Comparative Research on Flat Steel and Damper Strengthening of Straight Type of Tenon-Mortise Joints

For better seismic reinforcement of Chinese ancient wooden buildings, based on the mechanical model for straight type of tenon-mortise joints the flat steel strengthening and damper strengthening of straight type of tenon-mortise joints were investigated respectively by taking the Yellow Emperor Temple in Qingcheng Mountain damaged in the Wenchuan earthquake as an example. The vibration period of the structure, the acceleration magnification factor of a strengthened joint and the internal force of adjacent members of the strengthened joint were analyzed by using the two strengthening measures, and compared with those of the original structure. The analysis results indicate that the seismic performance of the structure is significantly improved by the two strengthening measures. However, the flat steel strengthening will increase the structural stiffness of the strengthened joint and the internal forces of its adjacent members to easily result in pulling-out-tenon of adjacent joints. The damper strengthening can significantly weaken the seismic responses of the structure without increasing joint stiffness and reduce the acceleration magnification factor of the strengthened joint by 12.8%and average tension force, shear force and bending moment by 48.3%, 40.6% and 52.1% respectively, so the damper strengthening has the effects of energy dissipation and preventing pulling-out-tenon.