Genius in Concrete

Behind every great architect there is a great engineer. Or more accurately, behind every great modern architect there is a great engineer, for until the twentieth century, the two professions were one. The accomplished—and largely anonymous—medieval master-masons who built the Gothic cathedrals, for example, were responsible equally for ornament and structure, which may be why it is often hard to distinguish between the two. The pointed arch, as the British scholar John Summerson observed years ago, is as much fanciful as functional, and what appear to be structural ribs in the stone ceilings are strictly decorative. On the other hand, window tracery made of lead and iron, while forming a pretty pattern, effectively resists gravity and wind forces; and although the stone piers that line the nave are designed to resemble bundled columns—a visual conceit—their mass is needed to support the great weight of the wall and the stone ceiling above. In a medieval cathedral, architecture and engineering are crucially combined.

The architects of the Renaissance, although sometimes less interested in structural virtuosity, were equally versed in construction. In his famous treatise On the Art of Building in Ten Books, Leon Battista Alberti devoted one entire book to the subject, and another to “Public Works,” that is roads, bridges, underground drains, and fortifications, which were all among the work undertaken by architects. The union of architecture and engineering continued for centuries. Christopher Wren designed and built the ingenious triple dome of St. Paul’s Cathedral in London, and a hundred years later, Thomas Ustick Walter designed the immense dome of the Capitol in Washington, D.C., whose form was modeled on St. Peter’s in Rome although it was built of cast iron.

The material that brought about a major change in the relationship between architecture and engineering was reinforced concrete. Concrete had been known for centuries—the Romans used pozzolana, a natural mixture of volcanic silica, lime, and fired rubble, as cement mortar and concrete. The manufacture of artificial cement (“Portland cement”) was introduced in Britain in the mid-nineteenth century. In the late 1800s three French inventor-builders, Joseph Monier, Edmond Coignet, and François Hennebique, independently discovered that concrete—strong when compressed but weak when stretched or bent—could be reinforced with iron and steel bars. The result, which combined the compressive strength of concrete with the tensile strength of steel, was fireproof, relatively cheap, and could be cast in a variety of shapes.

Both Monier and Hennebique built bridges out of reinforced concrete, but it was Robert Maillart, a Swiss engineer and a student of Hennebique, who was the first master of the new material. He built a series of light, elegant Alpine bridges whose extraordinary beauty is impressive, one hundred years later. Immediately after World War I, the engineer Eugène Freyssinet tested the limits of the new material still further when he designed two airship hangars for Orly Airport whose thin concrete vaults were three hundred feet wide and two hundred feet high—the largest such structures of this early period.

The great advantage of reinforced concrete was that the designer could maximize the strength of the material by varying the number and location of the steel bars; adjusting the precise proportions of cement, water, gravel, sand, or crushed stone that made up the concrete mixture; and giving it the most efficient shape. Designing effectively, and creatively, in concrete required a high degree of computational and analytical skill. In its early days there were a few accomplished engineer-architects, such as Eduardo Torroja in Spain, Félix Candela in Mexico, and Pier Luigi Nervi in Italy, who could work in reinforced concrete; but most architects did not have adequate training in math and physics for this task. They were obliged to rely on engineers for the detailed design of the reinforced concrete structures that supported their buildings.

Nonetheless, reinforced concrete became the preferred material of most modern architects. Since their designs usually included exposed structural elements such as columns, beams, and other supports, and challenging structural effects such as cantilevers and long, unsupported spans, engineers came to have an increasingly important part in the building design process. This was not necessarily acknowledged by architects, however, who continued to refer to themselves as “master builders,” and to engineers as “consultants.”

Louis I. Kahn, who liked to portray architectural design as an individual and personal, not to say poetic, act, worked with different structural engineers, particularly August E. Komendant. Like Kahn, Komendant was a native of Estonia, which may be why he treated the architect as an equal rather than as a revered master.^* Whatever the reason, there is no doubt that Komendant’s contribution to Kahn’s work was considerable. The three buildings that are considered Kahn’s masterpieces—the Richards Medical Center in Philadelphia, the Kimbell Art Museum in Fort Worth, and the Salk Institute in La Jolla—all benefited from Komendant’s work. In all three, use of reinforced concrete is central to the striking effect made by the building—even when the architectural concept makes it somewhat illogical, as in the Kimbell overhead vaults which span in the long direction and, as the engineer Peter McCleary has pointed out, are neither pure vaults nor pure shells, since they are reinforced by edge beams and hidden post-tensioned cables. Conversely, when Kahn did not collaborate with Komendant, such as in the Philip Exeter Academy Library, in the Bryn Mawr dormitory, and in the Yale Center for British Art, the structural solutions are much less convincing.

