SV波入射下峡谷地形对多支撑大跨桥梁地震反应影响分析  

Canyon topography effects on seismic responses of multi-support bridge under incident SV seismic waves

作　　者：周国良[1,2] 李小军[2] 李铁萍[1] 侯春林[1] 

机构地区：[1]环境保护部核与辐射安全中心,北京100082 [2]中国地震局地球物理研究所,北京100081

出　　处：《岩土力学》2012年第5期1572-1578,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.50708100);国家自然科学基金重大研究计划(No.90715038)

摘　　要：以二维河谷地形在SV波垂直入射和斜入射下的结果作为地震动输入,分析了地形因素导致的地震动差异对一座桥墩高差悬殊的连续刚构桥地震反应的影响,并与一致激励下的结果进行了对比。结果表明:与一致激励相比,考虑地形效应的多点激励作用下,刚构桥地震反应存在显著差异,难以找到规律性,不同的结构部位其最大内力的表现各不一样;多点激励使主梁遭受不利反应;斜入射对低墩和主梁有显著影响,使其内力显著增加或使结构各部位内力分布明显不均衡;与低墩相比,高柔的桥墩对多点激励相对不敏感;大跨度桥梁抗震分析与设计应考虑局部场地和入射波的入射方向和角度的影响。The seismic response of a reinforced concrete continuous rigid frame bridge is analyzed considering the scattering of SV seismic waves by canyon topography.The differences of structural responses between uniform and nonuniform seismic excitation cases are revealed.The results indicate that the canyon topography has significant and complex effects on the seismic response of the bridge.Different structural members suffer critical responses in different analysis cases.The low piers and rigid frames are more sensitive to the nonuniform ground motions obtained from the seismic response analysis of canyon topography in the case of oblique incidence of SV waves;otherwise the flexible high piers are insensitive.Canyon topography effects as well as the incidence angle of the waves should be regarded as important factors taken into account in aseismic design.

关 键 词：河谷地形 连续刚构桥 改进大质量法 多点激励 地震反应 

分 类 号：TU443[建筑科学—岩土工程]