Eric Mankin
February 26, 2007 —
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Worlds first: It looks like wood or steel, but it's really bamboo.
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Bamboo, one of the world's oldest building materials, is the raw material for some of mankind's newest.
A Viterbi engineer who has created and demontrated the use of ply-bamboo and other new materials is organizing an international conference on emerging bamboo technology and its message for a world increasingly focused on sustainability.
Yan Xiao, an associate professor in the USC Viterbi School Department of Civil and Environmental Engineering, spent the last year in China's Hunan province, creating new ways to use the ultra-tough, resilient giant grass as raw material for new composite materials.
Hunan and its capital Changsha is a major center of bamboo production.
Though bamboo has been used in buildings in China and elsewhere in the world for millennia, it has not penetrated the industrialized construction market (though bamboo scaffolding is used in Asia in the construction of high-rise buildings)
Xiao, working with collaborators in Hunan, approached the challenge of creating materials that could be used in existing processes and designs for modern structures, such as bridges and buildings with huge potential for strong, economical and environmentally friendly structures of all kinds.
Xiao's research created laminated bamboo sheets, like plywood but far stronger, and ways to reinforce concrete with bamboo.
The new techniques and material came together in the construction of a footbridge, the world's first of its kind.
All the main structural elements, including girder beams, columns, beams for stairways and railings are made from laminated bamboo sheets. Steel and fiber reinforced plastics are used for connectors at limited locations. The pavement was made with bamboo reinforced pre-cast concrete.
Xiao says the bridge cost about half of what it would have cost using steel. The construction saving was due not only to the material savings but also savings in labor and equipment. In addition to the pedestrian bridge, Xiao and his team also built a portion of a laboratory addition with 20-meter high walls using a hybrid of steel, timber and bamboo.
With worldwide attention focused on sustainability, bamboo as a basic building material has immense potential, says Xiao. It can be grown on farms; reaching maturity in three years or less, which is much faster than trees. The structural qualities of bamboo as a material are superior to wood in many ways: bamboo has higher strength, tenacity, tractability, and has equivalent or even better physical performance.
Worldwide, the use of bamboo in structures is rising, particularly in Asia and South America. In the US, several members of the American Bamboo Society (ABS) are pushing the use of bamboo in buildings, and the use of natural materials general in order to promote sustainability in construction. Xiao maintains that even a partial replacement of concrete or steel by natural and green materials such as bamboo could begin to relieve pressure on limited resources and reverse some environmental degradation.
Bamboo is a totally renewable resource, Xiao points out. Unlike making steel, growing bamboo actually takes carbon dioxide out of .the air. It is not an endangered species, but a domestic plant. "We believe the potential is great both in Asia and in the West."
Xiao has organized an international conference on modern bamboo structures io be held October 13-17 2007, in Changsha, Besides USC, academic sponors include Hunan University and Japan's Oita University. The conference has been endorsed by most of the major organizations promoting bamboo in the world. More details about the conference are available at:
http://www.eurekalert.org/pub_releases/2007-03/uosc-ico030107.php
