【摘要】 研究目的:近年来,近断层地震对桥梁响应的影响日益引起研究者的注意,现有铁路规范对近断层效应的考虑较少。为研究方向速度脉冲效应对高速铁路桥梁地震响应的影响,基于Pacific Earthquake Engineering Research Center(PEER),Next Generation Attenuation Relationships for Western US(NGA West)强震数据库,采用ANSYS分析软件、ANSYS-APDL语言和弯矩曲率关系计算程序,建立了高速铁路桥梁全桥模型,考虑了轨道不平顺的影响,计算了近/远断层地震作用下桥梁的弹塑性地震响应。研究结论:(1)相比于远断层地震以及非脉冲型地震,方向脉冲型近断层地震对短周期结构地震响应影响较大,会增加桥梁位移及内力响应,其滞回特性表现出荷载-变形曲线中间加强的特点,会增加桥梁的结构和非结构损伤;(2)由于近断层地震较大的竖向地震动会改变桥墩轴力,导致梁体竖向挠度比远断层地震增加较多,《铁路工程抗震设计规范》(GB 50111—2006)等规范规定竖向地震为横向的65%,会低估梁体竖向动力响应;(3)本文研究成果可以为高速铁路桥梁抗震设计提供参考,也为今后相关设计规范、标准的修订提供技术支持。更多还原

【Abstract】 Research purposes: Recently,the more attentions have been paid to the influence of the near-fault ground motion on the dynamic response to bridge,but there is a little concerns about the near-fault ground motion effect in the current railway codes. To investigate the influence of the seismic response of the near-fault ground motion on high-speed railway bridge,by using the Pacific Earthquake Engineering Research Center(PEER),the Next Generation Attenuation Relationships for Western US(NGA West) strong ground motion database,the ANSYS software,the ANSYS-APDL language and the moment-curvature program,the finite element model for the multi-span simply-supported bridge of the high-speed railway was built on consideration of the influence of the track irregularity to calculate the elastic-plastic seismic responses of bridge subjected to the near / far-fault ground motions.Research conclusions:(1) Compared with far-fault ground motion and non-pulse-like motion,the directivity pulse-like Near-fault ground motion had a big influence on the seismic responses on the short-period structure,increased the displacement response of inelastic bridge structures and it also increased the structural and nonstructural damage because the hysteretic properties of the near-fault directivity pulse-type earthquake was characterized by the central strengthened hysteretic cycles.(2) The big vertical acceleration of near-fault directivity pulse-like motion could notably change the axial load of the bridge piers,resulting in big increase of vertical deflection in the mid-span of girder,but the vertical earthquake force is specified as 65% of the lateral earthquake in the《Code for Seismic Design of Railway Engineering 》(GB 50111-2006) and it causes the smaller vertical deflection in the girder.(3) The calculation results could provide the reference to the seismic design of high-speed railway bridge,and provide the technical support for the revisions of the design specifications and standards.更多还原