残损古建筑木结构不对称榫卯节点抗震性能试验研究

Experimental Study on Seismic Performance of Irregular Mortise-and-Tenon Joints in Damaged Ancient Architectural Wood Structures

为研究残损古建筑木结构不对称榫卯节点的力学特性,共设计4个足尺古木结构榫卯节点,包括1个连接完好及3个存在不同松动程度的不对称榫卯节点,通过拟静力试验获得其弯矩-转角滞回曲线,对其滞回特性、骨架曲线、耗能能力及刚度退化规律等进行分析。结果表明,残损节点滞回曲线呈反“Z”形,捏缩效应显著;存在松动的不对称榫卯节点峰值弯矩及转动刚度均小于连接紧密的节点试件,而极限转角大于连接紧密的节点试件。随着节点松动程度的不断增大,各试件峰值弯矩、转动刚度峰值及滞回耗能逐渐降低。控制位移不变时,连接紧密完好节点的滞回耗能及刚度明显高于松动节点;各不对称榫卯节点正、负向刚度不等。同时,本研究获得了不同松动程度下节点的正、负向刚度理论公式,为工程加固修缮提供理论依据。

To investigate the mechanical properties of asymmetric mortise-tenon joints in ancient wooden structures,four full-scale mortise-tenon joints were designed.This included one intact joint and three joints with varying levels of damage.Moment-rotation hysteretic curves were obtained for the mortise and tenon joints under low cyclic reversed loading tests.The hysteretic characteristics,skeleton curve,energy dissipation capacity,and stiffness degradation were analyzed.The experimental results indicate that the shape of the hysteretic curve changes from an"S"shape to an inverted"Z"shape as the level of damage increases,with the pinching effect becoming more pronounced.The ultimate bending moment and rotational stiffness of the damaged mortise and tenon joints are less than those of the intact joints,while the ultimate rotation capacity of the damaged joints is greater.As the looseness of the joints increases,the ultimate bending moment,peak rotational stiffness,and hysteretic energy decrease gradually.Under the same load displacement level,the hysteretic energy and stiffness of the intact joint are significantly higher than those of the damaged joints.A positive and negative stiffness theory formula was derived,providing a theoretical basis for engineering applications.