Tensile Structures for Roofs

Tents

• Tents have been the choice of shelter for nomadic people across the continents for millennia. These light buildings are derived from ancient structures clad with animal hides. Like all tensile structures, tents require compressive members, such as posts or poles, to create height from which the tensile materials can hang. Architects use tent structures to create light, diaphanous canopies protecting large areas from sun and rain. Frei Otto's Munich Stadium is an excellent example of a tent structure used in contemporary architecture.

Catenary Roofs

• Catenary roofs hang from two buttressed walls in compression. The roof takes the exact curve of a chain hanging from two elevated surfaces, called a catenary curve. Although these structures require a great deal of material in the buttressed walls, the roof is extremely thin, like a shell. Eero Saarinen's Dulles Airport is an example of a catenary roof structure.

Domes

• Traditional domes were built with compressive elements, but contemporary domes for stadiums and amphitheaters use tensile structures to shelter the interior space. This is accomplished by creating positive pressure on the interior of a building. The tensile roof puffs up to accommodate the difference in interior and exterior pressure, like a balloon. Although these domes require a system to keep the interior artificially positive in pressure, the domes use very little material and are extremely economical. Almost every domed stadium uses a tensile structure dome

Pneumatic Roofs

• As the tensile structure dome was developed, others created vaults, arches and walls with positive pressure. These building elements are balloons at the scale of architecture and are called "pneumatic" structures. The pressure inside the balloon-like vaults, arches and walls place tension on the structural skin, and the elements develop rigidity and integrity. Many tennis courts and swimming pools use pneumatic structures to house the facilities in winter. Perhaps, the most famous pneumatic structure is the Fuji Pavilion from Osaka, Japan's 1970 World's Fair. This structure housed an exhibit and could withstand weather and strong winds often found around Osaka.