The majority of existing ancient timber structures have different degrees of damage. The looseness of mortise-tenon joints is a kind of typical damage type. In order to study the influence of looseness on the seismic performance of mortise-tenon joints, six through-tenon joints and six dovetail-tenon joints with scale 1:3.2 were fabricated according to the requirements of the engineering fabrication method of Chinese Qing Dynasty. Each type of joints consisted of one intact joint and five artificial loose joints, and the artificial defect was made to simulate looseness by cutting the tenon sectional dimension. Based on experiments of two types of joints under low-cyclic reversed loading, the seismic behaviors of joints such as failure modes, hysteretic loops and skeleton curves, strength and stiffness degradation, and energy dissipation capacity were studied. Moreover, the comparative analyses of seismic performance between two types of joints were carried out. The variation tendency of seismic behaviors of two types of joints has similarities, and there are some differences due to their different structural styles. The results indicate that squeeze deformation between tenon and mortise of two types of joints occurred. The shape of hysteretic loops of two types of joints is reverse-Z-shape, and the pinching effect of hysteretic loops becomes more obvious with the increase in looseness, among which of through-tenon joints is more obvious than that of dovetail-tenon joints. The carrying capacity, stiffness, and energy dissipation capacity of loose joints are significantly lower than that of the intact one, and the energy dissipation capacity of dovetail-tenon joints is better than that of through-tenon joints. The rotation angles of two types of joints can reach 0.12 rad, and the loose joints still have great deformation capacity.

To study the influence of wooden walls on the seismic performance of traditional Chinese column-and-tie timber structures, two 1/2-scale two-story and two-span timber structure models were fabricated. The infill wall was not installed in model 1, while model 2 deployed wooden walls for comparison. The damage characteristics, seismic responses, and energy dissipation behaviors of the two models under the seismic ground motions of varying intensity were obtained through shaking table tests. The comparative analyses of the seismic performance of the two models indicated that the pull-out length of the tenon and the slippage degree of the column foot of model 1 were greater than those of model 2 with the same input. Moreover, the first natural frequency of model 2 was greater than that of model 1 due to the existence of the wooden walls, and the stiffness degradation rate of model 2 was lower than that of model 1. The first damping ratio of model 1 was between 10.2% and 15.0%, and that of model 2 was between 9.3% and 21.9%. The acceleration amplification factors of the two models were basically less than 1, which was significantly different from regular reinforced concrete structures or steel structures. When the input peak ground acceleration reached 0.22g (the maximum considered earthquake for the region with intensity seven), the maximum story drifts of the two models were 1/47 and 1/59, respectively, which met the story drift limit of 1/30 for timber frames in the Chinese Seismic Code for Timber Structures. The lateral stiffness of model 2 increased because of the existence of the wooden walls when compared with model 1. The energy dissipation of model 2 was greater than that of model 1 under the same earthquake excitation in terms of the deformation of the wooden walls and squeezing interaction between the timber frame and wooden walls.