LRB隔震桥梁空间变异性地震随机响应分析  

STOCHASTIC RESPONSE ANALYSIS OF SEISMICALLY ISOLATED BRIDGES WITH LRB TO SPATIALLY VARYING EARTHQUAKE GROUND MOTIONS

作　　者：江宜城[1] 杨德喜[1] 李黎[1] 胡亮[1] 

机构地区：[1]华中科技大学土木工程与力学学院,武汉430074

出　　处：《振动与冲击》2007年第1期104-107,120,共5页Journal of Vibration and Shock

基　　金：湖北省建设厅科技项目(K200553)

摘　　要：对装有铅芯橡胶支座(Lead-Rubber-Bearing,LRB)的隔震大跨连续梁桥进行了考虑地震动空间变异性的随机响应分析。地面运动加速度功率谱模型为零均值的平稳高斯过程,描述为过滤白噪声施加于支撑各点。地震动空间变异性综合考虑空间不相干效应、行波效应和局部场地土效应。推导了LRB隔震结构多点激励运动方程,并运用随机等价线性化方法以计入铅芯橡胶支座(LRB)的滞回非线性性能。对一大跨LRB隔震梁桥进行了一致激励和综合考虑地震动空间变异性的三种工况计算,得到了各工况下响应的拟静力项、动力项和总响应项的各自最大值的均值,并进行了对比分析。结果表明,对于带有铅芯橡胶支座的减隔震大跨连续梁桥,多点激励效应不容忽视,一致激励会对结构产生不安全的估计。Considering spatial variability effects of ground motions,seismic responses analysis of a long-span continuous bridge wity lead-rubber-bearings(LRB) is conducted.The power spectral density function of ground acceleration can be described as filtered white noise applied on each support point.The spatial variability effects of earthquake ground motions including the incoherence,the wave-passage and the local site-response effects are taken into account.Equation of motion of LRB structures to multiple excitations is derived,the stochastic equivalent linearization method is used to(linearize) the equation of motion.Furthermore,a seismically isolated bridge with LRB is calculated in three cases under uniform excitation and multiple excitations.Mean values of the maximum quasi-static,dynamic and the total response in three cases are obtained and analysed.It is shown that in the stochastic analysis of longspan seismically isolated continuous bridges with LRB,multiple excitations should be included while uniform excitation may cause unsafe estimation.

关 键 词：LRB隔震桥梁 地震动空间变异性 随机响应分析 随机等价线性化 

分 类 号：TU311[建筑科学—结构工程] P315[天文地球—地震学]