisenheimer) is inherent in architectural structures, so scale, movement, rhythm, gesture, and even the transfer of psychological components can certainly be determining factors, whose significance and actuality keep changing cyclically, but which remain focused on the central concern, the intent to define space. The game of dissolving boundaries can therefore lead to innovation, but it also runs the risk that the matter under consideration, the generation of space, might lose its status as a central concern. af  Your practice works on projects in China, Germany, Austria, and Switzerland. Do you consider there to be clear-cut differences from country to country in the collaboration between architects and engineers—and if so, what is their nature and what conditions do they originate in? ak  There are certainly differences—resulting from tradition—between those countries in the culture of design, which as a rule fluctuate between the attempt to continue a tradition unbroken and the attempt to transcend it. It must be said, however, that the integral motors of any sustainable, synchronous effort to determine

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structural form are at their most fruitful in Switzerland—a fact that can be attributed to an iterative cultural practice that has evolved over a long period. China is in transition in this regard and, at the moment, is still too divided between the erratic presence of its history and the dubious allures of the West. The ability to learn and to criticize, however, is increasing there exponentially. af  In your extension to the Rietberg Museum in Zurich, an elaborate system of specifically positioned shear walls enables an arrangement that appears unspectacular on plan, but is essential for the room layout and for transmitting the extremely high slab loads. The greater height of the lower of the two underground levels is a result of this structural concept, which functions as a complementary multistory support system of slabs and walls, based on principles derived from bridge-building. The great technical ingenuity that is evident in the cross-section is played down in the rooms themselves, it seems that the intention is neither to illustrate a principle nor to implement it in such a way that it is explicitly experienced, is that right? ak  The structural system that we developed with the engineers, Ernst Basler + Partner AG from Zurich, to such subtle effect, originated in an unspectacular but nonetheless radical idea, namely to explore the spatial and structural possibilities offered by a structure whose elements interact with each other over two stories. The discreet nature of this solution lies above all in its multistory, multifaceted approach and in the inability of the observer, who is only ever located on a single floor, to make a quick diagnosis. The resulting large column-free areas, on both underground levels, generate two complementary volumetric units that simultaneously embody both the structural and the spatial design. In a museum, discretion in expressing the structure ultimately allows the artifact on display to receive due attention without distraction. af  In the interview with the three engineers, Aurelio Muttoni, Heinrich Schnetzer, and Joseph Schwartz (in: werk, bauen + wohnen 5I2009), I asked

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All plans: Rietberg Museum, Zurich 2007 Architect ARGE Grazioli/Krischanitz, Zurich Engineer Ernst Basler + Partner AG, Zurich

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about the associations that ‘strong structures’ evoke for them. To put it in a nutshell, they thought that the value of structures that are noticeable but by no means obvious lies in their potential for meeting a broad variety of conditions, as well as in the challenge of dimensions, spans, and the physical presence of the mass itself. What ideas do you associate with strong structures? ak  So-called ‘strong structures’ naturally make up a significant part of any sculptural canon of architecture and are rightly involved, as key factors, in the process of redistributing the potential for attention. A strategy of cooperation between the engineer and architect as equal partners may originate in the common search for a specific design idea, which can also free up creative potential, as long as it is not (yet) exhausted in its spatial and structural vocabulary. This interactively developed idea, as concrete as it is abstract, represents a process of exploration whose structural and form-generating potential can permanently determine the “integral ordering structures.” Ideally, the architect and the engineer play this game as an alternation of disclosure and reassurance, although to start with it is a matter of finding the right questions. These need to be defined in detail and accurately enough that, over the course of a lengthy exchange of opinions, they ultimately produce sound answers that can be incorporated into the specific interaction between the spatial concept and the generation of form. af  In your new book, Architektur ist der Unterschied zwischen Architektur [Architecture is the Difference between Architecture], the matter of structuring the schedule of accommodation is mentioned several times, the differentiation and modulation of the brief before the actual act of designing. Looking at the floor plans of the Novartis Campus laboratory building, the eye is drawn to the host of space-defining shafts that dominate the footprint, reflecting the influence of Louis Kahn’s Richards Medical Research Laboratories in Philadelphia. To what extent is the “interpretation of the brief” related to strong structures for you? And what words would you use to sum up the chronology of collaboration between the architect and the engineer? ak  The footprint, in particular, of our laboratory building for Novartis was developed jointly by the architect, the engineer, and the laboratory planner and as such it is the culturally inspired pattern resulting from structural, technological, and spatial collaboration. The structural and infrastructural elements are incorporated in a straightforward manner in the building-as-container, without any kind of sublimation, as a technical, space-defining, strong structure, echoed iconographically by the central atrium as a kind of glorified shaft. The question of the chronology of a discursive process is ultimately based on the notion that one of the two proponents—architect or engineer—had a flash of inspiration before the other. In the light of my experience of collaborative architectural design work with a great varie-

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Research Laboratory, Novartis Campus, Basel, 2008 Architect Krischanitz & Frank Architekten, Berlin/ Zurich Engineer Ernst Basler + Partner AG, Zurich

ty of partners, such as artists, craftsmen, building owners, and naturally engineers, the question of “who had the crucial idea when” is less important subsequently Forschungslaborinto Novartis Basel, Grundriss 2. OG, M 1:333 than the process of transforming this inspiration anCampus architectural concept. It is therefore important to keep that process open for as long as possible, in order to gather and evaluate new ideas and ultimately to make the right choice or decision. In student project work, I very often see excellent ideas that, for lack of insight and experience, have neither been recognized nor expanded into an architectural concept: this is where the teacher’s responsibility comes into play. Once the architect—in most cases—has assumed the ultimate cultural responsibility, it is usually he who decides—not that this necessarily demonstrates that he was the initiator— the manner in which the technical structure is employed and the status assigned to it in the general trade-off among the aspects of what is ultimately a work of architecture. On the other hand, I can imagine that this is handled in the opposite manner in certain technically ambitious structures such as bridges, factories, and the like—to the extent that an architect has to transform, in a kind of follow-up, a preliminary project formed by engineers. Given a degree of ambition, however, this transformation on different levels of design can unleash the very energy of sublimation that helps to emancipate the design concept from all of the functional and technical requirements, and only then does it become an autonomous architectural concept. af  To conclude, something else that interests me is the aspect of symmetry, which appears in many of your projects. Are these symmetrical floor plans based on Semper’s notion that each natural shape has three axes: symmetry along the horizontal axis, proportion along the vertical, and direction in depth? Perhaps this is ultimately an expression of the conditions for structural equilibrium.

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ak  Symmetry is equal measure or equivalence, just as it is also the application of certain congruence properties of surfaces and bodies and thus, also, of architectural spaces. In addition to that, certain schools of thought within Modernism associated the use of symmetry with particular historical hangovers, such as duplication in the form of identical reflection (reinforcing significance) and the creation of hierarchy by emphasis on the central zone (imposing order). Now that neither modern architecture nor modern art have persuaded us—though not for lack of trying—to abandon order, this classic design tool is now back in use. The cathartic ambitions of Modernism and its contrary historical ambitions now permit a more relaxed exploitation of symmetry as an organizing principle, in the way that it is inherent in the human body.

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Strong Structures Heinrich Schnetzer, Aurelio Muttoni, Joseph Schwartz and Aita Flury

This interview took place on January 22, 2009 and first appeared under the title (in German): “Structure and Space. The engineers Aurelio Muttoni, Heinrich Schnetzer, and Joseph Schwartz in conversation with the architect Aita Flury.” It was published in: werk, bauen + wohnen 5|2009, pp. 40—47. Here we present a longer version of that discussion, which includes the topic of competitions.

In the specialized and long-separated professional spheres of the engineer and the architect, a common language is needed if collaborative work is to produce positive results. This conversation addresses the challenges and objectives that focus the mind of the engineer when constructing buildings today, and attempts to pin down the essence of filigree structures, diagonals and ‘strong structures.’ Aita Flury (af)  The exhibition “Constructors’ Dialogue,” held three years ago at the Zurich Architectural Forum, examined current collaborative work by engineers and architects in Switzerland. All three of you took part, in one way or another, in this exhibition, represented by your own projects, or by theoretical research. For today’s conversation I’ve asked each of you to bring a project along to illustrate the aspects of building construction that interest you as engineers. Heinrich Schnetzer (hs)  The requirements in this area are now very extensive, resulting in a pressing need for coordination between the professions. The sum of parameters for a load-bearing structure (which needs to be developed in close cooperation with the architect and to be refined during the design process) requires the engineer to incorporate the structure into the overall design on the levels both of concept and construction. I am fascinated by this process of extracting and crystallizing a structural system from an architectural idea. The concept for the Actelion Pharmaceuticals headquarters in Allschwil, Basel, is the result of an approach that we developed in the course of several projects with the architects Herzog & de Meuron. The five upper floors consist of ‘office beams’: hollow box beams stacked in layers to form a single dynamic volume with some quite large cantilevers. This guarantees the interior flexibility necessary for the office complex. The steel trusses visible in the facade are a combination of trussed and Vierendeel girders. In exploring the technical possibilities, we believe that we reached the limits of what is feasible, although it has to be said that not everything that is technically possible is necessarily sensible. The pace of development in building construction has greatly accelerated in recent years, and it definitely shows similarities to developments in the financial and banking systems.

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Aurelio Muttoni (am)  The focus is always on progress, especially in old and familiar areas. Developments in engineering have always occurred when new requests have come to us from other professions. The increase in complexity due to ever more differentiated parameters has caused our work in building construction to become much more interesting in the last twenty years. A key element of that is the quality of cooperation with the architect. Livio Vacchini’s competition entry for the city hall in Nice was based on analytical considerations, as are all of his designs. I considered the fact that Nice is located in a seismically active area to be of the utmost importance. This led us to develop a structural system based on the principle of seismic isolation. For that, the best thing is a self-contained superstructure that is supported on only a few points at ground level. In this case, the technical reasoning perfectly matched the architectural concept, which had reached a similar conclusion for other reasons: an urban building, but with a ground floor that should be as open as possible. When the technical and architectural considerations both point in the same direction, you have the ideal conditions for collaboration between the architect and the engineer. Joseph Schwartz (js)  Working with the architect is of central importance to me too. There are very few architects, however, with whom it is possible to have a fruitful dialogue beginning at the conceptual stage. Within this dialogue, it is essential for both sides to develop mutual understanding, a feeling for what lies behind a design idea proposed by the other party. The engineer must understand the architectural intention in order to design solutions that specifically support it. In return, the architect must recognize the engineering constraints and be able to see their potential for showing the way ahead. Ideally, architectural and technical ideas feed off each other and thus enhance the design. The other crucial point, for me, is an interest in the construction process itself: how is a concept realized, transformed into something tangible? It is not enough to be involved at the design phase; you need to supervise the building work as well. That includes talking to the foreman, for example, who might, if you involve him, become really enthusiastic about a complicated but ingenious solution. am  That is an important observation. Something profoundly well-designed is inseparable from elegant building solutions. js  At the same time, a good design solution is also characterized by the absence of structural problems at the construction stage. af  Let’s stay with the design concept stage and the example that you have brought, Joseph: Leutschenbach school in Zurich by Christian Kerez and yourself. js  The task we set ourselves at Leutschenbach school was to occupy the smallest

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possible area of ground by stacking the uses. The more discrete uses, namely the classrooms on the first to the third floor and the gym on the fifth floor, are embedded in trusses, which thanks to their cantilevers generate completely open intermediate floors: the ground floor and fourth floor, which are used communally. When the project entered the design development phase, two decisions were made jointly with huge implications: firstly, the load-bearing trusses at the facades were moved to the exterior for aesthetic reasons. Secondly, the floors, which had originally been designed as lightweight, steel-concrete composite floor decks, were changed to a solid construction, so as to optimize the space. The use of a newly developed product, recycled lightweight concrete, allowed the loads to be brought under control. af  Diagonals and Filigree Structures   Two of the three projects that you have brought along contain reinterpreted or enhanced truss structures: structures with filigree cross-sections appear to be in vogue in the building industry at the moment. These systems’ capability for multistory use and their bridge-like dimensions are properties known to us from shear-wall/ slab systems. From the clear relationship between ‘open’ and ‘closed’ in the latter, architects’ interest has clearly shifted towards filigree structures, which aspire to an ambiguity of wall and opening within the same structural element, and which visually maintain a balance between stability and lightness. An especially striking aspect of this is the departure from the old horizontal-vertical rule book, with diagonals now increasingly coming into use for dynamic effect and ornamentation. In one case, the trusses even come to rest externally, which required considerable effort in the treatment of materials, insulation, and detailing. It is therefore sometimes presumed that architects nowadays exploit such structures in a decorative way for largely formal reasons. So from your point of view, what structural potential do they really have? js  To this day, not a single architect has encouraged me to develop a solution using trusses. In most cases, the architect’s reaction is decidedly defensive when the engineer proposes diagonals. In my opinion there has been no change in this regard; architects generally respond to such a suggestion by asking straightaway whether a Vierendeel girder wouldn’t be possible instead. It is not the norm for a static, diagonal element to be an architectural feature in a space or in the facade, even if there are one or two recent examples of it. hs  The load-bearing structure itself, coupled with an interest in large spans, has increasingly become an architectural topic in the last twenty years. Shear walls, trusses, or Vierendeel girders are inevitably associated with it. js  On top of that comes a new architectural trend towards three-dimensionality:

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Actelion Headquarters, Allschwil 2007–2010 Architect Herzog & de Meuron, Basel Engineer WGG Schnetzer Puskas Ingenieure, Basel

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spatial compositions in which things do not simply lie on top of each other in a well-behaved way, and which therefore stimulate the search for three-dimensional solutions. af  In your opinion, then, no real tendency in favor of filigree structures is detectable. Instead, the main focus of interest is on large spans and threedimensional compositions, for which different systems can be used. The fact is, though, that shear-wall/slab-designs rather belong to the recent past. hs  Shear-wall/slab-designs are always associated with certain functional limitations, which, in another form, also afflict diagonals. On the subject of trusses, I would like to add that we are talking about them in the context of steel. Complex structures for highly ambitious architectural compositions can only be constructed in steel, as this permits a large degree of prefabrication, which saves time and reduces the weight. af  In the Leutschenbach school building, the usual haunch-like thickening at the truss nodes was avoided by optimizing the dimensions of individual elements and the material thicknesses. The particular characteristics that distinguish the truss as a structure are disguised as a result. js  The haunches were optimized mainly on account of the manufacturing process and the cost, although this also suited our preference for structural clarity. The structure was positioned outside the glazing, however, solely in order to achieve the desired architectural effect. A truss behind glass is always perceived as something different to a truss in front of a glass skin. Keeping in mind the goal of giving the building a greater impact from the outside by means of a unifying structure, the decision to address this challenge was ultimately taken jointly by the architect and the engineer. hs  On the project for Prada in Tokyo, which we undertook together with Herzog & de Meuron, the facade skin and the supporting structure were fused together. Here, too, this was done solely to create a particular architectural impression, and it similarly required a certain amount of hard work. af  Integration of the Entire Structural System  The competition entry for Nice is based on a radically different architectural approach. In this project, the facade plane is used to generate monumentality, clarity, a grid, order, mass, and depth. The facade clearly takes the prime role, the structural role, and radically separates the outside from the inside. Apart from this difference, however, there is a striking parallel to Leutschenbach school: the idea of reducing the load-bearing structure to a minimum at ground floor level. Seen architecturally, the ground floor volumes of both designs give the impression

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of being compressed open space, emphasizing the primacy of the uninterrupted open ground (urban or rural) above which the building more or less floats. Is this not a structural tour de force? js  In my opinion, this does not require extreme technical measures; we are talking here of cantilevers at a 1:1 ratio and of structural costs that are entirely within the normal range. af  Such structures don’t exactly represent the simplest way of transmitting loads and optimizing energy loss through the building envelope, though, do they? am  You can’t generalize about that. Spans must always be considered relative to the structural height, that is, the height of the load-bearing structure. If the whole height of the building is in fact available to us, we can achieve practically any span with relatively modest means. js  The cost of materials, for example, is really not an issue with such systems. If we do want to look for a weakness in such systems, then we’re most likely to find it on the construction site, for example in the form of endless temporary shoring. The fact is, surely, that the efficiency of such complex systems depends on how cleverly they are designed from day one. am  In my opinion, it is simpler and more logical to integrate the large-span loadbearing structure—the console, so to speak—into the structure as a whole, rather than reducing it to a slab or a single story, as it was in the table-like structures of the 1950s and 1960s. These were not simple structures and they consequently took up a great deal of space.

