1967: West German Pavilion Roof – Montreal, Quebec
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Innovation: Tensile Cable Roof (dynamic relaxation)
Location: West German Pavillion Roof, Montreal, Quebec
By: Frei Otto
Developed using a form-finding structural engineering principle called dynamic relaxation, the aim of which is “to find a geometry where all forces are in equilibrium”
The West German Pavilion Roof, designed for the Expo 67 at Montreal, is one of the many lightweight and tensile membrane structures for which Frei Otto is known. Although it took him several years to develop this system, it took only six weeks for the German Pavilion to be built in 1967.
His system used a network of steel cables suspended from eight slender steel masts of varied height, situated at irregularly intervals and supported by steel cables anchored outside the structure. The roof was then covered by a translucent plastic skin. The roof produced a new beautiful interior space lit through the transparent plastic odd-shaped windows in the roof. The tent and all of its components were fabricated in Germany.
Although the building wasn’t cheap to build since it was a new concept, Frai Otto’s innovation had potential not only because its steel and plastic roof weighted only 150 tons, about one third to one fifth of normal roofing materials, but also because it had the ability to adapt to the irregular topography of any site. `