Seismic Performance of Hoop Head Tenon Frame Structure Reinforced by Sparrow Brace Type Damper

In order to study the seismic performance and reinforcement method of the wooden structure of Guangfu ancient building, two typical hoop tenon frames of Guangfu wooden ancestral halls with different structural forms were designed and manufactured by using merbau wood. A sparrow brace type damper for strengthening the tenon and mortise joints of the wooden structure was proposed and manufactured. Cyclic loading tests were carried out on the wooden frames before and after strengthening using the sparrow damper and the seismic performance of the structure and the reinforcement effect of dampers were studied. The results show that the damper can repair the damage caused by the cyclic loads, and provide higher initial stiffness in small rotation angle for the damaged mortise joint. It cooperates with the mortise joints well, so as to improve the joint stiffness, ultimate bearing capacity and energy consumption capacity, so that the ultimate bearing capacity of the reinforced specimens is higher than that of the unreinforced specimens. The unreinforced specimen show the phenomena of mortise and tenon separation and local compression buckling of mortise and tenon joints after loading, while the failure modes of the reinforced specimen are mainly mortise and tenon separation, local compression buckling of mortise and tenon joints, and vertical splitting cracks along the grain. The hysteresis curves of each joint show obvious "pinching" phenomenon. The strength degradation coefficients of all tenon joints are greater than 0.83, which shows stable bearing capacity under cyclic load. The ring stiffness and the equivalent viscous damping coefficient of each joint gradually decrease and tend to be stable with the increase of rotation angle. Equivalent viscous damping coefficients of the side-span frame specimen joints gradually stabilize from 0.1 to 0.2, while those of the mid-span frame specimen joints gradually stabilize from 0.05 to 0.1. With the reinforcement of damper, the total energy consumption of the mid-span frame specimen and the side-span frame specimen increases by 67% and 19%, respectively.