Mechanical behaviors of Tou-Kung in historic timber structures subjected to vertical load

Abstract

This paper investigates the mechanical behaviors of Tou-Kung under the action of vertical loads. A 1/3.52 scaled model of intact Tou-Kung fabricated according to the Building Standards of the Qing Dynasty was carried out on vertical loading test. The failure modes, vertical load–displacement curves, and vertical stiffness analysis are analyzed. The results show that the main failure modes of Tou-Kung are the compressive splitting of Da-Tou and plastic compressive deformation of Qiao’s middle part along the radial direction. The vertical load–displacement curves of intact Tou-Kung can be divided into three stages: elastic, plastic, and hardening. In general, the vertical load and displacement of Tou-Kung increases as the loading progresses. And the vertical stiffness increases first, then decreases, and finally increases. On this basis, numerical simulation is used to investigate the effect of overall tilting on Tou-Kung’s mechanical behaviors. It can be found that the tilting of Tou-Kung significantly changes the load transferring path in Tou-Kung, and the stress distribution of Da-Tou and Qiao gradually changes from symmetry to asymmetry as the tilting angle increases. Furthermore, the stress in the embedded area between the Da-Tou and Qiao is the highest, which is consistent with the test results. The vertical load–displacement curves of all damaged FEMs show the same change trend. However, with the increase of tilting angle, the initial stiffness, ultimate load and ultimate stiffness decrease.