Experimental investigation on the flexural behavior of laminated bamboo-timber I-beams

Abstract I-beams are widely used in construction structures because of their excellent mechanical properties. This research experimentally investigated the flexural performance of composite I-beams made of timber and bamboo to enhance the structural performance of I-beams. A total of six groups of laminated bamboo-timber I-beams with 12 specimens were tested. The laminate materials included bamboo scrimber and Douglas fir. The test parameters included the number and position of the bamboo laminates. Four-point bending experiments were employed to study the failure modes, flexural performance, load-displacement relationships, and strain curves of the bamboo-timber I-beams. The results indicated that the bamboo-timber I-beams mainly showed three failure modes: lower flange tensile failure, web shear failure, and web horizontal penetration crack failure. The load-displacement curves and load-strain curves of all specimens were linear. The deformation capacity of the bamboo-timber beams was significantly improved compared with that of the control timber beams. As the number of layers of the bamboo scrimber increased, the flexural stiffness of the bamboo-timber beams also increased. However, the ultimate bearing capacity of the I-beams was not directly proportional to the number of layers of bamboo scrimber. The bearing capacity and stiffness of the bamboo-timber beams increased by 44.8% and 23.4% on average compared with the control timber beams.