【摘要】 考虑行波效应,研究某大跨度连续刚构桥在多点非均匀调制演变随机地震激励下的响应。采用Priestley提出的非均匀调制演变随机过程来描述地面运动的双重非平稳随机场特性,即考虑地面随机激励强度非平稳的同时,又考虑其频率的非平稳。演变随机激励下结构地震响应的计算,采用高效精确的虚拟激励法。对不同的地震波视波速,分别计算桥梁在纵桥向、横桥向和竖向地震动输入下的响应,以及三向地震动同时输入下的响应。结果表明,地震动的行波效应对大跨度桥梁结构地震响应有较大影响;若忽略地震动的空间效应,一些情况下会带来偏于不安全的分析结果。更多还原

【Abstract】 Seismic behavior of a long-span continuous rigid-framed bridge under multi-support earthquake excitations was studied,with traveling wave effects of ground motion considered.The earthquake excitations were regarded as nonuniformly modulated evolutionary random processes and Priestley’s mathematical model was adopted.Priestley’s model takes into account the non-stationary characteristics not only of the excitation intensity,but also of the excitation frequency components.The relevant computation of long-span structures subjected to non-uniformly modulated evolutionary random excitations was solved by using pseudo excitation method,which is an accurate and very efficient way for stochastic vibration analysis of structures.Seismic waves were assumed to spread along the longitudinal bridge,and different seismic apparent wave velocity was investigated.Seismic responses of the bridge under the longitudinal,transverse and vertical ground motion inputs were simulated respectively.Simulation results show that it’s necessary to consider the spatially varying effects of ground motions in the seismic analysis of long-span continuous rigid-framed bridges.If the spatially varying effects of ground motions are neglected,in some cases it may lead to unsafe seismic design.更多还原