In 1966 when I was a young architect in Moshe Safdie’s office, Komendant was working with Safdie on Habitat, the experimental precast concrete housing project that was part of Montreal’s world’s fair. By then the design work was done and the building was under construction. My work involved checking the so-called shop drawings of the fabricator of the precast concrete elements against Safdie’s architectural drawings, to make sure that everything would fit together as planned. The three-dimensional geometry of the project meant that the exact dimension and location of the parts of the building were sometimes difficult to determine (this was before the widespread use of computers). Whenever I came to a dead end I would consult Komendant’s drawings. They were inelegantly drawn compared to the architectural drawings, and according to office gossip they were drafted by Komendant himself. Yet in these drawings I would always find what I needed. The engineer had recorded every critical dimension necessary to construct the building. It was all there.

As it happens, a long list of winners of the Pritzker Architecture Prize—I.M. Pei, Richard Meier, Robert Venturi, Renzo Piano, Norman Foster, Rem Koolhaas, Jacques Herzog, Pierre de Meuron, Jørn Utzon, and Zaha Hadid—have all built buildings with the same structural engineer: the London-based engineering firm popularly known as Arup, a global organization with more than seven thousand employees in seventy-five offices spread over thirty-three countries. Arup is responsible for the structural engineering of some of the most striking new contemporary buildings, including new office buildings such as the high-tech Hongkong and Shanghai Bank headquarters, the rocket-shaped Swiss Re building in London, and the forthcoming China Central Television headquarters in Beijing. It has done the engineering for much-admired museums such as the Tate Modern in London, the Menil Collection in Houston, the Nasher Sculpture Center in Dallas, and the new addition to the High Museum in Atlanta. It has helped build innovative stadiums such as the Olympic stadium in Beijing, currently under construction; and airport terminal buildings at Kennedy and Stansted, as well as the $7 billion Kansai Airport in Japan. If you are a star architect with an unusual structural problem, you will probably turn to Arup and they will solve it for you.

Arup has worked on some finely engineered civic projects, such as I.M. Pei’s glass pyramid for the Louvre, Rem Koolhaas’s new library in Seattle, and the recently opened new building for the de Young Museum in San Francisco. But the firm is also responsible for large infrastructure projects such as the Channel Tunnel Rail Link, the twelve-kilometer sea-crossing Incheon Bridge in South Korea, and the Øresund Bridge, a combination road and rail tunnel/bridge that links Denmark and Sweden. The firm’s divisions deal not only with structures but also with transportation, lighting, telecommunications, water engineering, urban design, and environmental services. The Engineering News-Record ranks Arup as the fourth-largest engineering firm in the world (according to income from design services performed outside its home country). Arup is not as large as Bechtel, or Kellogg, Brown & Root, which are also construction companies with huge government and other contracts; but it is unrivaled in its ability to create superb engineering for many of the world’s leading architects.

This unusual company was founded sixty years ago in London by a fifty-one-year-old Danish immigrant named Ove Nyquist Arup. Though technically a native—he was born in Newcastle in 1895—Arup was the son of a Norwegian mother and a Danish father, a veterinarian, who had moved to England six years earlier to work as a government inspector of beef cattle. Shortly after the boy’s birth, the family relocated to Hamburg. The young Arup grew up in Germany and was sent to Denmark, where he went to the university and graduated with a degree in philosophy. After being turned down for a lectureship, he enrolled in engineering at Copenhagen’s Polyteknisk Laereanstalt, did well in his studies, and upon graduating in 1922 got a job with a large Danish construction firm, Christiani & Nielsen, one of a handful of European civil engineering companies that specialized in the design and construction of reinforced concrete structures. (Rudolf Christiani trained under Hennebique.) The firm built harbor installations, and Arup, who was fluent in German, was first posted to the port city of Hamburg, but a year later was transferred to the London office. He stayed in Britain the rest of his life.

