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This book is a fascinating journey along the history of architectural structures over the last 150 years, taking the World Expos as an original unifying thread. Nevertheless, it does not solely focus on the exhibition buildings; on the contrary, these are continuously being related to buildings beyond the scope of the Expos, thus ultimately providing a general vision of the history of modern structures.




This essay is destined to become an essential work of reference within the history of architectural structures. It is generously illustrated with more than nine hundred large-scale illustrations, many of which have not appeared in contemporary publications. It offers innumerable facts that will interest architects, engineers or art historians. Likewise, members of the general public far-removed from these fields will also be able to enjoy many of the passages which are accessible to those who do not have any specific knowledge of architecture or engineering.

ISBN 978-84-946257-3-2


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WORLD EXPOS A History of Structures

This book has been published with the support of the Bureau International des Expositions (BIE), Paris

Editorial Project By Architect Publications S.L. Carrer Llobateres, 16-18, Talleres 7 Nave 10 08210 Barberà del Valles Barcelona Publisher Marti Berrio Prieto Author Isaac López César English Translation Rebecca S. Ramanathan

When time, inexorable, has devoured us, history will remain. For those who have yet to come.

To my son Jacobo.

Art Director and Layout Geny Castell Cover Design Geny Castell Cover Photo Bettinotti, Massimo

© 2017 Isaac López César © 2017 By Architect Publications S.L. By Architect Publications S.L. Carrer Llobateres, 16-18, Talleres 7 Nave 10 08210 Barberà del Valles Barcelona © Of illustrations, their authors ISBN: 978-84-946257-3-2 D.L.: B-16526-2017 Print in EU

All rights reserved. No part of this publication may be reproduced by any means or procedure, including reproduction, electronic storage or the distribution of copies by hiring or public lending, without the prior written permission of the owners of the copyright.


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Foreword: Vicente González Loscertales.


Secretary General of the Bureau International des Expositions (BIE), Paris. 21

Preface: Javier Estévez Cimadevila. PhD Architect. Full Professor in Structures in the Higher Technical School of Architecture in A Coruña.



CHAPTER 1 The Crystal Palace and the development of iron structures.


1.1 Foundations of the Industrial Revolution.


1.2 The Industrial Revolution in architecture.


1.2.1 Scientific breakthroughs.


1.2.2 New materials and typologies.


1.3 The Crystal Palace.


1.3.1 The Crystal Palace and prefabrication. A synthesis of the Industrial Revolution.


1.3.2 The Crystal Palace and the birth of the portal frame.




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2.2.3 An extraordinary achievement: the Rotunde Building in the

World Expos in the 19th century. Developments in large

Weltausstellung in Vienna 1873.

span decks.



2.2.4 An undervalued milestone: the main building in the Exposition Universelle, Internationale et Coloniale in Lyon 1894.


2.1 The search for large spans and typological innovation in rectangular decks.



2.1.1 Alexis Barrault and the expansion joint: the Palais de 69

The World Expos and the race for the tallest building Precedents and a descriptive introduction.


in the world. The problems of horizontal stabilisation and thermal movements.

76 The controversy surrounding the span record.


l’Industrie in the Exposition Universelle of Paris in 1855.

2.1.2 Neutralising thrusts in the metal arch and the Galerie des Machines in the Exposition Universelle of Paris in 1867.


2.1.3 A new portal frame typology for large spans: the Galerie des Machines from the Exposition Universelle of Paris in 1878.

93 Historical Precedents.

94 The solution to the thermal problem?


2.1.4 Origin and evolution of the metal arch: the Galerie des Machines from the Exposition Universelle of Paris 1889.



3.1 The Eiffel Tower: its precedents.


3.1.1 High-rise constructions: projects never built.


3.1.2 High-rise construction: the actual achievements.


3.1.3 The experience of Gustave Eiffel and his collaborators.


3.2 The Eiffel Tower: Project and construction.


3.2.1 The Tower project.


3.2.2 The structural principle.


3.2.3 The structural skeleton and puddled iron.


3.2.4 The foundations and Triger’s system.


3.2.5 Workers assaulting the skies: the prefabrication, assembly and lifts.

202 Precedents of the metal arch.

101 Main characteristics of the structure.

111 Horizontal stabilisation, thrusts and thermal issues.

120 The controversy surrounding the span.


CHAPTER 4 The metal three-hinged arch after the Gallery erection in 1889.


The arrival of reinforced concrete.

3.3 The Eiffel Tower and its architectural consequences.



2.1.5 The american response: the Manufactures and Liberal Arts Building from the World’s Columbian Exposition in Chicago 1893.

126 134 Contributions. 2.2 The search for large spans and typological innovation in circular decks.


2.2.1 The first iron and glass dome in the world: the Halle au Blé of Paris.



4.2 Reinforced concrete: the first large architectural structures.


4.3 Reinforced concrete and the World Expos.


4.3.1 Reinforced concrete up until the Brussels Expo in 1958.


4.3.2 Reinforced concrete after Brussels 1958: late shell structures and 242

proposals with a sculptural character.

2.2.2 Fire in the first american iron dome: the Crystal Palace from the 136

New York Expo 1853.



4.1 Reinforced concrete: first developments.


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CHAPTER 5 Tension decks: origin and peak.


6.2.3 Osaka 1970: the Expo as an exponent of design singularity.


6.2.4 Osaka 1970: the Expo as a pneumatic structural ensemble.


6.2.5 Osaka 1970. Unbuilt projects: the Expo as a catalyst for th

5.1 Tensile structures in the 19 century.


the imagination.


5.1.1 The technological context: intermittent contributions.


6.2.6 Osaka 1970: the Expo as a generator of building codes.


5.1.2 Expos in the 19 century: brilliant, intermittent contributions.


6.2.7 Pneumatic structures in Expos after Osaka 1970.



5.2 The enormous boom in tensile structures in the 20 century. th

264 264

5.2.1 The technological context. 5.2.2 World Expos in the 20th century: the triumphant entrance of


tensile structures. The Travel and Transport Building in the World’s Fair in Chicago 1933: an isolated structural experiment.

269 The rebirth of structural brilliance in Expo ’58 in Brussels.

278 The New York State Pavilion in the 1964-1965 New York’s World’s Fair: the continuation of the “bicycle wheel”.

CHAPTER 7 Space frames: the Expos between utopia and reality.


7.1 Space structures: origin and development.


7.2 The brilliant contribution made by the World Expos.


7.2.1 Space frames and false tensegrities.


7.2.2 Space megastructures: between utopia and reality.


310 The Seattle Center Coliseum in the Century 21 Exposition in Seattle 1962: “limitless spans”.


CHAPTER 8 The return to wood. The Federal Republic of Germany Pavilion in Expo ’67 in


Montreal. Frei Otto: utopia and formal innovation through “natural autoshapes”.


8.1 Wooden structures: origin and development.

513 The influence of the change in direction initiated by Frei Otto.


8.2 The contribution of the Expos at three key moments.

531 Other historically relevant structures in the World Expos.

354 “Tensile designed” structures: the contribution of the Expos.

362 Tensegrity structures: the contribution of the Expos.




Notes and bibliography.


Biographic reference.


CHAPTER 6 World Expos: the zenith of pneumatic structures.


6.1 The origin of pneumatic structures.


6.2 The World Expos: the zenith.


6.2.1 The Expos prior to Osaka ’70: sporadic contributions.


6.2.2 Osaka 1970: the Expo as a stage for great structural milestones.





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First of all I would like to offer my thanks to the Bureau International des Expositions (BIE) for supporting this book, and in particular to the Secretary General Mr. Vicente González Loscertales and the Deputy Secretary General Mr. Dimitri Kerkentzes for the enthusiastic backing they have given me. I thank Professor Javier Estévez Cimadevila for his encouragement, advice and his critical reading of each one of the chapters, which has undoubtedly contributed to refining the content. I am also indebted to the following people who have either directly or indirectly made a contribution: Juan Pérez Valcárcel, José Antonio Vázquez Rodríguez, Emilio Martín Gutiérrez, Pablo García Carrillo, Manuel Fernández Corral and Arturo López de la Osa Manso. I would furthermore like to thank Rebecca S. Ramanathan, who has been in charge of translating the book to English, for her high level of commitment and earnest work. To the editor of By Architect Publications, Martí Berrio, and the publisher’s graphic designer, Geny Castell, I express my thanks for the excellent collaboration that we have developed over the course of this project. Finally, I wish to say thank you to my family for all their effort. To my parents, Paz and Antonio. To my wife Nieves, who has accompanied me on this intense voyage. To Araceli Gil César and Manuel Casanova Ceniza.

For everyone, my deepest thanks.



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World Expos are transformative and innovative mega-events that have a defining role in knowledge-sharing, cultural diplomacy and the promotion of progress for all. Gathering hundreds of countries from across the globe, World Expos are visited by millions, offering organisers and participants the opportunity to showcase their prowess, their ideas and their vision for the future. What defines a World Expo, as set out in the 1928 Paris Convention relating to International Exhibitions, is its duty to educate the public, its transient nature lasting no longer than six months, and its purpose to foster exchange around a universal challenge of the time. In reality, however, each World Expo offers much more than this. As global meeting points and ephemeral manifestations of progress, World Expos serve to push innovation to its boundaries, spreading ideas and leaving remarkable intellectual and physical legacies. The innovative role of World Expos is well documented; in the late 19th and early 20th centuries, Expos were the event of choice to showcase new inventions in the era of industrialisation. From the 1950s onwards, Expos have become a key platform for sharing solutions to the many challenges facing humanity, whether it be urban living, transport, energy or food. Throughout the past 160 years, the constant feature of World Expos is innovation. This technological, scientific, intellectual and artistic innovation is showcased, promoted and developed in multiple domains, including architecture and structural engineering. The very nature of Expos creates unique opportunities for architects and engineers to design and create novel types of structure that shape modern and future architecture. Beyond the visual impact of Expo pavilions, their innovative structures have a lasting influence on the adoption of new architectural techniques, building designs and construction materials. This evolution in structural typologies, functionality and protagonism can all be traced through the history of World Expos, from the Crystal Palace at the Great Exhibition of 1851 to the futuristic and self-sustaining pavilions designed for Expo 2020 in Dubai. In this book, Isaac LĂłpez CĂŠsar draws a clear line between developments in architecture and World Expos, embarking us on a technical yet engaging illustrated journey through the modern history of structures. The author skilfully demonstrates that since 1851, the structures designed and constructed for Expos have not only been stunning buildings, but also drivers of innovation.



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In World Expos, architects, designers and engineers find ripe testing grounds for new methods, new materials, new shapes, and new applications. As major events visited by millions, reported by the world’s media and noticed by industry professionals, Expos are open laboratories for pushing the boundaries of architecture and construction. International and corporate participants compete for visibility and esteem in a non-confrontational setting, encouraging host countries and participants to take bold decisions and to give maximum creative independence to architects. In turn, the ephemeral nature of Expos – most pavilions are not designed to be permanent – removes constraints on durability and lifespan that would otherwise limit the experimental nature of the structures.

Isaac López César vividly demonstrates that World Expos have a fundamental role in the evolution and development of structural systems and architectural methods. While the focus of Expos has shifted to respond to the different challenges facing humanity, progress remains at the core of their mission, and innovation remains central to their essence and legacy. In the case of the structures we build for today and for the future, it is certain that bold advancements are spurred on by the unique platform created by Expos. Vicente G. Loscertales. Secretary General of the Bureau International des Expositions (BIE).

The result is a “perfect storm” for structural innovation, giving architects a blank canvas to test new technologies, use new materials and try alternative approaches. The findings laid out in this book demonstrate the transformative power of Expos, which stems not just from their physical and intellectual impact, but also from the opportunities they create. These opportunities encourage ambition and progress, calling on engineers, architects and designers to make use of the latest methods and technologies to build a better future for humankind, one that is more comfortable, more sustainable, and more enjoyable for all. In 1851, the Great Exhibition’s pioneering Crystal Palace revealed the possibilities of using iron as a structural support and of incorporating prefabrication as a construction method. The lessons learnt paved the way for the construction of structures on ever-greater scales, a trend that led to such marvels as the Rotunde at Expo 1873 in Vienna and the Eiffel Tower at Expo 1889 in Paris. The latter, which remained the tallest structure in the world until 1930, reflected the growing international frenzy for height and marked the pinnacle of “iron architecture”. The intertwined history of architecture and World Expos is just as evident in other construction trends of the 19th, 20th and early 21st centuries. The use of reinforced concrete, used as a technical element for the Grand Palais and Petit Palais at Expo 1900 in Paris, culminated in the Palais du Centenaire built for Expo 1935 Brussels, and the highly recognisable Philips Pavilion of Expo 1958 in the same city. The Expos of the post-war period served as a ripe testing ground for the development of modern tension-based structures, the space frame, as well as a return to wooden structures. World Expos are the perfect environment to experiment with these forms of architecture, with dozens of pavilions reflecting and embodying bold new methods and styles – “Man the Explorer” at Expo 1967 Montreal, Takara Beautilion at Expo 1970 Osaka, or Japan’s pavilion at Expo 1992 Seville to name but a few. Moving into the late 20th and early 21st centuries, a tangible link is evident between developments in architecture and World Expos’ increased focused on sustainability. Pavilions at Expo 2000 Hannover, Expo 2010 Shanghai and Expo 2015 Milan continue to push the boundaries in terms of sustainability, low-carbon emissions and recyclability.




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PREFACE Thanks to their transitory nature and the competitive spirit between the participating nations vying to display their eminence before the thousands of visitors that flock to these events, the World Expos have constituted occasions of huge significance in the technological development of structures. The spirit of these Expos was clearly evinced in the words of Frei Otto in the International Congress on Light Structures for Large Spans held in Seville in 1992: “Expos are a wonderful opportunity to experiment and pave the way for the future”. On the other hand, in spite of the numerous publications that exist in the area of structures, most of them focus on calculation, while the number of publications dealing with the conceptual, historical and design aspects of structural systems is much lower. It is for this reason that this book represents a resource of great value, inasmuch as it presents a thorough and widely documented analysis of the World Expos from a structural perspective, bringing together historical and technological points of view in its appraisal of the buildings erected. Through this new approach, these Expos can be understood as laboratories of structures where new shapes and materials are experimented with, novel structural typologies are addressed, or the spans between supports and building heights are taken to limits never before imagined. In addition, it is worth noting the author’s wise decision to avoid falling into the trap of turning the publication into a mere collection of buildings. On the contrary, his analysis has focussed on those buildings which have made an indisputable contribution to the history of structural systems, and he has put their historical contribution into context through references to both the buildings that preceded them as well as those that were erected afterwards, and which could thus be considered as consequences of the same. In conclusion, the present book is a tour de force thanks to its approach, the thoroughness of its analysis, and its invaluable documentary contribution. In short, it is a highly useful resource for anyone interested in an in-depth journey through the great architectural events marked by the World Expos held since the mid-19th century. Javier Estévez Cimadevila. PhD Architect. Full Professor in Structures in the Higher Technical School of Architecture in A Coruña.



