Abstract:
In order to study the axial compression performance of the inclined Pingshenke Dou-Gong bracket, four full-scale bracket specimens with different inclined angles were fabricated. Wooden wedges were inserted into the lower surfaces of the Zhengxin-Heng, the Tiaoyan-Heng, and the top surface of the Pingban-Fang to realize the overall inclination. Through the axial compressive loading test, the failure patterns, load-displacement curves, the degradation of bearing capacities and stiffness, deformation abilities, and load-displacement relationship of components were obtained. The finite element method was used to simulate the axial compression, and the simulation results agreed with the experimental results. On this basis, parameter analyses were carried out. The effects of compressive strength and elastic moduli in the perpendicular-to-grain direction of wood, and friction coefficients among timber components on the vertical stiffness and deformation abilities of the bracket were studied. The results show that when uninclined brackets and brackets with a 5° inclination angle were compressed as a whole, the Da-Dou was crushed and both ends of the Zhengxingua-Gong and Dan-Qiao were split and damaged. The damage of the components of the brackets with 7.5° and 10° inclination angles was relatively slight, and the failure mode was changed to large rotation. With the increase of the inclination angles, the degradation degree of the bearing capacities of the bracket increased, and the deformation capacity and the recovery ability after unloading decreased. In the direction of width (overhanging) of the inclined bracket, the compressive stiffness of the components increased (decreased) sequentially from top to bottom. Increasing the compressive strength and elastic moduli in the perpendicular-to-grain direction, and friction coefficients could increase the stiffness in the plastic stage and decrease the ultimate displacement. The research results can provide a reference for the mechanical analyses and scientific protection of the inclined Pingshenke Dou-Gong bracket in ancient timber-frame buildings.