空间相干效应对山区高墩刚构桥随机地震动响应的影响  

Influence of spatial coherence on stochastic seismic responses of rigid-framed bridge with high piers in mountainous district

作　　者：洪浩[1] 郑史雄[1] 贾宏宇[1] 于力[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《世界地震工程》2013年第3期54-60,共7页World Earthquake Engineering

基　　金：铁道部科技研究开发计划项目(2010-G018-A-4)

摘　　要：为了研究不同墩高和有墩高差的山区高墩桥梁在强震作用下,激励点功率谱完全不相干,部分相干和完全相干时结构的随机地震响应规律,基于随机地震动场功率谱模型,对ANSYS随机振动计算理论进行了推导,建立了三维有限元模型。研究了不同工况下主梁和墩内力的变化规律,并对结果进行了比较,为高墩桥梁的抗震分析采用随机振动方法提供一定的参考。研究结果显示:输入谱矩阵不同,结构类型不同,对结构内力的影响也会不同。对于高墩刚构桥梁,仅采用一致激励法(完全相干)进行抗震分析往往会错估其梁、墩的抗震能力,应取考虑完全相干、部分相干和完全不相干时的最不利值作为设计参考。在地形允许的情况下,应对可能建造的桥型(不同墩高和墩高差)进行分析,以确定地震力最小的桥型并注意桥梁截面抗力的提升和附加减震措施。To make a research on the random response regularities of high-pier bridge subjected to strong earth- quakes and with piers in different height in the mountainous district by considering the coherence effect between ex- citation points, based on the power spectral model of the stochastic earthquake ground motion, the formula of ANSYS random vibration theory was derived and the three-dimensional finite element model was established. The change law of the internal force of main girder and piers under different loading conditions was researched and compared to give a reference to the random vibration method for the anti - seismic analysis of high-pier bridge. The results show that the structural internal force changes with the input spectra matrix and structure type. For rigid frame bridge with high piers, using only the uniform excitation method to do the anti - seismic analysis would misestimate the seismic capacity of girders and piers of the bridge so that the most disadvantageous values under completely coherent partially coherent and incoherent conditions need to be considered in design. If the terrain is allowable, it is neces- sary to analyze different types of bridges with piers in different height to find optimum type of the bridge with the minimum seismic force and take measures to improve the seismic reduction capacity of the brid^e .

关 键 词：桥梁工程 相干效应 随机振动 高墩桥梁 

分 类 号：TU311.3[建筑科学—结构工程]