近场脉冲型地震下增量动力分析烈度指标的选择

Intensity Measure of Incremental Dynamic Analysis Under Near-field Pulse Earthquake

合理选择烈度指标IM是基于性能的抗震设计理论的关键.为了研究近场脉冲型地震下合理的烈度指标,以一座常规5跨连续梁桥为例,用增量动力分析方法对OpenSEES软件所建立的有限元分析模型进行一系列非线性动力分析,结果表明:近场脉冲型地震下,不建议采用峰值加速度PGA作为烈度指标,建议采用基本周期对应的谱加速度Sa(T1)或峰值速度PGV.

Intensity measure(IM)is a key problem of performance-based seismic design.In order to study reasonable intensity measure under near-field pulse earthquake,a conventional 5span continuous bridge is taken as an example,using OpenSEES software to build a finite element model and incremental dynamic analysis method to perform a series of nonlinear dynamic analysis.The results show that under the near-field pulse earthquake,the peak acceleration PGAis not recommended as an intensity measure,while the spectral acceleration corresponding to the fundamental period Sa(T1)and the peak velocity PGVis recommended.