The Inelastic Method To Analyze The Loading-carry Capacity And Deformation Of Bamboo(wood) Beam-columns

The failure of the bending and compression-bending components of the bamboo(wood)structure exhibited nonlinear progressive process under the ultimate state. However, current wood structural design specifications around the world calculate the response of beam-columns based on the linear elastic theory without considering the nonlinear damage progress, which cannot accurately estimate the ultimate loading-carry capacity and deformation of components.For these issues above, the nonlinear stress-train relationships and failure mechanisms of components were investigated by the experiments for mechanical properties of wood(bamboo)composites and experiments of wood(bamboo) beams and columns under eccentrically compressive loading. Eventually, the method to analyze loading-carry capacity and deformation under inelastic state was established. The main contents and results can be concluded as follows:(1)According to the conclusions of experiments for the mechanical properties of parallel strand bamboo(PSB) and laminated veneer lumber(LVL), the general expressions for the linear elastic constitutive law and nonlinear stress-strain model of wood(bamboo) composites along the parallel to grain direction were proposed in this study.(2)The failure of components exhibited nonlinear progressive process by experiments.The failure mechanisms can be expressed as: the bamboo fibers in the upper compressive zone were first buckling, followed with the interface failure in the tensile zone, finally the bamboo fiber bundles are broken without the loading-carry capacity. Therefor, the ultimate loading-carry capacity of the bending and compression-bending components could be defined by the ultimate stress of wood(bamboo) composites.(3)An inelastic model for analyzing beam-columns was developed based on the Euler thorium and nonlinearities of wood(bamboo) composites. The practical expressions for calculating the loading-carry capacity and deformation of beam-columns, which was suitable for the designs of bending members, compression-bending members and flexural members reinforced with CFRP, were derived.(4)Eventually, the inelastic analysis method to analyze the loading-carry capacity and deformation of bamboo(wood) beam-columns proposed in this paper was validated through the bending experiments of PSB beams, LVL beams reinforced with CFRP and PSB columns under eccentrically compressive loading.