【摘要】 基于平稳随机地震动场理论 ,研究了地震动空间变化 ,包括行波效应、相干损失和局部场地条件 ,对大跨度斜拉桥地震响应特征的影响。采用虚拟激励方法计算结构的随机响应。计算的响应量包括塔顶位移、塔底弯矩、辅助墩底弯矩等 ,得到的主要结论是 :与一致地震激励相比 ,地震动空间变化可以使斜拉桥的地震反应改变达 4 0 % ,仅考虑行波效应可以得到响应的偏于保守的估计值 ;局部土场地条件对斜拉桥的地震反应有重要影响 ,当各塔、墩处的土质条件差异较大时需进行详细的抗震分析。更多还原

【Abstract】 The response characteristics of long-span cable-stayed bridges under seismic action with spatial variation, including traveling effect, coherence loss and local site condition, are investigate in this paper. The pseudo-excitation method is employed to calculate the random response of the bridges, and the conclusions are the follows:(1)the response of the cable-stayed bridges under seismic action with spatial variation differ from those under uniform seicmic action up to 40%, therefore it is necessary to take the spatial variation of the seismic ground motion into account in the seismic design of long-span cable-stayed bridges; (2)traveling excitations is to give the conservative values of the response, compared with those by taking the coherence loss into account; (3)the large differences of the site conditions at the bottoms of the towers and piers of the bridges significantly change the response of the bridges, which should be included in the seismic design of the bridges.更多还原