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In 1851, the date of the first World Expo, electricity was not yet used for lighting or as a power source, the internal combustion engine did not exist, neither the radio nor the telephone had been invented, and the first motorised aeroplane had yet to take off. In architecture, the use of industrial iron was just beginning, while steel was not yet used in building. Reinforced concrete had not been invented. Since this date, the Expos have borne witness to and been the venue of the advances that have transformed the world to that which we know today. The Expos have been, and continue to be, places in which nations have substituted fighting on the battlefields with competence in fields of technological and industrial development, education and culture; the true engines of worlds past, present and future. From an architectural perspective, the structural contributions of the Expos have had enormous relevance and historical significance, intrinsically and permanently linking the Expos to the history of architectural structures. The role of the Expos as exponents of cutting-edge structural development came about for various reasons. In the first place, the chronological interval in which the Expos develop constitutes a period of huge structural productiveness. From the first that was held in 1851 to the present day, the Expos have witnessed significant developments in the field of structures: the development of iron engineering in the 19th century, the invention of reinforced concrete, the appearance of glued laminated timber, the development and far-reaching spread of space frames, the birth of cable networks and textile membranes, the development of pneumatic structures, as well as the revolution in the field of applied computer science. Consequently, we can find buildings that are bona fide paradigms of the history of structural systems. On the other hand, competition between nations to display their technological power would lead to a race in which each Expo aimed to outdo the structural achievements of the previous one. This gave rise to novel constructions, which in turn led to advances in the spans reached, the appearance of new structural typologies, and experimentation with new materials or research into new shapes. Other aspects favoured greater creative freedom in the field of structures. The transient nature of these events meant that certain issues such as durability were avoided; together with the purely representative or symbolic conception of numerous buildings which lacked a particularly rigid programme, the fact that many of them were built through architecture competitions enabled earlier research to be put into practice and the pioneering application of patents, as well as the implementation of new ideas that were in need of complete development or prior technological experience. On the other hand, the universal nature of these events granted these novelties widespread dissemination, brought about both by the millions of people who visited the Expos, and by the publication of the buildings and proposals presented to the various competitions in specialised journals. 23


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Another aspect that is intrinsically linked to the Expos is the transitoriness of its architecture. While some of the edifications associated to these events were built to stay, it is true that most of them were provisional. For this reason, exhibition architecture has usually been referred to as “ephemeral architecture”. One must therefore reflect on the relative nature of this term. From the perspective of time, if we take the existence of a man as a point of reference, then little architecture is “ephemeral” since inert molecular structures tend to outlive us. On the other hand, if we take the last thousand years (an insignificant period of time in geological terms) as an example, then a considerable portion of architecture has been “ephemeral”. In short, “ephemeral” is normally used as a metaphor for our own existence, as if the fate of our architecture was other than to dissolve into the earth. It is therefore reasonable to value this type of architecture not for its longevity over time, but for the historical impact it has had. It is no wonder that several Expo buildings are to be found in classic handbooks of modern architecture, in spite of having physically disappeared. We could ask ourselves whether the historical-architectural relevance of the Eiffel Tower would have been less had it been taken down at the end of the Exposition Universelle of 1889, according to plan. These reflections are not futile, given that the world in which we currently live is perversely drifting towards a tendency to disparage anything that does not generate an immediate and direct economic benefit; this type of short-lived architecture is sometimes seen as an expense of little use, and its cultural component and huge influence beyond the events for which it was created is forgotten. The present book offers a journey through the history of the architectural structures of the past 150 years, with the Expos as the unifying thread. While the book focuses on the structural contributions of the Expos, it is not exclusively limited to them. On the contrary, buildings not erected specifically for the Expos are mentioned on numerous occasions, and examples of these have gradually defined the historical-cultural context and been included through both written references and graphic material. This book is not a collection of buildings, but rather a historical narrative that has chosen those edifications which have been relevant from a structural point of view because of their singularity, their impact on later buildings or because they constitute important examples of architectural trends based on structural state-of-the-art technology. As mentioned earlier, there is a constant interrelation between the exhibition buildings and others unconnected to the Expos with the aim of putting them into context and constructing a coherent historical account. The book therefore acquires a dimension that transcends the Expos and offers a general view of the modern history of structures. The chapters are principally organised according to structural types or materials, since the most relevant contributions have been made in these two areas. This organisation allows for correlations to be made between edifications of the same type or material while each of them is contextualised by establishing its precedents and consequences, hence the part they play in the technological and architectural context of the time. Thus, the book may be read either as a monograph, by taking each chapter independently, or the characteristics of a specific building, the history of a material or of a specific structural type may be consulted via the index. With the aim of achieving the highest level of documentary soundness in this book, the following have pre-eminently been used: sources contemporary to the buildings in question, documents written by the project authors or collaborators themselves, official Expo



reports and documents by prestigious authors. The same criterion has been observed when including quotes or choosing graphic material. In this sense, the basic information search methodology has consisted in going over the documents that make up the basic bibliography, that is, the books and articles that cover the general history of architecture, or the general history of structural systems. Apart from being a source of information, the bibliographies of said documents have enabled a search for more specific references. From there, the search for a new document begins, proceeding iteratively from the general to the specific, thus weaving a web of information that has led to the closest source on the subject – the document written by the creator of the project. All this documentation is geographically widespread, a fact that has implied requesting more than three hundred documents from international libraries. The Internet has also been a source of information, albeit a cautious one, for primarily consulting electronic libraries and official institution websites. Another method of searching for information has been through journal databases. This method has been used for Expos and “modern” edifications due to the fact that the detailed technical information relating to old buildings is to be found in old engineering and building publications whose content has yet to be transferred to architectural databases. Said documents have been accessed through the first method described above. The way of accessing reliable information will undoubtedly become easier in the near future, thanks to the digitalisation of complete text documents that is being carried out in national libraries and other institutions, as well as by private companies. Be that as it may, I would finally like to thank the following libraries for their help in contributing documentation for this book: Bibliothèque Nationale de France; British Library; Biblioteca Nacional de España; National Gallery of Canada Library; Bibliothèque du Conservatoire National des Arts et Métiers (CNAM), France; National Library of Australia; Bibliothèque Université Laval, Québec; Harvard College Library; Library of the University of Michigan; Queen Elizabeth II Library, Memorial University of Newfoundland, Canada; Centro Superior de Investigaciones Científicas (CSIC), Spain; Chalmers Tekniska Högskola Biblioteket, Gothenburg, Sweden; Bibliothèque Universitaire de Sciences de Grenoble, France; Swiss Federal Institute of Technology, Zurich, Switzerland; Bibliothèque Municipale de Lyon, France; Bibliothèque Sainte-Geneviève, Paris; Universitätbibliothek Hamburg, Germany; Institutt for Kunsthistorie og Klassisk Arkeologi, Universitetet i Oslo, Norway; Owen Library, University of Pittsburgh U.S.A.; Institutt for Stalkonstruksjoner Norges Tekniske Hogskole Bibliotek; Università degli Studi di Firenze, Biblioteca Umanistica, Italy; Seattle Public Library, U.S.A.; Universidad Politécnica de Madrid; Engineering and Science Library Queen’s University Kingston, Ontario, Canada; Biblioteca Nacional Vittorio Emanuele III, Naples; Université Libre de Bruxelles; Bibliothèque Universitaire Lille, France; Universidad Politécnica de Cataluña; Robarts Library, University of Toronto, Canada; Institut National d’Histoire de l’Art, France; Ohio State University Library, U.S.A.; Humboldt-Universität zu Berlin. Isaac López César A Coruña, winter of 2017


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THE CRYSTAL PALACE AND THE DEVELOPMENT OF IRON STRUCTURES 1.1 FOUNDATIONS OF THE INDUSTRIAL REVOLUTION The Industrial Revolution began in England in the mid-1800s and spread to other countries during the 1900s. The Industrial Revolution would imply an unprecedented technological breakthrough and a radical change in the production system, the economy and society. Changes in architecture were a result of scientific progress, with the large-scale use of iron and glass and the appearance of new typologies deriving from the needs of a new society. From 1750 onwards, England underwent a rapid population increase from 6.5 million inhabitants to 14 million in 1831. This population growth was due to neither immigration nor higher birth rates, but rather health factors, principally thanks to breakthroughs in the field of medicine, as well as improvements in hygiene and diet. This growing population demanded an increase in manufactured goods, thus motivating the development of the textile and iron and steel works industries. Thus, the production of iron in England rose from 20,000 tonnes in 1760 to 700,000 tonnes in 1830. This escalation can be explained by the needs of the industrial machines, the new iron ships and the development of the railway system, with its locomotives, rails and stations. Another determining factor in the increase of iron production would be the depletion of English forests, which would also trigger an increase in coal mining. Given its high calorific value, coal rendered the smelting of iron minerals easier in order to obtain iron. This could be treated in two different ways: forging or casting. In forging, iron was heated in a forge and beaten to eliminate the slag, while at the same time being shaped and given a fibrous, compact structure, thus obtaining wrought iron. Alternatively, casting or moulding consisted in smelting the iron and consequently pouring it into a mould, allowing it to cool slowly to get cast iron. During the first years of the 18th century, Abraham Darby replaced coal with coke, which has an even higher calorific value. This breakthrough would become widespread in the mid-1800s, thus acting as a catalyst for the iron and steel works industry. Meanwhile, the traditional process for manufacturing steel was well-known, a process in which wrought iron and coal were heated over the course of various days during which the iron absorbed enough carbon to transform into steel. However, in 1855 Henry Bessemer invented the converter bearing his name which was capable of transforming smelted iron mineral into iron or steel by regulating the quantity of carbon in the process called decar-




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general equation to determine the neutral axis and carried out studies on torsion, arches and the thrusts generated by land. In 1826 Louis Marie Navier published another seminal work, “Résumé des leçons données à l’École des ponts et chaussées, sur l’application de la mécanique à l’établissement des constructions et des machines”. This work synthesized and completed the theories drawn up during the 17th century, and would have far-reaching repercussions.

bonisation. The Bessemer Converter paved the way for large-scale iron and steel manufacture (Fig 1.1). Undoubtedly, however, the main achievement of the period was the transformation of a continuous flow of steam moving through the steam engine. Invented by Watt and patented in 1769 by Watt himself, it enabled the leap from a traditional manufacturing process to a mechanised, industrial system and led to the arrival of new means of communication such as the railway and steamboat. The first locomotive was built by Robert Stephenson. The first passenger train would travel from Liverpool to Manchester in 1830.

Likewise, empirical studies on various buildings would be carried out in this atmosphere of growing interest in knowledge. In 1748, the Italian physicist Poleni published a study on the stability of the dome of St. Peter’s Basilica. On the other hand, the church of Sainte Geneviève in Paris would be studied. There would also be considerable progress made in the field of project instrumentation: The invention of the decimal metric system, set up in various European countries during the first two decades of the 19th century, and in other South American countries from 1830 onwards. This system offered accuracy to all project scales. Once it became widespread, it would foster scientific exchange.

Fig 1.1. Perspective and cross-section of the Bessemer Converter. Henry Bessemer, 1855. [Source: its authors]

Gaspard Monge invented descriptive geometry based on the generalisation of advances from the Renaissance. Descriptive geometry allows any three-dimensional object to be represented in two dimensions, thus offering technicians an unambiguous method of representation and promoting the exchange of architectural information.


The examples cited above are merely a sample of the scientific innovations that came about. Given the availability of this material and this climate of cultural revolution, it is therefore unsurprising that both architects and engineers aimed to move on from traditional materials and construction systems.

Being as it is a result of the social, cultural, economic and technological reality of any given period, architecture was not immune to the changes taking place in this revolutionary period. The principal factors in the Industrial Revolution that were to have an impact on the historical development of architecture would be the scientific advances on the one hand, and the large-scale application of new materials (such as iron and glass) and the arrival of new building typologies on the other. These new typologies were the result of industry’s emergent needs and the development of means of transport which called for bigger and bigger spaces. Thus, railway stations, factories, warehouses, bridges, storage tanks, etc. would be built.

1.2.2 New materials and typologies The new materials were mainly iron and glass; while their use goes back to ancient times, it was in this period when they became widely used in construction. Iron was traditionally used for secondary purposes such as the connection between ashlars, ties, etc. It had also been occasionally used as a complete structural solution for certain decks, such as that of the Théâtre Français by Victor Louis (1786) (Fig 1.2).

1.2.1 Scientific breakthroughs In this period, there were highly significant scientific and technological breakthroughs. Science continued along the path begun in the previous era of the Enlightenment: In 1676, Robert Hooke established a law that bears his name. At the end of the 17th century and beginning of the 18th century, Bernoulli, Leibniz and Mariotte studied the strain caused by flexure. Mariotte established the concept of the neutral axis, although he mistook its position. In 1713, Parent specified its correct position. In 1773 Charles A. Coulomb published “Essai sur une application des règles de maximis et minimis à quelques problèmes de statique relatifs à l’architecture”, which became a principal reference in the history of the resistance of materials. In this work, Coulomb established a




Fig 1.2. Théâtre Français. Victor Louis. 1786. Arched deck with iron structure. [Source: Ref (97) Blanc, Alan]



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With the development of the iron works industry in England that was largely due to the substitution of coke for coal, as mentioned above, the availability of wrought and cast iron increased exponentially, and with it, its use in architecture. We can see that there are three main fields of application in construction: bridges, large iron and glass decks and multi-storey buildings with metallic structures. Thus, erection of the first iron bridge over the River Severn near Coalbrookdale began in 1777. The architect was T.F. Pritchard. Completed in 1779, it was made up of two joined cast-iron semi-arches and had a span of 30.5 metres (Fig 1.3 and Fig 1.4).

