As a child growing up in northern China, Yan Xiao loved flying kites. A born engineer, he made them himself out of paper sails and plain bamboo frames. The kites were durable and cheap. On a trip to the region’s vast bamboo forests, the memory of those kites gave the 47-year-old Xiao a flash of inspiration: Bamboo was strong enough for kites, but he suspected that it could be fortified to make even sturdier things, like bridges and houses.
Xiao, now an engineering professor at the University of Southern California, scoured textbooks and the Internet, hoping to find historical precedent for structural bamboo. His research had urgency. Most of China has been stripped of timber-worthy trees, so rural buildings are often made of shoddy concrete, which is exactly what led to the catastrophic school collapses during the earthquakes in Sichuan province in May. What Xiao found wasn’t terribly useful: a wealth of arty one-off projects, but nothing a contractor could ever build with.
At the USC Stevens Institute Innovation Showcase, held on March 28th, 2007, Prof. Yan Xiao’s innovative design of modern bamboo bridges was selected as one of the only three exhibitions. Professor Xiao spent his sabbatical leave in 2006 conducting and directing collaborative research at the Hunan University of China, creating ways to use the “giant grass” as basic fibers for making composite materials for structural applications. The new structural material is trademarked as GluBam®.
Prof. Xiao came up with the idea of using bamboo materials in modern structures, such as buildings and bridges, because of its huge potential for structurally sound, economical and environmentally-friendly structures of all kinds. With his collaborators in Hunan, Prof. Xiao designed and constructed several prototype GluBam pedestrian bridges and a truck-safe roadway bridge, which was awarded by the Popular Science Magazine as one of the Best of What’s New in 2008.
After the great Wenchuan Earthquake in China, Dr. Xiao immediately went to work designing and deploying bamboo shelters for the schools and villages in the quake devastated Sichuan area. In 2009, working with INBAR, one of the major international organization promoting bamboo usage and plantation, Dr. Xiao designed and built a California-style demonstration house in the famous Black Bamboo Park in Beijing. It is expected 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.
Bamboo is a remarkable material. Some species have stalks as dense as hardwood. It’s the world’s fastest-growing woody plant, and it’s an exceptionally good absorber of carbon. But its irregular, knotty form is a problem. Making a reliable bamboo structure used to mean picking through stalks to find the ones that met precise measurements. Timber, on the other hand, can be cut to standard sizes. So Xiao set about developing a process to transform bamboo strips into easy-to-manage beams. In 2006 he devised GluBam, bamboo timber sturdy enough for beams and trusses. Last winter, he returned to China and, using just an eight-man crew and no machinery, built a 33-foot GluBam bridge capable of supporting eight tons in the remote, ramshackle Hunan province town of Leiyang. The feat was so surprising, it was covered on China’s national news.
The bridge Yan Xiao built in Leiyang with GluBam was the town’s first. Each beam that spans the brick columns was created using Xiao’s novel process of transforming irregular bamboo into a practical building material. First he tore strips of bamboo from the stalk and arranged them in such a way as to provide the most strength. He then coated the strips with glue and compressed them in a self-built hydraulic press into beams, 33 feet long and up to three feet wide, each capable of supporting eight tons. Xiao says that the beams cost just 20 percent as much as imported lumber. Better still, rural China has a constantly replenishing supply of bamboo.
Since then, Xiao has been busy building GluBam houses and classrooms in parts of Sichuan leveled by earthquakes. But he hopes that GluBam’s most positive effect might be an overhaul of the bamboo industry itself. China produces up to a third of the world’s bamboo—Hunan a quarter of that output—but much of it goes to low-value, barely profitable uses, such as concrete molds and chopsticks. GluBam could spark a dynamic industry in China and provide a sustainable replacement for current forestry operations worldwide. “That was the intent all along,” Xiao says. “This could open a vast market. It could create a whole new source of money and jobs.”—Cliff Kuang
Read more:
http://www.glubam.com/http://www-bcf.usc.edu/~yanxiao/
