大跨拱桥三维多点随机地震响应分析  

Random seismic response analysis of long-span arch bridge under three-dimentional multi-supports excitation

作　　者：吴玉华[1] 楼文娟[1] 

机构地区：[1]浙江大学土木系,杭州310027

出　　处：《振动与冲击》2009年第6期183-187,共5页Journal of Vibration and Shock

摘　　要：对大跨度钢管混凝土拱桥进行三维正交地震动多点激励下的平稳随机响应分析。建立了跨径308m中承式钢管混凝土拱桥的精细有限元模型,采用多维多点平稳随机地震响应分析方法,数值仿真了该拱桥在一维P波、一维SH波、一维SV波多点激励下的地震响应以及考虑互谱的三维多点激励地震响应,研究了三维地震动、行波效应和部分相干效应对拱肋内力的影响。数值分析结果表明:考虑地震动的空间效应对拱肋内力有很大改变,地震动的行波效应对拱肋内力的影响比部分相干效应的影响更大,三维地震作用比单维地震作用的拱肋内力有较大增幅。对大跨度钢管混凝土拱桥,必须进行多维多点地震激励的响应分析,否则有可能严重低估结构的地震设计内力。The random seismic analysis of long-span concrete filled steel-tube (CFST) arch bridge under multi-supports excitations of three-dimensional orthogonal earthquake motion was performed. The precise finite element model of a 308 m span half-through CFST arch bridge was established. The seismic response of the arch bridge under one-dimensional P-wave, one-dimensional SH-wave, one-dimensional SV-wave and three-dimensional earthquake excitations, considering cross-power spectrum of multi-supports, were numerically simulated by using the method of stationary random seismic analysis, and the influences of three-dimensional earthquake motion, traveling-wave effect and partial coherence effect on internal forces of arch rib were studied. The results show that the internal forces of arch rib may be greatly changed by considering the spatial variation of seismic motion. The traveling-wave effect of the earthquake motion on the internal forces of arch rib is greater than the partial coherence effect. The internal forces of arch rib under three-dimensional earthquake excitations are greater than that under one-dimensional excitation. The random seismic analysis under three-dimensional multi-supports earthquake excitations must be performed for the long-span CFST arch bridge, otherwise the seismic designed forces of the structure are likely to be underestimated seriously.

关 键 词：拱桥 地震响应 随机振动 多维输入 多点激励 

分 类 号：U441.5[建筑科学—桥梁与隧道工程]