Fig 1.5. Bridge over the River Wear. Tom Paine. 1786. [Source: Ref (94) Benévolo, Leonardo]

By the end of the 18th century, iron chain suspension bridges, which are lighter than those made up of arches, were beginning to be built in Europe. Erected in 1741, the first was a footbridge over the River Tees that reached a span of 21.34 metres. Also worthy of mention are the Conway Suspension Bridge of 1826 by Telford (Fig 1.6), and the Clifton Suspension Bridge over the River Avon in Bristol with a span of 214 metres, one of the most spectacular bridges of the century that was erected by Isambard Brunel in 1836 (Fig 1.7). In this sense, it should be made clear that the first documented iron chain suspension bridges were erected in the 14th century in China, although they were very primitive typologies (Fig 5.10).

Fig 1.3. Bridge over the River Severn in Coalbrookdale. T.F.Pritchard. 1779. [Source: Ref (94) Benévolo, Leonardo]

Fig 1.4. Bridge over the River Severn [Source: Ref (94) Benévolo, Leonardo]

Fig 1.6. Conway Suspension Bridge. Telford. 1826. [Source: Ref (94) Benévolo, Leonardo]

Fig 1.7. Clifton Suspension Bridge over the River Avon in Bristol. Isambard Brunel. 1836. [Source: Ref (94) Benévolo, Leonardo]

In 1786 Tom Paine built an iron bridge over the River Wear. In this case, it was made up of a diminished arch with a span of 71.9 metres (Fig 1.5). In 1796 Telford built another iron bridge over the Severn with a span of 39.6 metres. In 1801 Telford designed a bridge for London with a cast-iron arch that has a span of 182 metres, although it was never built.






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In 1849 Robert Stephenson erected the Britannia Bridge, a truly singular structure because of its use of a tubular girder (Fig 1.8 and Fig 1.9).

Meanwhile, the use of iron in building was becoming more widespread, particularly in English textile factories; the use of cast-iron beams and columns facilitated the greater spans needed by these industrial buildings, as well as being a nonflammable structural material which gave it a fundamental advantage after the fires recorded in these buildings in the last years of the 18th century. A good example is the Philips & Lee cotton mill (1801) in Manchester, designed by Baulton and Watt (Fig 1.10).

Fig 1.8. (Left) Britannia Bridge over the Menai Strait. Robert Stephenson. 1849. [Source: Ref (261) Peters, Tom F.] Fig 1.9. (Right) Britannia Bridge. [Source: Ref (261) Peters, Tom F.]

Fig 1.11. Halle au Blé. Paris. François J. Belanger and F.Brunet. 1811. [Source: Ref (305) Vierendeel, Arthur] Fig 1.13. Halle au Blé. Paris. Assembly drawing. Note the nuts and bolts tightening process. [Source: Ref (267) Picon, Antoine]

Fig 1.12. Halle au Blé. Paris. Engraving from the period. [Source: Ref (237) Marrey, Bernard]

The development of the iron works industry in France took place later, beginning its growth in the first years of the 19th century. Thus started the application of iron to bridge construction and even to buildings of certain significance. Examples of these are the new Dome of the Halle au Blé in Paris (1811) by François J. Belanger and F. Brunet, which is the first system of iron pieces forming a framework of meridians and parallels joined with bolts, a truly unusual joining method for that time, reaching a span of 39 metres (Fig 1.11 to Fig 1.13), the deck of the Marché de la Madeleine (1824) by Vignon, or the substitution of the wooden deck in Chartres Cathedral for an iron one (1837).




Fig 1.10. Philips & Lee cotton mill. Manchester. Baulton and Watt. 1801. Plan and sections. Structure made up of beams and iron columns stabilised horizontally via masonry walls. [Source: Munce, James F.]



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The glass industry would also make considerable progress. Until the first half of the 19th century, the glass for glazing was manufactured through glass-blowing, creating cylinders that were cut lengthwise and stretched. This was known as the cylinder process. In 1848 Henry Bessemer patented glass manufacture by extrusion, a process in which the glass was stretched by being passed between two cylinders, thus enabling the manufacture of glass sheet up to 2.5 metres wide. As a consequence, there was a surge in glass production as it became a larger-scale construction material, used in conjunction with iron in both decks and vertical enclosures. The slenderness of iron as a new structural material enabled the dematerialisation of walls and decks. When iron was paired with glass, the results were examples such as the aforementioned Marché de la Madeleine by Vignon; the Galérie d’Orléans of the Palais Royal (1829), a prototype for the nineteenth century shopping arcades and designed by Percier and Fontaine (Fig 1.14); the Jardin des Plantes in Paris (1833), which is a greenhouse erected by Rouhault (Fig 1.15 and Fig 1.16); the Great Conservatory at Chatsworth (1837) by Paxton (Fig 1.17 to Fig 1.19), which is a mixed structure with curved wooden parts and iron columns; Palm House at Kew Gardens (1846), erected by Richard Turner, with cast-iron columns and wrought iron H-shaped beams that were precursors of modern metal girders (Fig 1.20 to Fig 1.23), and the London Coal Exchange (1846-1849) by J.B. Bunning, which was a structure wholly built of cast iron and topped with a dome covered in glass sheets (Fig 1.24).

Fig 1.16. Jardin des Plantes in Paris. Rouhault. 1833. Section. [Source: Ref (226) Loyer, François]

Fig 1.17. (Left) The Great Conservatory at Chatsworth. Joseph Paxton. 1837. [Source: Ref (200) Hix, John] Fig 1.18. (Right) The Great Conservatory at Chatsworth. Photograph of construction work. [Source: Ref (200) Hix, John]

Fig 1.14. Galérie d’Orléans in the Palais Royal. Percier and Fontaine. 1829. [Source: Ref (226) Loyer, François]

Fig 1.15. Jardin des Plantes in Paris. Rouhault. 1833. [Source: Ref (226) Loyer, François]




Fig 1.19. The Great Conservatory at Chatsworth. Joseph Paxton. 1837. Construction section. Note the curved wooden structural parts, combined with iron columns. [Source: Ref (267) Picon, Antoine]



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Fig 1.22. (Left) The Greenhouse at Kew Gardens. Richard Turner. 1846. Section. [Source: Ref (200) Hix, John] Fig 1.20. The Greenhouse at Kew Gardens, also known as the Kew Palm House. Richard Turner. 1846. [Source: Ref (200) Hix, John]

Fig 1.23. (Right) The Greenhouse at Kew Gardens. Richard Turner. 1846. Plan. [Source: Ref (200) Hix, John]

Fig 1.24. London Coal Exchange. J.B. Bunning. 1846-1849. Period engraving. [Source: Ref (197) Hitchcock, Henry-Russell] Fig 1.21. The Greenhouse at Kew Gardens. Richard Turner. 1846. [Source: Ref (200) Hix, John]






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Examples of the new construction typology that was the railway station also appeared, for which large iron and glass decks were created. Among the first examples erected are Euston Station in 1835, a work by Robert Stephenson and P.H. Hatdwick which, according to R.J.M. Sutherland, was probably the first wrought iron truss with bolted joints [Ref (294) Sutherland, R.J.M] (Fig 1.25 and Fig 1.26), and the Tri Junct Railway Station in Derby, erected in 1839 by Robert Stephenson and Francis Thompson with a 17 metre-span deck (Fig 1.27). Fig 1.25. Euston Station. Robert Stephenson and P.H. Hatdwick. 1835-1839. [Source: Ref (267) Picon, Antoine]

Fig 1.27. Tri Junct Railway Station. Robert Stephenson and Francis Thompson. 1839-1841. [Source: Ref (197) Hitchcock, Henry-Russell]

Finally, we come to the Crystal Palace by Joseph Paxton for the Great Exhibition of 1851, a transition piece which, while building on many of the previous contributions, would highlight new problems and serve as experience for future structural developments.

Fig 1.26. Euston Station. Robert Stephenson and P.H. Hatdwick. 1835-1839. Details of the wrought iron trusses with bolted joints. [Source: Ref (229) Mainstone J. Rowland]

1.3 THE CRYSTAL PALACE There had been industrial expositions before 1851 in France, though exclusively national. Thus, the first was held in 1798, followed by those held in 1801, 1802, 1806, 1819, 1823, 1827, 1834, 1838, 1844 and 1849. England had also been the venue of, again exclusively national, exhibitions of industrial products in 1847, 1848 and 1849. It would be in this country where the first World Expo would be held in 1851, and thanks to the liberal English economy, imported products were welcome. In 1850, a competition was held for the building that would house the first World Expo and which would be erected in Hyde Park. 245 competitors entered, among which we can mention names such as Horeau and Turner with an iron and glass building, as well as H.A. Bunning, the creator of the aforementioned Coal Exchange in London (Fig 1.24). Nevertheless, the appointed committee would decide against green-lighting any of the projects presented and instead chose to design their own building proposal, consequently holding a competition to decide who would build it. It was at that point after the first competition ruling and before the construction was awarded, when the gardener and greenhouse builder, Joseph Paxton, presented his project to Prince Albert and Robert Stephenson, one of the committee members, and published it in the “Illustrated London News�. These first building drawings made a good impression on the committee, which decided to abandon their own Project proposal and award Paxton with building the project. Paxton built on the experience gained on works such as the aforementioned Great Conservatory at Chatsworth (Fig 1.17 to Fig 1.19) to create a building on a monumental scale that was the Crystal Palace. The structure design and calculations were done by Charles






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Fox, a railway engineer, and Charles Heard Wild, under the guidance of William Cubitt and Matthew Digby Wyatt. Charles Heard Wild and Owen Jones represented the Royal Commission’s Building Committee, the body in charge of supervising and controlling the building design and erection.

1.3.1 The Crystal Palace and prefabrication. A synthesis of the Industrial Revolution Fig 1.28. Crystal Palace. Joseph Paxton. 1850. First sketches of the section and elevation of the building. [Source: Ref (141) Dunlop, Beth]

The Crystal Palace was made up of a large, longitudinal, tiered space of exceptional dimensions: 563.25 metres long by 124.35 metres wide. In the central area, the space was cut across by a transept. Although the transept was a flat volume in its uppermost part according to the initial proposal, Paxton finished it off with a barrel vault, as better befitted the tastes of that period. There were five naves across the building, two side naves, two intermediate ones and a central nave. The intermediate naves laterally included two floors, the central nave having three, all of which were connected by walkways crossing the building.

Fig 1.30. Crystal Palace. Ground floor. [Source: Ref (141) Dunlop, Beth]

Fig 1.31. Crystal Palace. First floor. [Source: Ref (141) Dunlop, Beth]

Fig 1.29. The Crystal Palace in Hyde Park. Joseph Paxton. 1851. Illustration from the period. [Source: Ref (243) McKean, John]






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Fig 1.32. (Above) Crystal Palace. Elevation / longitudinal section. [Source: Ref (233) Mallet, Robert]




Fig 1.33. (Below) Crystal Palace. Elevation / cross-section. [Source: Ref (233) Mallet, Robert]



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the whole, that probably more accurately represented the structure of the building as it stood in 1851, than any other part of it now does. More than enough was destroyed to prove that Professor Airy was not so widely wrong after all”. [Ref (233) Mallet, Robert]

Fig 1.71. Munich Kristallpalast. 1853. Period photograph. Note the absence of triangulations in the vertical planes. [Source: Ref (181) Gössel, Peter]

Nevertheless, Professor Airy would consider the diagonals included to be insufficient in the Crystal Palace: “It would be observed, that since the design of the building had been originally formed, a number of diagonal stays and ties had been introduced into various parts; as far as I could ascertain, from the information I had received, the space between one of those diagonals and another, measured along the length of the building, amounted to 192 feet [58.5 m]. […] and it was quite conceivable, that when the wind blew violently, the parts intermediate between these diagonals might be blown down, leaving in a standing state the frames which were strengthened with diagonals.” [Ref (311) Wyatt, Matthew Digby]. When the building was taken down and later rebuilt, more diagonal bracing bars were added. Even so, the structure partially collapsed. This is how Robert Mallet described events in an article in 1862: “ […] and has been re-erected at Sydenham in a manner greatly to increase its stability, as regards the greater part of the structure at least; and from 1851 to the present day London has never been visited by one of those ‘first-class’ tornadoes that about twice in a century sweep over even our temperate regions. Yet, nevertheless, a very large wing of the Crystal Palace has been actually blown down in the interval – that proportion of CHAPTER 1



The Munich Kristallpalast (Fig 1.71 and Fig 1.72) was built for the Industrial Exposition in Munich. It was a slightly rectangular building that measured 234 x 67 metres, therefore much smaller than the Crystal Palace. Unlike its predecessor, the Munich Kristallpalast had been designed to be permanent and be used after the exhibition. There is no cross bracing system in vertical planes, as it cannot be seen in the period photographs or drawings, nor in the structural details. It seems that the building turned out to be significantly more stable

Fig 1.70. Crystal Palace. Note the triangulations of the horizontal stabilisation. Copy of the original by Dickinson. [Source: Ref (138) Dickinson]

Fig 1.72. Munich Kristallpalast. 1853. Period photograph. [Source: Ref (181) Gössel, Peter]

than it should have been, probably due to the greater stiffness of the connectors that joined the trusses with the columns. This stability was demonstrated by its permanence, since the building stood until 1931, when it was destroyed by a fire. 63


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WORLD EXPOS IN THE 19TH CENTURY. DEVELOPMENTS IN LARGE SPAN DECKS To a great extent, the history of the World Expos in the second half of the 19th century makes up the history of iron architecture. The desire of each country to outdo the previous Expo in a display of economic and technological power led to the creation of buildings that were real structural milestones for their time. Along these lines, France wanted to emulate England to become the standard in the industrial world, with Paris and London being the cities in which the most World Expos were held during the 19th century. In this way, iron was used in each building, the previous boundaries of knowledge were defied, and evident innovation occurred in structural typologies leading to greater spans and new technological images. At the same time, the progress made through these singular buildings would translate into applications in ordinary construction. This process would come to a head in the Exposition Universelle held in Paris in 1889, with buildings such as the Galerie des Machines by F. Dutert and V. Contamin and the Eiffel Tower, an authentic emblem of the city. The erection of the first large buildings in the World Fairs were causing a huge impact and creating an atmosphere of technological optimism that seemed to portend great achievements. Thus, in an article already published in the February 1856 issue of the French architecture and engineering journal “Nouvelles Annales de la Construction”, the following can be found: “The buildings created for the World Expos are the most impressive and characteristic manifestation of modern architecture. Their appearance in the history of art is an example that may be used as a starting point for a new era of modernity. The surface area of the Crystal Palace in London is four times bigger that St. Peter’s in Rome. The surface area of the Palais de l’Industrie in Paris is two and a half times bigger than this basilica. These buildings lead us to believe that modern construction will produce colossal designs in the 19th century that will go down in the annals of History”. [Ref (38) Nouvelles Annales] Between 1851 and 1889, numerous World Expos were held: New York 1853, Paris 1855, London 1862, Paris 1867, London 1871, Paris 1872, Lyon 1872, Vienna 1873, Philadelphia 1876, Paris 1878, Sydney 1879, Melbourne 1880, Amsterdam 1883, Antwerp 1884, New York 1885, London 1886, Barcelona 1888, Brussels 1888 and Copenhagen 1888. The historical analysis will focus on those buildings that are key pieces in the typological evolution of iron structures. To do this, we will distinguish decks with a basically rectangular layout on the one hand (made up of parallel arches or portal frames) and those with a circular layout on the other.




