近断层长周期地震波对桥台−引桥−刚构连续梁结构体系地震响应的影响

Influence of long period seismic wave near fault on seismic response of abutment-approach bridge-rigid frame continuous girder bridge system

为研究近断层长周期地震波对桥台−引桥−刚构连续梁桥结构体系地震响应的影响,以某实际桥梁结构体系为研究对象,充分考虑桥墩塑性铰、桩土相互作用、桥台背土相互作用和碰撞接触等非线性边界条件,采用峰值加速度和卓越频率相近的近断层脉冲型地震波、近断层类谐和地震波、近断层长周期地震波和普通近场地震波各3条分析不同类型地震波对结构体系地震响应的影响。同时,选取不同脉冲周期的近断层脉冲型地震波分析脉冲周期对结构体系地震响应的影响。研究结果表明:长周期地震波使结构体系地震响应明显更大,其中近断层脉冲型地震波最大,近断层长周期地震波略大于类谐和地震波。另外近断层脉冲型地震波的脉冲周期越大,其对结构体系地震响应的影响也越大。因此建议在进行抗震设计时考虑桥址处实际条件和脉冲周期等因素的影响。

In order to study the influence of near-fault long-period seismic waves on the seismic response of abutment-approach bridge-rigid frame continuous girder bridge system,a practical bridge structure system was taken as the research object,and nonlinear boundary conditions such as the plastic hinge of the pier,pile-soil interaction,abutment-back soil interaction and collision contact were fully considered.The influence of different types of seismic waves on the seismic response of structural system was analyzed by using three near-fault pulse wave,near-fault quasi-harmonic wave,near-fault long-period wave and near-fault ordinary wave,which weresimilar to PGA and superior frequency.At the same time,the near fault pulse wave with different pulse periods was selected to analyze the influence of pulse periods on the seismic response of the structural system.The results show that the long period seismic waves make the seismic response of the structural system significantly larger,and the near fault pulse seismic wave is the largest,and the near fault long period seismic wave is slightly larger than the quasi-harmonic seismic wave.In addition,the larger the pulse period of near-fault pulse seismic wave is,the greater its influence on the seismic response of structural system will be.Therefore,it is suggested that the influence of the actual conditions of the bridge site and the pulse period should be considered in the seismic design.