板式橡胶支座摩擦滑移抗震性能试验研究

Experimental study on seismic performance of laminated rubber bearings with friction slipping

为了研究板式橡胶支座摩擦滑移后桥梁的抗震性能，完成了5个试件在不同竖向荷载作用和往复荷载作用下的拟静力试验，分析了支座摩擦滑移前后的滞回曲线、骨架曲线、支座变形、滑移位移、强度和刚度退化规律以及耗能能力等抗震性能指标．试验结果表明，加载位移较小时，支座主要发生弹性剪切变形，滑动位移较小．当支座剪切变形达到73％一110％时，发生明显滑移，滑移位移与支座所受的竖向荷载和支座规格有关．支座与钢板之间的摩擦系数与施加竖向荷载成反比，摩擦力与竖向荷载成正比，支座加载和卸载刚度基本不变，等效刚度退化明显，但退化到一定值后基本稳定．板式橡胶支座橡胶层厚度的增加会导致支座摩擦耗能性能改变，加载位移相同时，支座自身的剪切变形随之增大，摩擦滑移位移和摩擦耗能则随之减小．

To investigate the seismic behaviors of the laminated rubber bearing with friction slipping, a series of experiments of five specimens subjected to pseudo-static tests under different vertical loads and reciprocating loads were conducted. The force-displacement hysteretic curve, skeleton curve, deformation, slipping displacement, degradation of strength and stiffness, and the energy dissipation capacity before and after friction slipping were analyzed. The experimental results show that when the load displacement is small, the elastic shear deformation of bearings is predominant and the slip- ping displacement is small. When the bearing shear deformation reaches 73% to 110%, slipping dis- placement is obvious and it is related to the vertical load and the type of bearings. The friction coef- ficient between the bearing and the steel plate is inversely proportional to the applied vertical load, while the friction force is proportional to the vertical load. The uploading and unloading of bearing are essentially unchanged. The bearing equivalent stiffness degradation is obvious; but after the deg- radation reaches a certain value, the equivalent stiffness is prone to stability. The increase of the rub- ber layer thickness can change friction energy dissipation, When the loading displacement is equiva- lent, shear deformation increases while friction slipping displacement and friction energy consump- tion decrease.