In this section we will refer to those decks with a slightly rectangular layout with structural typologies consisting of trusses, portal frames or arches arranged in a basically parallel fashion.

2.1.1 Alexis Barrault and the expansion joint: The Palais de l’Industrie in the Exposition Universelle of Paris in 1855 The “Première Exposition Universelle des Produits de l’Industrie” was held in Paris in 1855, in response to the earlier Expo in London in 1851. From this date onwards until the end of the 19th century, and in spite of the aforementioned rivalry between England and France, the most important Expos would take place in France, mainly due to its economic prosperity. The main building for the Expo was the Palais de l’Industrie, a construction with a metal inner structure and an ashlar enclosure that intended to align with French tastes of that time. Created by the architect M.M. Viel and the engineers Alexis Barrault and G. Bridel, the building would be located between the Champs Élisées and the Seine. Precedents and a descriptive introduction To bring the technological context of the time into focus, we should mention two precedents to this building which, in turn, held the world record for span. They are Lime Street Station in Liverpool, which was built by Turner in 1849 and which reached a span of 150 feet (45.72 metres) (Fig 2.1 to Fig 2.3), and New Street Station in Birmingham, designed by E.A. Cowper from the firm Fox, Henderson & Co., the builders on the Crystal Palace in London, and finished in 1854 with a span of 212 feet (64.62 metres) (Fig 2.4 to Fig 2.7). Originally, railways stations were built with decks made up of various short spans supported by intermediate iron columns; examples of this are Euston Station (Fig 1.25 and Fig 1.26) and Tri Junct Railway Station (Fig 1.27), both mentioned earlier. This was a disadvantage for the movement of merchandise, passengers and machinery. Lime Street Station and New Street Station are two of the first examples of a large station in which the deck has only one span. Lime Street Station made use of curved trusses supported at two points and made of bars and cables. These trusses lay on a cast-iron column at one end, and on a masonry



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wall at the other. They were hinged to the columns and supported on the wall with rollers, which eliminated any risk of horizontal thrust. Following traditional techniques in stations, horizontal stabilisation was achieved along the building with a masonry wall running longitudinally at one end and arched iron girders joining the columns at the other end. A curved truss was also used in New Street Station in Birmingham, although in this case with X-shaped bars. The truss was hinged on a masonry wall and was connected to a cast-iron column with rollers. Along the building, horizontal stabilisation was achieved in the same way as in the case above, with a masonry wall running longitudinally and arched girders that joined the columns. In terms of span, these two buildings were the immediate precedents. The Palais de l’Industrie in the Exposition Universelle of Paris in 1855 was made up of a main volume that was 252.2 metres long by 108.2 metres wide (Fig 2.8 to Fig 2.14). Six other, smaller blocks were added to this structure, housing the accesses, stairs and other secondary uses. The building enclosure was formed by ashlar walls, while the inner structure was made up of wrought and cast iron. The deck of this large space had a truly novel design for a metal structure. It had a central vault flanked by two side vaults (Fig 2.13). The central vault had a span of 48 metres, while that of the side vaults was 24 metres. These side vaults encircled the building and can also be seen in the longitudinal section of the same (Fig 2.14). The

Fig 2.4. New Street Station, Birmingham. E.A. Cowper. 1854. Cross-section. [Source: Ref (305) Vierendeel, A.]

Fig 2.5. (Left) New Street Station, Birmingham. E.A.Cowper. 1854. Longitudinal section. [Source: Ref (305) Vierendeel, Arthur]

Fig 2.1 Lime Street Station, Liverpool. Turner. 1849. Cross-section. [Source: Ref (305) Vierendeel, Arthur]

Fig 2.6. (Right) New Street Station, Birmingham. E.A.Cowper. 1854. Detail of the joint between chords, vertical members and diagonals. [Source: Ref (305) Vierendeel, Arthur]

Fig 2.2. Lime Street Station, Liverpool. Turner. 1849. Longitudinal section. [Source: Ref (305) Vierendeel, A.] Fig 2.3 Lime Street Station, Liverpool. Turner. 1849. Structural details. Note the sliding support in the two upper details. [Source: Ref (305) Vierendeel, A.]




Fig 2.7. New Street Station, Birmingham. E.A. Cowper. 1854. Sliding joint between the truss and the cast-iron column. [Source: Ref (305) Vierendeel, Arthur]



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central vault was 192 metres long and measured 35.96 metres at its highest point above ground level. There were two galleries with a ground and first floor between the central and the side vaults. These galleries had a span of 4 metres measured at the column axes. There was another gallery along the perimeter with two levels and a span of 2.1 metres measured at the column axes. All these galleries also encircled the building and could be seen in the longitudinal section (Fig 2.14). The three vaults were covered with glass sheets. The intermediate and perimeter galleries were covered with zinc sheets. The three vaults were made up of wrought iron X-shaped trussed arches 2 metres deep (Fig 2.15). The main vault had 26 arches. The distance between axes was 8 metres, except at the ends, where it was 4 metres. The vaults were finished with Pratt trusses joined to the arches through quarter-circle rigid connections (Fig 2.21). Likewise, there was a third structural order which measured 50 cm at the axes, followed the curve of the arches and made up the ironwork for the glass panes. Fig 2.10. Palais de l’Industrie. A. Barrault, G. Bridel, M. Viel. 1855. Inside view in a period painting. [Source: its creators]

Fig 2.8. Palais de l’Industrie. A. Barrault, G. Bridel, M. Viel. 1855. [Source: Ref (101) Bouin, Philippe / Chanut, Christian-Philippe] Fig 2.9. Palais de l’Industrie. A. Barrault, G. Bridel, M. Viel. 1855. [Source: Bibliothèque Nationale de France]

Fig 2.11. Palais de l’Industrie. Photograph taken during an exhibition in 1896. [Source: Ref (226) Loyer, François]

Fig 2.12. Palais de l’Industrie. Plan. [Source: Ref (305) Vierendeel, Arthur]






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Fig 2.13. (Above) Palais de l’Industrie. A. Barrault, G. Bridel, M. Viel. 1855. Cross-section. [Source: Ref (38) Nouvelles Annales]

Fig 2.14. (Left) Palais de l’Industrie. A. Barrault, G. Bridel, M. Viel. 1855. Longitudinal section. [Source: Ref (28) Algemeine Bauzeitung]

Fig 2.15. (Right) Palais de l’Industrie. A. Barrault, G. Bridel, M. Viel. 1855. Elevation of one of the truss modules in the side vaults. [Source: Ref (38) Nouvelles Annales]






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In terms of span, the previous example was followed by the former Berlin East Railway Station (Fig 2.67 to Fig 2.69). Built by Johann Wilhelm Schwedler in 1866, it had a span of 36.25 metres. Masonry buttresses were used to neutralise the arch thrusts in this case as well. There is a special similarity between this example and the arch curve in the Galerie des Machines of 1889.

Fig 2.64. (Above) Retortenhaus or Great Hall of the Imperial Continental Gas Association in Berlin. Cross-section. [Source: Ref (305) Vierendeel, Arthur]

Fig 2.67. Former Berlin East railway station railway station. Johann Wilhelm Schwedler. 1866. [Source: Ref (305) Vierendeel, Arthur] Fig 2.66. Retortenhaus. Detail of the hinged joint at the base of the arch. [Source: Ref (305) Vierendeel, Arthur]

Fig 2.65. Retortenhaus. Detail of the apex hinge of the arch. Note that the joint between both semi-arches is only riveted in the upper area, thus enabling the turning movement. [Source: Ref (305) Vierendeel, Arthur]




Fig 2.68. Former Berlin East railway station. Hinged joint at the base of the arch. [Source: Ref (305) Vierendeel, Arthur]



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Fig 2.81. Galerie des Machines, 1889. Cross-sectional perspective. The arch depth was variable, being 3.7 metres at the base and decreasing to 3.15 metres at the apex. Each arch was made up of 50 panels, alternating narrow and wide panels. These measurements were varied in order to guarantee that there were vertical members to which the trusses could be attached. [Source: Ref (305) Vierendeel, Arthur]

Fig 2.80. Galerie des Machines, 1889. Side gallery. [Source: Ref (141) Dunlop, Beth / Hector] Fig 2.78. Galerie des Machines, 1889. Expo photograph. [Source: Ref (141) Dunlop, Beth / Hector]



Fig 2.79. Galerie des Machines, 1889. Arch springer hinges and the joint with the floor of the side galleries. [Source: Ref (141) Dunlop, Beth / Hector]




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times. It was also common knowledge that steel had to contain more carbon than wrought iron, and that an excessive amount would transform it into cast iron, thus losing its ductility to the point of rendering it fragile and therefore impeding the forging process. In spite of this knowledge and following the invention of the Bessemer converter in 1855 and the Martin Siemens system in 1857 which would enable the industrial manufacture of steel, its use did not become generalised immediately. Apart from a certain initial mistrust on the part of architects and engineers, this was due to the technical manufacturing difficulties at the beginning, its high cost, and the greater development of iron production plants. Nevertheless, the favourable structural benefits of this metal compared with iron, as well as the overcoming of the technical difficulties and lowering of production costs, would slowly foster a more generalised use of steel.

Fig 2.103. Manufactures and Liberal Arts Building. Chicago 1893. Cross-section. [Source: Ref (307) Werner, Emerik A.]

Fig 2.105. Manufactures and Liberal Arts Building. Chicago 1893. Arch springer hinge. [Source: Ref (275) Rydell, Robert W. / Gilbert, James]

Fig 2.106. Manufactures and Liberal Arts Building. Chicago 1893. Arch springer hinge in a period engraving. [Source: its creators]

Fig 2.104. Manufactures and Liberal Arts Building. Chicago 1893. Longitudinal section. [Source: Ref (307) Werner, Emerik A.]






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Fig 2.147. Main building in the Exposition of Lyon 1894. Cross-section. [Ref (158) Fournier, V.]

Figs 2.148 y 2.149. Main building of the Exposition of Lyon 1894. [Source: Archives Municipales de Lyon]






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The building was made up of a central nave surrounded by two perimeter indoor galleries and a cantilevered outdoor gallery. The central nave was designed with a dome made up of parabolic arches with spans of 110 metres and 55 metres high. These variable depth trussed arches had a depth of 1.8 metres at the top. The arches were hinged at the springers and finished with an upper compression ring. It is surprising how little of an impact this building made on the specialised publications of the time. Neither structural descriptions nor detail drawings are to be found in the French engineering publications contemporary to the building, nor in more recent publications. The graphic information presented here comes from several publications that cover the Expo in a general way, and which are to be found in the Archives Municipales of Lyon. Another source was an article published in issue 50 of the German building journal “Centralblatt der bauverwaltung” from December 16th 1893 [Ref (280) Sarrazin, Otto / Hofsfeld, Oskar]. This building’s lack of notoriety was probably due to the fact that this Expo, modest in comparison with others, was held in a less relevant city than London, Paris, New York or Vienna.



In any case, the building from the Exposition in Lyon was a worthy achievement in building structure. Note that while it was built merely five years after the Galerie des Machines of Paris 1889, it managed to attain a similar span, although with another typology. Its span would also be similar to that of the Rotunde in Vienna in 1873, although in this case, the structural typologies were again different. The outside image of the building was devalued because of the use of a series of access portals that were historicist in character, as well as quite an inelegant shape. In contrast, the structure is quite naked on the inside. The light was dealt with successfully, as it highlighted the rotundity that connected well with the industrial spirit of the time. Due to an initial lack of documentary dissemination, this building has been marginalised historically. Nevertheless, thanks to its structural value and spatial quality, this marginalisation is undeserved.

From ancient times, mankind has entertained the fantasy of making a building higher than anyone else. Loaded with an obvious symbolism, this yearning for great heights has been reflected in ancient religious texts. Such is the case of the Old Testament, in which the epic tale of the unfinished tower erected in the city of Babel is told, that city to the south of Bagdad in which this desire was intertwined with man’s ambition to reach heaven. This story is also an example of the belief in mankind’s great abilities when everyone is working towards the same goal (Fig 3.1).

Fig 2.150. Main building of the Exposition of Lyon 1894. [Source: Jules Sylvestre. Bibliothèque Municipale of Lyon]




Fig 3.1. One of the representations of the Tower of Babel. [Source: its authors]



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Religion has not been the only catalyst stoking the desire for great height; the symbolism derived from political, economic and technological power has been seducing the human race right up to the present day. Thus, 2001 witnessed the collapse of the Twin Towers in New York after the terrorist attack which not only meant the loss of hundreds of lives, but also the destruction of one of the symbols of Western power exemplified through great height. In this way, menhirs, pyramids, obelisks, columns or basilicas have marked the history of great civilizations, representing a variety of symbolic aspects achieved through tall constructions (Fig 3.2).

Fig 3.2. Representation of some of the tallest edifications in Ancient Times. 1884. Most of them are funerary, religious or commemorative constructions. The tallest building is the Washington Monument. [Source: its authors]

3.1 THE EIFFEL TOWER: ITS PRECEDENTS The historical precedents of the Eiffel Tower can be classified into three groups: - Projects that were never made. This includes those projects for towers which aimed to beat records for height but which were never built. In spite of this, they contributed to the interest generated in the subject of great height. Many of the projects came about precisely on the occasion of World Expos. -Real achievements. These are svelte constructions made with iron structures. They had a similar effect to those projects which never came to fruition, as well as encouraging competition to make the highest building. -The experience of Gustave Eiffel and his collaborators themselves, which crystallised in some of his works in particular, through which they were to gain enough experience and use the technological resources which would later enable the design and construction of the tower.

3.1.1 High-rise constructions: projects never built

After iron began to be applied as the main structural material in building, it would start to fan the desire to erect a construction higher than any other. In this way, the first project we have any evidence of is the tower that Richard Trevithick wanted to build in London in 1832, called the Reform Column (Fig 3.3 and Fig 3.4). Trevithick, builder of the first steam locomotive, proposed erecting a tower 1,000 feet high (304.8 metres). It was a cast-iron, perforated column with a 30-metre diameter at the base and a 3.6-metre diameter at the top. There would be a tube on the inside along which a lift would ascend, propelled by a compressed air mechanism. 1,500 cast-iron sheets would be used to build it. In the end, after Trevithick passed away, the tower was never built.

