Tension and suspension buildings

Historically, post-and-beam construction and the arch (with its three-dimensional extensions) were regarded as the only ways to build. Both were constrained by a belief in the necessary permanence of architecture. Because the only available durable materials masonry of various kinds were strong in compression, structural systems exploited that property. A third way of building, the structure that used stretched filaments and membranes, was limited to short-life buildings like Arab tents because it was made from nondurable materials wood and animal or vegetable fibers. Two events would change that: the advent of structural steel and reinforced concrete after 1865, and synthetic membranes, after about 1950, combined to create architectural opportunities. Together, these new means to support and enclose provided architects with extensive esthetic possibilities; at last they were able to use the long-span systems that had long been available to bridge builders. The German architect-engineer Frei Otto advocated tensile-stress construction in a 1954 book Das hangende Dach (The Hung Roof). The following year the Australian architects Barry Patten and Angel Dimitroff of the firm Yuncken Freeman began design work for the Sidney Myer Music Bowl (completed 1959), an open-air theater in the city of Melbourne. Its structure comprises a network of steel cables supporting a roof of aluminum-plywood sandwich panels. The main cable is anchored on each side of the open end to large reinforced concrete blocks and draped between two 75-foot-high (22.8-meter) steel masts, 110 feet (33.5 meters) apart. Secondary cables span about 195 feet (60 meters) from the primary cable to converge on a reinforced concrete ground anchor, and the transverse tertiary cables that carry the roof cladding are draped over them and fixed to individual ground anchors. This early experiment in suspended roof construction is presently (2001) undergoing extensive restoration. Another early and important innovator was the Finnish-American architect Eero Saarinen (1910 1961). In 1958 he designed, in conjunction with structural engineer Fred Severud, the 3,300-seat David S. Ingalls Ice Hockey Rink at Yale University. Saarinen used a 300-foot (92-meter) concrete arch that undulates (supposedly with the grace of a skater) on the long axis, crossing the arena and the entrance. From this structural backbone, which reaches 76 feet (23 meters) at its highest point, steel cables stretch to the building perimeter and carry a wood slat and an aluminum roof. Saarinens second essay in tensile construction, hailed as the third most significant building in U.S. history, was the dramatic main terminal at Dulles International Airport, Chantilly, Virginia, built in 1962. Assisted by the structural engineer Joseph Vellozzi, Saarinen covered the 50-foot-high (15-meter) glass-walled space with a curved roof of insulated precast concrete panels covered with a ply membrane, high at the front, lower in the middle, slightly higher at the back.