基于首超准则的随机车流下悬索桥加劲梁动力可靠度评估  

Dynamic reliability assessment for girders of suspension bridges under random traffic flow based on the first-passage criterion

作　　者：肖新辉[1,2,3] 鲁乃唯[1] 刘扬[1] 郭鑫[3] XIAO Xinhui LU Naiwei LIU Yang GUO Xin(School of Civil Engineering and Architecture, Changsha University of Science and Technology, Changsha 410114, China Hunan Province Engineering Laboratory of Bridge Structure, Changsha University of Science and Technology, Changsha 410076, China Transportation Research Institute, Changsha University of Science and Technology, Changsha 410114, China)

机构地区：[1]长沙理工大学土木与建筑学院,湖南长沙410114 [2]长沙理工大学桥梁结构安全控制湖南省工程实验室,湖南长沙410114 [3]长沙理工大学交通科学研究院,湖南长沙410114

出　　处：《中南大学学报（自然科学版）》2016年第10期3491-3497,共7页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展计划(973计划)项目(2015CB057700);国家自然科学基金资助项目(51378071);桥梁结构安全控制湖南省工程实验室(长沙理工大学)开放基金资助项目(14KD05)~~

摘　　要：为了研究考虑车辆运行状态的大跨度悬索桥加劲梁动位移概率特征及桥梁运营期的安全水平,基于实测车流数据和动力可靠度理论分析悬索桥加劲梁在运营期内车致响应的动力可靠度。建立考虑车辆占有率的桥梁动力可靠度数学模型,分析主跨为820 m的悬索桥在运营期内稀疏运行车辆和密集运行车辆作用下的加劲梁位移动力可靠度。研究结果表明:在随机车流作用下,悬索桥加劲梁在1/4跨节点的位移动力响应均方根最大,且加劲梁位移的界限跨越率随车辆样本数量的增大趋于稳定;在100 a内,实际运行状态下的动力可靠指标由5.92降至5.11,介于密集运行状态与稀疏运行状态之间;在不考虑桥梁抗力退化的情况下,随机车流作用下悬索桥加劲梁位移超限失效事件主要由密集运行车辆引起,但随着密集运行车辆的增大,可靠指标下降趋势减缓。In order to analyze the probabilistic characteristics of dynamic responses and safety level of stiffening girders for long-span suspension bridges considering the actual vehicle states, the vehicle involving vibration and the dynamic reliability indices were studied based on the measured vehicle data and dynamic reliability theory. The mathematic models of dynamic reliability were established considering the proportion of heavy vehicles. The dynamic reliability of a suspension bridge with 820 m mid-span under spare and heavy vehicles loads were discussed. The results show that the root-mean-square of displacement responses reaches the peak value in 1/4 span of the suspension girders under random traffic flow. The boundary cross rates of dynamic responses are stable with the increase of random vehicle sample number. In 100 years, the dynamic reliability index will drop to 5.11 from 5.92 under the actual operational state, which is caused by heavy and spare operation. Without considering resistance deterioration of the bridge, the failure events of over-ranging displacement are caused by the existence of heavy traffic flow. The dynamic reliability slows down with the increase of the heavy vehicles.

关 键 词：桥梁工程 悬索桥 动力可靠度 随机车流 响应均方根 

分 类 号：U448.25[建筑科学—桥梁与隧道工程]