Building Up Bamboo- MIT researchers study bamboo for engineered building material, similar to plywood.
Categories: Building Methods
The researchers cut sections of bamboo from the inside out, noting each sample’s radial and longitudinal position along a culm, then gauged the stiffness and strength of the samples by performing bending and compression tests. In particular, they performed nanoindentation, which uses a tiny mechanical tip to push down on a sample, to gain an understanding of bamboo’s material properties at a finer scale. From the results of these mechanical tests, Gibson and her colleagues found that in general, bamboo is stiffer and stronger than most North American softwoods commonly used in construction, and also denser.
The researchers then used the stiffness and density data to create a model that accurately predicts the mechanical properties of bamboo as a function of position in the stalk. Gibson says wood processors that she works with in Canada may use the model as a guide to assemble durable bamboo blocks of various shapes and sizes.
Going forward, the processors, in turn, will send the MIT team composite samples of bamboo to characterize. For example, a product may be processed to contain bamboo along with other materials to reduce the density of the product and make it resistant to insects. Such composite materials, Gibson says, will have to be understood at the microscale.
“We want to look at the original mechanical properties of the bamboo culm, as well as how processing affects the product,” Gibson says. “Maybe there’s a way to minimize any effects, and use bamboo in a more versatile way.”
Oliver Frith, acting director of programme for the International Network for Bamboo and Rattan, headquartered in Beijing, says that very few species of bamboo have been classified, and the lack of knowledge of the material’s microstructure has impaired efforts to design efficient, optimal structural products.
“MIT’s work is very timely and has great potential to support development of the sector,” says Frith, who was not involved in the research. “While bamboo has similarities to wood, as this study shows, the material also has very distinct properties. Although current approaches to developing structural engineered bamboo have tended to focus on mimicking engineered wood products, the future will probably lie in innovating new approaches that can better enhance the natural advantages of this unique material.”