Eric Mankin
December 12, 2007 —
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The 10 meter long modern bamboo bridge under 8 ton traffic loading testing.
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In China bamboo is used for furniture, artwork, building scaffolding, panels for concrete casting — and now, truck bridges.
Yan Xiao, a professor in the Viterbi School's Sonny Astani Department of Civil and Environmenal Engineering is the designer of a new span in the city of Leiyang, Hunan Province, which opened for traffic December 12.
Made from pre-fabricated structural elements, the bridge in the Shangxun area of Leiyang was erected atop masonry supports in a week by a team of eight workers without heavy construction equipment.
"Of course, it isn't traditional bamboo we're talking about," Xiao told reporters from the
China Daily. "The superstructure was all made of modern bamboo, processed with grayish silver-colored waterproof materials that combat the effects of the sun and rain.
While traffic on the Leiyang bridge will be limited to the 8-ton design capacity, preliminary tests on a duplicate bridge erected on the campus of Hunan University have shown much higher strength – as much as 90 tons.
The bridge was completed in late October and has a life expectancy of 20 years, according to Xiao, who said bamboo bridges cost just half as much as equivalent steel ones.
"They have a much shorter construction cycle than concrete bridges, and also cause less pollution."
according to a China Daily report. The reporter also spoke to a nearby resident, 72-year-old Huang Xianrong. ""It was built within a month," he said. "I've never seen any bridge this good in my entire life."
Another article about the technology appeared December 19 in New Scientist.
The new bridge is the latest installment in research on structural bamboo being carried on by Xiao, who in addition to his appointment at the USC Sonny Astani Department of Civil and Enviornmental Engineering holds an appointment at the College of Civil Engineering of the Hunan University, China.
Xiao spent his sabbatical leave last year conducting and directing collaborative research at the Hunan University of China, creating ways to use the “giant grass” as raw material for making composite materials for structural application. He believes bamboo has huge potential for structurally sound, economical and environmentally-friendly structures of all kinds.
Last year, Xiao demonstrated a high capacity bamboo footbridge, which was a featured attraction at October conference on structural uses for bamboo in Changsha, China, a conference that Xiao helped organize.
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View from below
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Prof. Xiao expects his modern bamboo bridge technology to be widely used in bridges in rural areas in China, as a environmental friendly and sustainable construction material. Besides bridges, Xiao’s team has also built a mobile house using similar technology they developed.
Meanwhile, they are also constructing a prototype 250-square meter, two-story single-family house, similar to the lightweight bungalows widely built in California.
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Xiao
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Xao believes that even a partial replacement of current concrete or steel construction by natural and green materials such as bamboo would significantly improve the growing environmental problems of the world.