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Tibor Joanelly, “Der Bau befragt das Universum” [The building interrogates the universe], in: Moritz Küng (ed.), Conflicts Politics Construction Privacy Obsession. Material on the Work of Christian Kerez, Ostfildern: Hatje Cantz, 2008, pp. 136–137

af  Chronology of a Process  So you are in agreement, then, that cleverly designed structures that, as systems, encompass the whole of the building, are relatively uncomplicated ways of freeing up entire stories. Let’s leave the individual designs for a while and return to the subject of cooperation between the engineer and the architect. The way we see the roles of the architect and the engineer always includes the question of the chronology of events. Heinrich, you spoke of a conceptual and structural incorporation of the load-bearing structure into an overall design. With regard to Leutschenbach school, the engineer’s involvement is described as a process of reinterpretation, in which the preliminary (architectural) design, the work of the ‘handyman,’ is developed into a structural concept, the work of the engineer.1 From this viewpoint, the engineer is responsible for adapting the structure to the conditions created by the architectural design. Jürg Conzett, on the other hand, has written an article

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proposing that when the issues are primarily urban and architectural, engineering competitions should be held only after the architectural competition has taken place. This is subject to the proviso that the chosen architectural design permits a meaningful structure of some kind, and conscious of the fact that in such processes, feedback from the structural design into the architecture will require a degree of openness from clients and architects.2 Altogether, none of the standpoints seems to consider a primacy of structural design. Is the figure of the engineer-architect (as personified by Pier Luigi Nervi) who is guided by his own ideas of form and effect and who, as designer and contractor, develops the architectural form from the principles of structure and the construction methods, an anachronistic concept today? am  In contrast to Nervi, I am far from wanting to have control over everything. Illustrations of Nervi’s projects certainly do exercise a fascination, but the buildings that I’ve seen in reality have not really convinced me. Although they are always very beautiful structures, they often don’t function very well as buildings. With Nervi, the structures are so important that other aspects are suppressed, but architecture is much more than a structure! af  Apart from Nervi—I’m thinking of Félix Candela and Eduardo Torroja, for instance—is there no one you can think of, who was or is able to bring both sides into harmony: architectural and structural design in one person? hs  Building construction requirements have become so complex these days that, working on my own, I wouldn’t dare to try to cover all the criteria that a building must satisfy. I see myself as a specialist planner who has an understanding of structural design and analysis, and who can contribute these skills to a project. am  That’s why teamwork is the only solution. js  The architect is much more dependent on consultants nowadays; a team usually needs to have at least five differently qualified people. So it is indeed difficult to name anybody who has managed to synthesize both sides perfectly in the course of a lifetime, in a still shorter working life. am  I also call into question the idea that the technical component should be dominant. af  My question is mainly aimed at understanding whether you really agree (and are happy) that the first draft comes from the architect, with the engineer in second place, ‘incorporating’ something afterwards? js  ‘Incorporation’ is the wrong term, in my view. We can make an essential contri-

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2 Jürg Conzett, “Bauingenieurwettbewerbe im Hochbau” [Structural engineering competitions in building construction], in: TEC21, 15/2007

Competition for Nice city council offices and center, 1999–2001 Architect Livio Vacchini, Locarno Engineer Grignoli Muttoni Partner, Studio d’ingegneria SA, Lugano

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bution—even at the draft design stage. Unfortunately, this is still the exception, but for me, it is clearly something to aim at. For years I have been turning down offers to work on projects that have already won a competition, or that have been developed quite a way already without any involvement on my part. That is, of course, a question of attitude—on the other hand, I do take on the burden of extremely time-consuming entries for architectural competitions. hs  With regard to competitions, I have the same attitude. You win or lose a competition as a team, in which you have all joined in the dialogue from the start. af  The fact is, unfortunately, that there are still contests in which engineers and other consultants invest in a particular entry right from the start, but after it wins, they are replaced by competitors with lower fees. js  For me, it’s a clear-cut case: if I win a competition as the engineer in a team, but don’t get the contract to work on it afterwards, then the architects aren’t worth working with on the design development anyway. In my experience, the architect is certainly in a position to insist that the engineer involved from the beginning is kept on board. af  Strong Structures  Let’s leave the subject of competitions and turn to the associations evoked by the title of the werk, bauen + wohnen 5/2009 issue on "Starke Strukturen". From an architectural point of view, the spectrum ranges from space-defining structures inside a building to the concentration of the external form into a sculptural composition, as well as structures that penetrate the building envelope and interpret the facade as a deep-field three-dimensional transition. As an extreme form, we can also identify “integral ordering structures,”3 which involve both the interior and the exterior in equal measure. Each of these strategies relies on different hierarchies, such as interior flexibility or variability, exterior and contextual appropriateness or responsiveness, and so on. What ideas does the engineer associate with strong structures? am  I am fascinated by structures that are refined in the sense that we recognize a certain presence, but do not realize straightaway how the structure works. As examples of that I would cite the results of collaboration between Louis Kahn and the engineer August Komendant, or between Oscar Niemeyer and the engineer Joaquim Cardoso. The structure is noticeable, but not at all obviously expressed: you can’t tell right away how the loads are supported. There is a kind of positive ambiguity about them, something mysterious, as well as the strength of humility. af  The project for the city hall in Nice contains, at an architectural level, rather abstract elements of a symbolic or metaphorical nature. Does its

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Joanelly, pp. 136–137

structure demonstrate the subtle characteristics that you are describing? am  In my opinion, yes—because it consists of a load-bearing facade, which is more than just a structure. As engineers, we had ultimately optimized all of the dimensions, but that went too far and made the facade too much of a structure alone. So the architects revised it again, or shall we say, reverse-engineered it. For compositional reasons, they gave certain elements greater dimensions than the statics indicated for the stresses that they were subject to. These architectural measures have strengthened the facades and now distinguish them from a purely structural concept. hs  The question of what constitutes a strong structure must surely be related, for one thing, to the question of the degree to which the load-bearing functions are expressed. Although they should certainly be expressed, this should (as Aurelio says) not be done in an obvious, trivial manner, but rather in the form of particular, surprising moments. A good example of that is Robert Maillart’s warehouse roof, the ‘shed’ at Chiasso railway station, where you don’t recognize the cable-trussed girder at first glance. Above all, though, for me a strong structure has connotations of complexity, in the sense that it can meet different conditions elegantly. Besides its structural function, it must fulfill the needs of the planned spaces and uses. It combines structural efficiency, an intelligent manufacturing process, and neat detail solutions. On these premises, a clad structure can also be perceived as strong. js  I like Aurelio’s remark about the sense of mystery. There is something academic about it, but also something metaphysical. Then there is the important aspect of the dimensions: I’ve always been fascinated by bridge construction. Standing under a bridge, you get a real physical sense of the challenge posed by the dimensions, the spans, and the mass! Those are the aspects of structures that always move me most strongly. The mass, in particular, is crucial in respect of the power of a structure. This becomes greater the purer the use of materials is, which is why I don’t associate cladding, for example, with strong structures. am  There are strong structures that are amazingly simple, pure, perhaps even monolithic. On the other hand, there are delicate, light structures in which I likewise see the attribute of strength. js  Talking about the purity of load-bearing structures, one requirement is becoming ever more important to me, which is that the form should somehow correspond to the internal forces, be in accord with them—at least to a minimal extent. I was less pedantic in the past, but as time goes by, the more important it seems. am  I agree with you that this should absolutely be the case up to a certain limit, or order of magnitude. Above this threshold, however, the whole thing can end up

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Leutschenbach school, Zurich 2009 Architect Christian Kerez, Zurich Engineer Dr. Schwartz Consulting, Zug/dsp Ingenieure, Greifensee

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rather trivial. If it begins to look as though different layers of structure, i.e. primary, secondary and so on, have been superimposed, the structure can seem weaker overall. A load-bearing structure generally feels strong to me if it is predominantly a primary structure. hs  The Olympic stadium by Herzog & de Meuron in Beijing has a structure that aims for exactly this blurring of pure structures. This structure meets the criterion that we raised earlier, namely that the way in which it functions is not obvious at first glance. am  With this project, we are talking about a beautiful image, I would say, but not a strong structure in the sense of a strong load-bearing structure. The fact that it is still a structure at all has degenerated, as it were, into a minor matter. js  The load-bearing structure of the Olympic stadium is neither highlighted, nor is it efficient. af  Structure and Space  Considered in spatial terms, the structure of the Olympic stadium in Beijing has the strength of permitting the exterior space to permeate the interior, with the result that the building is interwoven with its surroundings. To finish with, I would like to take up the subject of display once more: how do you view the relationship between space and structure? And where is there potential for improvement in the dialogue between the engineer and architect? js  One major problem, it seems to me, is really the point that the languages of the engineer and the architect have no common ground. We are often very technical and very physical in our thinking and we describe things using models without ultimately understanding what lies behind them. On the other hand, the concept of ‘space’ remains rather abstract for most engineers and they lack the ability to visualize spaces. The architects, in turn, often lack an understanding of elementary structural principles. am  The system-based thinking of engineers really doesn’t contribute, in this sense, to a fruitful dialogue with architects. As Joseph says, engineers are often fixated on models and on analytical thinking, so they neglect to develop a sense of spatial composition. hs  I have learned from experience that architects think just as analytically as the engineer; they simply focus on other parameters. What I have been wanting to know for some time, however, are the reasons why architects often prefer to ignore the aspect of construction? In my opinion, too little weight is attached to construction by the designers’ side.

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af  Architects who would count as designers with a highly developed understanding of construction obviously form a dwindling minority, especially on the international scene. Firstly, the separation of design from technical and structural planning is increasingly a fait accompli, owing to the complexities of today’s construction process. In addition, many architectural strategies are inspired by an abstract idea and focus on creating images, objects, or jumbo-sized ornaments, while the “origin of the form” in such cases has little to do with structures. js  This trend is, unfortunately, not only evident at the ETH nowadays, but also in the architectural departments of technical colleges. am  Overall, that is not really a new development, is it? It has been becoming ever more apparent over the last two hundred years, ever since the profession split into engineering and architecture. hs  Architects’ conceptions have undergone yet another crucial turning point in the last twenty years. In design seminars, students are now generally expected

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Palazzetto dello Sport, Rome 1956–58 Engineer Pier Luigi Nervi, Rome

to produce three-dimensional images on the computer, but they are no longer capable of realizing these visions themselves. They come to the engineer with the expectation that he will make their designs buildable. js  Do you mean that if architects had better structural skills, their designs would be different? hs  I mean rather that architects are missing an opportunity if, for lack of understanding of the structure, they deprive themselves of control over the realization of their designs. If the architect ceases to act in any structural capacity at all, he will become a mere provider of design services, having surrendered his management role, his function as the leader of a team.

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Isambard Kingdom Brunel

The engineer as a hero

META-DI A Personal Collage by Aita Flury

The “constructors’ dialogue” is the cultivation of aided discussions between two related disciplines with different perspectives. It is a continued search for understanding, an ongoing questioning of the positions, a continuous chain of conversation repeatedly encircling the subject. In our contemporary culture, the general separation of words from things—or theory from real-world practice—is a source of the breach and the disturbance. The Meta-Dialog suggests—in an informal, subjective way—possible interpenetrations of layers from the

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There seems to be something in the work of the engineer which suppresses talk, even useful talk. This is very well in a way but can be carried too far. Engineers ought not to hide their light under a bushel and expect the world to reward them for their silent work’s sake. The world is too busy ... to study engineering and would perhaps take more interest in engineers, if they were to take the trouble to explain things.

IALOGUE

John Galbraith

You know, engineers simply shouldn't make themselves out to be worse than they are! past and present, superimposes the visually perceived with the verbally formed, and enables these to mutually redefine themselves. Because built structures receive their meanings within architecture from, on the one hand, a built reality, and on the other hand, the logic of the prevailing discourse. Only when the collaboration between architect and engineer moves from its silent existence to a condition of discourse will its appropriation by society also be possible. And, the engineer comes on stage and plays to the crowd.

Peter Marti

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CRITICISM

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211 Illustrations: Barbara Wiskemann, Zurich

Let's talk about the moral aspect of creative work.

Mario Monotti

Jürg Conzett

I first learned the meaning of the word design after completing my studies—in my work at Zumthor’s architectural office.

Paul Kahlfeldt

Equilibrium condition Mxa=Mxgxsin(ψ) Equation of motion d 2/dt2=g/Lsin(ψ) ……………………

BABYLON Constructors in Dialogue The difference between structurally undefined and structurally over-defined systems?

Christoph Wieser

Aita Flury

And what, may I ask, is the spatial benefit?

Mario Monotti

Joseph Schwartz

And they do in fact really differ—the mentalities of architects and engineers—their professional socialization is simply different ...

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The discussion is no more dangerous than life itself ...

By specifying the slab’s boundary condition, the architect defines the equilibrium problem of the slab.

Adolf Krischanitz

Paul Kahlfeldt

Adolf Krischanitz The integral moments of incessant synchronous effort at finding the structural form are certainly very fruitful in Switzerland.

Carlo Galmarini

Mike Schlaich

I don’t mind if the spatial concerns are given form through interpretation of the structural concepts.

The world can be divided into tension and compression—I need no references in order to design.

We are always searching for something new. The reason lightweight buildings usually come about is naturally connected with the fact that one seeks to minimize the weight.

Joseph Schwartz I definitely know engineers who work with references. But apropos history: all these stories of prestressing are thorny precisely with regard to documentation.

Ueli Brauen The pace of development in building construction has greatly accelerated in recent years, and definitely shows similarities to developments in the financial and banking systems.

Hans Kollhoff

Andreas Hagmann The engineers have no idea about urban design and history—do they? We “Neotektoniker” have no need for the ingenious.

Symposia in DAZ Berlin, March 18, 2010 / April 21, 2010

Heinrich Schnetzer

Markus Peter

Scientific specialization cannot simply be seen offhand as a corruption of thought. 213

For those who really wish to collaborate teaching its own discipline in the other discipline is an optimal model.

Kahn was very eager to learn and enquired about the connections, transport, erection, steam curing, and overall economy of the prefabrication in comparison with standard construction.

August E. Komendant

Architect? Engineer? Why raise the question, why debate it? The important thing is to build. But, one can see immediately from this that the architect also has to be an engineer; without that he cannot seriously defend his idea.

Today there’s lots of talk of interdisciplinarity, but I’m of the opinion that there’s also an art to our own discipline and that one first needs to cultivate that. Our profession should be able to solve its problems by itself! Jean Prouvé Decision Tree by

Frank Newby

There is no demarcation between the role of an architect and that of an engineer, but rather a broadly interlocking interdependence. That’s why I’d rather not have attributions to any occupational groups in the captions. The Hagia Sophia was built by Anthemius of Tralles (amateur mathematician) and Isidore of Miletus (sculptor), it would have been foolhardy to appoint the latter as architect and the other as engineer. Stefan Polónyi

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Jürg Conzett

That the notion of dialogue or teamwork alone is not an agenda in itself is demonstrated by the products of greatly differing quality developed under this label. Interdisciplinarity as a slogan for the beneficial dialogue between architecture and related disciplines now belongs to the basic marketing vocabulary of many institutions, companies, and associations, but upon closer inspection, beyond the proclamation stage it often appears not to be very productive. At the technical-constructional level, one of the key problems currently facing the production of architecture is apparently the high degree of specialization: the progressive opening up of knowledge in many autonomous disciplines has led to an intrinsic fragmentation of experience, which manifests itself in ever more differentiated technical terminology. Construction expertise today is also coupled to an increasing amount of ever-changing market products. A non-hierarchical approach can easily lead astray inasmuch as it results in a kind of reversal of the causality in the designerly logic. The interdependence of structure, construction, space, and form at the level of collaboration between architecture and technology is self-evident—yet at the same time, it also seems clear that the structural engineer can only develop his design assumptions under certain conditions, which are also spatial in nature. The main prerequisite for a productive collaboration—in the sense of a “constructors’ dialogue”—in today’s clearly separated and specialized disciplines of engineering and architecture requires a common language and critical analysis with respect to hierarchy, chronology, and causality.

DIALOGUE? 215

Wilhelm Ritter

Arthur Vierendeel George Stephenson

Robert Maillart Othmar H. Ammann

Eugène Freyssinet

Heinz Hossdorf

Carl Culmann

Ove Arup

Konrad Wachsmann

Sir Jack Zunz

Frank Newby The professional ethos of civil and structural engineers is currently weak. Inadequate social recognition of the intellectual accomplishment is often given the blame for this. Of course, the importance of their role is not clear in the public mind, but in contrast to architecture, they also see themselves confronted to a lesser degree with the problem that their profession itself is being leveraged by general planners, prefabricated house builders, or private “bricolage”: in contrast to architecture’s perceived questions of pure taste, the engineer can at least calculate something that the layman does not believe he can do himself. Nevertheless—apart from the cult of star architects that has evolved over the last two decades—those architects who were outstanding in their time, their achievements, and their works are known within professional circles and they are accorded appreciative recognition. It is the contemporary generations of architecture students who show a rekindled desire for studying the masters, their work, and their efforts—because the digital noise has become boring. At the same time, a lack of knowledge about leading figures in engineering and their Felix Samuely

Buckminster Fuller

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August E. Komendant

Eladio Dieste

Peter Rice

Heinz Isler

Pierre Lardy

Identity Pier Luigi Nervi

Isambard Kingdom Brunel

Félix Candela

achievements, both generally and in the discipline itself, has been diagnosed: this is because their work and contributions have for the most part not received equal treatment in the architectural discourse and are extolled less, which is not only due to the lack of technical competence of the critics themselves, but also the dearth of role models. Lately the engineers, like the architects, are emerging as individuals and proactively* communicating the context of the works they have designed. They convey what they do and how they wish to be seen: engineering can be glamorous, thrilling, and sexy—alone the power of the dimensions! The contributions are perceived better and more deeply, and they are no longer attributed to the architects (alone), because the engineer has accepted communication as another core competence—he propagandizes his figure and has stepped out from his anonymity. Then the answer will also shed light on the question of why those engineers who admire the architects are not necessarily those who admire the engineers themselves.