Arup’s work at Christiani & Nielsen included designing railway bridges, silos, jetties, and deep-water berths. But in the early 1930s, he began to be drawn to modernist architecture, specifically the work of Le Corbusier, whose reinforced concrete buildings, such as the Swiss pavilion (1932) at the Cité Universitaire, made a deep impression on him. He was invited to join Modern Architectural ReSearch (MARS)—a sort of architectural think tank affiliated with CIAM (Congrès Internationaux d’Architecture Moderne), which had been founded in 1928 by Le Corbusier and Siegfried Giedion, among others. Arup, with his knowledge of reinforced concrete construction, was a welcome addition. His later recollection of this period is characteristically blunt:

The puzzling part was that these architects professed enthusiasm for engineering, for the functional use of structural materials, for the ideals of the Bauhaus, and all that; but this didn’t mean quite what you might suppose. They were in love with an architectural style, with the aesthetic feel of the kind of building they admired; and so they were prepared and indeed determined to design their buildings in reinforced concrete—a material they knew next to nothing about—even if it meant using the concrete to do things that could be done better and more cheaply in another material.

Arup, who by now was working for another Danish engineering firm, collaborated with a number of talented architects in the 1930s. Above all, he was sought after for his expertise in showing how concrete construction could be used to create—and support—bold new architectural forms. One of Arup’s innovations was to show, as he later wrote in an influential 1946 article, that reinforced concrete need not be treated “as a substitute for timber and steel,” using the same traditional forms of “columns, piers, architraves, beams, trusses, rafters, as the elements of architecture.” To the contrary, Arup realized, reinforced concrete could be “moulded and built up to any shape, after which the whole structure forms one jointless unit.” This, combined with the fact that a horizontal concrete slab of large dimensions was capable of resisting a great deal of force in its own plane, meant that it was possible to design concrete shell roofs that were only a few inches thick, yet spanned two hundred feet across or more.

Arup’s most fruitful association before World War II was with the mercurial Russian émigré architect Berthold Lubetkin, with whom he built two reinforced concrete structures that became celebrated examples of early British modern architecture. One was the dramatic Penguin Pool (1933– 1934) at Regent’s Park Zoo, whose two exceptionally thin intersecting helical ramps were the quintessential expression of the new aesthetic. (The design was made possible by Arup’s insight that a ramp could be understood as a beam, and that increasing the thickness toward the inside edge would give it the structural strength it needed, without further supports.) The other was a seven-story apartment building, Highpoint I (1933–1935), designed with the flat roofs, white walls, and cantilevered balconies of the nascent International Style. Mies van der Rohe, Le Corbusier, and Walter Gropius had already built comparable buildings at the famous Weissenhof housing exhibition in Stuttgart eight years earlier, a reflection of how much British modernism lagged behind its Continental counterpart. But Highpoint’s reinforced concrete structure was unusual in making use of an ingenious system of reusable forms into which concrete could be poured, one story at a time, dispensing with the need for cumbersome scaffolding.

Lubetkin, whom Arup called his “first real teacher of architecture,” was the leading British modernist of the interwar period and exercised a considerable influence on the engineer. At the same time, Arup could be critical of him:

A wall like the one at Highpoint would have been cheaper to build with bricks, but [Lubetkin] claimed it was functional and economic. It wasn’t functional at all: it had to be “Modern.” Functionalism really became a farce. What is wrong with a sloping roof? They can’t afford to pay what it costs to make a flat roof really waterproof. Lubetkin didn’t care. He just cared for the picture in the architectural magazines.

