April_1970 — Page 15

Italian pavilion – interlocking slanted structures

Netherlands pavilion – metallic cubist sculpture

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French pavilion – air dome snowballs

Pavilions

Sifting through the plethora of new ideas for the individual pavilions, from the largest the steel-framed unfurl. ing flag of the Russian pavilion to the most fantastic the 1,444 welded steel tetrapods of the Toshiba pavilion that form a tower and space frame to support a 300-ton theatre it is the air-supported structures that reveal a new engineering potential for tem- porary buildings or specific purposes.

The two principal pneumatic struc- tures which attract attention are those of the Fuji Group and the United States.

The Fuji pavilion, like an enormous covered-wagon, was made by joining together 16 air beams U-shaped cloth-made tubes 13 ft. in diameter and 262.4 ft. long, filled with com- pressed air. The dome is 105 ft. tall and its base has a diameter of 164 ft.

After two years of research, a synthetic fibre, vinylon, coated with synthetic rubber, was chosen for the tubing. These beams, 13ft. in dia- meter, are linked to larger steel cylin- ders set into a concrete ring founda- tion. Some 300 concrete piles, 16 to 46 ft. long, are capped by the ring foundation. With this base the light- weight structure can withstand winds of 212 ft. per second intensity.

Air compressors maintain a pres- sure of 16.2 p.s.i. in the air beams and a standby unit ensures a continuous flow of air. Without a steady input a beam would begin to deform in about one hour.

Not so eye-catching, since it is mostly underground, the U.S. pavilion is nevertheless an equally interesting form of air-supported structure. It has an elliptical roof measuring 462 ft. by 271 ft.; this consists of a translucent fibreglass fabric skin, tensioned on a rectangular grid of high-strength steel cables, anchored to a concrete rim.

The roof forms a clear-span dome that permits sunlight to pass through, while glowing from interior light at night. Four air compressors keep the roof inflated.

A third, very much smaller, air beam structure at Expo is the theatre of the Electric Utilities pavilion. This uses three air-beams, 10ft. in diameter and 131 ft. long, looped to support a 75 ft. diameter plastic cover over the theatre.

Most of the pavilions at Expo in- volve the distinctive use or a further development of materials and struc tural systems which are already uni- versal. Steel framed or cable-supported

Far East BUILDER, April 1970

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