Emily Roebling

*proactive (in the style of an architect) means, for example, sending catchy descriptions of projects to relevant professional journals for publication, or preparing exhibitions, monographs, etc., intended to reach a larger audience.

Gustave Eiffel

Eduardo Torroja

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Fazlur R. Khan

For Fuller, history was to be repudiated in favour of nature ... . Fuller invariably regarded construction as nothing more than a special case of man’s interaction with nature ... .

Our intellectual work and curiosity has been reduced today, to an alarming degree, to reading and applying the all too many standards. Many engineers have an inhibited relationship with their own background and are generally ignorant and incompetent on cultural issues. (2010)

Kenneth Frampton

Eugen Brühwiler In any professional activity ... there are two main important basics – knowledge and inspiration. Knowledge is the sum of truth or facts accumulated and systematized in the course of time; inspiration gives rise to thought, feeling, and spirit and guides or controls action. Knowledge without inspiration is dead. Inspiration without knowledge becomes decadent and untrustworthy.

The architectural tradition is what gives the creator, artist, architect or engineer the power of anticipation from which the creator knows what will last when he creates.

An ambitious structural engineer could not have found himself in a more opportune setting than Chicago in the late 1950s/early 1960s. The division between architecture and engineering, though present there as elsewhere, was balanced by an enduring recognition and appreciation of the city’s architectural heritage of structure partnered with architecture.

It helps to repeat oneself, if it is the case.

Fazlur R. Khan

August E. Komendant 218

Peter Handke

Yasmin Sabina Khan

TRADITION What is missing today in the education of the engineer is a course on the history of engineering so that he can locate himself in time and be given the opportunity to appraise the state of change in his specialization. (1988) Many of the concepts that had been central to his work (of my father) – fundamental concepts, such as perceiving a building as a vertical cantilever, utilizing the geometry of the structure to resist lateral loads, and minimizing structural premium for height – were emphasized once again. Understandably, each generation needs to work its way through a line of reasoning before moving on to uncover yet other structural principles.

Type is at its root a kind of constellation, and engineering is necessarily typological.

Specific answers to specific questions can in time produce generalized answers to generalized questions; and it is these generalized answers, which have been deduced from a whole series of specific solutions, that can eventually lead to a new architectural language and so to a new and useful vernacular.

Frank Newby

Traditionally there are completely different cultures of construction, which generally range between attempting the unbroken continuation of a tradition and, on the contrary, attempting to overcome this.

Nothing whatsoever comes from nothing.

Guy Nordenson Denys Lasdun

Quatremère De Quincy 219

Adolf Krischanitz

The impulses that lead to innovative achievements in civil engineering are as numerous and creative as the methods employed. Innovation can bear upon new structural inventions (e.g. introduction of the joint as the key for breakthroughs in lightness). Innovation can be fueled by the needs of new functions (new building types such as train stations or, today, CO2free cities) or new gigantic scales (euphoria of height and affiliated issues of oscillation). Innovation entails the development of new materials (e.g. erstwhile steel, concrete) or technology transfer (e.g. ferrocemento or the gerberette). New materials or new challenges thus bring new forms. But innovation also per-

tains to construction processes or issues of implementation themselves, determines the methods of calculation or design, generates rules, and thereby assures quality—although specifically-defined limits in the standards can also interfere with structural progress. Constructional innovation also leads—not only based on economic constraints—to new manifestations. Structural innovation is not conceivable without experience. A paradigm shift in architecture is often based on an engineering achievement (e.g. structural glazing), which was developed as a reaction to certain architectural concerns (e.g. dissolution of space). Starting with a material, structural spa-

INNOVATION Epistemology?

There has been much discussion of the identity of the engineer who first conceived of the concept of the “tube”, with a handful of engineers being so named. It seems to me that it was an idea in need of realization, making it not unlikely that several engineers more or less simultaneously came up with the same concept. In any event, I neither lay claim to nor do I disavow authorship, believing instead that ideas are creatures of their time, not of an individual.

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Leslie E. Robertson

Today’s computerized designs and fabrications have made all efforts of Konrad Wachsmann, Buckminster Fuller, Max Mengeringhausen, Frei Otto, and others obsolete. ... Hopefully our roof for the DG Bank Building in Berlin (architect Frank Gehry) represents a new freedom in design and fabrication, but this freedom must not be misused or it will end in chaos. The former discipline imposed on us by manual fabrication should be replaced by mental self-discipline.

Jörg Schlaich

tial consequences, in other words atmospheric qualities, can and must be explored. Because not every technical innovation necessarily also poses a spatial contribution. At the same time, technical aspects do not comprise a neutral set of knowledge that can be appended at the end. To what extent this is a dilemma or cross-fertilization in the research of the two disciplines—the engineers’ scientistic “pure” research and the freer, “applied” research of architects—arguably depends most notably on the personalities conducting the research and their understanding of the other discipline.

Our engineering is not tied to any one stylistic approach; it is responsive but also encourages appropriate innovation. This can be found at many levels, whether it is in the design of roads to maximize the use of unskilled labour and minimize the use of machines in the Third World countries; whether it is in the passive solar design of low cost housing to minimize heating bills; the use of materials in unfamiliar ways. ... or the underpinning of a five hundred year-old Cathedral. Innovation is not tied to a style, it comes from an enquiring open mind which strives for the most appropriate solution.

As a child, Müller thought he knew everything worth knowing. This was not the case—he was still a child—nevertheless it was absolutely conceivable.

Gyorgy Kepes

Robert Emmerson 221

Our media-based culture has, in the last twenty years, produced a new formal structuralism that focuses on rapid, inflationary visibility and immediate recognizability. In the new symbolization, buildings appear as jumbo-sized ornaments—the megastructure of a stadium today evokes images of a life preserver, car tire, or nest. Buildings become objects, things, abstract or figurative patterns appear to be transferable to any form whatsoever, independent of material and scale. Such ‘living structures’ place themselves at the service of bold ideas for branding

... a structural system which, being a style, could only emanate from an architect.

Frank Newby 222

and are subservient to iconographic, symbolically-laden pictorial language: the engineer develops the appropriate functional structure in order to make possible the “sculpture," the object, the painting of pictures by the architect. This hegemony of the symbol not only leads to an intrinsic denial of the space (which is legitimate for a sculpture, but is precisely what distinguishes it from an architectural space: internal and external form have no meaningful relationship to one another), but with such ‘design,’ the engineers are also led astray: hand in hand with it usu-

The resistant virtues of the structures that we are searching for depend on their form. It is because of the form that they are stable, not because of an awkward accumulation of matter. From an intellectual perspective, there is nothing more noble and elegant than resistance through form. When this is achieved, there will be nothing else that imposes aesthetic responsibility.

Eladio Dieste

ally comes the loss of the rational, of the economic, of the structurally evident—the technical maximization takes place without scrutiny of the spatial articulation. The Eiffel Tower had symbolic strength as well. Still, it differs considerably from today’s structural icons, because it certainly also simultaneously constituted an ingenious, masterly achievement, with calculations aimed at proportion and elegance.

Andrew Saint

... but now the relation between structure and architecture stood in danger of losing some of its dialectical discipline. In an art-obsessed world, the architect had dragged the engineer out of the temple of reason and beguiled him to worship in the temple of art.

I am also a house.

Duck (House)

For years they’ve asserted that I myself am a house—and suddenly they put down this huge nest for me?

SYMBOL 223

The morals of the future will be different than those of today, and those of today are different than those of yesterday. STRUCTURE + MORALS = The question of the relationship between art and technology = The question of the pressure of the construction on the space and to what extent this will be accepted by the architect = The question of the drama of loads and bearing = Persuasiveness of the space (the form) over the logic of a structural principle = The question of the dictates of gravity and how narrowly these are seen = The question of the honesty of expression

Your question is a valid one. The elements and their shapes, like the structure they form, evolve so logically from the architectural requirements that ‘structure’ and ‘building’ cannot be separated, the one evolves the other.

of the load-bearing traits of the structural parts = The question of the purity of the construction = The question of the mysterious and the apparent, the legible = The question of visual rhetoric and the logic of the form = The question of the constructional ethics The supremacy of the form (where is the space?) over the matter, over the structure or vice versa, is the central question that is continually answered anew in the debate between engineer and architect.

... the notion that it is of particular architectural value to make the structure visible has, in my opinion, been proven erroneous. The currently prevailing moral attitude toward structure is something fairly new. The Greeks were far less unequivocal in that regard.

Lou, do you consider your Medical Research Laboratory Building an architectural or a structural success?

When in doubt, for the space.

Eero Saarinen

Louis Kahn

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Roger Boltshauser

Denys Lasdun

With Freyssinet’s hangar at Orly, in view of its function and its context, no attempt has been made to transform it into art. The arch and its catenary or parabola shape have not been destroyed—you immediately see their purpose. ... But is that architecture? No! Not yet! Here is the work of a great engineer, not of an architect.

Some people are convinced that architecture will be outmoded and replaced by technology. Such a conviction is not based on clear thinking. The opposite happens. Wherever technology reaches its real fulfillment, it transcends into architecture.

Mies van Der Rohe

Auguste Perret

MORALS

The Greek column supports not because it is compelled to do so, but of its own accord. Max Raphael

The Hongkong and Shanghai Bank has become well-known for its architectural imagery ... as well as for many innovative features in its design and construction. ... All these features are interesting but the central issue here is that again despite the apparent and to many, appealing technical imagery, structural means have rightly been subordinated to architectural ends. ... so that the chosen solution owes as much to functional need as to aesthetic preference.

Jack Zunz

I am fascinated by structures that are refined in the sense that we recognize a certain presence, but do not realize straightaway how the structure works.

Aurelio Muttoni 225

Every bridge structure is a spatial object in the landscape that sets new limits, gives structure and rhythm to the space, and exists in a certain relation to its context. Bridge construction is consequently not exclusively a technical challenge, but just the same as a building, also an urban, spatial engagement with the place, time, and material. The form of a bridge is essentially shaped by its relationship between supporting structure and traffic surface. The factors of feasibility, durability, and economy impact with onerous force on the design,

exponentially more intense than with a building. The leeway for planning is narrower, and impossible to explore without knowledge of the modes of action, which is something the architect abruptly feels as the ‘design’ consultant. The number of bridges influenced by architects rises steadily—but to this day, the most impressive bridges actually appear to be unmitigated works of structural engineering. The architects’ contributions range from a focus on secondary elements like railings, lighting fixtures, etc., or show, on the other hand, tendencies toward the imposition

FROM SHORE T BRIDGING THE Excerpt from the jury report on the Negrellisteg competition, Zurich 2011 9. Conclusions The task was challenging: in the central urban setting of the Negrellisteg Bridge, the competition called for a built structure that meets the highest functional and aesthetic demands. It was necessary to develop, under economic constraints, a secure and permanent bridge construction that can be constructed without interrupting railway operations. Additionally, consideration had to be given to the valuable landmark-protected central railway control tower. The functional design and urban positioning of the access ramps proved to be a particularly difficult issue. All these aspects could be given different weight by the participants and the range of solutions submitted for the competition is correspondingly diverse. In some entries, an imbalance in elaboration of the architectural and engineering concepts can be discerned. Technically well-developed proposals foundered on functional and urbanistic shortcomings. Conversely, some structures appeared to have been subordinated to somewhat rash visual or sculptural aspirations, which in these cases resulted in structural proposals that were too inefficient and not always coherent. In its judgment, the jury tended to assess weaknesses in the structure as easier to correct than deficiencies in the urban planning; for this reason, the issue of the alignment of the bridge and its approaches for pedestrians and bicycles came before issues of the structure in the decision hierarchy. This stance should not be misconstrued as a lack of interest in issues concerning structural design; it is based much more on the insight that, for a bridge, the correct location and proper integration with the surroundings are necessary preconditions upon which a good structural design can first be established. The goal of finding solutions that are convincing in both architectural and engineering terms was difficult to achieve. The winning project is fascinating in terms of its generosity, technical innovation, and boldness. Its implementation will necessitate engaging developmental work that will lead to valuable experiences. Realized in such a fashion, the Negrellisteg Bridge will possess great radiance and enrich Zurich with a markedly distinctive structure.

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of visual, emblematic themes that are not very structural and ultimately dominate the bridge’s guise in an unfavorable manner. With bridge design, the architect can only be a viable consultant to an engineer if he brings along a solid fundamental/basic understanding and curiosity about the ties between design and form at a large scale. He must also be willing to endure ‘reality,’ meaning he must be prepared to sharpen his take on spatial aspects under harsh conditions—this will protect him from lapsing into the decorative through the pursuit of original ideas. Ultimately,

however, especially for bridge designs in the urban context, negotiating the issue of assigning relative weights to the urbanistic and structural criteria is key. This can not only be seen in Otto Wagner’s urban rail network in Vienna, but is also beautifully demonstrated by the current competition in 2011 for the Negrellisteg pedestrian and bicycle crossing in Zurich (see below).

TO SHORE E GAP

Sadly, many recently constructed bridges have forms imagined by architects, but as these chapters (of the book “The Art of Structural Design: A Swiss Legacy”) will show, the best bridges are purely the work of engineers. ...

The present tendency toward banal bridge engineering, even in prestigious projects, has led to the placing of architects, often so-called star architects, above bridge engineers. These architects, who consider bridge design only as a hobby or a market slot, are convinced that they can design bridges even though they have no structural knowledge. Certainly authorities, the public, and, unfortunately, even engineers themselves believe that.

Christian Menn

David P. Billington 227

The Earth’s surface, as we find it today, is the result of continual, gradual adaptation and mutation. The most profound modulation of the landscape and progressive urbanization has taken place over the last 200 years—a period that has also been massively influenced by the outcomes of engineering production. Within a very short time, gigantic infrastructure networks have been created in large territorial undertakings, ones which most likely will not be surpassed in their extent for a long time, and which will go down in history as the exclusive work of our epoch: in Europe, for example, highway construction was begun in the 1920s and was, in large part, completed by the end of the twentieth century. Fitting a highway into the terrain, especially in a mountainous area like that represented by the Alpine region, entails—along with matters of economics and convenience—a number

of technical issues: especially the initial, primary definition of the road alignment is decisive in establishing the degree of topographic sensitivity in which the various elements involved can be developed. Where will which type of highway structure be used, how will its insertion in the landscape be resolved, what manner of dealing with mass (terrain) displacements will be developed, what will the conceptual strategies be for constructing highway junctures? Although the economic significance of the entire infrastructure is indeed alone a reflection of its importance (which can also become a national burden, as shown by the morbid infrastructure in the USA), the spatial and visual impacts that depend on its quality are little known to most lay people and architects, often enough also among the engineers themselves. The fo-

INFRA The state, which uses laws, regulations, and townscape commissions to exert control over such things as, for example, the construction of a small vacation house, permits, on the other hand, that interventions of great scope and importance (roads, highways, water bodies, port facilities, dams...) can be realized without any significant aesthetic control. Rino Tami

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cus of interest—if at all—is placed on heroic works from the supreme discipline of bridge construction, where the engineering achievements are apparent and directly tangible. Too often, tunnels, retaining walls, underpasses, etc., are treated as objects of a secondary, ‘inferior’ category, and they are relinquished to vulgar utilitarianism: but it is precisely the imperative standardization and integration of industrial products pertaining to such structures, which demand great creative ability in the added need to deal with the constraints of the specific context. When the engineer is made aware of these opportunities, the importance of his active, major role in ordinary structural transformation will come across—this will also change the perception and appreciation of the public.

According to th e U.S. Departm ent of Transpor tion, more than ta25 percent of Am erica’s nearly 600,000 bridge s need significa nt repairs or ar burdened with e more traffic th an they were designed to carry. According to th e Federal Highw ay Administrat approximately ion, a third of Amer ic a’s major roadways are in su bstandard cond ition – a signifi factor in a thir cant d of the more th an 43,000 traf fatalities in the fic United States ea ch year. The Te Transportation xas Institute estim ates that traffi jams caused by c insufficient infr astructure was four billion hour te s of commuters’ time and nearly three billion ga llons of gasolin e a year. The As sociation of Stat e Dam Safety Of ficials has foun that the numbe d r of dams in th e United States could fail has gr th at own 134 percen t since 1999 to 3,346, and mor e than 1,300 of those are cons ered ‘high-haza idrd’ – meaning th at their collaps would threaten e lives. More than a third of all da failures or near m failures since 18 74 have happened in just th e last decade. Ac cording to the Environmental U.S. Protection Agen cy, aging sewer systems spill an estimated 1.26 trillion gallons untreated sewag of e every sing le year, resulting an estimated 50 in .6 billion dollars in cleanup cost http://theecon s. omiccollapseblo g.com/archives/ americas-crum bling-infrastruc ture

STRUCTURE Rino

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Ta m i ,

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PLASTICITY’S INFARCT Or: New Exoskeletonism*?