This was not a case of an engineer exposing the pretentions of an ambitious modern architect. Arup was a trained philosopher and a talented pianist and collector of art. He was an advocate of Scandinavian socialism, although his practical Danishness kept him from subscribing to the more extreme political positions of some of his Marxist colleagues. In his new biography, Ove Arup: Masterbuilder of the Twentieth Century, Peter Jones describes him as an “endlessly doodling, whimsically rhyming, cigar-waving, beret-wearing, accordion squeezing, ceaselessly smiling, foreign sounding, irresistibly charming, mumbling giant.” Tall (6’3″), handsome, a bon vivant, Arup was sociable and outgoing, which helped him to attract clients when he established his own consulting business in 1946. (During the war he built air-raid shelters, underground facilities for the RAF, and contributed to the design of D-Day’s Mulberry Harbor.) Arup was also very good at recognizing, attracting, and keeping talented associates. He encouraged collegiality and teamwork, and he early saw the global possibilities of his profession—within a decade of its founding, his firm had branch offices in Ireland, Southern Rhodesia, Nigeria, Ghana, and South Africa.

Ove Arup & Partners took on a variety of large-scale engineering projects such as bridges, factories, and warehouses (the latter often with breathtakingly thin concrete shell roofs, an Arup specialty), and was also involved in developing a low-cost emergency prefabricated house by the Arcon company in Britain. At the same time, Arup worked with virtually every leading British architect of the postwar period, among them Alison and Peter Smithson, Ernö Goldfinger, and Denys Lasdun. He also collaborated with Basil Spence on Coventry Cathedral, probably the most highly publicized building project in postwar Britain. The thin concrete shells spanning the nave are a critical feature of the architecture.

Arup often challenged the architectural orthodoxy that considered design to be absolute, as in the comments on some of the Bauhaus architects I have quoted. For Arup, meeting functional and cost requirements were equal considerations. In a lecture titled “Structural Honesty,” he wrote, “To me, the skill of an Architect, and the excellence of an architectural solution is measured by the ratio between what is obtained, and what is expended.” Tongue in cheek, he expressed this ratio as a formula, based on the famous Vitruvian trilogy of Commodity, Firmness, and Delight (he took Firmness for granted):

Excellence = (Basic Commodity x Excess Commodities x Delight) ÷ Cost

When I was a practicing architect I would sometimes run across structural problems that were beyond my limited experience, usually involving a particularly long span. When I turned to an engineer friend for advice, he said, “Do you want it cheap, or architectural?” What he meant was that the most elegant or attractive solution, and the cheapest, were not necessarily one and the same. Arup similarly differentiated between economy and beauty in architectural structures, and he challenged the belief in structural “honesty” that underpinned modernist theory:

…The idea that the correct functional, the correct structural and the best possible aesthetic solutions are one and the same thing must, I am afraid, be abandoned together with the older philosophers’ dream about the harmony and ultimate identity of truth, goodness, justice and beauty.

Arup recognized that while economy of means sometimes produces beauty in large engineering structures such as bridges, dams, and long-span roofs, it rarely does so in buildings.

Arup was an empiricist, who, as Jones writes, considered theories to be provisional hypotheses, subject to continual revision, and was skeptical of what he called “paper-design.” “I dislike preconceived ideas or theories about architecture,” he once wrote to Philip Johnson. At the same time he did not think of engineering as a science. “Science studies particular events to find general laws. Engineering design makes use of these laws to solve particular practical problems,” he once said in a lecture. “In this it is more closely related to art or craft; as in art its problems are underdefined, there are many solutions, good, bad and indifferent.” He was committed to combining architecture and engineering, and his firm eventually established its own architectural division, Arup Associates, headed by Philip Dowson (who was later awarded the Royal Institute of British Architects Gold Medal).

Arup was too good an engineer to want to be an architect, but he had strong ideas about design. “Simplicity of design makes economic and aesthetic sense,” he once said. He remained a committed modernist, but in the pragmatic Scandinavian mold. For Arup, modernism was not a style but a set of beliefs, social as well as aesthetic. When he built his own house at Highgate in London, he did not commission one of his famous architect friends but a Danish cousin, and he clearly contributed himself to the design. The house is distinctly ungrand, and incorporates brick and wood, as well as a reinforced concrete roof. It appears practical, unsentimental, and without pretensions, like its owner.

