摘要
考虑到火车、汽车与风荷载的长期作用以及多荷载的随机性,评估大跨多荷载桥梁的疲劳可靠度是一项富有挑战的任务。该研究基于健康监测系统提出了大跨多荷载悬索桥的疲劳可靠度分析框架,并应用到香港青马大桥。首先,定义了疲劳可靠度的极限状态函数,基于监测数据建立火车、汽车与风荷载的概率模型。基于概率模型和蒙特卡洛模拟方法,利用疲劳关键位置上多荷载的每日随机应力响应,估计每日应力幅m次方之和的概率分布。假设交通保持不变,可确定在给定时段内应力幅m次方之和的概率分布。最终得到桥梁不同疲劳关键位置不同时间点的疲劳失效概率。结果表明,在目前的交通状态下,青马大桥的疲劳健康状况可保持良好。
The estimation of fatigue reliability of multi-loading suspension bridges represents a challenging task in the consideration of randomness in multiple types of loading. This study presents a framework for fatigue reliability analysis of multi-loading long-span suspension bridges equipped with structural health monitoring systems(SHMS), and the Tsing Ma suspension bridge in Hong Kong is taken as a case study. A limit state function is first defined for fatigue reliability analysis. Probabilistic models of railway, highway, and wind loading are established based on the measurement data acquired from the SHMS. The daily stochastic stress responses induced by the multiple types of loading are simulated at the fatigue-critical locations of the bridge deck by using the finite element method and the Monte Carlo simulation(MCS) together with the loading probabilistic models established. The probability distribution of the daily sum of m-power stress ranges is estimated based on the daily stochastic stress responses. Finally, the fatigue failure probabilities of the bridge at the fatigue-critical locations are calculated for different time periods. The results demonstrate that the health condition of the Tsing Ma Bridge at the end of its design life will be satisfactory under current traffic conditions without growth.
出处
《工程力学》
EI
CSCD
北大核心
2014年第7期99-105,共7页
Engineering Mechanics
基金
国家自然科学基金项目(NSFC-51108395)
中央高校基本科研基金项目(2012121032)
江苏省工程力学分析重点实验室开放课题基金
关键词
疲劳可靠度
多荷载桥梁
健康监测系统
可靠度评估
概率模型
fatigue reliability
multiload bridge
structural health monitoring system
reliability assessment
probabilistic model