The World Expos have also played their part in this fabulous longing. As described in the previous chapters, the evolution of iron had led to important structural developments, thus creating an atmosphere of considerable technological optimism which would feed the fantasies of architects, engineers and politicians. Industrialised iron would present possibilities for high-rise construction that had previously been unimaginable. On the other hand, the desire to build a tower taller than any other building was nothing new. A large Exposition Universelle was held in Paris in 1889 to commemorate the centenary of the French Revolution. This Expo would undoubtedly be the most important display of structural technology of the 19th century, with the erection of the Galerie des Machines with the largest deck span ever built, and the Eiffel Tower which was the tallest building in the world for its time. The so-called iron architecture would reach its technological peak in this Expo.




On the occasion of the World Expo in New York in 1853, James Bogardus proposed building a cast-iron tower that would be 91.5 metres high and with a 23-metre diameter at the base (Fig 2.112). This tower would support the building’s circular 122-metre deck with iron chains. It could also be considered an early precedent of modern tension decks. This project never saw the light either. In 1852, a year after the inauguration of the World Expo in London, Charles Burton put forward a proposal for an iron tower that would recycle the structural elements from Paxton’s Crystal Palace (Fig 3.5 and Fig 3.6). It was made up of three slightly square-plan bodies, the sides of which decreased in height and evolved into three circular-plan structures. We can see the modular arrangement of the columns horizontally and the recycled enclosure elements from the Crystal Palace vertically. Chapter 1 includes a description of the issues with horizontal stabilisation suffered by the London building which had even led to the collapse of part of the same after its reconstruction in Sydenham. We can deduce that a project for a tower with these characteristics with the same components and criteria would be impracticable. Nevertheless, whether the author would have made provisions for modifications or a new system of horizontal stabilisation remains unknown. 165


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Fig 3.3. (Above left) Reform Column. Richard Trevithick. Project from 1832. Elevation. [Source: Ref (178) Glibota, Ante / Edelmann, Frédéric]

Fig 3.4. (Above right) Reform Column. Richard Trevithick. Project from 1832. Plan and cross-section. [Source: Ref (178) Glibota, Ante / Edelmann, Frédéric]

Fig 3.7. Tower proposed by Clarke, Reeves & Company. 1874. [Source: Ref (261) Peters, Tom F.]

Fig 3.5. Charles Burton’s Tower. 1852. Elevation. [Source: Ref (102) Brino, Giovanni]



Fig 3.6. Charles Burton’s Tower. 1852. Plan. [Source: Ref (102) Brino, Giovanni]


Fig 3.8. Tower proposed by Clarke, Reeves & Company. 1874. Plan. [Source: Ref (261) Peters, Tom F.]



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“I take a quantity of limestone, such as that used for making roads; but if I cannot procure a sufficient quantity of the above from the roads, I obtain the limestone itself, and I cause the puddle or powder, or the limestone, as the case may be, to be calcined. I then take clay, and mix it with the limestone and water to a state approaching impalpability. After this proceeding I put the above mixture into a slip pan for evaporation. […] Then, I calcine it and it is ready for use.” [Ref (94) Benévolo, L.] The industrial production of artificial cement would commence in 1844, the same year in which Fox and Barret would patent a slab system consisting in cast-iron joists embedded in lime concrete. The patent was titled:


“Cast-iron joists spaced 45 centimetres and sunk into lime concrete.” [Ref (127) Collins, P.]

THE ARRIVAL OF REINFORCED CONCRETE As described in previous chapters, the Industrial Revolution had promoted the generalisation of the use of iron and steel as structural materials, which led to the extraordinary development of metal structures in the 19th century. Following these significant developments, the most relevant historical event in structural terms was undoubtedly the invention and development of the technique of reinforced concrete; this in turn would lead to the birth of new structural typologies and novel architectural creations.


The invention of reinforced concrete cannot be attributed to only one individual. On the contrary, it is a material that was invented and developed through the contributions of various people, some of which bore little or no relation with architecture or engineering. Up until 1900, the theoretical and practical studies on reinforced concrete carried more weight than architectural or engineering works; it was during this initial stage that the first patents related to this new material were registered. From 1900 onwards, there would be an increase in the number of patents associated with large companies which would be responsible for commercialising and promoting this new material. It was therefore at the beginning of the 20th century when the use of reinforced concrete as a structural material started to be more widespread; in constructions of various types such as bridges, factories, warehouses, commercial buildings or tanks. Thus, the development of the first large structures in reinforced concrete would begin at the turn of the century. Reinforced concrete is a material with ancient precedents. The Romans used concrete in their constructions, made of natural cement or pozzolans. It was what they called “opus caementitium”. Returning to more recent times, the engineer John Smeaton noticed that lime mixed with clay hardened upon coming into contact with water; he went on to build the Eddystone Lighthouse in 1774 using this new conglomerate or cement in its stone masonry (Fig 4.1). However, it would be the discovery of artificial cement by Joseph Aspdin in 1824 that would signify the launch pad towards the invention and development of modern concrete. Aspdin’s patent describes the following:




Fig 4.1. Eddystone Lighthouse. John Smeaton. 1774. [Source: Ref (288) Simonnet, Cyrille]



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In 1848, Joseph-Louis Lambot would build the famous cement boat reinforced with metal bars (Fig 4.3), and after presenting it in the Exposition Universelle in Paris 1855, he would patent a material “to substitute wood” (Fig 4.2) which he named “Ferciment”. Lambot’s patent reads as follows:

Fig 4.3. Reinforced cement boat with metal bars. J.L. Lambot. 1848. Exhibited in the Exposition Universelle in Paris 1855. [Source: Ref (288) Simonnet, Cyrille]

“The objective of my invention is to replace wood in shipbuilding and in any element at risk of being damaged by damp, such as wooden floors, water tanks, flowerpots, etc. This new substitute material is made up of a metal mesh of wires that are connected or woven in some way. This mesh is shaped in a way that best adapts to the object we wish to make, and is then embedded in hydraulic cement”. [Ref (217) Kind-Barkauskas / Kauhsen / Polony / Brandt] A fundamental contribution would be made by William Wilkinson in 1854; he introduced the idea of placing metal rods inside the slabs “in the parts subject to tension forces”. [Ref (103) Brown, J.M.]

Fig 4.4. Joseph Monier’s patent for flower boxes and pipes. 1855. [Source: Ref (217) Kind-Barkauskas / Kauhsen / Polony / Brandt]

Fig 4.5. Joseph Monier’s patent for reinforced concrete decks. 1881. [Source: Ref (94) Benévolo, Leonardo]

Fig 4.6. (Left) First slab with metal joists and iron bars arranged orthogonally. William Ward. 1875. [Source: Ref (115) Casinello, F.] Fig 4.2. J.L. Lambot’s patent for “Ferciment” as a substitute material for wood. 1855. [Source: Ref (217) Kind-Barkauskas / Kauhsen / Polony / Brandt]




Fig 4.7. (Right) Use of torsioned metal bars as reinforcement. Ernest L. Ransone. 1880. [Source: Ref (115) Casinello, F.]



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It was at the end of the 19th century, however, when the first constructions of a considerable size would begin being made. In this sense, Matthias Koenen would build the bridge for the 1890 Bremen Industrial Fair (Nord-West-Deutsche Gewerbe und Industrie-Ausstellung) in Germany following the Monier system. This work is notable for its svelte cross-section, surprising to find in such an early period (Fig 4.9). Fig 4.10. Hennebique’s patent for the “continuous beam on various supports”. 1897. [Source: Ref (288) Simonnet, Cyrille]

In 1892 Hennebique built the first beam with stirrups and patented his system of reinforced concrete. This system would be highly perfected and eventually have a standardised use (Fig 4.10 to Fig 4.12). Likewise, Hennebique erected a reinforced concrete bridge with a span of 32 metres in Switzerland in 1894, while in 1895 he built the first reinforced concrete silo in Roubaix. Incidentally, F. Le Coeur erected the first reinforced concrete dome in 1897.

Fig 4.8. First slab solely reinforced with round bars. François Hennebique. 1888. [Source: Ref (135) Delhumeau, Gwenaël / Gubler, Jaques]

According to Cyrille Simonnet and other authors: “This makes him the real inventor of the procedure, since he was aware of its specific mechanical action, in spite of the fact that in 1877, Hyatt would experiment with and measure the mechanical interaction between both materials, placing particular emphasis on the strong adherence of the iron to the concrete”. [Ref (288) Simonnet, Cyrille] Another notable figure was the French gardener Joseph Monier, who would patent a flower box construction system in 1867 in which wires were crossed orthogonally (Fig 4.4). In the years to come, Monier would bring out more patents for the construction of girders, decks, stairs and bridges, and in 1880 would establish the so-called “Monierbeton” system (Fig 4.5). In 1875 William Ward would make the first reinforced concrete slab with metal joists and a grid of iron bars (Fig 4.6). In order to improve the adherence between the metal and the concrete, Ernest L. Ransone would use torsioned bars with a square cross-section in 1880; these can be considered a precursor of modern corrugated bars (Fig 4.7). The French engineer François Hennebique would build the first concrete slab solely reinforced with round bars in Belgium in 1888 (Fig 4.8).

Fig 4.11. The Hennebique stirrup. 1892. [Source: Ref (288) Simonnet, Cyrille]

Fig 4.9. Bridge for the Industrial Fair in Bremen, Germany. Matthias Koenen. 1890. [Source: Ref (267) Picon, Antoine]




Fig 4.12. Hennebique’s reinforced concrete system. [Source: Ref (181) Gössel, Peter / Leuthäuser, Gabriele]



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Fig 4.66. Civil Engineering Pavilion. Scaffolds and formwork. [Source: Ref (256) Paduart, A.]

Fig 4.63. Civil Engineering Pavilion in Expo ’58 in Brussels. J. Van Doorselaere and A.Paduart. Longitudinal section. [Source: Ref (256) Paduart, A.]

Fig 4.65. Civil Engineering Pavilion. Cross-section along the reinforced concrete shell. [Source: Ref (256) Paduart, A.]

Fig 4.64. Civil Engineering Pavilion. Reinforcing bars in the cantilever. [Source: Ref (256) Paduart, A.]



Fig 4.67. Civil Engineering Pavilion. Placing the cantilever reinforcing bars. [Source: Ref (256) Paduart, A.]




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Fig 5.1. (Above, left) Saharan nomadic tent. The fabric is superimposed on a series of cables anchored to supports and to the ground. Note the triangulation in the two main directions. [Source: Ref (95) Berger, Horst]



A significant number of buildings with structural typologies fundamentally based on tension were erected on the occasion of World Expos. Some of these works have become paradigms in the history of structural systems because of their value in terms of innovation. It is a noteworthy fact that some Expos have managed to gather together such important or so many tensile structures so as to create a historical link with certain typologies. This is the case, for example, of Expo ‘58 held in Brussels and its association with structures made with prestressed cable nets, or Expo Osaka 1970 and the Exposición Universal de Sevilla 1992 with the notable presence of prestressed cable nets with textile enclosures and prestressed textile membranes. Upon analysing the technological context within the chronological period covered by the World Expos, two stages can be differentiated: on the one hand, there were specific and intermittent experiences during the 19th century, some of which form the cornerstone of modern, tensioned typologies. On the other hand, the second half of the 20th century witnessed a great boom and development of modern tensile structures.

Fig 5.2. (Above, right) Ottoman tent from the 17th century on exhibit in the Royal Palace in Dresden, Germany. Floor plan: 20 x 8 m. Height: 6 m. [Source: its creators] Fig 5.3. (Centre left) Chinese sailboat. [Source: Ref (95) Berger, Horst] Fig 5.4. (Centre right) Phoenician sailboats. [Source: its creators] Fig 5.5. (Below, right) Fresco discovered in Pompeii which shows the “velum” or amphitheatre sunshade. [Source: its creators] Fig 5.6. (Below, left) Reconstruction of the Roman “velum” by Rainer Graefe. Vitruvius includes this element’s folding mechanism in his treaty. [Source: Ref (95) Berger, Horst]

The large spans made possible by this way of working were exploited by civilisations located in mountainous regions in the building of suspension bridges made with ropes fashioned out of plant fibres. Those built by Andean and Himalayan tribes are particularly noteworthy (Fig 5.7 and Fig 5.8).

5.1 TENSILE STRUCTURES IN THE 19TH CENTURY 5.1.1 The technological context: intermittent contributions Structures whose mechanical principle is based on tension have been built since ancient times. The structural airiness achieved through this modus operandi was fundamentally exploited for building provisional or mobile structures, or those that could be dismantled. Such is the case of the tents of nomadic groups, made with wooden masts, fibres, ropes and animal skins or fabrics (Fig 5.1 and Fig 5.2). Other examples derive from the state-of-the-art technology attained by Phoenician, Roman or Chinese sailboats (Fig 5.3 and Fig 5.4). There are also documented examples of textile decks designed to cast shade over Roman amphitheatres, found in various frescoes discovered in the city of Pompeii (Fig 5.5 and Fig 5.6).




Fig 5.7. (Left) Bridge over the Río Pampas on the road from Cuzco to Jauja (Peru). Span: 41 metres. Disappeared at the end of the 19th century. [Source: Ref (155) Troyano, L.] Fig 5.8. (Right) Traditional construction of a Peruvian bridge with plant fibre ropes. These are always bridges in which the deck is not independent of the catenary, but rather adopts its shape. [Source: Ref (221) Kronenburg, Robert].



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Bridges with iron chains were known to have been built in China from the 14th century onwards, although they are not believed to have reached the modern solution of hanging a horizontal deck from vertical cables attached to a parabolic cable. All known oriental chain bridges are catenary bridges with little deflection; for this reason the deck was not separated from the cable (Fig 5.9 and Fig 5.10) [Ref (155) Troyano, Leonardo]

chains attached between them; these are anchored to an iron support embedded in the masonry walls at each corner of the building. There are lighter, secondary chains attached perpendicularly to the main chains, with plaited wires crossing the former. The result is a mesh that Schnirch suggested covering with either cast-iron tiles or with planks and iron or copper plates. In short, it is a hanging deck in which stability is dependent on the weight of the overlay material, since there are no cables with opposing curvature to stabilise the whole against the suction force of the wind. According to Schnirch, the main advantage of this deck would be its low weight compared to that of a conventional deck.

