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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.

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    The relationship between the two men is described in Komendant’s revealing 18 Years with Architect Louis I. Kahn (Aloray, 1975).

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