Bamboo Makes Better Bridges
Bridges of bamboo could provide a cheaper, more environmentally sustainable engineering solution than steel. New Scientist reports that a prototype bridge has been built in China using horizontal beams made from a bamboo composite. The 33-foot span proved strong enough to support even heavy trucks. It was also cheaper to build and more environmentally friendly to make than steel or concrete, says developer Yan Xiao of the University of Southern California and Hunan University.
Pound-for-pound, bamboo is stronger than steel when stretched and more robust than concrete when compressed. Stalks mature in a few years, rather than decades for trees, so more can be harvested from the same amount of land. Plus bamboo is a grass that is harvested like mowing a lawn, leaving the roots intact to regrow. Whereas cement production releases 5-10% of total global carbon dioxide emissions, bamboo soaks it up as it grows. All this suggests a more sustainable engineering solution in China, says New Scientist... Sure, for China, but why not everywhere?
Julia Whitty is Mother Jones' environmental correspondent. You can read from her new book, The Fragile Edge, and other writings, here.