采用SMA智能橡胶支座的近断层大跨斜拉桥易损性分析  

Seismic Fragility Analyses of Long-span Cable-stayed Bridge Isolated by SMA Wire-based Smart Rubber Bearing in Near-fault Regions

作　　者：王景全[1,2] 李帅[1,2] 张凡[1,2] 

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏南京210096 [2]东南大学国家预应力工程技术研究中心,江苏南京210096

出　　处：《中国公路学报》2017年第12期30-39,共10页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51378110);江苏省"六大人才高峰"第十一批资助项目(JZ-007);东南大学优秀博士学位论文培育基金项目(YBJJ1611);国家留学基金项目

摘　　要：为提高大跨斜拉桥的抗震性能,提出了一种基于形状记忆合金(Shape Memory Alloy,SMA)的智能橡胶支座。以苏通长江大桥为研究对象,分别采用铅芯橡胶支座(LRB)和SMA-铅芯橡胶支座(SMA-LRB)对其进行抗震控制。基于PEER强震数据库选取了20条近断层地震动记录,采用增量动力分析(IDA)方法得到了该隔震斜拉桥的地震响应,基于可靠度概率方法建立了各构件及桥梁系统的易损性曲线,系统评估了采用传统支座及智能隔震支座的大跨斜拉桥体系及各构件的易损性。研究结果表明:斜拉桥体系的损伤概率高于单一构件的损伤概率;近断层地震动作用下,在斜拉桥体系发生中等、严重和完全损伤状态时,隔震支座的损伤概率均为各构件中最高,主塔损伤概率较低,仅出现轻微损伤;相较于LRB,安装SMA-LRB可明显降低斜拉桥体系的损伤概率;在强震作用下,主塔、桥墩及斜拉索发生完全破坏的概率小;安装LRB和SMA-LRB后斜拉桥体系发生完全破坏的损伤概率分别为0.07和0.009,表明该体系具有较强的抗震能力。In order to improve the seismic performance of long-span cable-stayed bridge, a new shape memory alloy （SMA）-based rubber bearing was proposed. The Sutong cable-stayed bridge in China was taken as an object of the research. Two types of isolation devices, namely, lead rubber bearing （LRB） and SMA-based lead rubber bearing （SMA-LRB）, were installed to control the structural responses. About 20 near-fault ground motions were selected from PEER strong ground motion database as the input. The seismic responses of the bridge were obtained by the incremental dynamic analyses （IDA） method. The fragility curves of the bridge and its components were established by dint of the probabilistic seismic demand model （PSDM）. The seismic fragility of the cable-stayed bridges equipped with LRB and SMA-LRB was evaluated. Results show that the damage probability of the cable-stayed bridge is higher than that of each component. The isolation bearings are the most vulnerable component in the moderate, severe and collapse damage state under near-fault ground motions. The towers with a low damage probability present the slight damage. The bridge system equipped with SMA-LRB undergoes damage with a smaller risk, compared with LRB. There is a low probability for the bridge tower, pier, and cable to occur the collapse damage under strong ground motions. The probabilities of the bridge equipped with LRB and SMA-LRB are 0.07 and 0. 009, respectively, in the collapse damage state under severe ground motions. It means that such bridge structures show good seismic performance.

关 键 词：桥梁工程 SMA智能隔震支座 易损性分析 大跨斜拉桥 近断层地震动 铅芯橡胶支座 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]