*Exoskeleton = supporting structure for an organism that constitutes a stable exterior shell around it.

It is on these occasions, when the structure is exposed and has to do more than to carry loads, that engineer/architect collaboration is essential. ... The architect and engineer must learn more about management and construction methods if they are not to have their positions in the design team replaced by energetic construction consultants and buildability experts.

Until the mid-1970s, the additional costs incurred by exposing more structure on the facade could be compensated through a less expensive building shell. With such external structures, the contribution of the engineer was clearly visible and required design abilities, above all in the formation of connections. Changing energy requirements and consequently, different design and manufacturing methods, have led to new relationships between load-bearing structure, space, and cladding—and thus to other spatial and sculptural qualities. What follows are spatial contradictions and ambiguities, and at the same time, new pinnacles of constructive feasibility continually arise. Time cannot be stopped in terms of constructive developments, but we are still poorly sensitized to the resulting consequences of great magnitude. The fact is that loadbearing structures—and with them the structural engineers—are being displaced more and more from the public realm and the field is left to the étui designers (architects and facade planners). Have we accordingly returned to the arrangement familiar in the train stations of the nineteenth century, in which the engineer overcame the large spans needed for the interior spaces and the architect styled the facade? With the ongoing renovation of most of the structural-sculptural buildings from the second half of the twentieth century, the last intertwined vestiges are also being obliterated—the world flattens; it loses depth. As counter-strategies, new exoskeletonisms are emerging in isolation, whose realization requires great constructive efforts and continually fuels the debate on the relationship between effort and return.

Frank Newby

A truss behind glass is always perceived as something different to a truss in front of a glass skin.

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Joseph Schwartz

The preservation of engineering landmarks is a topic that is steadily gaining importance. The most important prerequisite for ‘preservation’ is understanding how the existing work functions. For the engineer, the concept of ‘reconstruction’ is associated with the debate about the authenticity of a structure—above all with the question as to what degree present-day techniques can and should be employed for preservation. How are traditional handicraft techniques intertwined with modern engineering techniques? To answer these questions, the engineer must have a good understanding of not only how forces have historically been transmitted into the ground, but also what significance the structure had in its time and in its use. What effect was actually sought? How does one best deal with technically unimportant parts, which however served to produce a specific effect, a certain expression? To decipher the meaning of a historical structure, it takes the skills of a detective, and it raises the question of where the necessary educational training is obtained. Whether for the engineer or the architect: every intervention in the existing built substance is a delicate balancing act between maintaining recognizability of the past and inventing something new for the purpose.

AMNESIA Transformation

It’s about a conflict between the will to not compromise the original landmarked substance through reconstructed parts and the desire to not lessen the impact of the landmarked substance with the parts being replaced. ...That’s a conflict that has been around a long time—the difference between contemporary architecture and the older landmarked substance has taken on an irreconcilable magnitude that endures to this day.

Roger Diener

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A vast number of engineers understand the challenges within a design as being independent of architectural preferences, and thus they see no contradiction in the fact that they make contributions to very different architectural positions. The position of the architect is, so to speak, integrated as an additional parameter within the framework of constraints, in the initial ‘problem matrix,’ without questioning the ultimate goal. However, the development of a position appears to be no less important for the engineer than it is for the architect. The engineer is authoritatively

Actually, not much is known about the relationship of architects to engineers, and vice versa. It’s a furtive relationship. Who had what idea when in the process of planning and building—that only rarely reaches the public. If there’s any doubt, the architect is medially at the fore. At best, the engineer has taken the vision from creative heaven and brought it down to reality.

Engineers should learn from architects and take the unmistakable, individual attitude of project authors.

Peter Marti

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Dietmar Steiner

represented in a design team and can estimate the consequences (often better than the architect)—he can proactively bring his opinion into the discussion, because he ultimately has the structural and economic skills, that can at least bring into question the architect’s creation of imagery. Especially in his collaborations with architects, he can sharpen his cultural and spatial knowledgeability, enhance his know-how, and as an engineer-architect, challenge the architects anew.

I crave engineers who are less modest: they must also challenge me in my field.

Marcel Meili

A considerable amount of time must elapse ... before any individual can achieve singly a complete and easy mastery of both the architectural and the engineering technique. The engineer and the architect have a long road to travel before their separate roles can be played by one man.

Owen Williams

CHAMELEON FACTOR

The architect is not a service provider.

I have often wondered how I can find myself working equally happy with a variety of different architects. Indeed I often find I can be working on the same day with two or three architects who would find each other’s architecture very difficult to accept. ... To an engineer, the design challenge can be independent of the preferences of the architect and an effective contribution can be found in either case.

Today the question as to what constitutes good architecture is possibly more open than ever before. Nowadays there are no rules. The plethora of architectural styles all have their protagonists as well as their detractors. Anything goes and the public is confused. ... This clearly underscores the dilemma in which we as structural engineers find ourselves. What is right, what is sensible, when are we wandering into or being led into wilderness?

Jack Zunz Valerio Olgiati

Peter Rice 233

RISK On a meeting about the CCTV building, I heard one of Balmond’s engineers describe, without irony or noticeable wavering, how the encounter and eventual joining, at 200 meters, of sloping steel structures that, through their relative positions on the ground were exposed to different amounts of solar heat-gain, could only take place at dawn, when both had cooled off during the night and were most likely to share the same temperature. I was elated and horrified by the sheer outrage of the problem that we had set them. Why do they never say No?

Contrary to Architecture, which promiscuously embraces uncertainty and risk, engineering is defined through its avoidance of possible/certain failure. The events of September 11, 2001, were devastating. Knowing that the Empire State Building had been struck by a Mitchell bomber in 1945, we had designed the project for possible impact by a 707 aircraft; the design was for a low-flying, slow-flying 707. The 767s that struck the buildings were a bit heavier, but were flying at a maximum speed, imparting significantly higher levels of energy into the building than had been anticipated.

Rem Koolhaas

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Leslie E. Robertson

At the outset of the history of civilization, it was a matter of containing natural risks. Whereas the threats remain of a natural variety well into the pre-industrial world, today we must increasingly grapple with self-generated risks that force us to prepare for an increased chance of danger. The approaches to solving these problems are sought in a multiplicity of engineering services. The civil and structural engineer must provide the answers to questions about the necessity of materials, mechanics, structure, and systems. Anticipation of the structure’s behavior is an important part of his delicate mission. In the process, he moves along a tightrope walk that, on the one hand, starts from over-dimensioned emergency situations: the structures must be capable of withstanding the greatest possible risk that could occur at any time or in presumed time intervals (300-year avalanche, 100-year flood, 200-year earthquake, etc.). He must therefore be able to create plausible depictions of the risks and make suggestions for possible means of averting his predictions. The engineer is thereby obliged to dissuade the architect from going over the edge. Simultaneously, he must be able to follow him all the way to the edge, or even pose a challenge to go there. On the whole, the predictability of the risk is always relative; the risk is always something imagined; the objectification of risk from an intuitive and speculative dimension: experimentation and risk are twins. How far one ultimately goes, how far the technology is stretched, how far one financially leans out the window—the engineer carries the risk in the name of society—the responsibility for ensuring that a structure does not collapse. This burden, however, is not at all perceived until an emergency occurs, because the moral risk for the appearance of a building—whether it is perceived as beautiful or ugly, and consequently considered a success or not—is always ascribed to the (star) architect.

The tallest build ing in the world is located on a sit e that is intrins ically unsuitable for building a skys craper. That’s because Taiwan is situa ted at the junction betwee n the Eurasian and the Philippine tecto nic plates and is therefore predestined for earthquakes . Yet despite the earthquake haza rd and despite the typh oons that occa sionally ravage several times a year at speeds of up to 250 km/h across the islan d, chief architect Chun g Ping Wand be lie ve s in the stability of the tower. Even if all of Taipei were to collapse, he is firmly convinced that this high-rise wi ll remain standing. Georg Küffner

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August E.Komendant Hans-Jürgen Heinrichs

I have learned from experience that architects think just as analytically as the engineer; they simply focus on other parameters.

This idea of form emerging is a thing that really fascinates me: from a random start, how does it happen? It happens through control and continual feedback. Take the knight or horse move in chess. It is a two-one random move. It looks very arbitrary, but wherever you start on the chessboard, if you play it out, you get these patterns that emerge, a sort of equilibrium. If you start somewhere else on the chessboard, you get another pattern, and so it goes.

Louis Kahn advised students that an architect’s first task after receiving a commission and the program accompanying it is to change the program, not to try to satisfy it, but to put it in the realm of architecture.

With designs that go beyond the scope of that which can be proven by science—with visionary and artistically determined concepts— truth and fallacy are not contradictory but complementary.

Cecil Balmond

* The concept of “wicked problems” originated with the philosopher Karl Popper and was used in the 1960s by Horst Rittel, professor at the Hochschule für Gestaltung in Ulm (Ulm School of Design) as an approach to a design methodology. In 1992, Richard Buchanan seized on the term again in his essay “Wicked Problems in Design Thinking” (Design Issues, Volume 8, Number 2, 1992, p 5–22). In his essay, he hypothesizes that every designer has a personal set of positions that are developed and tested through experience. The inventiveness of a designer lies in his natural or cultivated artistic ability to be able, at all times, to draw upon these positions in order to apply them to a new situation or to discover aspects of the situation that have impact on the design.

Heinrich Schnetzer 236

WICKED

The concept of ‘design’ is not precise but speculative. Nowhere is the diversity of the two disciplines’ perspectives more evident than it is upon examining their argumentation and the consequent decision chains in a design process. The discipline of ‘design’ is often conveyed to the engineer in the form of a linear design model, because therein a logical understanding of a design process is seen. The procedure consists, in a first analytical phase, of defining as comprehensively as possible all elements of the design problem, as well as all the requirements needed for a successful solution (cost effectiveness, viability, sustainability, etc.) The aspects are usually reduced in the process to comprehensible, numerical ‘hard facts,’ are dealt with in written form (matrices), and remain unchallenged as a more or less neutral set of information. An individual, particular way of viewing the task or sensibilization for spatial aspects is neither promoted nor expected. In a second, synthetic phase, the different requirements are then combined and weighed against one another in order to reach the final product of design. This method suffers from the suggested linearity of phases 1 and 2 (analysis and decision making), because it disregards the fact that design problems contain a large degree of uncertainty and are characterized by a contradictory requirement—that they are so-called ‘wicked problems‘ These cannot be resolved linearly, but in fact require particular perspectives, subjective mental images, and opinions. These produce consequences and set in motion cascades of decisions. Each design problem, in other words, is unique and access to it is marked by individuality—accordingly, no analytical list can conclusively define the operations to be performed. Design problems never lead to correct or incorrect answers, but to better or worse ones. This complexity, produced by in- or over-determination of the design problem and the multitude of alternative perspectives on a single aspect, is engraved in the minds of architecture students from day one: in an almost inverse relationship to the engineer, the aspiring architect is confronted with the conflicting realities and is trained to bring these together for interaction. For this purpose, he must take up perspectives that are as individual as possible and develop particular intellectual ‘ideas.’ The architecture student is taught to reduce complex problems, sometimes accepting that concrete physical or programmatic aspects, so-called objective criteria, are neglected in favor of a ‘concept’—the ‘idea.’ If the engineer’s ‘scientistic’ approach to design suffers from an impossible linearity and the tendency toward self-contained sequences, the architect’s patterns of argumentation, on the other hand, often astonish just the same when they are robbed of all collective and universal humanistic principles and draw their intoxication solely from the sphere of the purely private, subjective, and intuitive.

Problems* 237

OPENING Each project, every cooperation is an opportunity to learn new things from it. This requires empathy for the problems of the other discipline and a strong mutual integration in the respective creative design process. The architect is thereby interested in an engineer who shows an interest and understanding of spatial issues. This he has obtained in the same way as the architect: empirically, through his own fundamental human experiences, which are based on elementary subjective impressions and have sensitized him to human behavior. This enables the engineer to avoid destroying the architect’s initially fragile spatial design concepts and instead to develop them, i.e. he is capable of proposing structural possibilities or materials for creating a specified spatial atmosphere intended to result in a certain effect. He can assimilate basic spatial ideas (e.g. protective space, observation space, vibrating space, etc.) and reformulate them into a new structural problem statement, without wandering astray from the central architectural moments. He has a feeling for the inner forces and a deep structural understanding, which is distinguished by how masterfully he can conceive and develop three-dimensional structures. He brings along the necessary technical and practical understanding and in the dialogue between architect and engineer, he remains—ideally without anxiety—the rational and reasonable voice. If, however, this same engineer—who is, so to speak, an ‘insider’—conversely expresses his deep uneasiness about a design approach, then usually something fundamental is terribly wrong and the arguments are to be taken seriously by the architect. The engineer, who views things in terms of their usefulness and has a functional and material understanding, senses whether the building will do justice to the task, e.g. whether the relationship between open and closed is harmonious or whether a material can achieve something or not, whether a material has the desired effect to its full degree, etc. The engineer must therefore be able to expect sensitivity for the ‘throes of construction’—tectonic, structural sensitivity—from the architect. In exceptional cases, not only is the architect not technically illiterate, but he himself has full knowledge of the flow of forces in all three dimensions of the building, all the way to its transmission into the earth. The level of the joint product is—similar to the evocativeness of the moves in a chess game—dependent upon the interpretative capabilities of the two players.

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Bibliography META-DIALOGUE John Galbraith: John Galbraith—Engineer and Educator, p. 113 BABYLON Symposiums in DAZ Berlin, 18 March 2010 / 21 April 2010 DIALOGUE? August E. Komendant: 18 Years with Louis Kahn, pp. 5/186 _ Jean Prouvé: World Architecture: Journal of the International Academy of Architecture, Issue 31-32, 1994 p. 67_ Jürg Conzett: TEC21 17/18, 2008, p. 15 _ Stefan Polónyi: E-mail from S. Polónyi to Aita Flury, February 23, 2011 IDENTITY TRADITION Kenneth Frampton: Casabella 542–543/1988, p. 119 _ Peter Handke: Ein Jahr aus der Nacht gesprochen [A year spoken from the night], p. 24 _ August E. Komendant: 18 Years with Louis Kahn, pp. 161/173 _ Fazlur R. Khan/Yasmin Sabina Khan: Engineering Architecture—The Vision of Fazlur R. Khan, pp. 12/59 _ Denys Lasdun: Denys Lasdun—Architecture, City, Landscape, p. 218 _ Adolf Krischanitz: Symposiums in DAZ Berlin, 18 March 2010 / 21 April 2010 _ Frank Newby: Casabella 542–543/1988, p. 120 _ Guy Nordenson: Seven Structural Engineers—The Felix Candela Lectures, p. 23 _ Eugen Brühwiler: TEC21 45/2010, p. 49 _ Quatremère de Quincy: motto, 1832 INNOVATION Leslie E. Robertson: Seven Structural Engineers, p. 69 _ Robert Emmerson: Casabella 542–543/1988, p. 121 _ György Kepes: Structure in Art and in Science, p. IX _ Jörg Schlaich: Seven Structural Engineers, pp. 144/145 SYMBOL Frank Newby: Casabella 542–543/1988, p. 121 _ Eladio Dieste: Eladio Dieste—Innovation in Structural Art, p. 187 _ Andrew Saint: Architect and Engineer—A Sibling Rivalry, p. 491 MORALS Denys Lasdun: Denys Lasdun—Architecture, City, Landscape, p. 208 _ Eero Saarinen: 18 Years with Louis Kahn, p. 19 _ Roger Boltshauser: often heard _ Auguste Perret: Les frères Perret, pp. 22/109 _ Jack Zunz: Structural Engineering—History and Development, p. 67 _ Aurelio Muttoni: “Starke Strukturen,” wbw 5/2009, p. 44 _ Max Raphael: Max Raphael—Tempel, Kirchen und Figuren, p. 183 _ Mies van der Rohe: Architectural Education at ITT 1938–1978, p. 62 FROM SHORE TO SHORE / BRIDGING THE GAP Christian Menn: Seven Structural Engineers, p. 126 _ David P. Billington: The Art of Structural Design—A Swiss Legacy, p. 13 INFRA-STRUCTURE Rino Tami: Rino Tami, p. 122 PLASTICITY’S INFARCT, OR NEW EXOSKELETONISM? Frank Newby: Casabella 542–543/1988, pp. 120–121 _ Joseph Schwartz: “Starke Strukturen,” wbw 5/2009, p. 43 AMNESIA TRANSFORMATION Roger Diener: Das Prinzip Rekonstruktion, p. 257 CHAMELEON FACTOR Jack Zunz: Structural Engineering, pp. 67/72 _ Marcel Meili: TEC21 3–4/2011, p. 34 _ Valerio Olgiati: TEC21 51–52/2011, p. 34 _Peter Rice: Peter Rice—An Engineer Imagines, pp. 145/147 _ Dietmar Steiner: Dialog der Konstrukteure, p. 17 _ Peter Marti: TEC21 3–4/2011, p. 34 _ Owen Williams: British Engineers Export Journal, July 1924, p. 30 RISK Rem Koolhaas: Content, pp. 498/515 _ Leslie E. Robertson: Seven Structural Engineers, p. 73 _ Georg Küffner: Ingenieurbaukunst in Deutschland, yearbook 2005/2006, p. 58 WICKED PROBLEMS* VERHEXTE PROBLEME Cecil Balmond: Seven Structural Engineers, p. 57 _ Heinrich Schnetzer: “Starke Strukturen,” wbw 5/2009, p. 44 _ August E. Komendant: 18 Years with Louis Kahn, p. 185 _ Hans-Jürgen Heinrichs: Max Raphael, Tempel Kirchen und Figuren, p. 10 OPENING

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Teaching In teaching architecture students about structures at ETH Zurich, Joseph Schwartz sees a priority in fostering an intuitive understanding of structures. Instead of analytical methods based on calculation, he relies on the clarity of a method, as offered, for example, by graphic statics. The visualization of internal forces illuminates the relationship between the stress on the load-bearing elements and their form. Christoph Wieser sees the interdisciplinary study program at ZHAW Winterthur as the foundation of an integrated consideration of spatial and technical questions. The synchronous design model gives engineering and architecture students an all-round awareness of the interaction of formal design and structural issues at different scales. Mario Monotti describes how structural engineering classes at the USI academy in Mendrisio are aimed at giving architects the expertise to select viable structural and geometric parameters for a load-bearing structure. Load transfer analysis and the behavioral models resulting from it can assist in devising structures that are more spatially efficient. Paul Kahlfeldt looks at the “Dortmund building model,” a joint training program for architects and engineers in which the communication of basic structural knowledge plays a central role without neglecting the issue of space. A student analysis is the starting point for Jürg Conzett, Roger Boltshauser and Aita Flury to spotlight the awareness of a productive overlap of the structure and the schedule of accomodation in architectural education.

