桥梁抗震剪力键的力学模拟及减震效应研究

针对一种带剪力键的滑板式橡胶支座系统的减震效果进行分析,根据基于性能的抗震设计思想以及我国抗震规范的规定,以桥墩内力和主梁位移为控制目标,明确了剪力键在正常使用、常遇地震、罕遇地震3种阶段下的性能目标,由此提出了剪力键的设计计算方法,结合数值分析方法建立了剪力键恢复力模型并给出了简易计算公式.以某等跨径桥梁为例,选取6条地震波,运用OpenSees建立了桥梁非线性动力模型并进行时程分析.结果表明:剪力键数目对滑板式橡胶支座的减震效果影响显著,合理布置剪力键能有效地防止主梁在常遇地震下发生滑移、明显减小震后残余位移,同时可大幅降低罕遇地震下桥墩内力.剪力键和滑板式橡胶支座的组合既能保证正常情况的适用性又能起到较好的减隔震效果.

Research of Mechanical Simulation and Seismic Mitigation Effect for the Bridge Seismic Dowel

This study investigated the effect of the seismic mitigation measure of a type of elastomeric bearing system with the sliding plate and seismic dowel. Firstly, combining the idea of the performance-based seismic and seismic guidelines of China, three performance metrics of the seismic dowel under different earthquake levels (normal service condition, frequent-occurred earthquake and rare-occurred earthquake) were proposed in terms of the seismic force of column or the displacement of the girder. Then, a detailed design methodology of seismic dowel was proposed to establish the hysteretic model and the simplified calculation formula. Finally, a medium-span beam bridge was taken as an example, six suitable earthquake records were chosen and the dynamic mode was established to apply the nonlinear time history analysis using OpenSees. The analytical results show that the proposed seismic mitigation measure can effectively reduce the displacement of the girder and the residue displacement under frequent-occurred earthquake, and it also can decrease the internal force of column dramatically.