新型橡胶隔震支座临界行为理论模型研究

摘要

Rubber seismic isolation bearings are usually subjected to large axial loads and lateral displacements at the same time during earthquakes,and they are prone to turn into critical state.The current design methods and calculation approaches cannot calculate the critical forces and corresponding displacements with enough accuracy,which poses a direct threat to the isolated structures.Therefore,a new theoretical model that could simulate the critical behaviors of rubber bearings was proposed.According to the mechanics regularity of bearings in critical state,the rotational behavior of rubber was represented by two groups of vertical springs,the shear behavior was modeled by a nonlinear horizontal spring,and then a mechanical model was established to analyze the critical behaviors of rubber bearings.By comparing with test curves,the results show that the model has the ability to simulate the critical behaviors of rubber bearings with ideal accuracy.It can tackle the problems of the necessity of relying on experimentally calibrated parameters and the appearance of considerable errors by existing models,and it is able to provide a powerful tool for isolated structures design.%橡胶隔震支座在地震作用下同时受到巨大轴力与剪切变形,易发生稳定性问题进入临界状态,现行设计方法及计算理论不能准确计算临界力及临界位移,严重威胁隔震结构安全.提出计算橡胶支座临界行为新型理论模型,根据支座进入临界状态时受力规律,以两层竖向弹簧模拟支座转动性能,非线性水平弹簧模拟剪切性能,建立力学模型对支座临界行为进行分析.通过与试验结果进行对比,表明建立的理论模型能够准确模拟橡胶支座的临界行为,解决了现存分析模型中需要依靠试验校正系数以及误差过大的问题,为隔震结构设计提供有力工具.