Fig 5.9. (Left) Chain bridge. Chuka Bridge over the River Wang in Bhutan. 15th century. [Source: Ref (155) Troyano, L.] Fig 5.10. (Right) Ching-Lung chain bridge over the Yangtze River. Span: 100 m. [Source: Ref (95) Berger, Horst]

In the Western World, the first documented proposals for suspension bridges are included in the book Machinae Novae by Fausto Veranzio, published in Venice in 1615. There are two proposals in this book: the Pons Canabeus (Fig 5.11), a suspension bridge made with hemp ropes and a wooden deck, and the Pons Ferreus (Fig 5.12), a cable-stayed bridge with iron chains. In our opinion, the latter is truly sophisticated, since the chains were arranged at an angle, thus making it a chain-stayed bridge rather than a suspension one. Nevertheless, the fact that the beams forming the deck were hinged does not seem to be the best solution, bearing in mind that these types of bridge transmit compression to the deck, therefore running the risk of creating an unstable situation.

Fig 5.11. (Below, left) Pons Canabeus by Fausto Veranzio, published in his book Machinae Novae, Venice, 1615. Suspension bridge with hemp fibre ropes. [Source: Ref (249) Nardi, Guido]

Fig 5.13. Proposal for a hanging deck for a theatre. Friedrich Schnirch. 1824. Note above on the left the configuration of the main chains; above in the centre is the anchoring piece for the chains embedded in the masonry wall; below on the left, the fastening for the enclosure panels. [Source: Ref (183) Graefe, Rainer]

Fig 5.14. Proposal for a hanging deck for a theatre. Friedrich Schnirch. 1824. Secondary chains on the left; main chains, above in the centre; below on the right, a general diagram of the deck structure. [Source: Ref (183) Graefe, Rainer]

Going back to periods that are contemporary to the World Expos, we can state that the immediate precedents to tensile building structures developed during the 19th century are the suspension bridges with iron chains that began to be built in Europe at the end of the 18th century, as well as those referred to in Chapter 1 (Fig 1.6 and Fig 1.7). The first significant, documented reference to a tensile building structure in the 19th century appears in the article published by the engineer Friedrich Schnirch in 1824 titled “On wrought iron decks” [Ref (183) Graefe, Rainer]. In this article, Schnirch, a man with experience in building chain suspension bridges, includes a deck project for a theatre (Fig 5.13 and Fig 5.14). It is a rectangular-plan deck made up of two wrought iron supports 48 metres apart with main




Fig 5.12. (Above, right) Pons Ferreus by Fausto Veranzio, published in his book Machinae Novae, Venice, 1615. Cable-stayed bridge with iron chains and wooden deck. [Source: Ref (249) Nardi, Guido]

A mast factory (Fig 5.15) was built in the military port in Lorient, France in 1839, in which the principle of iron chain suspension bridges (parabolic chain, vertical hanging chains and horizontal deck) was applied directly. It had a span of 44 metres and a width of 20 metres, the dimensions needed to manoeuvre the masts. The parabolic cables were anchored to the masonry walls in the adjacent naves. This building was published in J.M. Sganzin’s “Cours de Construction”, a very well-known engineering manual in the United States.

Fig 5.15. Mast Factory in Lorient military port, France. 1839. [Source: Ref (300) Thorne, Robert]



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a width of 51 metres. In this case, the mesh had double curvature in the area of the two semi-circular ends, and simple curvature in the area of the two straight sides. Additionally, it can be seen how Shukhov varied the opening in the plate mesh, making it denser in the whole perimetral area. Two other rectangular pavilions were built following the same technique, both 35 metres wide and 50 metres long (Fig 5.25 and Fig 5.26). In this case, a central row of trussed columns was used.

Fig 5.25. The Rotunda or Pavilion of Structural Techniques and the Rectangular Pavilion, under construction. All-Russia Exhibition held in Nizhny-Novgorod. Vladimir Shukhov. 1896. [Source: its creators]

Fig 5.26. Rectangular pavilion in the All-Russia Exhibition held in NizhnyNovgorod. Vladimir Shukhov. 1896. [Source: Ref (267) Picon, Antoine]




Fig 5.27. The Rotunda or Pavilion of Structural Techniques, under construction. The All-Russia Exhibition held in NizhnyNovgorod. Vladimir Shukhov. 1896. [Source: its creators]

Fig 5.28. The Rotunda or Pavilion of Structural Techniques. The All-Russia Exhibition held in NizhnyNovgorod. Vladimir Shukhov. 1896. [Source: Ref (267) Picon, Antoine]



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and Fig 5.81. The generatrices were formed by the aforementioned fish belly beams hinged with the cables at their joints. The longitudinal façades were constituted by a succession of hyperbolic paraboloids in which the joists were hinged directly in the foundations and in the steel tubular rigid edges BrCr and CrDr.

Fig 5.79. Marie Thumas Restaurant Pavilion. Note the arrangement of fish belly beams. [Source: Ref (267) Picon, Antoine]

Fig 5.80. Marie Thumas Restaurant Pavilion. Structural diagram. [Source: Ref (279) Sarger, René / Vandepitte, D.]

Fig 5.81. Marie Thumas Restaurant Pavilion. Structural diagram. [Source: Ref (279) Sarger, René / Vandepitte, D.]

theses carried out in the absence of references to a known construction type or results of tests on models. The initial project was thus re-designed incorporating the reduction in the number of cables and the use of light, semi-rigid beams.” [Ref (279) Sarger, René / Vandepitte, D.] In short, the building was made with a succession of conoids, each of which was limited by a concave ridge cable and another convex valley cable, as well as rigid edges made of tubular steel profiles with a square cross-section, labelled BrCr and CrDr in figures Fig 5.80




As explained above, the whole structure was supported by eight inclined columns that lay on four foundation points via hinged joints (Fig 5.82). These hinges were key in prestressing the structure (Fig 5.83), since prestressing the vertical cables at the ends of the building would move the column heads, thus turning them and tensing the concave ridge cables (cable 1 in Fig 5.83); the latter tended to raise, thus tensing the beams (3 in Fig 5.83) that were prone to raising the convex valley cables (2 in Fig 5.83). In short, the whole ensemble would be tensed except for the columns. As with the case of the French Pavilion, the prestressing value would be calculated so that none of the elements would be completely relaxed in the face of any combination of forces, such as in the case of the concave ridge cables faced with suction wind load.



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The lower family of cables was prestressed by the weight of the central tension ring itself, which helped stabilise the deck via gravity. Additionally, the upper family of cables was prestressed by applying tension to the order of 22 tonnes, contributing equally to stabilising the deck against possible suction forces (Fig 5.106). It is clear that the shape of the deck, with its enclosure of translucent plastic sheets, enabled the rain water to drain towards the building perimeter, while the central tension ring, under which a pond was located, remained open. As with the French Pavilion, wind tunnel tests were carried out in the absence of similar structural typologies as a reference. In this sense, we should remember the spectacular collapse of the Tacoma Narrows Bridge, a suspension bridge in Seattle, on November 7th 1940, four months after its inauguration; it became a classic example of collapse due to flutter, and at that time it would encourage reflections to be made on phenomena of dynamic instability, as well as contribute to the generalisation of wind tunnel tests.

As with cases described earlier, the American Pavilion in Expo ’58 in Brussels would have architectural consequences in the shape of buildings constructed beyond the Expos. Thus, this pavilion is the immediate precedent to the Utica Memorial Auditorium in New York, erected in 1959 by the engineer Lev Zetlin and the architect Gehron Seltzer (Fig 5.108 and Fig 5.109). With a diameter of 73 metres, it has a similar typology, though more sophisticated. Thus, the central tension ring is lighter, the upper and lower cables are prestressed, and there are rigid vertical bars connecting both families of cables, enabling any potential snow loads to be transferred to the lower family and thereby increasing the stiffness of the upper family.

Fig 5.107. American Pavilion in Expo ’58 in Brussels. [Source: its creators]

Fig 5.108. Utica Memorial Auditorium, New York. Lev Zetlin and Gehron Seltzer. 1959. This building is an immediate consequence of the American Pavilion in Expo ’58 in Brussels. [Source: Ref (255) Otto, Frei]

Fig 5.109. Utica Memorial Auditorium, New York. Lev Zetlin and Gehron Seltzer. 1959. Explanatory structural diagram by Horst Berger. [Source: Ref (95) Berger, Horst]






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Although he would continue to develop idealistic proposals over the span of his career, Frei Otto’s first tensile structure was the simple Music Pavilion in the Federal Garden Exhibition (Bundesgartenschau) held in Kassel in 1955 and built with Peter Stromeyer (Fig 5.147). It was a basic surface in the shape of a hyperbolic paraboloid. It had two high vertices linked to cable-stayed columns and two low vertices directly connected to the foundations. Edge cables pre-tensioned this membrane made of 1-mm-thick cotton fabric, giving it a span of 18 metres.

that are remarkably utopian. Such is the case of the “City in the Antarctic” in 1953 (Fig 5.146), in which a structure made up of a cable net connected to an arch covers an urban settlement with the aim of climate control.

Fig 5.147. Music Pavilion in the Bundesgartenschau in Kassel in 1955. The structure belongs to the four-point typology in which two high and two low vertices support a hyperbolic paraboloid surface. Frei Otto and Peter Stromeyer. [Source: Ref (177) Glaeser, Ludwig]

Another example of Otto’s first tensile structures is the aforementioned portable Hangar built together with Stromeyer (1956) (Fig 5.76), consisting of columns, ridge and valley cables with opposing curvature and a prestressed membrane. We have also referred to the first application of a prestressed textile membrane with high and low inner vertices for the Interbau in Berlin in 1957 (Fig 5.39 and Fig 5.148).

Fig 5.145. Aerial view of the Federal Republic of Germany Pavilion in Expo ’67 in Montreal. Frei Otto and Fritz Leonhard. [Source: Ref (299) Thomas Nelson & Sons]

Fig 5.146. Sketch for “City in the Antarctic”. Frei Otto. 1953. [Source: Ref (254) Otto, Frei]




Fig 5.148. First application of a prestressed membrane with high and low inner vertices. Interbau in Berlin 1957. Reduced model in elastic fabric. Frei Otto. [Source: Ref (254) Otto, Frei]



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to the hot-air balloon, although it was not until 1897 when David Schwarz would build the first airship with an inner skeleton. This technology would continue to be developed by Ludwig DĂźrr in 1905 when he built the Zeppelin LZ-2, made with polygonal rings connected by longitudinal bars, a typology that would be perfected over the following years (Fig 6.3).


WORLD EXPOS: THE ZENITH OF PNEUMATIC STRUCTURES Pneumatic structures belong to the group of structural typologies whose mechanical principle is based on tension, covered in the previous chapter. Nevertheless, given the specificity of pneumatic structures and the notable contribution of the World Expos to the history of this typology, they deserve their own chapter. Their specificity is primarily based on the fact that they are membrane structures that are prestressed via the differential pressure between an internal and external fluid, thus generally needing a permanent electricity supply in order to maintain their shape.

6.1 THE ORIGIN OF PNEUMATIC STRUCTURES From bubbles made of liquid to membranes with pressurised fluids inside them, there are many examples of pneumatic structures in nature that have inspired mankind (Fig 6.1). However, the beginnings of the history of artificial pneumatic structures are linked to that of aeronautics. Thus, the hot-air balloon could be considered as the first artificial precedent of pneumatic structures for construction. Invented in 1783 by Joseph Michel and Jacques Etienne Montgolfier, its main link to construction typologies resides in the fact that it is a membrane that keeps its structural shape thanks to a difference in pressure between external and internal air (Fig 6.2). Invented by Jean Baptiste Meunier, the airship is contemporary

Fig 6.3. The airship LZ-126 under construction. A typology comprising polygonal rings connected by longitudinal bars. 1924. [Source: Ref (267) Picon, Antoine]

Fig 6.1. The soap bubble as a natural pneumatic structure. [Source: Ref (195) Herzog, Thomas]



Fig 6.2. Lift-off of the hot-air balloon invented by Joseph Michel and Jacques Etienne Montgolfier. 1783. [Source: Ref (195) Herzog, Thomas]




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The enormous engineering effort invested in developing these giant, flying, pneumatic structures would be mirrored in construction. In this way, the English engineer Frederick William Lanchester would patent a provisional pneumatic hospital in 1917 (Fig 6.4) that would constitute the first known application to construction of the technology developed for air transport; unfortunately, it was never built. While there was no immediate continuity to Lanchester’s works, the patent brings to light some of these structures’ main architectural characteristics: their provisionality, easy transportation and speedy assembly.

Fig 6.5. (Above, left) Pneumatic decks to protect radars installed in the U.S. after World War Two. [Source: Ref (195) Herzog, Thomas]

Fig 6.4. Fig 6.4. Frederick William Lanchester’s patent for a provisional pneumatic hospital. 1917. [Source: Ref (195) Herzog, Thomas]

Once World War Two had broken out, these characteristics would contribute to the design of various pneumatic elements such as pneumatic boats. Military applications would continue to be developed after the war; thus, at the beginning of the ‘50s and in the context of the Cold War, the United States would begin construction of several radar antennae to protect their borders. Often located in inhospitable areas, these antennae needed a protective cover that would not interfere with the signals (Fig 6.5 and Fig 6.6). Along these lines, the engineer and Director of Cornell Aeronautical Laboratory, Walter Bird, studied and built several pneumatic decks. Bird’s works would be highly relevant in the development of pneumatic decks thanks to his inclusion of wind tunnel tests; the conclusion he reached through these tests was that structures with a diameter of 15 metres would be stable in winds of up to 240 Km/h [Ref (267) Picon, Antoine]. He also tested various synthetic fabrics such as nylon coated in neoprene, vinyl or hypalon.




Given the satisfactory results obtained with pneumatic structures for military antennae covers, they would continue being used in the ‘60s to cover large telecommunications antennae, reaching spans of around 60 metres. An example of this is the low-pressure pneumatic cover of the Space Telecommunication Station of Pleumeur-Bodou (Fig 6.7 to Fig 6.9).

