Experimental study and finite element analysis on seismic behavior of Pingshenke Dou-Gong brackets

The ‘single-Qiao and single-Ang five-Cai’ Pingshenke Dou-Gong bracket in the Yihe Hall of Shenyang Imperial Palace was selected as the prototype in this study. Two full-scale Pingshenke Dou-Gong specimens were fabricated, conforming to the ‘Requirements of engineering fabrication method’ of the Qing Dynasty. The failure modes, hysteretic characteristics, degradation of stiffness and strength, ductility and energy dissipation capacity of Dou-Gong brackets were obtained by the low cyclic reversed loading test in the overhanging and width directions. The results indicate that the main failure patterns of Dou-Gong brackets are the shear failure of Mantou-tenon (a kind of dowel) between Da-Dou (square timber blocks) and Pingban-Fang (a kind of beam under Da-Dou), the split of Da-Dou along the transverse grain and split of single-Qiao (rectangular square wood with circular arc), the tenon pulling between Fang (rectangular square wood) and Heng (cylindrical wood), and the rotation deformation of the whole model. The pinching effect of Dou-Gong bracket in the overhanging direction is obvious, and the bearing capacity and energy dissipation in this direction are worse than the width direction of Dou-Gong bracket. The stiffness and strength degradation of the two specimens are apparent, and the average displacement ductility coefficient is about 5. 0, showing good deformation capacity. A finite element model of Dou-Gong brackets was built to conduct numerical simulation analysis, and the simulation results are in a good agreement with the test results. Parameter analysis considering the effects of the vertical load, friction coefficient, elastic modulus and compressive strength perpendicular-to-grain along radial direction of the wood on the seismic behavior of Dou-Gong bracket was performed. The results show that the larger the vertical load and friction coefficient, the larger the lateral stiffness and the bearing capacity of Dou-Gong bracket. However, the elastic modulus and compressive strength perpendicular-to-grain along radial direction of the wood has a relatively small influence on the lateral stiffness and bearing capacity of the Dou-Gong bracket. © 2023 Science Press. All rights reserved.