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Structural Theory and Structural Design Joseph Schwartz

History  Analytical methods of calculation, which were developed primarily in the nineteenth century and were based on the theory of elasticity, allowed the planning and construction of increasingly more sophisticated structures. In the theory of elasticity, developed by mathematicians and physicists, the structural engineers were presented with a closed analytical model. This theory mathematically formulated ideal, linear, elastic behavior for the relationship between load, stress, and deformation. This placed the practice of engineering, as opposed to architecture, on a solid scientific base. It was accompanied, towards the end of the nineteenth century, by the beginnings of a split into the professions of architect and structural engineer. On the one hand, ever more complicated building methods required each to concentrate on its own specialties; on the other hand, it emerged during the twentieth century that the engineer’s outstanding scientific tools not only have benefits, but also significant risks for the development of the engineering profession as a whole—owing to the scientific approach on which the calculation methods are based. The development of classic structural analysis—based on exact science—was the product of a deductive, rational way of thinking. This caused the inductive approach to science to be pushed increasingly into the background.1 Conversely, there were also recurrent swings away from analytical methods of calculation, which brought much more descriptive methods to the fore. As an example, it is worth mentioning graphic statics, which was developed in the second half of the nineteenth century. During the twentieth century, the theory of plasticity was developed. This evaluates the bearing capacity of a structure by considering the plastic behavior of the materials, and not the way a structure behaves in use, as in the theory of elasticity. The application of the static limit load theorem of plasticity theory, in particular (see illustration: reinforced concrete beam according to Thürlimann et al., 1989), makes it possible to visualize internal forces with the help of lattice models and stress fields.2 Once it had been perfected, the theorem provided a solid theoretical basis for graphical analysis methods, which had been proposed since the beginning of the twentieth century (see illustration: reinforced concrete beam according to Mörsch, 1929).3

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1 Stefan Polónyi, Revision des Wissenschaftsverständnißes, [Revision of the concept of science], published by the School of Architecture of the Polytechnic/University of Kassel to mark the award of an honorary doctorate to Prof. Dipl. Ing. E.h. Stefan Polónyi, February 1986 2 A. Muttoni, J. Schwartz, and B. Thürlimann, Bemessung von Betontragwerken mit Spannungsfeldern [Design of concrete structures with stress fields], Basel: Birkhäuser Verlag, 1997 3

E. Mörsch, Der Eisenbetonbau, seine Theorie und Anwendung [Concrete-Steel Construction] 6th editon. Stuttgart: Konrad Wittwer Verlag, 1929

Reinforced concrete beam according to Emil Mörsch, 1929

Reinforced concrete beam according to Bruno Thürlimann et al., 1989

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Defining the Problem  The equilibrium equations based on the theory of plasticity and partially based on inductive methods have the big advantage, thanks to the visualization of the internal forces, of being able to illustrate the relationship between shape and stress in load-bearing elements. The corresponding calculation method, as opposed to the elastic calculation method, is well suited to creative design of structures and to the structural design of the supporting elements. The use of this method, however, requires creative thinking—and this seems to be a stumbling block. Engineers, especially, find it extraordinarily difficult to design structures creatively. A survey of the best work by the great engineers of the last century, however, makes clear beyond all doubt that these individuals stand out precisely because they did not restrict themselves to calculation for dealing with structural problems, but intuitively also took the approach of carefully tracking the internal forces (see illustration: Pier Luigi Nervi, Stadio Giovanni Berta [now renamed Stadio Artemio Franchi], Florence, 1932); it was this that enabled them to work creatively. The scientific tools developed from the theory of plasticity reached such a level of complexity in the late twentieth century that they increasingly represented a challenge to structural engineers in their already demanding work. The extremely useful tools of conventional structural analysis, on the other hand, offered many engineers a wall to hide behind. Structural calculations are still favored over conceptual thinking—an approach that gets in the way of creative work. The introduction of computer-based calculation programs in the 1980s, which even today are mostly based on linear elastic models, aggravated this negative trend. An attempt is being made in many schools to teach architecture students a simplified program of structural engineering. One motivation for this way of teaching is the need to introduce the students to the technical vocabulary and the methods of working used by structural engineers. The attempt, however, has proven to be less than successful because for one thing the condensed content is difficult to understand, and for another, it relates mainly to structural analysis and is barely suited to structural design. This situation appears to be one of the main causes of the difficulties that architects and engineers have when collaborating in practice. Method and Solution  A good structural design is worked out at a conceptual level, and during the conceptual phase, its calculation remains in the background. If structural engineers were more aware of this, they would increasingly resort to simple handwritten and mental calculations—something that might allow them the time needed to reflect and reactivate their creative faculties. During the conceptual phase in particular, it is imperative for the engineer to pay special attention to the internal forces, to make the load-bearing form congruent with these forces and, most importantly, to exhaust the possibilities offered by three-dimensional structural analysis. The qualitative evaluation of the forces using an inductive process—for example, graphic statics—does not require exact calculation, just practice and experience. This method is understandable to architects,

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Stadio Giovanni Berta [now Stadio Artemio Franchi] Florence 1932 Engineer and Architect Pier Luigi Nervi, Rome

too, and offers a good basis for working together. This approach is implemented at our institute in the program for students of architecture, limiting ourselves to teaching graphic methods of structural analysis, leaving out analytical methods completely. The photographs of students experimenting with the forces in cables, and of Álvaro Siza’s Pavilion of Portugal, in Lisbon, serve as examples of how students of architecture at the ETH Zurich gain exposure to the subject of cable and membrane structures. A course with a similar emphasis would also be very useful in the first semester of a structural engineering curriculum, before learning about structural analysis calculations. For collaboration between engineers and architects to bear fruit, openness to the other profession is essential. Prejudices need to be removed and mutual understanding needs to practiced as a basis for building up trust. A common language needs to be learned—an indispensable prerequisite for a close dialogue between the architect and the engineer. Successful cooperation between engineer and architect also requires trust as the basis for a sustainable personal relationship, together with social respect on both sides, a solid professional education, and an interdisciplinary view. It is essential to establish the proper awareness at university, so as to avoid turning out graduates who may well be thoroughly trained in their specialty, but remain largely ignorant of the building profession as a whole. The objective, therefore, is to communicate a culture that ought really to be expected in academic graduates as a matter of course. Every possible means must be used to strengthen the awareness that, besides the technical and architectural issues, there is an ethical and social duty to be carried out. This would be a culture in which the dialogue between architects and structural engineers can begin to grow—a culture that would enable the development of designs in which structural and formal needs merge.

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'Portugal Pavilion' in Lisbon, Álvaro Siza. From: J. Schwartz, lecture hand-outs for Structural Design I–III, 2008 and 2009

Experiment with forces in cables: workshop with first-year students at the Department of Architecture of the ETH Zurich

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Art and Science Christoph Wieser

Complementary interaction between architects and structural engineers at the Center of Constructive Design (ZKE) of Zurich University of Applied Sciences in Winterthur (ZHAW).

Collaboration between architects and structural engineers is common in the world of work, but infrequent during the years of study. The respective degree courses have long followed separate paths: although architecture students gain a basic knowledge of structural design and budding engineers learn how to approach simple design briefs, the other discipline’s way of thinking and working remains rather foreign to most of them. The trend towards greater specialization in the construction industry is driving different professions further apart. Closer, regular cooperation is badly needed, because the core form and the artistic form make up a unity, as Karl Bötticher 1 emphasized in 1844. A building without structure is inconceivable. The structurally necessary framework only becomes architecture if it takes the form of a spatial structure, if spaces are defined, materialized, and related to each other—in other words, when they gain shape and expressive character. At the School of Architecture, Design and Civil Engineering of ZHAW, we maintain a dialogue between the designers: in the first year, two full-day modules are attended jointly by students of architecture and students of structural engineering, taught by teams of staff from both disciplines. Structural matters continue to play an important role in the subsequent semesters of the architecture program, especially in design and in the course units offered by the Center of Constructive Design (ZKE). This education and research unit is a major component 2 of the school as a whole. It acts as an umbrella for separately conducted courses taught by teams with an interdisciplinary composition. This essay takes a closer look at collaboration between architects and engineers at the ZKE in the area of education. Role Models  The ZKE aims to be a skills center for ‘today’s art of building.’ Our modernization of the classic notion of the ‘art of building’ assumes its undiminished relevance: the claim to consider cultural and design issues alongside technical and economic ones as a unified whole. We continue to see the roles of architects as being those of generalists. They work as designers and coordinators, refining the premises of building itself in team work, against the backdrop of today’s standards and requirements. What contribution to this should the structural engineer be making? How is cooperation implemented in the work of education? One thing is certain: the mentalities of students of architecture are different from those on the structural engineering course. Socialization within the one profession

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1

Karl Bötticher, Die Tektonik der Hellenen [The tectonics of the Hellenes], Potsdam, 1844; excerpts printed in: Werner Oechslin, Stilhülse und Kern [The Evolutionary Way to Modern Architecture: The Paradigm of Stilhülse und Kern], Zurich/Berlin: gta/ Ernst & Sohn, 1994, p. 181

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The other major component, the Center for Urban Landscape, concentrates on studying the city and human settlement

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cf. Christoph Wieser, ”Vom Aussenseiter zum Vorbild. Die Rolle des Ingenieurs in der Ideologie des Neuen Bauens“ [From outsider to role model. The role of the engineer in the ideology of Neues Bauen], in: Dialog der Konstrukteure, catalogue of the eponymous exhibition at the Zurich Architecture Forum, May 2006, pp. 23–28

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Per Olaf Fjeld, Sverre Fehn. The Thought of Construction, New York: Rizzoli, 1983, p. 44

differs from the other (exemplified, for instance, in their different working hours) and of course their main interests lie elsewhere. For these cultures to enrich each other, it takes a willingness to engage with what the others are thinking and doing, and a readiness to learn something from which one’s own work may only benefit indirectly. Because neither can assume that their counterpart has the same understanding—concerning terminology at the very least—they need to explain their own point of view more clearly than they would to colleagues within the profession. Structural engineers are generally regarded as precise thinkers and cool calculating machines; in the early days of the Modern Movement, they were hyped by the architectural avant-garde as the epitome of the New Man, who is objective, sober and entirely rational in his work.3 At the same time, these architects saw in the engineer a ‘noble savage’ in the sense propagated by Jean-Jacques Rousseau, because, being free of the weight of tradition, they supposedly acted in the spirit of the age, seemingly unconsciously—or in other words, instinctively. This crude merging of rational and irrational aspects to form an ideal image may seem strange today, but it highlights an important point: engineers, too, have to develop a ‘feeling’ for a problem and to find pleasure in ‘beautiful’ and ‘elegant’ solutions; they have to be able to ‘estimate’ consequences and they need good ‘intuition’—all attributes that are readily ascribed to architects. Conversely, architects do not, of course, simply design on the basis of a gut feeling. Drawing up compelling solutions requires a large dose of persistence, self-criticism, and a clear mind. In his book on the Norwegian architect Sverre Fehn, Per Olaf Fjeld writes that construction is the expression of logical thought.4 Just as structural considerations can be employed as a design tool for refining a draft, the precision of the engineer’s way of thinking also helps to give a structure an understandable logic. In educational work this is evident, for instance, in the fact that when the load-bearing structure is unclear, there is often something wrong with the whole design. In other words, if teachers from both architecture and engineering were to evaluate students’ designs, each bringing their expertise to bear, both aspects would be covered. This complementary interaction requires a lot from all the parties involved—not least, tolerance—and brings with it the possibility of failure, because their differences are numerous and cannot simply be explained away. At the ZKE, we decide the composition of teaching teams and select the semester’s design project in such a way as to do justice to the different requirements and situations of the two disciplines with respect to the arts and the sciences. Of the courses offered by the ZKE, the interdisciplinary approach is perhaps most clearly manifested in the “Basic Structural Design” unit, during the first year of study, and in the two “Structural Project” and “Structural Research” units at master’s level. Basic Structural Design (First Year)  Nearly a hundred students take the full-day “Basic Structural Design” unit in the first semester. Two thirds of them are studying architecture, one third structural engineering. Half of the teaching team consists

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Basic Structural Design (first-year unit) Analytical exercise: objects from Nature, the construction industry and daily life are examined with the aim of discovering the reasons underlying their composition. In addition, the effects of the shape-preserving framework (structure) in interaction with the other parameters of an object (function, form) are analyzed and documented—in this case using a horsetail. Teaching staff: Frank Mayer (arch), Daniel Meyer (eng). Students: Reto Bleiker, Alessandra Kanne (arch); Lars Thaler, Valentino Tesic (eng); autumn semester 2009–2010

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of structural engineers and half of architects. The focus lies on the relationships of structure and space, of design and form. The lectures are given by teams of teachers from both disciplines, who also jointly supervise the two exercises focusing on analysis and design. The students, too, work in mixed groups. This empirical approach to education and training is based on the idea that experience gained through observation and experiment is a reliable source of knowledge that leads to an understanding of the whole. The unit’s educational concept does not reflect the division of labor involved when architects and structural engineers cooperate in the real world. The aim is, rather, to lay the foundations necessary for their future cooperation as equal partners, allowing them to search for solutions together.

Basic Structural Design (first-year unit) Generic design exercise: construct a simple, architecturally and technically considered load-bearing structure. The focus is on the interrelationship of structure, space, design, and form. Civil engineering issues are an essential part of the brief, in this case to design underground rooms with natural lighting and rudimentary protection from wind and weather. Teaching staff: Frank Mayer (arch), Bruno Patt (eng). Students: Patric Barben, Nina Jud (arch); Roger Straub (eng); autumn semester 2008–2009

Structural Research (Master’s Program)  In the “Structural Research” unit at master’s level, which takes up one day a week and is run by one member of staff from architecture and one from engineering, students deepen their understanding of the interdependence of material, structure, and the expression of form in architecture. The relationship between method of construction, structural design, and formal design is critically analyzed on the basis of known concepts of design, with the intention of exploring potentially innovative construction methods and novel uses for materials. In analytical exercises, students acquire the ability to describe structures and grasp the concepts behind them. Findings from this research serve as a resource for further work, design case studies in which students are encouraged to find their own way of applying the principles previously learned. The focus is either on questions of structure or of specific materials, depending on the semester’s theme: structural behavior might be examined, or the structural properties of materials might be analyzed for their innovative potential. The brief does not require a final design scheme, instead the focus lies on inquisitive research and experimental construction. The unit is designed to mediate between education and research: aspects of research at the ZKE are selected and studied as part of the teaching program. Students expand their accustomed way of working by acquiring elements of analytical research, while results from their semester work feed back into the research.