Fig 6.6. (Above, right) Pneumatic decks to protect radars installed in the U.S. after World War Two. [Source: Ref (195) Herzog, Thomas]

Fig 6.7. Space Telecommunication Station of Pleumeur-Bodou. Assembly of the membrane in the ‘60s. [Source: Ref (267) Picon, Antoine]



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Fig 6.31. The U.S. Pavilion in Expo ’70, Osaka. Pressurised membrane. Inside under construction. [Source: Ref (195) Herzog, Thomas]

The U.S. Pavilion was made up of a low-pressure pneumatic vault reinforced with cables covering a space with a super-elliptical shape of exponent 2.5 measuring 83.5 x 142 m (Fig 6.31 to Fig 6.33). The low-profile vault was only raised 6.5 m above the ground and was encircled by a reinforced concrete compression ring, while the exhibition space remained half-buried. The super-elliptical shape was chosen for aesthetic reasons [Ref (173) Geiger, David].

Fig 6.29. The U.S. Pavilion in Expo ’70, Osaka. David Geiger and Horst Berger. [Source: Ref (206) Ishii, Kazuo]

Fig 6.32. The U.S. Pavilion in Expo ’70, Osaka. Arrangement of the cables, di-

Fig 6.30. The U.S. Pavilion in Expo ’70, Osaka. David Geiger and Horst Berger. [Source: Ref (206) Ishii, Kazuo]




mensions and mathematical formulation of the super ellipsis. [Source: Ref (206) Ishii, Kazuo]



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Fig 6.56. Tokyo Dome, also called “Big Egg”. Nikken Sekkei and Takenata Komuten. 1988. [Source: Ref (206) Ishii, Kazuo]

Fig 6.58, Fig 6.59, Fig 6.60 y Fig 6.61. Tokyo Dome. Nikken Sekkei and Takenata Komuten. 1988. Various stages in the process of pressurising the membrane. [Source: Ref (206) Ishii, Kazuo]

This too was made with a fibreglass membrane coated in PTFE and fitted with a snow melt system, while the most remarkable characteristic is its sophisticated computerised monitoring system connected to internal and external barometers, wind gauges, devices for measuring snowfall and shifts in the membrane, and systems controlling the number of open doors. This system automatically varied the internal pressure from 30 mm of water pressure (30 Kg/m2) up to 90 mm (90 Kg/m2), according to the previous parameters (Fig 6.62).

Fig 6.62. Tokyo Dome. Nikken Sekkei and Takenata Komuten. 1988. Membrane shift sensor. [Source: Ref (206) Ishii, Kazuo]

Fig 6.57. Tokio Dome. Nikken Sekkei and Takenata Komuten. 1988. [Source: Ref (206) Ishii, Kazuo]




As we can see, while having obvious variations and progressively incorporating technological advances, all these decks were based on the same principles as the ground-breaking U.S. Pavilion in Expo ’70 in Osaka: low-pressure and low-profile vaults, reinforcing cables arranged diagonally to the main axes, and perimetral compression rings. In this way, the enormous impact that building had on various proposals for making large urban settlements in inhospitable areas is evident. Nowadays, these proposals are viewed from a utopian perspective; in 1970, however, the belief in technological development and an energetic optimism led to a worldview of great expectations in this sense. All the aforementioned issues underscore the enormous historical transcendence of that Pavilion in structural and architectural fields.



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When dealing with the pneumatic pavilions in Expo ’70 in Osaka that had acquired an individual value both in terms of structural innovation and size, reference has to be made to the Fuji Group Pavilion. Created by the engineer Mamoru Kawaguchi and the architect Yutaka Murata, it was the largest high-pressure pneumatic structure ever built [Ref (74) Kawaguchi, Mamoru], as well as displaying a brilliant design of organic inspiration (Fig 6.63 to Fig 6.71).

Fig 6.63. Fuji Group Pavilion. Expo ’70 in Osaka. Mamoru Kawaguchi and Yutaka Murata. Aerial photograph. [Source: Ref (206) Ishii, Kazuo]

Fig 6.64. Fuji Group Pavilion. Expo ’70 in Osaka. Mamoru Kawaguchi and Yutaka Murata. [Source: Ref (31) Osaka Official Photo Album]

Fig 6.65. Fuji Group Pavilion. Expo ’70 in Osaka. Mamoru Kawaguchi and Yutaka Murata. Photograph of the inside. [Source: Ref (206) Ishii, Kazuo]




The structure was made up of 16 tubes 72 m long and with a diameter of 4 m filled with pressurised air. The tubes arched and were inter-connected by 50-cm-wide strips placed every 4 metres. The plan of the tube bases formed a circumference with an outer diameter of 50 metres. Each tube was connected at its base to a metal ring anchored to circular pile caps. All the tubes were the same length, while the central ones were semi-circular and the others were progressively raised the closer their bases were.



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Fig 6.68. Fuji Group Pavilion. Expo ’70 in Osaka. Details. [Source: Ref (206) Ishii, Kazuo]

Fig 6.66. Fuji Group Pavilion. Expo ’70 in Osaka. Floor plan. [Source: Ref (206) Ishii, Kazuo]

Fig 6.67. Fuji Group Pavilion. Expo ’70 in Osaka. Cross-section. [Source: Ref (206) Ishii, Kazuo]






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7.1 SPACE STRUCTURES: ORIGIN AND DEVELOPMENT Several examples of metal space structures had already materialised during the 19th century. Along these lines we can highlight the single layer domes made by the German engineer Johann Wilhem Schweller to cover various gas tanks in Berlin, good examples of which are the tank from 1875 with a span of 54 metres (Fig 4.52), or that from 1893 with a span of 65 metres (Fig 7.1).


SPACE FRAMES: THE EXPOS BETWEEN UTOPIA AND REALITY The evidence that any structure is created in a three-dimensional space indicates that all built structures can be defined as spatial. In this way, a structure made of columns, girders and joists is a space structure. Nevertheless, when using the term space structure we are normally referring to those made of bars with axial rigidity with a principal characteristic: an absence of any structural hierarchy in terms of the transmission of loads (from the slab to the joists, and from these to the girders, then to the columns and finally to the foundations). External forces are therefore not transmitted from one structural-hierarchical order to another in these typologies, but rather the stresses generated by the external loads are distributed spatially between the various bars that make up the structure. Within what we call space structures, a typology called space frame in modern times stands out in particular. Its singularity with respect to previous typologies resides in the fact that it comprises a group of independent bars, generally short in length when compared to the total size of the structure, arranged in what is called a bar and joint system; alternatively, they are prefabricated in polyhedral modules making modular systems. The bars or members are connected between them with joints or nodes that are generally standardised and designed to allow bars to be connected in different directions within the space. The bars may be organised in a sole layer or in various through polyhedral groupings, and are basically subject to axial stresses (tension or compression). The spatial distribution of these fundamentally axial stresses between a large number of bars implies using ones with a considerably thinner section than with other typologies; the weight of the bars thus being lower, this typology is particularly suited for covering large areas. It should be noted that the most frequently used materials in this typology have been steel and aluminium, both with tubular profiles, while other materials such as wood and bamboo have figured to a considerably lesser extent.

Fig 7.1. Gas tank in Berlin. Johann Wilhem Schweller. 1893. [Source: Ref (181) Gössel, Peter / Leuthäuser, Gabriele]

Another of the most noteworthy examples in construction is the unique deck built by the Russian engineer Vladimir Shukhov in Vyksa, Russia in 1897 (Fig 7.2). Made of spherical caps, it represents one of the first metal space structures with one layer and double curvature. Each of the caps is a space structure in the sense that there is no structural hierarchy. Nevertheless, it is not a space frame in the modern sense of the term, since the bars are not independent but rather continuous pieces that cross in space and are riveted at the joints; nor does it have a standardised independent joint piece. In any case, it is a brilliant example and a precedent of modern space frames.

This chapter presents an examination of some of the main historical milestones of space frames, while bringing to light the magnificent contributions made by the World Expos in this field.

Fig 7.2. Deck in Vyksa. Russia. Vladimir Shukhov. 1897. [Source: its creators]






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In this sense, Alexander Graham Bell is considered to be the great forefather of the modern space frame. During the first years of the 20th century, and coinciding with the development by the Wright brothers of the first aeroplane in the world, the Flyer III (1905), Bell experimented with space frames made of tetrahedra and octahedra. While it would appear that the invention was linked to aeronautics, Graham Bell published an article in 1903 in National Geographic Magazine titled “The tetrahedral principle in kite structure”, in which he claimed:

Fig 7.4. Prototype of a space frame. Alexander Graham Bell. 1907. [Source: Ref (79) Appelbaum, Stanley]

“The use of the tetrahedral cell is not limited to the construction of structures for aeroplanes. It is applicable to any type of structure in which we wish to combine lightness and strength.” [Ref (185) Graham Bell, Alexander] He made innumerable tetrahedral space frame prototypes along these lines. Particularly notable examples date back to 1903 (Fig 7.3) and 1907 (Fig 7.4). In that same year, he would build various kites with space frames (Fig 7.5); additionally, he would build the first known application of a space frame in construction together with the engineer Casey Baldwin. It was the Outlook Tower in Beinn Bhreagh, United States, consisting of tetrahedral modules made of steel tubes with a height of around twenty metres (Fig 7.6 to Fig 7.8).

Fig 7.5. Kite made with a space frame. Alexander Graham Bell. 1907. [Source: Ref (230) Makowski, Z.S.]

Fig 7.3. Prototype of a space frame. Alexander Graham Bell. 1903. [Source: Ref (161) Frazier, Charles]




Fig 7.6. Outlook Tower in Beinn Bhreagh. Alexander Graham Bell and Casey Baldwin. 1907. [Source: Ref (230) Makowski, Z.S.]



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The modular Space Deck System was developed along these lines in the ‘50s and commercialised in 1958 (Fig 7.10 and Fig 7.11). It was made up of pyramid-shaped modules that were easily stacked, with a square plan measuring 1.22 metres along the sides and with heights of 1.05 and 0.61 metres. As it was a modular system, it was ideal for speedy dismantling.

During the ‘30s and ‘40s, other researchers such as Richard Buckminster Fuller, Konrad Wachsmann and Robert Le Ricolais would elaborate on the principles and development of the space frame. In this sense, one of the determining factors in the development of this typology was the design of the joint. This was one of the aspects upon which the researchers focussed their efforts, eager to design a joint that was simple to assemble and to which bars could be attached in various spatial directions. The invention of the MERO System by the engineer Max Mengeringhausen in 1943 would signal the start of a huge profusion in the use of space frames in architecture (Fig 7.9). The MERO System was the first to be available commercially, and probably the most used to date in both its original version and the innumerable imitations that sidestepped its patent. It basically consists of a sphere with eighteen threaded holes that allow another eighteen bars to be connected to it.

Fig 7.7. (Left) Outlook Tower in Beinn Bhreagh. Alexander Graham Bell and Casey Baldwin. 1907. Erecting the structure. [Source: Ref (219) Klotz, Heinrich] Fig 7.8. (Right) Outlook Tower in Beinn Bhreagh. [Source: Ref (143) Eekhout, Mick]

Fig 7.9. Joint from the MERO System. Max Mengeringhausen. 1943. [Source: Ref (79) Appelbaum, Stanley]

During the ‘50s and ‘60s, there were many patents for space frame systems, and ultimately innumerable space frame systems have been developed over time. Some of the most outstanding examples will be explained below, as well as some of the most significant works.




Fig 7.10. Sketch of the modular Space Deck System. [Source: Ref (118) Chilton, John]

Fig 7.11. Space Deck System. Stacked modules. [Source: Ref (118) Chilton, John]

Stéphane du Château also registered various patents, the earliest being for the Tridirectionelle S.D.C System in 1957 (Fig 7.12 and Fig 7.13). In this case, the bars were welded to the node. An interesting example of a construction following this system is Boulogne Swimming Pool from 1962; it was made with a double layer frame with a plan of 50 x 50



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Fig 7.137. The Festival Plaza. Expo Osaka in 1970. Kenzo Tange, Yoshikatsu Tsuboi and Mamoru Kawaguchi. [Source: Ref (296) Tange, Kenzo]

Fig 7.135. Spatial City. Yona Friedman. 1960. The space frame is a habitable place. [Source: its creators]

Fig 7.138. The Festival Plaza. Expo Osaka in 1970. Kenzo Tange, Yoshikatsu Tsuboi and Mamoru Kawaguchi. [Source: Ref (96) Bettinotti, Massimo]

Fig 7.136. “Spatial Paris”. Yona Friedman. 1960. Superposition of a residential space megastructure over Paris. [Source: its creators]

These proposals had a profound influence on the Japanese Metabolism Group and even the Archigram Group. Established in 1960 by Kenzo Tange, Kiyonori Kikutake and Kisho Kurokawa, the Metabolism Group aimed to present proposals, some of them on an urban scale, that were based on technological development and capsule addition systems, in line with a society under continuous vital and technological change. Metabolic proposals are rooted in the Japanese cultural and sociological reality of that time: a huge demographic explosion; limited space in the island cities; a population with a high level of geographical mobility, whereby about 10% change cities every year; as well as the characteristic modulation of traditional Japanese architecture. These extremes led to urban proposals that reflected this continuously mutating reality, in a biological analogy of changing cells [Ref (313) Martín Gutiérrez, Emilio]. Thanks to their position in the technological cutting edge of that time and their aggregative nature, space frames would be the ideal vehicle to make these proposals a reality. Some of the structural works that approximate the previous proposals are the Festival Plaza by the architect Kenzo Tange and the engineers Yoshikatsu Tsuboi and Mamoru Kawaguchi, and the Takara Beautilion by Kisho Kurokawa. The Festival Plaza from Expo Osaka in 1970 was formed by a double-layer space frame with an exceptionally large rectangular floor plan measuring 108 x 291.6 m and a height of 30.11 m up to the lower layer of the structure. The height of the frame was 7.63 measured from the bar axes (Fig 7.137 to Fig 7.140).






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The World Expos have housed buildings with structures made of wood or its derivatives which have made significant contributions to the history of structural systems. The following chapter will outline the reciprocal influence that the Expos have had, as well as the evolution of wooden structures. Subsequently, this interaction will be shown to have fundamentally occurred in three key moments in the history of this material. Fig 7.165. Expo Tower. Kiyonori Kikutate. Expo ’70 in Osaka. [Source: its creators]

Fig 7.166. Expo Tower. Elevation of one of the prefabricated capsules. [Source: Ref (31) Osaka 1970 Official Photo Album]


We should point out that there has not been any historical continuity in terms of built examples of space frames applied to high-rise buildings, with the exception of those constructions that solely resort to using triangulation as an element of horizontal stiffness without representing integral applications of the principle of space frames.

As a natural element that is easy to handle, wood was used as a construction material by the oldest civilizations, and was probably the first to be used by mankind to make structures. These first deck structures must have been quite rudimentary, presumably involving a few branches intertwined and covered with vegetal elements or skins. In some cases, the construction tradition of certain typologies has prevailed and their simplicity and precariousness can still be seen among some primitive societies (Fig 8.1).

