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NIPPONIA No.31 December 15, 2004

Special Feature*
The Wisdom of Nature Passed Down Through the Ages
The World Exposition in Japan will highlight the wide diversity of nature and show how technology can support eco-societies. These pages examine new ways to work with nature to ensure a brighter future.
Written by Sanada Kuniko, Photos by Moritake Takashi
Illustrations and photo credits: Nihon Sekkei, Inc.; Chubu Regional Bureau, Ministry of Land, Infrastructure and Transport

The exhibition hall of the Japan Pavilion in Nagakute will be a two-story wooden structure (total floor area: 6,000 m²). The lumber will come from selectively cut (thinned) woodlands. The bamboo latticework that will cover the building resembles a cocoon giving shelter to life.

A huge bamboo cocoon covers the entire building
Japan Pavilion in Nagakute
The Japan Pavilion in Nagakute is an experiment in innovation and eco-friendly technologies. The building is made from natural materials—for example, the exterior wall panels are composed of a biodegradable plastic based on starch and kitchen scraps. The electricity comes from new forms of energy.
The most stupendous feature is the huge bamboo latticework covering the entire pavilion. Made from natural bamboo, the covering is 90 m long, 70 m wide and 19 m high. The world has never seen anything like it before. It creates a shady environment beneath it, like a bamboo grove with a breeze blowing through. By reducing the sun's rays striking the pavilion building, the heat buildup inside is expected to be reduced by 23%.
Why bamboo? It is strong, light, flexible and beautiful, and it has long been admired by the Japanese as a material for construction, and for making everything from baskets and brooms to tea ceremony utensils. Bamboo plants readily reproduce and grow quickly. And bamboo fits in with one of the Expo sub-themes, "Development for Eco-Communities."
Pairs of madake bamboo "logs" about 7 meters in length and 6 centimeters in diameter are placed side by side to form double strands of the latticework. The strands are then woven together in the hexagon pattern often seen in traditional bamboo crafts. This yields an attractive, sturdy structure.
Traditional hexagon weaving for small crafts is easy because the bamboo is first split into long thin pieces. But the bamboo for the latticework is not split, and it would be very difficult to weave long round stalks of bamboo into a hexagon pattern. The Ecology Dry System (EDS) treatment method provided the solution.
Illustration showing bamboo lattice structure.
"The bamboo is smoked using special equipment to change its molecular structure. Then it is possible to bend the bamboo. EDS also makes it stronger and more resistant to splitting, retards mold, and makes the surface more resistant. So we have dealt with many of the weak points inherent in untreated bamboo," explains Ishii Sachio, the representative director of EDS Laboratory.
In this way, Japanese traditional techniques are combined with high-tech innovation to create an entirely new kind of structure.

Top left: Binding pieces of bamboo together to make supports for the woven bamboo latticework.
Top right: Two bamboo poles are placed side by side, then woven together to make the covering.
Above left: The EDS process was used to treat this bamboo. About 23,000 bamboo poles are needed to cover the Japan Pavilion. They have to be very straight, and workers had a difficult time going deep into the hills to find suitable ones.
Above right: The traditional hexagon pattern is achieved by weaving bamboo strips into adjoining triangles. This pattern gives a sturdy structure and is often chosen when making bamboo baskets.


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