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Structural Research (master’s program unit) The structural potential of sheet metal in the contemporary context has, as yet, hardly been investigated. A hands-on workshop exercise is the starting point for a search for innovative methods of construction and application. For the construction of a pavilion, trapezoidal sheets were connected in differing alignments to form rigid panels, spaced internally by cylindrical elements made of twisted metal strips. Teaching staff: Alexis Ringli, Katharina Stehrenberger (arch), Reto Bonomo (eng). Students: Stephan Flühler, Andreas Pfister (arch); autumn semester 2008–2009

Structural Project (Master’s Program)  Two days a week in the master’s program studio are spent acquiring grounded design expertise in the development and implementation of complex architectural and structural concepts. Structural design is assigned a core status, with technical, spatial, material, cultural, and structural aspects among its facets. The method of the course differs from the usual didactic structure by postulating a synchronous design process. In contrast to the linear design process, which is characterized by a step-by-step progression from large scale to small, the parallel processing of different scales, subjects, and design aspects is intended to reinforce the research-based approach and, through concurrent analytical, pictorial, and structural means, to turn individual areas into fruitful catalysts for others. The method makes it possible to design large construction projects, despite the brief duration of the semester, by focusing on the load-bearing structure or the choice of material, for example, in relation to the architectural design and then exploring it in greater depth. The laboratory character of our design teaching, in which issues are addressed and non-traditional projects are developed, allows us to expand the room for maneuver, which in the real world of building is often very

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Structural Design Project (master’s studio unit) This production building for a quarry, with a range of uses, is designed as a long, prefabricated timber structure. The requirement to design a space without internal columns to accommodate a crane runway acts as the spatial and structural catalyst of the design solution: very deep Vierendeel girders spanning the entire width of the building. Teaching staff: Astrid Staufer, Beat Waeber(arch), Daniel Meyer (eng). Students: Patric Furrer; autumn semester 2006–2007

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tight, being defined by building codes and costs, as well as demands on functionality and structural realities. This opens up an area that can be used to develop the art of building further. That is where the thesis projects come in: students define a topic by themselves, in consultation with the ZKE, which they then explore, with a focus on research and analysis, by producing a design of their own. Structural Design as a Design Generator  The joint course unit for first-year architecture and structural engineering students at the ZKE and its institutionalized collaboration between teachers of architecture and engineering are not a ‘forced marriage’ or the result of an educational experiment. They rather express our conviction that structural design can be used as an overall design generator. This requires a thorough understanding of the spatial/architectural and technical/ structural parameters of building, as well as the cultural and material ones—an understanding that is easily swept away by the flood of images propagated in architecture today. The emphasis on the structural element in the study of architecture at ZHAW is a tradition. Robert Rittmeyer, a partner in the Winterthur architects’ practice of Rittmeyer + Furrer, which produced buildings of national significance in the early decades of the twentieth century, taught at the School of Building Technicians, as our school was called at that time, from 1899 to 1933. In a letter to the technical school supervisory commission in February 1903, he wrote: “According to the program and purpose of the school [...] it is not the exterior composition, but the structural design in the plans that plays the largest role, and it is in this that the students are encouraged to be independent, as far as possible, without wasting time.”5 In essence, this credo has remained unchanged. The Italian Renaissance, which at the time served both as a style to imitate and as a model for practicing design skills, has long since had its day. A partnership between the architect and the engineer, on the other hand, is something that we continue to strive for, despite all the difficulties.

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Letter to the president of the technical school supervisory commission, Regierungsrat A. Locher, Zurich. Written in February 1903 by Robert Rittmeyer, signed by the teaching staff of the building section. Source: State Archive of the canton of Zurich, files on Technikum U 113

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Constructing as a Science Mario Monotti

Engineers are trained in analytical thinking based on mechanical principles: daily tasks are abstracted from reality and, using rational and empirical methods, they are explained and quantified. On the other hand, the didactic path of architects is based primarily on mental and cultural imagery: in search of optimal spatial relationships, everyday programs are put in relation to their context. Evidently, the weaknesses of both disciplines are already predetermined in their training. The first group masters the ‘rules of the construction’ without regard to the context and the program, whereas the second lacks the means to give tangible form to the spatial concepts. The significance of the “constructors’ dialogue” will first be brought into discussion by way of an example illustrating the structural behavior of a slab as a spatially defining element. This theme serves as the basis for a presentation of the didactic path at the Accademia di architettura in Mendrisio. Example: Analysis of a Slab  As a main component of many load-bearing structures, a slab represents an optimal conceptual platform for the engineer as well as the architect. Surprisingly, this building element is only seldom recognized as a design object. The reason for this is the structural redundancy, which allows for the independence of design and dimensioning through multiple equilibrium states. With these constraints, the importance of the dialogue between the disciplines and the rudimentary organization of structural engineering are both already evident. The cognitive model transitions from the analysis of the slab’s structural behavior and the interpretation of the resulting design model to a spatial structure of great efficiency. The Structural Engineer’s View  The behavior of a structure is ascertained by examining the flow of forces. In slabs, loads are transferred by lateral forces. From the analysis of these magnitudes, which means formulating the vertical equilibrium at an infinitesimal element, one discerns that the transfer of forces in the slab only takes place in a certain direction, namely the principal direction. Like with a beam, the flow of forces requires a change in moment perpendicular to the direction of load transfer, which is clearly defined by the variation between the principal moments. The trajectories of the load transfer and the principal moments determine

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the slab redundancy. For the transfer of forces in a slab, it is proposed to split this structure into a sandwich construction in which the core is assigned the shear stress while the sandwich’s outer layers assure the moment resistance. This model representation is the basis for dimensioning the slab. The principles of the flow of forces and the dimensioning relate to a slab element without regard to the surroundings. The Influence of the Architect  By specifying the slab’s boundary conditions, the architect defines the equilibrium problem of the slab. The load transfer from one slab element to another and ultimately to the supports is resolved by integrating the equilibrium relationships. In mathematical respect, the boundary conditions delimit the selection of the principal stress trajectories and determine the value of the principal stresses along the stress paths. In a practical sense, the boundary conditions define the structural task of the system, which is to conduct the forces to the points of bearing. Even though nearly any selection of boundary conditions enables an equilibrium state, an unfavorable definition of the boundary conditions impairs the efficiency and structural behavior of the structure. Constructors’ Dialogue  Beginning with an analysis of the transfer of forces and working with the resulting behavioral model of the slab, changing the scale of the sandwich model by scaling it up to the height of a story leads to an innovative spatial system of great efficiency: increasing the static height—the rigidity—by a factor of 100 results in an ability for the span to increase by a factor of 10. By changing the scale of the load-bearing structure, the constructors’ task description is redefined. The forces flow around usable space, and disposition and organization of the sandwich core—of the space—involves both the engineer and the architect. Analogous to the representation of the shear trajectories as elements for dividing space, by resolving the principal moment trajectories in the sandwich’s outer layers, a closer relationship between form and structural behavior is achieved in shell structures. Conclusion  Mechanical principles and freedom of spatial organization are the instruments needed to divide the building discipline into the fields of engineering and architecture, and also to reunite both in the constructors’ activities. In fact, good mechanical skills can also lead to makeshift solutions, whereas the freedom of spatial organization constitutes the basis for defining an appropriate and optimal structural system. It is significant to note that structural analysis encompasses both fields: structural properties and innovations are elicited from the dialogue between the constructors. Structural Engineering in Mendrisio  The University in Mendrisio solely offers the training to become an architect. This is, on the one hand, conveyed theoretically in the form of historical-humanistic and technical-scientific lectures and, on the other hand, trained as a practical activity in the form of semester projects carried out in the design studio. The theoretical education builds upon selected lec-

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Development of a sandwich structure, competition for a new building for the Natural History Museum St. Gallen, 2009 Architect Francesco Buzzi, Locarno Engineer Mario Monotti, Minusio

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tures during the six semesters of the bachelor’s program and a range of electives in the following three semesters of the master’s program. Structural engineering is taught in the bachelor’s program in one lecture course each semester. The objective of the course is to convey the structural fundamentals as well as design skills that are related to construction. It implies scientific description of the constructive task in all its complexities. With reference to the example of the slab, it is a matter of attaining the expertise for choosing plausible structural and geometric boundary conditions for the load-bearing structure. The first two semesters provide an introduction. Load-bearing structures are presented through the progressive mastery of geometry, by analyzing the flow of forces with the aid of structural diagrams, and also paying special attention to parameters for construction and efficiency. Under the title “Structures of Buildings,” the third-semester course builds upon the introductory lectures by applying the design criteria to complex load-bearing structures. Individual structural elements are assembled into a stable system and the required building dimensions are determined by limit analysis. In the upper semesters (fourth to sixth semester), the building materials steel, reinforced concrete, and wood are examined in-depth. At center stage are the implications of the various materials on the dimensioning principles, as well as the material-specific procedures and specific construction requirements. At the beginning of the study program, the design studio is at the core of the didactic path of instruction, and its goal is to implement the theoretical education in planning activity. In this framework, concrete projects are implemented in small working groups (about twenty-five students) under the direction of the design professors and their teams of assistants, with the involvement of visiting professors for ongoing support throughout the semester and at interim and final presentations. The studios constitute continual experimental research, whose findings permanently nurture enthusiasm for the program and support the subject matter taught in the lectures. With regard to the students’ enthusiasm, the design of the structure can be thought of as the tailoring of a suit. Efficiency, elegance, and reconciliation with the general objectives can engender curiosity, and these can be brought as a message into the working groups. The needs of the studio activity formulate the core of the open content of the lectures in the master’s program, which augment the basic knowledge gained in the bachelor’s program by engendering fascination for the achievements of constructors. The training is limited to the five-year program of study, but is intended to have continued and lasting effects for an entire lifetime. As a starting point for establishing an independent constructor-culture, the program has recently been amended to require master’s students to formulate two theoretical works. Identity and Tools of the Constructors  A professorship in structure at an architecture school is a privileged position for strengthening both the identity and the tools of constructors through research activity. Instead of pursuing architectural and

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engineering research that is focused on either detailed numerical analyses of discrete construction details or defining scientific methods and insights, the thoughts of the ‘constructor’ should instead combine the results of these two approaches, provide an overview, and avoid problems by using pragmatic strategies. The power of the ‘constructors’ philosophy’ can be seen in the slab example: only conscious and systematic examination of a structure can enable an increase in the span with a sandwich construction.

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Construction Transforms Material into Space Paul Kahlfeldt

At TU Dortmund, engineers and architects have been teaching and conducting research within a joint faculty since the educational institution’s founding at the beginning of the 1970s. The students in both programs of study are taught the basics in the construction of buildings and load-bearing structures, building history, construction economics, and building physics in joint lectures, exercises, and seminars. A central focus of the education is composed of three projects of differing complexity that are integrated into the course of studies, and which each constitute the respective culmination of an educational unit. Pairs of engineering and architecture students work together on a design project, from the formation of a conceptual idea to working out the construction details. The first project in the third semester comprises a small house, the second project in the fifth semester consists of a multistory office or apartment building, and the third project in the seventh semester is a complex task such as a bridge, a high-rise building, or a conversion. The projects are each conceived and supervised by both an architecture and an engineering chair. Additional chairs—like building services engineering, building physics, building materials science, and the building sector—are integrated and serve the ambition of providing training that’s as close to reality as possible. Two aspects define the project work: First, wherever possible the students receive a specific and comprehensive knowledge of issues concerning construction. The transfer of knowledge and an orientation towards practical applications have priority. Second, reciprocal influences on the design and the conceptual idea are thematized. Particular attention is paid to the creative implementation of the construction and its artistic significance for the architectural space. Working together serves to establish, at an early stage, respect for differing concerns and to integrate them into a coherent, unified work. Reunification of Architect and Engineer  Upon establishing the “Dortmund model”—the joint education of architects and engineers—there was the desire to override the distance, and the associated isolation of the professions, discernible since the separation and specialization of the areas of responsibility in the nineteenth century, in order to restore the necessary unity of construction and architectural significance. This approach is recognized to this day as being necessary and is intensively pursued further. Thus joint education also constitutes the central

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Choir vaulting of St. Vitus Cathedral in Prague, 1385 Architect Peter Parler

substance of the new bachelor’s and master’s degree programs. Given the continually changing requirements, the substantive positioning and theoretical fundamentals are subject to shifting treatment and an attendant redefinition of the respective self-image of architect and engineer. Beyond the Fashionable to the Meaningful  The basis and indispensable foundation of contemporary training remains the teaching of basic knowledge of construction in all areas of the building industry. The experimental exploration of new construction methods and the application possibilities for components made of new materials are self-evident constituents of the exercises, in which their necessity, purpose, and architectural significance are addressed beyond serving a fashionable aspiration for originality. Given a perceived sense that apparently no restrictions whatsoever exist anymore when building today and that each and every absurd idea somehow appears feasible, the evaluation criteria are concentrated on the question of the architectural. The two-way debate does not relate to the feasibility of possibly spectacular construction methods, but to the anticipated spatial benefit. At least since Friedrich Dürrenmatt’s 1960s play, The Physicists, a moral component of production has emerged in the natural sciences. The mathematical temptations of an unnatural load transfer solely for its own sake must be confronted: “It works, but it’s not right!” Functionality vs. Artistic Identity?  Taking a precise position appears to be urgently needed these days, since without clarification of intentions, neither productive collaboration between engineers and architects is imaginable, nor is adequate training with a clear tenor attainable. The problem touches upon the traditional perception of roles and the still customary assessment of achievements. The scientification of the world since the nineteenth century apparently also necessitated the specialization and division of work between architect and engineer in the building industry. For architects, engineers, and especially for art historians, the assessment of the findings and results takes place to this day according to the same rules and perceptions determined in the early twentieth century: that a putative new era already shines from the train stations and exhibition halls erected solely in iron and glass, and the facades and entrance buildings designed by the architects remain locked in a formal historicism that must be overcome. This classification and assessment defines one of the theories behind a self-image that pays homage to the technological possibilities, even though today a distinct transformation is emerging, especially in the public mind. The intellectual idolization of both the abstract reduction toward nonexistent design and the formal minimization of all issues is opposed by a desire for visual understanding and appropriate significance. With the Romantic traditionalists of the guild, who in their ostensible simplifications sought ultimately to attain a goal that is firmly established forever, their view of architecture and construction—which comes from and is restricted by ‘modernism’—reveals two convictions:

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1.  In terms of architectural and art history, what is of importance for the nineteenth century are primarily the engineering achievements. They are precursors of a ‘modernism’ that needed to show little or no regard for architectonic questions and which spawned ‘honest’ constructions that revealed themselves. The loadbearing elements are reduced to that which is calculated to be necessary, and the material used is sufficient unto itself. Aside from some indisputably impressive spaces, however, the architectural details were thereby degraded to structural ornamentation, and the space of construction was reduced to a diagram of building physics. The homage paid to the functional form honors the engineer, and ever since, a technical solution alone is misunderstood as being design in itself. Thus what remains today for the architect is merely the artistic demeanor of an artist, and the technical universities serve as educational institutions. 2.  Everyday construction—the functional building without architectural significance, whether an industrial building or the conventional residence—has forfeited all craftsmanly and regional conventions whatsoever and follows purely commercial, functional, and technical requirements. Mass dissemination impairs the appearance of our cities and landscapes, and what has resulted is the call for more pleasing and attractive design. The competence for this, in turn, is assigned to the architects, and they get the task of taking what are actually self-evident and proven constructive solutions and ‘intensifying’ them in design terms. Once a mark of craftsmanship, today’s detail is ingenious, becoming a ‘work of art’ that often yields structural damage. Construction as an Integral Component  The inference drawn from the observations is that architecture is to be understood once again as the art of construction, as a cultural and intellectual achievement within ordinary construction. Significance only emerges when all the concerns are given equal consideration. Neither the construction nor the form nor the technology has the right to dominate the architectural form, that is, the space. It remains the result of an idea materialized through the construction. The construction is, in other words, architecturally necessary and must accordingly be ‘correct,’ but not necessarily visible or technically honest. Recognition of the indispensability is also the basis of the structural understanding and the form-giving representation of the construction. Commensurate with this significance, the construction is an integral and not singular component of a solution that is indeed found jointly. Viewing the result, this complexity comes across as impressively simple, as do a Gothic cathedral’s choir or the Neue Nationalgalerie by Mies van der Rohe. It is essential to establish links and to learn this self-image once again.

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Ceiling of the Neue Nationalgalerie in Berlin, 1968 Architect Mies van der Rohe

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Program and Structure Roger Boltshauser, Aita Flury and Jürg Conzett

Excerpt from the summer semester program 2009, Faculty of Construction and Design, HTW Chur [Chur University of Applied Sciences]. Lecturers in design: Roger Boltshauser, Aita Flury, Maurus Frei, Andreas Hagmann. Supervisor for structures: Jürg Conzett

Phase I — Analysis A building is like a human, an architect has the opportunity of creating life. The way the knuckles and joints come together make each hand interesting and beautiful. In a building these details should not be put in a mitten and hidden. Space is architectural, when the evidence of how it is made is seen and comprehended. One day I visited the site during the erection of the prefabricated frame of the building. The crane’s 200-foot boom picked up 25-ton members and swung them into place like matchsticks moved by the hand. I resented the garishly painted crane, this monster which humiliated my building to be out of scale. I watched the crane go through its many movements calculating how many more days this ‘thing’ was to dominate the site and the building before a flattering photograph of the building could be made. Now I am glad of this experience because it made me aware of the meaning of the crane in design, for it is merely the extension of the arm like a hammer.

