拔榫状态下古建筑燕尾榫节点性能试验研究

为了解决木结构古建筑榫卯节点老化抗震能力下降的问题，以木结构古建筑加固的无损性和可逆性为原则，以保留榫卯节点半刚性特点为出发点，以是否设置活动槽和加固件是否与柱螺钉连接为区分，设计了4种不同形式的扁钢加固装置，并将其应用在半榫、透榫和燕尾榫节点.以宋《营造法式》中大木作二等材为原型，按照缩尺比例为1：3.52制作了3组试验模型，其中半榫、透榫和燕尾榫节点各4个.进行试验的节点均为反复加载过的有损节点，通过静力推复试验，对比榫卯节点加固前后的破坏状态、荷载-位移滞回曲线、骨架曲线、刚度退化和耗能能力等抗震性能参数.试验结果表明：榫卯节点加固前后滞回曲线都有明显的

Experimental study on mechanical behavior of dovetail joint in historic buildings out of mortise

To solve the problem of anti-seismic capacity decline of aging mortise and tenon joints, four types of flat steel reinforcement devices were designed and manufactured based on the reversibility, nondestructive and intention of preserving the semi-rigid characteristics of mortise tenon joints. The devices were distinguished from each other in whether with a moveable slot and the reinforcement was fixed to the column or not. The flat steel reinforcement devices were applied to half tenon joints through tenon joints and dovetail joints. 12 tenons and mortise joints were designed and manufactured according to the Fabrication Methods of Song Dynasty, including 4 half tenon joints, 4 through tenon joints and 4 dovetail joints. The scale ratio was 1:3.52. All the joints were slightly damaged by cyclic loaded before the low-cycle reversed loading experiment was carried out. The seismic performance parameters of joints such as reinforcement load-displacement hysteresis loops, skeleton curves, degradation of rigidity and energy dissipation capacity were compared and studied before and after reinforcement. The results show that all the hysteresis loops of joints have obvious pinch effect which indicates slippage occurred between the mortise tenon joints and the semi-rigid characteristics of joints were reserved after reinforcement.The energy dissipation capacity of the joints grows in a parabolic way with the increase of displacement loads. The rigidity, peak load and energy dissipation capacity of the joints were improved after reinforcement. The reinforcement effect of the strengthening devices which was fixed to the column was better than others. The results show the seismic capacity of mortise tenon joints can be effectively improved by strengthening the connection between reinforcement and wood components. Finally, suggestions on how to further enhance the reinforcement effect of the four types strengthening devices were put forward.