近场地震作用下连续梁桥的动力响应分析

Analysis of continuous girder bridges' seismic response under the near-fault ground motion

结合工程实例,利用有限元分析软件SAP2000建立3跨连续梁桥有限元模型,模型的桥墩分为高墩和低墩2种情况,基础考虑桩土作用和固结2种情况,研究墩高和桩土作用对桥梁抗震性能的影响。为了模拟近场地震动,选取台湾集集地震的地震动。研究不同桥梁模型在近场地震下的动力特性,结果发现桩土作用延长桥梁结构的周期,没有改变结构的振型特征;墩高可以改变结构的周期,并且也影响结构的振型特征。在近场横向地震作用下,桩土作用和墩高主要影响桥梁跨中的位移、弯矩和墩底弯矩、剪力。

In this paper,Three-span continuous girder bridges were set up with finite element analysis software SAP2000,comparing dynamic responses of bridge was analyzed under height and low pier,with and without pile-soil interaction,studying the effect of high pier and pile-soil on seismic behavior of the bridge. Near-fault earthquake were selected from Chi-Chi earthquake in Taiwan. Through different models of bridge dynamic characteristics under near-field earthquake,and found that an extended period with pile-soil interaction,no change mode characteristics of the structure; height pier can change the periodic structure,and may also affect mode characteristics of the structure. Under the near-fault transverse seismic action,with pile-soil interaction and height pier mainly affects bridge span displacement,span moment and shear force and moment at the bottom pier.