【摘要】 根据显式有限元方法采用人工透射边界,设置不同入射角度,对一河谷地形进行二维场地地震反应数值模拟,分析SH波入射下河谷地形的地震动分布特征;以场地地震反应分析结果作为各桥墩的地震动输入,分析连续刚构桥地震反应的特点。结果表明:SH波入射下河谷地形各点的地震动分布存在明显的差异;入射方向是影响河谷地震动分布的重要因素;斜入射情形下,河谷各点的位移差动明显增大。考虑河谷地形影响后,刚构桥地震反应存在显著差异,但难以找到一致规律性。一致激励不能代表最不利地震作用情况,地形因素和入射方向对结构内力反应具有重大影响,大跨度桥梁抗震分析与设计应予以充分考虑。更多还原

【Abstract】 Using explicit finite element method with artificial transmitting boundary,the seismic response of a canyon is analyzed under incident SH waves with the assumption of different angles of incidence.The distribution features of ground motion parameters,which include peak ground acceleration(PGA),peak relative ground deformation(PRGD)and acceleration response spectrum,are summarized.The ground motions are used as excitations of a continuous frame bridge with the improved Large Mass Method.It indicates that canyon topography has significant influences on the surface ground motions in terms of the angle of incidence.The ground surface has been characterized by larger deformations in the case of oblique incident waves.It is also concluded that it’s hard to find out any regularity of structural seismic responses considering the canyon topography effects under incident SH waves.In general,the canyon topography should be a carefully considered factor in structural seismic response analysis and aseismic design.更多还原