CFRP布加固榫卯节点M-θ滞回曲线定性分析

摘要

In order to effectively protect Chinese ancient buildings,the aseismic behaviors of their tenon-mortise joints strengthened by CFRP (Carbon Fibre Reinforced Plastic) were studied.Part of the timber structure of Tai - he Palace in the Forbidden City was taken as examples,its 1:8 scale model of timber frame with 4 beams,4 columns and concrete roof were built.Low cyclic reversed loading tests were carried out.The initial timber structure were tested firstly.Then its tenon-mortise joints were wrapped by CFRP,the strengthened structure was tested to get the aseismic effects.The M- θ (moment-rotation) hysteretic curves of the tenon-mortise joints were obtained.For each hysteretic loop,qualitative analysis on parameters such as bearing capability,rigidity,ductility,energy dissipation and so on of the tenon-mortise joints were carried out to evaluate strengthening effects of CFRP.The quantitative analysis further verified the effects.Results show that compared to each unstrengthened tenon-mortise joint,the CFRP strengthened joint has better bearing performance as well as rotation rigidity,which still has good ductility and energy dissipation capabilities.%为更好地保护古建筑,采取拟静力加载方法,定性研究了CFRP布(Carbon Fibre Reinforced Plastic)加固榫卯节点的抗震效果.以故宫太和殿某开间梁柱框架为原型,制作了1:8缩尺模型.采取水平低周反复加载方式,首先进行未加固节点抗震性能试验,在此基础上采用CFRP布包裹各榫卯节点,进行加固后节点对比试验.基于试验获得的节点M-θ 滞回曲线,对每一个滞回环曲线的承载力 、刚度 、延性 、耗能等力学参数变化进行了详细对比论述,定性评价了CFRP布加固榫卯节点的抗震效果,并进行了量化分析验证.结果表明:榫卯节点加固前具有较好的延性与耗能性能,其主要抗震缺陷包括较低的承载力 、较差的转动刚度;与未加固节点相比,CFRP布加固后的榫卯节点可弥补上述不足,且加固后的节点仍具有较好的延性和耗能性能.