Experimental and numerical investigation into the bending behavior of stiffened hollow glulam beams

Inspired by the configuration of nature bamboo that have relatively high stiffness and stability when subjected to lateral load, a new engineered wood product with hollow section and internal stiffener is proposed in this paper. This study investigates the bending behavior of the proposed stiffened hollow glulam beams. Twenty-seven specimens were designed and tested under monotonic loading protocol. The failure modes, moment-resisting capacity, elastic stiffness and moment-rotation responses of the solid beam, hollow beam, stiffened hollow beam were compared and analyzed. The results show that compared with the hollow beams, the stiffened hollow beams with bamboo-like stiffeners give an improvement of 3.6% for the elastic stiffness and 24.6% for the load-carrying capacity. The stiffener also led to a more ductile failure mode. Moreover, the influence of different stiffener configurations (e.g., the thickness of web plate, the thickness of bottom plate and the spacing of web plate) on the bending behavior of the stiffened hollow beams were discussed. Nonlinear numerical models were further developed to analyze the mechanical performance of such stiffened hollow beams and were validated by the experimental results. Then, parametric analysis was carried out using the validated numerical models. The presented experimental and analytical results can be used as reference for the development of design guidelines for the stiffened hollow glulam beams.