Jones sums up Arup’s lifelong professional concern as a desire “to establish frames of mind, attitudes and organisational structures that would enable architects and their engineers to co-operate from the very outset of a commission.” The difficulty of achieving his goal of breaking down the barriers between the two professions was highlighted by one of his largest, and certainly longest-running, projects: the Sydney Opera House. In 1957, an unknown Danish architect, Jørn Utzon, won an international competition to build a large, multi-theater complex in Sydney. Arup volunteered his engineering services to his fellow Dane, and was eventually appointed structural engineer on the project. At this point in his career, Utzon, thirty-eight, had won a number of architectural competitions, but had built little, and his inexperience was evident in the design of the concrete structure of the halls, whose distinctive sail-like roofs looked like huge shells, but which weren’t in fact self-supporting. It was up to the engineers to make it work.

Jones, who had access to the private Arup office archives, devotes several chapters to the sixteen-year history of the Sydney Opera House. He quotes extensively from correspondence between the engineers and an increasingly mistrustful Utzon, who at one point forbade any direct communication between the Arup firm and the client. As costs went out of control (the final price was ten times the original estimate) the architect became increasingly isolated. “I wonder whether you really are master of the situation and can manage without help except from sycophantic admirers,” Arup wrote Utzon. “I have often said that I think you are wonderful, but are you all that wonderful?” The building was finally completed, after many delays and controversies that included—halfway through the process, and before construction drawings were completed—Utzon’s rancorous resignation on grounds that his conception was being undermined.

The story of the Sydney Opera House sometimes sounds like an Ayn Rand novel, with Utzon cast as the aggrieved Howard Roark. While Arup, whose firm stayed on to complete the building, was not seen as a villain (despite Utzon’s well-publicized vilification of him), he was effectively written out of the plot. In 2003, when Utzon was awarded the Pritzker Prize, the citation read: “There is no doubt that the Sydney Opera House is his masterpiece.” Yet the reader of Jones’s well-researched account comes away with the distinct impression that Arup and his colleagues deserve an equal share of the credit for the building’s structural virtuosity: the huge spans of its challenging shell roofs were made possible by an innovative system of prefabricated fanlike roofs, the application of epoxy glues, and the pioneering use of computers to make the complex calculations.

While we learn much about the Sydney Opera House from Jones, he describes many important projects, such as the Penguin Pool and the Kingsgate footbridge, much too briefly, and the illustrations—and their captions—bear little relation to the text (some of the projects pictured are not mentioned at all). Just how much Arup was personally involved in specific buildings is not always made clear, and although the book includes a chronology, there is no comprehensive list of built work. Jones, an emeritus professor of philosophy at the University of Edinburgh, is neither a biographer nor an architectural writer. While his philosophical background helps him describe Arup’s early life, Arup was not a philosopher but an engineer. The author writes that his book “is not a history of engineering or of architecture, or of a firm and its evolution.” It should have been. Arup was one of the leading structural engineers of his time, and while it is diverting to read about his adolescent romances, his political activities, and his family vacations, one wants to learn more about his practice as an engineer, and his specific position in a field to which he contributed so substantially.

During his long life (he died in 1988, at ninety-two), Arup received many honors, including the Gold Medals of both the Institution of Structural Engineers and the Royal Institute of British Architects. The architect Richard Rogers, who worked with the Arup firm on the Centre Pompidou in Paris, Lloyd’s of London, and a new terminal at Madrid’s Barajas Airport (and was recently awarded the Pritzker Prize), considers Arup “one of the greatest structural designers of the twentieth century.” According to the architect Félix Candela, Arup was “the only legitimate successor of Maillart, and in several respects he even excels his predecessor.”

A bridge is a true test for an engineer, and Arup built several, in Africa as well as Britain. The spans are generally not exceptional but they are distinguished by their elegance, which derives in large part from their evident economy of means. One of the last projects that Arup designed personally was the Kingsgate footbridge across the Wear River in the university city of Durham. The budget of £35,000 was considered sufficient for only a short span at the foot of the deep valley. Instead, Arup designed a bridge three times longer, at the top of the valley. Two Y-shaped, 150-ton concrete sections were cast separately, one on each bank, then swiveled 90 degrees to meet in the middle. His colleagues in the firm later claimed that it could have been done even more cheaply, but it is hard to imagine that it could have been done more gracefully, or more beautifully.