地震动空间效应与土-基础相互作用效应对隔震桥梁临界碰撞间隙的影响  

Effects of spatial variation of ground motion and soil-foundation interaction on critical pounding gap length of seismic isolated bridges

作　　者：李忠献[1] 周莉[1] 岳福青[1] 

机构地区：[1]天津大学滨海土木工程结构与安全教育部重点实验室,天津300072

出　　处：《土木工程学报》2010年第7期85-90,共6页China Civil Engineering Journal

基　　金：国家杰出青年科学基金项目(50425824);国家自然科学基金项目(90715032;51021140003)

摘　　要：基于随机振动理论和虚拟激励法,研究了地震动空间效应与土-基础相互作用效应对隔震梁桥临界碰撞间隙的影响。建立了临界碰撞间隙计算方法,分别研究了仅考虑地震动空间效应、仅考虑土-基础相互作用和同时考虑地震动空间效应与土-基础相互作用三种情况下各参数对临界碰撞间隙的影响。研究表明:当地基土剪切波速较小且部分相干效应不显著时,临界碰撞间隙随地基土剪切波速减小而减小;当地基土剪切波速较大时,不论是否考虑地震动空间效应,地基土剪切波速对临界碰撞间隙的影响很小;行波效应与部分相干效应对临界碰撞间隙的影响不能忽视,且部分相干效应的影响更突出,部分相干效应越显著,临界碰撞间隙越大;临界碰撞间隙随隔震支座阻尼比的增大而减小,且当部分相干效应显著时,随隔震支座周期的增大而增大。Using random vibration theory and pseudo excitation method, the influence of spatial seismic effect and soilfoundation interaction on the critical pounding gap length of seismic-isolated bridges is studied. A method for calculation of the critical pounding gap length is developed. The influences of different parameters on the critical pounding gap length are investigated for three cases： soil-foundation interaction only, spatial variation effect of ground motion only, and both spatial variation effect of ground motion and soil-foundation interaction. It is shown that the critical gap length decreases as the shear velocity of soil decrease when the incoherence effect is not significant. A relatively large shear velocity of soil has little influence on the critical gap length whether the spatial variation effect of ground motion is considered or not. Wave passage effect and incoherence effect can not be neglected for calculation of the critical gap length. The critical gap length increases as the incoherence effect becomes more prominent, and decreases as isolation bearing＇ s damping ratio decreases. When the incoherence effect is significant, the critical gap length increases when the period of isolation bearing increases.

关 键 词：隔震桥梁 地震碰撞 临界碰撞间隙 地震动空间效应 土-基础相互作用 虚拟激励法 

分 类 号：TU435[建筑科学—岩土工程] TU446[建筑科学—土工工程]