Louis I. Kahn 1

As a preliminary to the design brief for a new hotel in the city of Chur, we will examine projects with structural transitions. What the designs to be analyzed have in common is that, in one way or another, they try to explore the boundaries of structural engineering. To this end, different structural systems and construction methods are used, which bring specific spatial effects with them. The reasons for using multistory structures with bridge-like dimensions are usually derived from the schedules of accommodation, or other constraints, specific to the situation, that require large, column-free spaces and therefore broad spans. Whether shear-wall/ slab designs, articulated truss structures, Vierendeel girders, suspended structures, or special ceiling solutions are concerned: all of the projects examined are ones in which the architects (or engineer-architects!) have accepted the influence of the structural concept on the space. Looking at the last twenty years, both an increased architectural interest in large spans and a new trend towards the three-dimensional exploitation of structures are discernible. In contrast to many of the examples listed here, today’s efforts often

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1

From: Heinz Ronner, Sharad Jhaveri, Alessandro Vasella (eds.), Institute of History and Theory of Architecture, Swiss Federal Institute of Technology (ETH) Zurich, Louis I. Kahn. Complete Works 1935–74, Basel and Stuttgart, 1977, p. 116

All images: Boots Factory extensions in Beeston/Nottingham, 1935–38 Engineer and architect Owen Williams Model: students of the HTW Chur, Michael Krähenmann, Lukas Mürner

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primarily end up producing sculptural forms with large cantilevers, or converting images/ornaments/objects from another order of scale (see the chapters “Ornament and Material” and “Synthetic” in Elementares zum Raum/A Primer to Space by Aita Flury and Roger Boltshauser). Conversely, the fascination of the examples selected for analysis is that these designs are often the result of appreciating the unique use of their spaces. The designers try to respond to a specific schedule of accommodation by reinterpreting it using surprising structural ideas. It is often the relationship between ‘served spaces’ and ‘servant spaces’ in such cases, as well as their treatment, that leads to greater diversity in the structural design. In many cases, this is accompanied by the need for particular attention to special coordination between the structural system and the building services, but also by a sense for the beauty of the design and building site (see Louis Kahn). Excerpt from Student Coursework. Students: Michael Krähenmann, Lukas Mürner  The design of the factory for the production, storage, and distribution of dry goods at the Boots site in Beeston, England, came from the pen of an engineer-turned-architect, Owen Williams. It was built from 1935 to 1938. The functional brief (dictated by the production process) required three different zones (1. delivery, storage; 2. production of pharmaceuticals; 3. packaging, dispatching) which resulted in a specific arrangement of volumes in the design. The loading and unloading docks, the raw material sorting area, and the preparation area are accommodated in two single-story side wings, which dock onto a five-story building. In the latter, the materials are transported by elevator to the top floor, from where they make their way back down via pipes in the course of the manufacturing process. The load-bearing structure is interesting, because it responds to the fundamental needs of the production process and emphasizes them in a surprising way. The structure of the high part of the building consists of flat floor slabs and expressive, geometrically stylized flared columns that run in two rows for the entire length of the building. The structure of the roofs over the single-story parts is especially remarkable: it consists of massive, Z-section beams that are poured together so as to form an open coffered ceiling, allowing the space to be lit naturally from above. These beams all project 9 m or 15 m beyond the facade, creating column-free covered spaces for the loading docks. Particularly impressive is the interface of this roof structure with the side facade of the five-story structure (see illustration). In order to keep the zone beneath the 15 m projection free of columns, the Z-section beams in this transitional area are suspended from concrete ‘tubes,’ which at first sight seem to be attached to the facade, running up the outer face like chimneys and dominating its appearance. In fact, they are suspended from external roof beams, which themselves rest in turn on the flat-slab-and-flared-column structure. The vertical ‘hangers,’ moreover, are formed as hollow boxes: this allows them, in addition to their sculptural potential, to accommodate ventilation ducts (see Louis Kahn, Richards Medical Research Laboratories, Philadelphia). With the intention of creating a specific quality of space in a certain area, the forces are ‘taken on a

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Boots factory D6 ‘Drys’ in Beeston, Nottingham, 1935–38 Engineer and architect Owen Williams Model: students of the HTW Chur, Michael Krähenmann, Lukas Mürner

walk’ from the bottom to the top and back down again—in effect directly reflecting the production sequence. The load-bearing structure thus contributes to the spatial impression of the building envelope—something that is difficult to achieve nowadays, owing to modern energy-consumption requirements.

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Authors and Interview Partners Christoph Baumberger is a senior research fellow at the Institute for Environmental Decisions (IED) at ETH Zurich and a member of the Centre for Ethics at the University of Zurich. From 2001 to 2006 he was a research assistant with the Philosophical Seminar at the University of Zurich, served from 2003 to 2005 as a lecturer at the School of Art and Design in Zurich (HGKZ), and was a visiting lecturer in 2004 at the F+F School of Art and Media Design. From 2005 to 2009, he taught within the program Master of Advanced Studies in Applied Ethics. In 2009 he earned his Ph.D. with the dissertation Gebaute Zeichen: Eine Symboltheorie der Architektur, Frankfurt am Main, Ontos, 2010. Elisabeth Boesch studied architecture at ETH Zurich, and together with Martin Boesch, has an architectural practice in Zurich that specializes in various forms of building within the existing fabric. She has held a guest professorship for design at EPF Lausanne and was a longserving board member of the Zurich Architecture Forum. She regularly serves on juries and as a consultant to townscape committees and the canton of Zurich’s Commission for the Protection of Nature and Cultural Heritage, and is vice president of the Federation of Swiss Architects. Martin Boesch studied architecture at ETH Zurich, and together with Elisabeth Boesch, has an architectural practice in Zurich that specializes in various forms of building within the existing fabric. He has held guest professorships at EPF Lausanne, HfBK Hamburg, ETH Zurich,

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and the Institut d’Architecture Université de Genève (from 1997 until the institute’s closure in 2007). He currently holds a Sutor professorship at HafenCity University in Hamburg and a professorship at the Accademia di architettura USI in Mendrisio. Roger Boltshauser is the principal of Boltshauser Architekten in Zurich. The firm has approximately thirty employees and realizes projects for educational, residential, and administrative buildings. Moreover, his practical activity places an emphasis on research into rammed earth construction, such as with the Rauch House in Schlins, which was constructed in collaboration with the pioneer of rammed earth architecture Martin Rauch. From 2004 to 2010, he was a lecturer in design at HTW Chur and the Chur Institute of Architecture (CIA). Jürg Conzett is a partner in the engineering firm Conzett Bronzini Gartmann in Chur. The firm has twenty employees and is instrumental in bridge construction and building design, and the treatment of existing structures plays an important role in the work. In 2010 Jürg Conzett curated the Swiss contribution to the Biennale in Venice, entitled “Landscape and Structures.” Aita Flury is curator of the exhibition “Constructors’ Dialogue: About the Collaboration of Civil Engineer and Architect in Switzerland.” From 2006 to 2010 she was lecturer of design and architectural theory at HTW Chur and the Chur Institute of Architecture (CIA). Her work as a self-employed architect

includes collaborations with Roger Boltshauser, and in addition, publications, exhibitions and symposia on architectural issues. Her most recent publication is A Primer to Space: Roger Boltshauser Works, Vienna: Springer, 2009. Carlo Galmarini earned his civil and structural engineering degree in 1977 from the ETH. From 1977 to 1985 he worked with Max Walt AG, and since 1985 with the firm Walt+Galmarini AG. Selected built works include: Hürzeler House in Erlenbach with Peter Märkli, Coca-Cola logistics center in Dietlikon with Matteo Thun, “OUI” Expo. 02 with M. & E. Boesch, Hallenstadion in Zurich with Pfister Schiess Tropeano, Park Hyatt Zurich with Meili Peter, Letzigrund Stadium in Zurich with Bétrix & Consolascio, Prime Tower Zurich with Gigon / Guyer, Bern waste incineration plant with GraberPulver, Toni site in Zurich with em2n. Andreas Hagmann has run an architectural practice in Chur with Dieter Jüngling since 1990. The constructed projects originate primarily from competition entries and commissioned studies. The work is broadly diversified and embraces no only educational, residential, and administrative buildings, but also includes banks, a military facility, and a museum. The buildings are often characterized by concepts and spatial articulation creating large, column-free spaces. Additionally, various restorations of protected landmark buildings and larger refurbishment projects have recently been undertaken.

Paul Kahlfeldt received vocational training as a joiner and finish carpenter, and he studied architecture at TU Berlin. He has an architectural practice together with Petra Kahlfeldt and has held a chair in building construction at the University of Kaiserslautern. He earned his Ph.D. at TU Delft with a dissertation on the influence of the structural principles of brick construction on architectural design. He currently holds the chair in principles and theory of building construction at TU Dortmund. Adolf Krischanitz is an internationally active architect with offices in Vienna and Zurich. Along with residential, educational, and laboratory buildings, such as a research laboratory on the Novartis Campus in Basel, he has realized numerous buildings for art and culture, such as the refurbishment of Joseph Maria Olbrich’s Vienna Secession building and construction of the Temporäre Kunsthalle Berlin, as well as additions and renovations for the Rietberg Museum in Zurich and currently, the 20er Haus in Vienna. He is co-founder of the magazine UMBAU and professor for urban renewal and design at the Berlin University of the Arts. His newest publication is Adolf Krischanitz: Architektur ist der Unterschied zwischen Architektur, Ed. Uta Graff, Ostfildern: Hatje Cantz, 2010. Mario Monotti is full professor in structural engineering at the Accademia di architettura in Mendrisio and the owner of the engineering firm Studio d’ingegneria Dott. Ing. M. Monotti, based in Minusio. In 1999 he received his degree as civil and structural engineer, and in 2004 he earned his Ph.D. under Prof. Dr. P. Marti at ETH Zurich. From 2004 to 2006 he was with the firm dsp Ingenieure & Planer AG in Greifensee, where his work included designing the structure for the Leutschenbach school complex in Zurich by the architect Christian Kerez. In 2007 he founded his own engineering firm, and since then

he has participated in the dialogue between engineer and architect by taking part in team competitions. Aurelio Muttoni is civil and structural engineer and, since 2000, professor of structural engineering at EPF Lausanne. He is concerned with research on reinforced concrete construction and teaches aspects of civil and structural engineering to both engineering and architecture students. From 1996 to 2000 he was professor of structural engineering at the Accademia di architettura in Mendrisio. As a civil and structural engineer, he has many years of experience in the design of highway structures and has worked together with numerous architects as a structural designer. Christian Penzel studied industrial design and architecture in Hamburg and Berlin. From 2003 to 2008 he was chief assistant to the chair for architecture and technology at ETH Zurich with Markus Peter and Peter Märkli, focusing on research and academic work. Since 2004 he has run his own architectural practice in Zurich, and together with the civil and structural engineer Martin Valier, runs an architecture and engineering practice in Zurich and Chur. In the context of this collaboration, diverse and ambitious construction projects are developed and realized, where the close alliance of load-bearing structure, construction, and design takes on a primary role. In addition, he holds a position at the Lucerne University of Applied Sciences and Arts and works as a freelance author for professional journals. Markus Peter is a partner of the architectural practice Marcel Meili Markus Peter Architekten, which was founded in 1987. The first built works were constructed in 1993, and in addition, many studies and experimental projects have been undertaken. Along with the architectural projects, urban design schemes and large-scale planning projects have

over time taken on an equally important role. Since no specialization is sought, the work encompasses a broad range of programs. Marcel Meili has been professor of architecture at the ETH Studio Basel since 1999, and Markus Peter is professor of architecture and technology at ETH Zurich. Marco Pogacnik has been professor of architectural history at the Università Iuav di Venezia since 1998 and has also taught at the following universities: University of Applied Sciences in Potsdam, Graz University of Technology, TU Dortmund University, and the University of Innsbruck. At the IUAV Faculty of Architecture in Venice, he directs a research group focusing on the relationship between architecture and the engineering sciences (www.iuav.it/artecostruire). His research topics are dedicated to Modernism in a historical context between the eighteenth and twentieth centuries. Currently he is working on a national research project about Italian architecture of the 1950s and ‘60s. Stefan Polónyi has had an engineering practice with various partners since 1957. From 1965 to 1973 he was a full professor of structural engineering at TU Berlin. From 1973 to 1995 he was professor of load-bearing constructions at TU Dortmund University. He was also cofounder of the Faculty of Civil Engineering and of the Dortmund model for integrated learning of architecture and civil engineering. His degrees include Dr.-Ing. E.h. from the University of Kassel (1985), Dr. h.c. from TU Budapest (1990), and Dr.-Ing. E.h. from TU Berlin (1999). He is a member of the Akademie der Künste and in 2007 he was an external member of the Hungarian Academy of Sciences. Distinctions include: Médaille de la Recherche et de la Technique (Académie d’Architecture, Paris) 1993, and the Grosser DAI-Preis 1998.

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Urs B. Roth received his architecture degree from ETH Zurich. After completing his studies, he was an assistant to Heinz Ronner and a research associate at the Institute for the History and Theory of Architecture (gta) at ETH Zurich, where he oversaw the archived legacy of his father, Emil Roth. From 1979 to 1992, he had his own architectural practice with Xavier Nauer. Since 1991 he has been working as a 'geometric engineer' under commission from numerous architectural and engineering firms, and since 1981 he has been a lecturer in spatial and geometric construction and design at the Zurich University of the Arts (ZHdK). Renato Salvi, after receiving his degree from ETH Zurich in 1981, completed the Sapienza courses in Rome on the restoration of historical buildings. As an assistant to Flora Ruchat-Roncati at ETH Zurich and together with her, he won the competition for the Transjurane highway in 1988 and established a joint venture for working on the project from 1988 to 1998. In 1998 he opened his own practice, Salvi Architecture, in Delémont in order to continue the work on the highway structures. Subsequent to his assistance of professor Vincent Mangeat at EPF Lausanne, from 1999 to 2000 he was guest professor at the University of Barcelona, where together with professor Aurelio Muttoni, he directed the course on structure and architecture. Mike Schlaich has been a partner at Schlaich Bergermann & Partner (Stuttgart, Berlin, and New York) since 1999, and has been professor for conceptual design and development with the Institute of Civil Engineering at TU Berlin since 2004. He studied civil and structural engineering at the University of Stuttgart and at ETH Zurich, and earned his Ph.D. from ETH Zurich in 1989 under professors Anderheggen and Thürlimann.

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Heinrich Schnetzer received his degree from ETH Zurich in 1988. He subsequently served as an assistant to Prof. Dr. C. Menn, and earned his Ph.D. between 1997 and 2000 under Prof. Dr. Peter Marti at ETH Zurich. Since 1993 he has been a partner in the engineering firm WGG Schnetzer Puskas Ingenieure in Basel. The field of activity focuses on bridge construction and structural building engineering in both concrete and steel construction. As a civil and structural engineer, he has many years of experience in pursuing complex structural concepts. Joseph Schwartz has been a full professor of structural design at ETH Zurich’s Faculty of Architecture since February 2008. In 1981 he received his degree from ETH Zurich’s Department of Civil Engineering and earned his Ph.D. in 1989 under Bruno Thürlimann. From 1989 to 1999 he held diverse teaching positions at various Swiss universities of applied sciences . From 2001 to 2008 he was a lecturer at the Fachhochschule Zentralschweiz. From 1991 to 2001 he was a co-owner of an engineering firm in Zug, responsible for the planning and construction of diverse bridge and building projects. Since 2002 he has run his own engineering firm based in Zug. Joseph Schwartz is president of SIA’s Bridge and Structural Engineering group and president of the commission overseeing SIA masonry standards. Judit Solt studied architecture at ETH Zurich. Since 1998 she has been a freelance architecture critic and journalist, with numerous published works appearing in newspapers, periodicals, and books, and has made many contributions to conferences and event series. From 2000 to 2007 she served as editor of the architectural theory magazine archithese. Between 2004 and 2007 she was a lecturer in architectural criticism at ETH Zurich, and from 2007 to 2008 she was a lecturer on architectural theory

at HTW Chur. Since October 2007, she has served as editor-in-chief of TEC21, a professional journal for architecture, engineering, and the environment. Yves Weinand is architect and engineer and founder of the firm Bureau d’Etudes Weinand in Liège (Belgium). Since 2004 he has been a professor at, and director of, the IBOIS laboratory for timber construction at EPF Lausanne. There he leads an interdisciplinary team of architects, engineers, mathematicians, and computer specialists, who conduct research into timber ribbed shells as well as folded and woven timber structures. He is currently working on projects in which timber is used for the load-bearing structure, such as a skating rink in Liège and the parliament building in Lausanne. Andrea Wiegelmann is an editor, an author and journalist for architecture, design and photography, and a maker of books. Since 1996 she has worked as a freelance journalist. From 2002 to 2007 the trained architect served as editor of the architecture magazine DETAIL and from 2007 to 2011 as editor for Birkhäuser Verlag. She writes as a freelance journalist and author for numerous magazines. Christoph Wieser is director of the Center for Constructive Design (ZKE) at the School of Architecture, Design and Civil Engineering of Zurich University of Applied Sciences in Winterthur (ZHAW). During the period 1997–2003 he was an assistant at ETH Zurich, and in 2005 he earned his Ph.D. and began teaching at ETH Zurich. Since 2006 he has been a lecturer in the master’s degree program in architecture at ZHAW, and since 2009 the director of the ZKE. From 2003 to 2009 he was editor of the magazine werk, bauen + wohnen, he has also given many lectures, and has contributed to numerous publications.

