LRB隔震桥梁空间变异性地震随机响应分析
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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.
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.
引文
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[2]林家浩,张亚辉,赵岩.大跨度结构抗震分析方法及近期进展[J].力学进展,2001,31:350—360.
[3]Soyluk K,Dum anoglu A A.Spatial variab ility effects ofground motions on cab le-stayed bridges[J].Soil Dynam icsand Earthquake Engineering Structures,2004,24:241—250.
[4]代泽兵,黄金枝,王红霞.基于智能阻尼器的大跨度斜拉桥多支承激励地震振动控制[J].振动与冲击,2005,24:66—70.
[5]张亚辉,林家浩.香港青马桥抗震分析[J].应用力学学报,2002,19:25—30.
[6]Sevket Ates,A Ayd in Dum anoglu,A lemdar Bayraktar.Sto-chastic response of se ism ically isolated h ighway bridges w ithfriction pendu lum system s to spatially varying earthquakeground motions[J].Engineering Structures,2005,27:1843—1858.
[7]克拉夫R W,彭津J.结构动力学[M].北京:科学出版社,1981.
[8]白国良,朱丽华.基于现行抗震规范的kanai-tajim i模型参数研究[J].世界地震工程,2004,20(3):114—118.
[9]欧进萍,王光远.结构随机振动[M].北京:高等教育出版社,1998.
[10]倪振华.振动力学[M].西安:西安交通大学出版社,1989.
[11]龙晓鸿.斜拉桥及连续梁桥空间地震反应研究[D].武汉:华中科技大学,2004.
[12]张俊平,周福霖,廖蜀樵,顾玉龙.桥梁隔震体系振动台试验研究(iv)—隔震桥梁的设计方法探讨[J].地震工程与工程振动,2002,22(3):149—153.
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