近断层地震下摩擦型隔震结构与限位装置碰撞反应及防护研究

采用不同的碰撞模型,研究了摩擦型隔震结构(P-F、R-FBI和FPS)在近断层地震作用下与限位装置相碰撞的动态反应特性,给出了不同碰撞的数学表达式以及各模型中参数的具体数值;研究发现,地震中隔震结构若发生碰撞将大大增加结构的层间剪力和加速度反应,且激起结构的高阶振型;不同碰撞模型的计算结果相差在10%以内,但非线性碰撞模型花费的计算时间长,因此在实际工程中采用线性的Kelvin模型精度已足够;上部结构的非线性对碰撞反应有很大影响,碰撞时非线性结构的底层最大剪力较线性结构有很大减小,且层间存在很大的残余位移;同时还研究了基底预留宽度以及上部结构的自振周期对隔震结构碰撞反应的影响;最后提出了加设高阻尼橡胶缓冲器减小隔震结构碰撞反应的防护措施。

Response and protection of the impact of base-friction-isolated structures and displacement-constraint devices under near-fault earthquakes

The seismic responses of the impact of base-friction-isolated structures and displacement-constraint devices under near-fault earthquake ground motions are studied by using various impact models.The analytical formulations of various impact models are outlined,and the model parameters studied in detail.The results indicate that the maximum acceleration and the shear force between the floors are significantly increased,and the higher-order modes are exited due to the impact.The differences between the numerical results of various impact models are within 10%,however,the non-linear impact models consume much more computing time,and the Kelvin linear impact model can be effectively employed for actual projects.In comparison with the linear superstructure,the maximum base shear force of the non-linear structure is decreased and the large residual displacement can be detected during the impact.The impact response of base-friction-isolated structures with different system parameters,such as size of gap and superstructure flexibility,is also studied.A protection measure is proposed for reducing the impact response by introducing high-damping rubber bumpers.