A Study on Torsional Behavior of Glued Laminated Bamboo Glubam

Glubam is a type of engineered bamboo increasingly attracting research and application interest. This study focused on the torsional shear properties of glubam. Prismatic specimens with square sections were tested using a torsional loading device along with both conventional strain gauge-based instrumentation and a digital image correlation (DIC) system. Testing parameters included thick- and thin-strip glubams, the influence of carbonization of thick-strip glubam, as well as comparative spruce-pine-fir (SPF). Mechanical behavior and properties, including failure process, shear stress-strain relationships, modulus, and strength, were examined. The testing results indicated that carbonization of thick-strip glubam increased its strength slightly; however, specimens failed with more brittleness. The existence of bi-directional bamboo fibers in the thin-strip glubam apparently contributed to the larger deformability compared with the unidirectional thick-strip glubam.