Study On The Seismic Behavior Of The Straight Mortise-tenon Joints Of Ancient Timber Buildings

The ancient building documents the change and development of our country’sarchitectural style for thousands of years, which has a important value of culture, historyand society. The mortise-tenon joint is one of the important characteristics of the ancientwood structure of our country, the destruction of the joints usually causes seriousdamage of the structure such as tilt and even collapse. Mastering the performance ofmortise-tenon joints is the foundation of repair and protection of the ancient woodstructure.Firstly, the straight mortise-tenon joint (one-way straight mortise-tenon joint,through mortise-tenon joint and half mortise-tenon joint) was taken as the example forresearching through the monotone or low-cyclic reversed loading experiment. Theresults shows that, the bearing capacity and flexural stiffness of one-way straightmortise-tenon joint is similar to the through mortise-tenon joint, but its energydissipation ability is lower than the through mortise-tenon joint. The seismicperformance of half mortise-tenon joint is poor. Increasing the length of the tenon ormodel scale can inprove the bearing capacity and flexural stiffness of one-way straightmortise-tenon joint obviously, and the bearing capacity is proportional to the square ofmodel scale of the joint, but the energy dissipation decreases with the increasment of themodel scale. Different type of wood has a big effect on the seismic performance ofjoints.Secondly, we adopted the method of artificial simulation of damage, consideringthe influence of different damage types and different damage degrees, the failurecharacteristics, moment-corner hysteresis curves, skeleton curves, rigidity degradationand energy dissipation of the straight mortise-tenon joints were studied through the low-cyclic reversed loading experiment. The results shows that, the rotation bearingcapacity,stiffness and energy dissipation capacity of the damaged joints is significantlybelow the intact one and reduces gradually as the damage degree increases.Under thesame degree of damage, the final rotation bearing capacity and stiffness of man-madefungi damage joints is bigger the man-made termites damage joints, but its energydissipation capacity is lower than the man-made termites joints.Lastly, we got the relationship between the bending moment and corner of thestraight mortise-tenon joints with theoretical analysis based on the mechanicalequilibrium condition and the deformation compatibility condition. The theoreticalresults are close to the experimental results.