Literature Architects + Engineers = Structures Ivan Margolius, Chichester: WileyAcademy, 2002 Surface Structures in Building: Structure and Form Fred Angerer, London: A. Tiranti, 1961 Architektur & Tragwerk [Architecture and structure] Stefan Polónyi and Wolfgang Walochnik, Berlin: Ernst & Sohn, 2003 Mit zaghafter Konsequenz: Aufsätze und Vorträge zum Tragwerksentwurf, 1961–1987 [With tentative consistency. Essays and lectures on designing structures, 1961–1987] Stefan Polónyi, Ulrich Conrads, and Peter Neitzke, Braunschweig: Vieweg, 1987 “Architektur und technisches Denken” [Architecture and technical thinking] Daidalos, vol. 18, Gütersloh: Bertelsmann, 1985 18 Years with Architect Louis I. Kahn August E. Komendant, Englewood NJ: Aloray, 1975 An Engineer Imagines/Peter Rice Peter Rice, London: Artemis, 1994 Structure as Space: Engineering and Architecture in the Works of Jürg Conzett and his Partners Mohsen Mostafavi (ed.), London: AA Publications, 2006

Die Geschichte der Ingenieurbaukunst aus dem Geist des Humanismus [The history of structural engineering in the spirit of humanism] Paulgerd Jesberg, Stuttgart: Deutsche Verlagsanstalt, 1996

Structures, or Why Things Don’t Fall Down J. E. Gordon, London: Penguin Books Ltd, 1978 2nd ed., Cambridge, MA: Da Capo Press, 2003

Light, Wind and Structure: The Mystery of the Master Builders Robert Mark, Cambridge, MA/London: The MIT Press, 1990

The Art of Structures: Introduction to the Functioning of Structures in Architecture Aurelio Muttoni, Lausanne: EPFL Press, 2011

Pier Luigi Nervi: dai primi brevetti al Palazzo delle Esposizioni di Torino 1917–1948 [From the first patents to the exhibition hall in Turin 1917–1948] Claudio Greco, Lucerne: Quart, 2008 Costruire correttamente: Caratteristiche e possibilità delle strutture cementizie armate [Building correctly: the characteristics and potential of reinforced concrete structures] Pier Luigi Nervi, Milan: Editore Ulrico Hoepli, 1965 Scienza o arte del costruire? Caratteristiche e possibilità del cemento armato [Building as science or art? The characteristics and potential of reinforced concrete] Introduction by Aldo Rossi Pier Luigi Nervi, Milan: Città Studi Edizioni, 1997 Structure and Form in Modern Architecture Curt Siegel, Huntington, NY: R. E. Krieger Pub. Co., 1975

L‘Architecture et les ingénieurs: Deux siècles de réalisations [Architecture and engineers: two centuries of building] Sylvie Deswarte and Bertrand Lemoine, Paris: Le Moniteur, 1997 Philosophy of Structures Eduardo Torroja, Berkeley: University of California Press, 1958 L‘Art de l‘Ingénieur: Constructeur entrepreneur inventeur [The art of the engineer: designer entrepreneur inventor] Antoine Picon, Paris: Le Moniteur Centre Georges Pompidou, ADAGP, 1997 Sergio Musmeci Organicità di forme e forze nello spazio [The unity of forms and forces in space] Manfredi Nicoletti, Turin: Testo & Immagine, 1999 Structural Engineering: History and Development R. J. W. Milne (ed.), London: E & FN SPON, 1997

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Arups on Engineering David Dunster (ed.), Weinheim: Wiley-VCH, 1996 The Art of the Structural Engineer Bill Addis, London: Artemis, 1994 Grenzüberschreitungen im Entwurf [Crossing boundaries in design] Departement Architektur der ETH Zürich, Andreas Tönnesmann, Zurich: gta Verlag, 2007 Casabella 542–543 [Double issue on engineering in architecture] Milan: Electa, 1988 Engineering Architecture: The Vision of Fazlur R. Khan Yasmin Sabina Khan, New York/London: W. W. Norton & Company, 2004 Architect and Engineer. A Study in Sibling Rivalry Andrew Saint, New Haven, CT: Yale University Press, 2007 The History of the Theory of Structures: From Arch Analysis to Computational Mechanics Karl Eugen Kurrer, trans. Philip Thrift, Ernst & Sohn, Berlin 2008

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Image Credits Flury Aita 01 Page 11 bottom left, Fred Angerer, Bauen mit tragenden Flächen: Konstruktion und Gestaltung, Munich, 1960 02 Page 11 bottom right, ibid., p. 57 03 Page 13 top right, Science et Vie, 1960 04 Page 14 center, Josef Killer, Die Werke der Baumeister Grubenmann, Dietikon, 1998, p. 127 05 Page 14 bottom, Zurich Cantonal Building Department Pogacnik Marco 01 Page 22 top, Zeitschrift für Bauwesen, 1865, from: ETH Library, Zurich, Rare Books Collection 02 Page 23 top, Zeitschrift für Bauwesen, 1872 03 Page 23 bottom, Janos Frecot & Helmut Geisert, Berlin in frühen Photographien 1857–1913, Munich, 1984 04 Page 26 top, Zeitschrift für Bauwesen, 1870 05 Page 26 bottom, Frecot & Geisert 06 Page 27 top, Zeitschrift für Bauwesen, 1870 07 Page 27 bottom, Frecot & Geisert 08 Page 29 center, Franz Reuleaux, Über den Maschinenbaustil, Braunschweig, 1862, Deutsches Museum Munich 09 Page 29 bottom, ibid.

Wieser Christoph 01 Page 34, Sigfried Giedion, Bauen in Frankreich, Leipzig/Berlin, 1928 02 Page 36 top, J. M. Richards, The Functional Tradition in Early Industrial Buildings, London, 1958 03 Page 37 top left, Fritz Block, Probleme des Bauens, Potsdam, 1928 04 Page 37 top right, ibid. 05 Page 37 center right, ibid. 06 Page 37 center left, ibid. Penzel Christian 01 Page 43 top left, Peter Carter, Mies van der Rohe at Work, London, 1999, p. 118 02 Page 43 top right, Phyllis Lambert, Mies in America, Montreal, 2001, p. 376 03 Page 43 center, ibid., p. 386, 4.214 04 Page 44 top left, Yasmin Sabina Khan, Engineering Architecture, The Vision of Fazlur Khan, New York, 2004, p. 91 05 Page 44 top right, Mir M. Ali, Art of the Skyscraper, The Genius of Fazlur Khan, New York, 2001, p. 55 06 Page 45 bottom left, Khan, p. 84 07 Page 45 center, ibid., p. 97 08 Page 45 bottom right, Architectural Record, vol. 139, 1966, p. 161 09 Page 47 marginal note, Christian Penzel 10 Page 48 Peter Rice, An Engineer Imagines, London, 1994, p. 43 11 Page 49 top right, ibid., p. 32 12 Page 49 top left, ibid., p. 32 13 Page 49 center, ibid., p. 116 14 Page 50 bottom left, Rem Koolhaas, Bruce Mau, S, M, L, XL, New York, 1995, p. 694 15 Page 50 bottom right, ibid., p. 674 16 Page 50 bottom left, el croquis 53+79, 1998, p. 89

17 Page 51 top from left to right, Koolhaas & Mau, S, M, L, XL, p. 677 18 Page 52 bottom, top fig., el croquis 53+79, 1998, p. 224 19 Page 52 bottom, bottom fig., ibid. 20 Page 52 bottom right, Arch+, 117, 1993 21 Page 54 top left, Rice, p. 108 22 Page 54 top right, Cecil Balmond, informal, Munich, 2002, p. 286 Baumberger Christoph 01 Page 59 top, Aita Flury, Zurich 02 Page 60 top, Process Architecture 23 (1981), p. 69 03 Page 60 top, marginal note, Process Architecture 23 (1981), p. 64 04 Page 61 bottom left, Jürg Conzett, Chur 05 Page 61 bottom right, Hans Rigendinger, Chur 06 Page 63 top left, Ruedi Walti, Basel 07 Page 63 top right, Miller & Maranta, Basel 08 Page 64 top Christian Kerez, Zurich 09 Page 64, marginal note, Ralph Feiner, Malans 10 Page 65 bottom, Ralph Feiner, Malans 11 Page 68 top, Hans Kollhoff / Helga Timmermann, Projecten voor Berlijn, Antwerp, 1994 12 Page 70 top, Jüngling & Hagmann Architekten, Chur; Conzett Bronzini Gartmann, Chur Conzett Jürg All photographs and plans are from the Adalberto Libera archives and are printed here by courtesy of Marco Pogacnik; all sketches are by Jürg Conzett.

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Weinand Yves 01 Page 94 top left, Markus Hudert, IBOIS, EPF Lausanne 02 Page 94 top right, IBOIS 03 Page 95 top right, Markus Hudert, IBOIS 04 Page 95 center to bottom, IBOIS 05 Page 96 top and center, ibid. 06 Page 96 center bottom, ibid. 07 Page 96 bottom, ibid. 08 Page 97 bottom, ibid. 09 Page 98 bottom, Masoud Sistaninia, IBOIS 10 Page 99 top, IBOIS 11 Page 99 center, Bastien Thorel, IBOIS 12 Page 99 bottom, ibid 13 Pages 100 and 101, Steve Cherpillod, IBOIS Flury/Conzett 01 Pages 104–113 Gabetti & Isola archives, Turin Model Photos Aita Flury, Zurich Peter Markus 01 Page 134 top left, Meili PeterArchitekten, Zurich 02 Page 134 top right, Heinrich Helfenstein, Zurich 03 Page 135 bottom, Meili Peter Architekten 04 Page 136 bottom, Heinrich Helfenstein Hagmann Andreas 01 Page 139 top, Arthur Rüegg, Ein Hauptwerk des Neuen Bauens in Zürich: Die Doldertalhäuser 1932–1936, gta catalogue, 1996, p. 101 02 Page 140 Stefan Schenk, Lüen 03 Page 141 bottom left, ibid. 04 Page 141 bottom right, ibid. 05 Page 142 Ralph Feiner, Malans 06 Page 144 top, ibid. 07 Page 144 bottom, ibid.

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Schlaich Mike 01 + 02 Pages 148 and 149 Gehry Partners LLP, Los Angeles; Schlaich Bergermann & Partner, Stuttgart 03 Page 150 Schlaich Bergermann & Partner Boltshauser/Flury/Conzett 01 Page 155 bottom left and right, Bernard Rudofsky, Architecture Without Architects, New York, 1964, pp. 152, 154 02 Page 156, Jürg Conzett, Chur 03 Page 157 ARGE Boltshauser Flury, Zurich 04 Pages 158 and 159 ibid. Polónyi Stefan 01 Page 162 center left, Polónyi archive, Cologne 02 Page 162 center right, ibid. 03 Page 162 bottom, ibid. 04 Page 163 top and top marginal note, E. Wittmann, Cologne 05 Page 163 marginal note, Polónyi archive, Cologne 06 Page 164 bottom, ibid. 07 Page 165 top left, J. Wiesmann, Dortmund 08 Page 165 top right, Polónyi archive 09 Page 166 entire top, ibid. 10 Page 166 center left and right, City of Gelsenkirchen 11 Page 166 bottom, Polónyi archive 12 Page 166 entire bottom, D. Münzberg, Bielefeld 13 Page 167 G. Schülke, Dortmund Salvi Renato 01 Page 169 Aita Flury, Zurich 02 Page 170 bottom left, ibid. 03 Page 170 right, Renato Salvi, Delémont 04 Page 171 top left and right Thomas Jantscher, Colombier 05 Page 172 top left, Yves André, Saint-Aubin-Sauges 06 Page 172 top right, Salvi 07 Page 172 center left, right and bottom ibid. 08 Page 173 ibid.

Boesch/Galmarini/Roth/Solt 01 Page 176 M. Boesch, Zurich 02 Page 177 top, center and bottom, M. & E. Boesch Architekten, Zurich 03 marginal note, Sol LeWitt Drawings 1958–1992, exhibition catalogue, Gemeentemuseum Den Haag, 1992 04 Page 181 top left, M. & E. Boesch Architekten 05 Page 181 top right, Urs B. Roth, Zurich 06 Page 181 center left, www.physicstogo.org 07 Page 181 center right, Roth 08 Page 181 bottom, M. & E. Boesch Architekten 09 Page 182 M. & E. Boesch Architekten Krischanitz/Flury All plans by Krischanitz & Frank Architekten, Zurich, Berlin Schnetzer/Schwartz/Muttoni/Flury 01 Page 196 top, WGG Schnetzer Puskas Ingenieure, Basel 02 Page 196 bottom left, Aita Flury, Zurich 03 Page 196 bottom right, WGG Schnetzer Puskas 04 Page 200 all figs. Studio Vacchini, Locarno 05 Page 203 top and bottom, Caspar Schärer, Zurich 06 marginal note Flury 07 Page 205 Flury Flury Aita Collage concept and contents: Aita Flury, Zurich Graphic implementation: gut&schön, Zurich

Image Credits

Schwartz Joseph 01 Page 244 top, E. Mörsch, Der Eisenbetonbau [Concrete-steel construction], 6th ed., Vol. 1, part 2, Stuttgart, 1929, p. 161 02 Page 244 center, A. Muttoni, J. Schwartz, B. Thürlimann, Design of Concrete Structures with Stress Fields, Basel, 1997, p. 42 03 Page 246 Claudio Greco, Pier Luigi Nervi, Lucerne, 2008, p. 103 04 Page 247 top, Bauen mit Beton [Building with concrete], issue 2002/03, cemsuisse (Swiss cement industry confederation), Bern, p. 42f. 05 Page 247 center, Joseph Schwartz et al., Structural Design III, lecture hand-outs, Chair of Structural Design, ETH Zurich, 2009, p. 31 06 Page 247 bottom, Chair of Structural Design archives, ETH Zurich Wieser Christoph pages 251–254, all image rights ZHAW Monotti Mario 01 Page 259 Studio Buzzi&Buzzi, Locarno Kahlfeldt Paul 01 page 265, Kahlfeldt Architekten 02 page 267, ebd. Conzett/Boltshauser/Flury 01 Page 270 top, Archive, Boots Pure Drugs Company Ltd., London 02 Page 270 center, Michael Krähenmann, Chur, Lukas Mürner, Zurich 03 Page 270 bottom, Archive, Boots Pure Drugs Company Ltd., London 04 Page 272 Michael Krähenmann, Chur, Lukas Mürner, Zurich

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Acknowledgements This publication is intended as a discursive contribution to an important subject. The essays collected here were mostly written as general and position papers for two symposia held in 2010 to accompany the “Constructors’ Dialogue” exhibition at the German Center for Architecture (DAZ) in Berlin. The authors have made enormous efforts to help this publication come into existence and we would like to thank all of you very much for the inspiring discussions and meetings and, of course, for the texts that took shape in the course of them. The appearance of the book in this form and its translation into English were made possible by generous financial assistance from the institutions and associations involved in “Constructors‘ Dialogue,” to all of which we would like to express our heartfelt gratitude!

Gesellschaft für Ingenieurbaukunst

Thomas Glanzmann GmbH Beratung im Bauwesen

Walt+Galmarini AG

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Imprint Concept: Aita Flury, Zurich Translation from German into English: David Koralek/ArchiTrans Berlin, Richard Toovey, Berlin Copy editing: Julia Dawson, Lindfield, West Sussex Project management: Andrea Wiegelmann, Basel Layout, cover design and typography: gut&schön, Zurich A CIP catalogue record for this book is available from the Library of Congress, Washington D.C., USA. Bibliographic information published by the German National Library The German National Library lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at http://dnb.d-nb.de. This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in databases. For any kind of use, permission of the copyright owner must be obtained. This book is also available in a German language edition (ISBN 978-3-0346-0793-3). © 2012 Birkhäuser GmbH, Basel P.O. Box, 4002 Basel, Switzerland Part of ActarBirkhäuser Printed on acid-free paper produced from chlorine-free pulp. TCF ∞ Printed in Spain ISBN 978-3-0346-0794-0 9 8 7 6 5 4 3 2 1 284

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