考虑橡胶支座随机性下隔震与非隔震近海桥梁地震易损性对比

Comparative analysis of vulnerability for offshore bridges with or without the isolated device considering randomness of the rubber bearing

针对目前在隔震桥梁地震易损性分析中隔震支座性能参数随机性研究薄弱、从失效概率的角度开展隔震与非隔震桥梁对比研究缺乏的现状,详细统计分析了橡胶隔震支座力学性能参数的不确定性,建立了近海隔震与非隔震桥梁非线性动力分析模型。在考虑支座参数、地震动及桥梁结构不确定性的基础上,利用拉丁超立方抽样分别生成90个结构-地震动样本对。利用Sap2000有限元软件对每个样本对进行非线性动力时程分析,通过对大量数据的回归分析,得到桥墩、支座的易损性曲线,进而对隔震前后结构的地震易损性进行了对比分析。结果表明:在同一破坏等级相同地震作用下,非隔震桥墩的失效概率大于隔震桥墩,非隔震支座破坏的概率大于隔震橡胶支座;采用隔震技术后,桥墩发生严重破坏和倒塌的概率极低,震后可修复的概率很大;而非隔震桥墩发生严重破坏的概率最大,说明其震后可修复的概率很小而产生不可修复损伤的可能性极大。

At present,the uncertainty of the mechanical parameters of the isolated rubber bearing is seldom considered and offshore bridge with or without the isolated device is also seldom studied based on failure probability. The uncertainty of the mechanical parameters for the rubber bearing according to test data from different manufactures was researched.Then,a non-linear dynamic analysis model of the offshore bridge was established. After the randomness of the bridge structure,the isolator and the earthquake ground motion were considered,90 bridge-isolator-earthquake ground motion samples were generated by using the Latin-Hyper-Square sampling method. By Sap2000 non-linear dynamic time history analysis program,the seismic response of every sample was calculated. A large amount of response data were analyzed by using regression analysis method,and the seismic vulnerability curves of the bridge pier and the bearing corresponding different damage states were obtained. Then the comparative analysis of vulnerability for offshore bridges with or without the isolated device was carried out. The result appears that under the same damage state and earthquake,the failure probability of the non-isolated bridge pier is larger than the isolated bridge pier,the damage of the non-isolated pot bearing is larger than the isolated rubber bearing,and the bearing is more likely damaged than the bridge pier. After using the isolation technology,the probabilities of serious damage state or nearly collapsed state of the bridge pier are very low,so the repairable probability of the bridge pier after earthquake is very large. On the contrary,the probability of serious damage state for the non-isolated bridge is the largest,which means that the repairable probability of the bridge pier after earthquake is very low,some irreparable damage may have already occurred.