Structure formed mostly of components acting in tension. rather than compression. It might include tents, suspen-sion-bridges, and suspended roofs (all types where weight can determine the form of the structure and its very stability); prestressed membranes and cable-roofs (where form and stability derive from forces in tension created by stressing); and pneumatic structures (which depend on air to support surfaces in tension). C20 tensile architecture evolved from the design of suspension-bridges (e.g. those by Brunel and Roebling): early uses of suspen-sion-bridge technology for buildings were pioneered by Bedr`ich Schnirch (1791–1868) in the 1820s in the Austrian provinces of Bohemia, Moravia, and Slovakia; in the Naval Arsenal, Lorient, France (1840s); and in the steel pavilions of the All-Russian Exhibition, Nizhny-Novgorod (1895) by Vladimir Grigor'evich Shukhov (1853–1939—who also designed the Shabolovskaya Radio Tower, Moscow (1919–22), a parallel to Tatlin's monument to the Third International). Indeed, nothing like Shukhov's pioneering tent-like structures and suspended roofs was to emerge again until the 1950s. Experimental tensile structures of the 1920s include Fuller's Dymaxion House (1927–30), and although various proposals were made in the 1930s, there were few examples (e.g. the French Pavilion, Zagreb Fair (1935), designed by Bernard Lafaille (1900–55) ), largely because the imagery demanded by the International Style cult inhibited any straying from approved clichés. Developments during the 1939–45 war led to a further understanding of tension structures, and this was demonstrated in a series of buildings in which suspended roofs were exploited (e.g. Saarinen's Dulles International Airport Terminal, Chantilly, VA (1958–63) ). Nervi used a suspension system for the roof of his paper-making factory at Mantua (1961–3), and there were various experiments with structures supported by cable-stays, decks carried from cables hung from masts, and other systems. Tensioned structures using cables were employed by Nowicki (e.g. Dorton Arena, NC (1948–53) ), Saarinen (e.g. David S. Ingalls Hockey Rink, Yale University, New Haven, CT (1953–9) ), and Tange (e.g. National Gymnasia, Tokyo (1961–4) ). However, using the tent as his precedent, Frei Otto departed from the suspension-bridge principle with numerous designs of the 1950s and 1960s, including the German Pavilion, Expo 67, Montréal, Canada (destroyed), and buildings for the Olympic Games, Munich (1967–72—destroyed). Employing flexible, wire-rope, cable-nets (to which covering membranes were fixed) suspended from masts and framed by cables around the edges which transferred the stresses to anchor-points, Otto's work was of great importance. SOM used steel pylons to support radial cables carrying conical tent-like fibreglass roofs at the Háj Terminal, International Airport, Jeddah (1981–2), and there have been other developments. The Aviary at London Zoo (1961–2—by Price, Lord Snowdon (1930– ), and Frank Newby (1926–2001) ) is a good example of Tensile architecture.
Pneumatic architecture (heralded by the design of balloons and airships) has suggested a way by which masts, etc., can be eschewed, air pressure alone supporting a membrane-enve-lope, covering the required volume. Separate chambers inflated with air form one type, and a membrane supported by air pressure kept constant by a continuous supply of air form another. Pneumatic structures, introduced from the USA to Europe in the 1950s, were developed by Otto, who further experimented with cable-reinforced air-supported membranes, offering many possibilities for enclosing space.