All of the issues that have been dealt with above highlight the importance of the role of the World Expos, not only in the history of structural systems from a technological perspective, but also as a stage for bringing to life proposals derived from those utopian architectural currents that have been largely sustained by the most cutting-edge structural advances.

Fig 8.1. Structure for a primitive cabin. [Source: Ref (229) Mainstone, Rowland J.]






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On other occasions, however, their ingenuity has reached surprising lengths, as in the case of the tent used by the nomadic people of the steppes of Central Asia, called a yurt, which consists of a perimetral wooden structure that can be deployed (Fig 8.2 and Fig 8.3). Wood has also been used in the construction of highly simple primitive bridges, made with basic logs supported at two points or with intermediate supports (Fig 8.4).

Fig 8.4. Berber bridge made of logs with intermediate supports. Atlas mountains. Morocco. [Source: López César, Isaac]

Fig 8.2. Mongolians setting up a yurt. Note above on the left, the perimetral structure being deployed. It is an extraordinarily ingenious structure that is quickly set up and easily transported. [Source: its creators]

Fig 8.3. Photograph of a yurt. [Source: Library of Congress]




The Greeks and the Romans used simple and trussed wooden beams and arches in both bridges and decks. Along these lines, Vitruvius presents a cross-section of the wooden deck of a Greek temple in Book IV of his “De Architectura”; an understanding of the mechanical workings of this structural typology can be clearly evinced in the deck design (Fig 8.5).

Fig 8.5. Cross-section of the wooden frame for the deck of a Greek temple presented by Vitruvius in Book IV of his “De architectura”. Note the layout of the lower tie member that counters the horizontal thrusts on the columns. [Source: Vitruvius]



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Basing themselves on descriptions by Julius Caesar, several authors have attempted to graphically represent the bridge that the Emperor commanded be built over the Rhine for his troops to cross, and which was destroyed eighteen days later to hinder persecution from his enemies. In the sketches drawn by Andrea Palladio, it is seen to be formed by transversal portal frames driven into the river bed and stabilised through triangulation on one of its sides. The beams would be placed over them (Fig 8.6).

Fig 8.7. Trajan’s Bridge over the Danube. Relief from Trajan’s Column. [Source: Ref (155) Fernández Troyano, L.] Fig 8.6. Julius Caesar’s bridge over the Rhine. Representation by Andrea Palladio in 1570 based on the Emperor’s description. [Source: Ref (155) Fernández Troyano, L.]

Another Roman bridge of huge significance is documented in the reliefs of Trajan’s Column and several coins from that period: the magnificent Trajan’s Bridge over the Danube (Fig 8.7), attributed to Apollodorus of Damascus. It had X-shaped trusses and arches made of concentric pieces connected to other radial ones, with masonry stone piers. The spans were around 35 metres and the total length over a kilometre. In the Renaissance era, Leonardo da Vinci also proposed various structural diagrams of triangulated girders to be used in bridges (Fig 8.8). In the 16th century, Andrea Palladio himself built various wooden bridges, including the Bridge over the River Cismone (Fig 8.9) with a span of 30 metres and made with a truss with metal joints. He also designed various truss girders and arches that are documented in his treatise “I quattro libri dell’architettura” (Venice, 1570), which profoundly influenced the construction of wooden bridges up until the 19th century (Fig 8.10).




Fig 8.8. Drawings of triangulated girders by Leonardo da Vinci. 16th century. [Source: Ref (155) Fernández Troyano, L.]



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Expo ’92 in Seville marked a trend towards the structural use of timber and its industrial derivatives; this tendency would reach its highest point in the World Expo held in Hannover in 2000. This Expo, called “Man, Nature, Technology”, would be the ideal ideological frame for the use of structural materials obtained with low energy consumption that were also recyclable and sustainable. In this way, this Expo presents several pavilions whose structure was made of timber, good examples of which are the Swiss Pavilion by Peter Zumthor that was designed with “walls” of stacked planks fastened with tensioners; the Hungarian Pavilion by G. Vadász with “walls” of leaning wood designed with an inner truss of sawn timber; the Hoffnung Pavilion by Buchalla & Partner with two-hinged arches, or the Finnish pavilion by SARC Architects Ltd. that was designed with rigid portal frames made of sawn timber. However, the building which undoubtedly represents this culmination and the return to wood at the end of the century is the Expo-Roof, made by the architect Thomas Herzog and the engineer Julius Natterer to cover the main entrance to the Expo (Fig 8.57 to Fig

Fig 8.57. (Above) Expo-Roof. Thomas Herzog and Julius Natterer. Expo 2000 in Hannover. [Source: Ref (196) Herzog, Verena]

Fig 8.59. Expo-Roof. Thomas Herzog and Julius Natterer. Expo 2000 in Hannover. Cross-section of one of the modules. [Source: Ref (196) Herzog, Verena]

8.64). This construction brilliantly manifests the structural possibilities of wood in all its variations: sawn timber, roundwood, glued laminated timber and micro-laminated timber boards, applied to a daring structural design that demonstrates a new dimension to structures made with timber shells.

Fig 8.58. (Below) Expo-Roof. Thomas Herzog and Julius Natterer. Note the modular aggregation. [Source: Ref (196) Herzog, Verena]

Fig 8.60. Expo-Roof. Photograph of the interior. [Source: Ref (196) Herzog, Verena]






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Fig 8.79. Japanese Pavilion. Expo 2000 in Hannover. Test in which a cardboard tube is bent to simulate the assembly process. The tube was subsequently fragmented and the fragments subjected to compression tests. [Source: Ref (244) McQuaid, M.]

The pavilion introduced the wide-scale structural use of cardboard, being the largest structure to be built in this material [Ref (254) Otto, Frei] and [Ref (244) McQuaid, M.]. As with iron structures in the 19th century, the pavilion synthesizes the desire to push the limits of knowledge on a material, clearly evinced in the final need to reinforce the structure with timber arches and triangulate it with steel cables.

Fig 8.75, Fig 8.76, Fig 8.77 and Fig 8.78. Japanese Pavilion in Expo 2000 in Hannover. Stages in the assembly process. [Source: Ref (88) Ban, Shigeru]

As mentioned earlier, the nearest precedent to the Hannover structure was the Paper Dome (Fig 8.67 to Fig 8.70) with its span of 27.2 metres, in terms of it being a vaulted deck made with cardboard tubes. In this sense, it should be noted that the Paper Dome had polygonal arches made of fragments of tubes with straight directrixes that were connected by wooden joints. In contrast, the assembly system applied in the Japanese Pavilion was novel, involving bending the cardboard tube during the assembly process. This is another of the Pavilion’s contributions, as it led to specific tests being performed in which the cardboard tube was subject to deformation corresponding to the maximum curvature that the piece would undergo during assembly; subsequently, the tube was cut into short fragments which were in turn tested under axial compression in order to detect any potential loss of strength (Fig 8.79). As a result of all this, the Japanese Pavilion in Hannover had an immediate architectural consequence in the dome erected by Shigeru Ban in 2000 in the Museum of Modern Art in New York, clearly inspired by the Japanese Pavilion and building on the experience acquired through it (Fig 8.80 to Fig 8.82). Its span of 26.5 metres is shorter that the Japanese Pavilion and the aim of the structure is not to enclose a space but rather to merely limit it; thus, the main load is the dead load. Nevertheless, its principal contribution is the fact that there are no wooden reinforcing arches; in their place, truss arches were used, formed by two cardboard chords bolted together and steel cable diagonals (Fig 8.81 and Fig 8.82). In this sense, the Japanese Pavilion would mark the jump from a hybrid structure with curved cardboard tubes and wood to a pure, curved, cardboard tube structure.




Fig 8.80. Dome erected in the Museum of Modern Art in New York. Shigeru Ban. 2000. [Source: Ref (244) McQuaid, M.]



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This book has travelled along a historical overview in which the structural contributions made by World Expo buildings have been interlaced within the context of the general evolution of architectural structures. This has revealed the significant role played by the World Expos in this field; they are genuine test-beds in which new structural typologies and materials have been trialled, in many cases attaining greater spans and extending the limits of knowledge. The World Expos enabled the construction of buildings which progressively incorporated the technological advances that were fundamental to the history of structures, and consequently the history of architecture. Through the global analysis of the events presented in this book, several periods can be differentiated in terms of the development of structures connected to the Expos:

•The first period spans from the first World Expo held in London in 1851 to the beginning of the 20th century. It is characterised by the development of a considerable number of Expos with huge structural protagonism, linked to the peak of iron architecture and engineering. The Crystal Palace is the trigger for a technological surge, giving way to other structural creations beyond the scope of the Expos and resulting in this building being connected to the historical progression of the portal frame, and consequently to the first high-rise buildings from the Chicago School. Each Expo strived to outdo the previous one, in a process that aptly illustrates the nature of these events as areas of exhibition and rivalry among nations in terms of technological development. •The second period encompasses the interval between the beginning of the 20th century and Expo ’58 in Brussels. In the first part of the 20th century, after the First World War (1914-1918), the World Expos primarily turn towards the display of decorative objets d’art, diversifying into small pavilions and abandoning their industrial roots. Behind this was a twofold crisis; on the one hand, an economic crisis, and on the other, what we have called an ideological crisis based on the prolongation of the war and its terrible cruelty originating in the development of arms brought about by industrialisation. In this sense, doubts begin to be cast on the idea of technology and industry as guarantees of welfare and infinite progress. As a consequence, the Expos relinquish the construction of a sole, large building, of a “Palais de l’Industrie”. The Second World War (1939-1945) would also signal a digression in the development of the Expos. While it is true that some interesting constructions were built during the inter-war period,



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there was generally no place for large-span typologies in the pavilions erected at this time. Furthermore, it is hard to find small-scale buildings showcasing any structural innovations worthy of mention. With a few exceptions, technological exhibition yielded centre stage to the recreation of historicist styles, to classical and even regional reinterpretations, and to scattered appearances of rationalist or neoplastic architecture. •The third period covers the interval between Expo ’58 in Brussels and Expo ’92 in Seville. After World War Two, the Expos once again became reference points for the important technological advances developed in the field of structures. This aspect is seen clearly in the enormous level of progress made in the Expos in terms of diversity in structural typologies and new materials: the huge development in structures based on tension (cable nets, pre-stressed membranes), the great steps forward taken in space frames, pneumatic structures (which in part developed thanks to the technology of the Cold War), or the use of new structural products derived from wood. In the wake of the extraordinary structural achievements of the Expos in the 19th century, the World Expo that would inaugurate this new era of splendour was Expo ’58 in Brussels. 1958 truly was the year in which the World Expo would steal the limelight in structural innovation that had languished since the turn of the century, with a few isolated exceptions. From this point onwards, there have been several Expos of great structural significance, among which we can specifically highlight Brussels 1958, Montreal 1967, Osaka 1970 and Seville 1992. During the 19th century, the World Expos identified with iron architecture, iron being a cutting-edge material. In this new era, there were many structural, typological and material representations; while a specific typology may have been predominant, the Expos with structural protagonism could be related to a variety of them. An example of this is Brussels ‘58, which was primarily characterised by tensile structures that were cable-stayed or based on cable nets; nevertheless, glued laminated timber with synthetic adhesives played a leading role at the same time, as did some examples of space frames. Cable nets and space frames typified Expo ’67 in Montreal. On the other hand, Expo ’70 in Osaka gained importance thanks to the presence of pneumatic structures and space frames, although there was also room for cable nets and prestressed membranes. Expo ’92 in Seville stood out in particular thanks to the appearance of pre-stressed membranes and cable nets, with the additional presence of other typologies such as space frames and even some pneumatic structures. In short, it was already common to see individual pavilions devoted to different countries, various regions of the host country and innumerable private companies during this brilliant era. The number of structurally significant buildings in the World Expos greatly increased.



•The last period defined here encompasses the final two decades of the 20th century, partially overlapping with the last fragment of the previous era, or qualifying it. In this last stage, we observe the growing demand for large, diaphanous spaces capable of housing large crowds of visitors. Thus, enormous sports or multi-purpose spaces, new airport terminals, transport transfer points, and new railway stations all competed for the structural cutting-edge protagonism that had formerly been so closely linked to the World Expos. The culmination of this period would be the World Expo Hannover 2000; christened “Man, Nature, Technology”, it would be the perfect ideological frame for the use of structural materials that were recyclable as well as procured with the minimum of energy consumption, particularly those derived from wood. After the era of optimism in terms of energy resources and the excesses of industrialisation, this environmental criteria opened up a new path which appears to be predominating not only in the World Expos held during the first decade of the 21st century, but also in a considerable part of architecture in general.

There has been no significant fundamental development in new architectural structural typologies in the first two decades of the 21st century. The buildings are essentially sustained by the same typologies, although they do showcase new designs and formalisations arising from the freedom granted by new computer resources. In many cases, the architecture has even achieved a certain level of plastic or sculptural innovation. This aspect of formal experimentation is not new; the architecture of the exhibition pavilion has been quite suitable for this purpose, given that it lacks a rigid functional programme and has often aimed at causing an impact among the public. What has happened is that the previous lack of existing calculation tools guided this innovation towards highly rational, structural shapes that were based on the logic of the physical laws governing our world. Nowadays, computer technology has provided us with practically limitless calculation, representation and manufacturing resources that facilitate the exploration of areas beyond this physical rationality. In short, the evolution of these periods has led to a mannerism in architecture in general terms that has been brought about by computers; this will undoubtedly mark an era that will be justly valued with historical perspective. While this phenomenon may prove to be positive from the perspective of plastic experimentation and innovation in space creation, we should be prudent and not forget that the machine is merely a means; the ultimate aim of architecture should unquestionably be mankind.


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Isaac López César (Ferrol, 1977) is a PhD Architect. University Specialist in the Design and Calculation of Building Structures. Professor of Physics and Structures at the Higher Technical School of Architecture in A Coruña since 2007. He has designed and calculated numerous structures in the spheres of both public and private construction. His research has centred on the field of deployable structures and the history of architectural structures. He is the author of several articles, as well as of a variety of patents related to mobile and deployable structures.



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World expos. A history of structures. Isaac López César. (Preview of sample pages)  

A history of architectural structures in 575 pages, with 950 illustrations. Avaliable in bookstores and online platforms. This book is a...

World expos. A history of structures. Isaac López César. (Preview of sample pages)  

A history of architectural structures in 575 pages, with 950 illustrations. Avaliable in bookstores and online platforms. This book is a...