考虑SSI三种效应的桩基础RC梁式桥抗震性能评估方法研究

桩-土-桥动力相互作用是桥梁抗震研究的热点和难点问题，需合理考虑地基土柔度效应、运动学效应及阻尼效应的影响。本文采用基于性能点轨迹法的结构非线性静力分析方法，引入FEMA440针对土-结相互作用运动学效应、地基阻尼效应的地震动需求谱修正算法，探讨建立综合考虑桩-土相互作用三种效应的桩基础RC桥梁的抗震性能评估方法。以某高速公路RC连续梁桥为算例，分别以三种设计谱及相应的人工波为输入进行非线性静、动力方法验算对比，两个水准下的计算结果表明本文建议方法在补充考虑后两种效应后，地震响应略小于以考虑第一种效应为主的动力时程法，所建议方法能用于有效评估桩基础桥梁在预期地震需求下的抗震性能。

A seismic performance evaluation method for a pile-foundation RC girder bridge considering three kinds of SSI effect

The dynamic interaction among pile-soil-bridge system is a hot spot and a difficult problem of aseismic design of bridges,and the flexible foundation effect,kinematics effect and foundation damping effect should be reasonably considered.Here,by introducing a seismic demand spectrum modification algorithm of kinematics interaction effect and foundation damping one with FEMA440,an aseismic performance evaluation method taking effectively three kinds of SSI effect for a pile-foundation RC girder bridge into account was developed based on structural nonlinear static analysis method.With a highway RC continuous girder bridge as an example,the nonlinear static and dynamic analysis were conducted respectively for the aim of comparison with three kinds of design spectra and the corresponding artificial waves as inputs.The results under two earthquake levels showed that the seismic response of the bridge taking the 2nd and the 3rd kinds of effect into account with the proposed method is slightly smaller than that of the bridge taking the 1st kind of effect into account with the dynamic time-history method,and the proposed method can be used to evaluate effectively the aseismic performance of a pile-foundation bridge under the anticipated earthquake demand.