Experimental and analytical study on the nonlinear bending of parallel strand bamboo beams

Parallel strand bamboo (PSB) is a new biocomposite made of bamboo strips which has superiority properties than wood products. It has been expected to be an attractive sustainable alternative for traditional structural materials. Several buildings have been constructed in China by using it as structural material in last 4 years. However, the structural behavior of PSB is not nearly as well understood as conventional construction materials, which results in difficulties to predict the performances of PSB structural members. This paper aims to develop a theoretical model to predict the nonlinear flexural performances of PSB beams. The uniaxial stress–strain relationships in parallel-to-grain direction of PSB composite were firstly studied by experiments, and then 4-point bending tests for PSB beams were carried out to investigate the flexural behaviors and the damage mechanism of them. The results indicated that the tensile stress–strain relationship in parallel-to-grain direction of PSB composite exhibits linear behavior, and that the compressive one remains in linear when the stress is within the proportional limit, while becomes nonlinear, which can be simulated by quadratic polynomial, once the stress exceeds the limit. Finally, an analytical model to evaluate the bending performances of PSB beams was proposed based on experimental studies and theoretical analysis. Well agreements were achieved between the results obtained by using the proposed model and those obtained by experiments.