既有铁路钢桥的系统疲劳可靠度评估

Systems fatigue reliability assessment of existing steel railway bridges

既有铁路钢桥承受着日益繁重的交通荷载,其使用安全倍受关注。针对铆接结构多破坏模式和铆接多成份、多构件的疲劳失效特点,在建立铆接构件双角钢概率疲劳破坏模型的基础上,提出铆接钢桥系统疲劳可靠性分析模型。基于M on te C arlo算法,建立计算系统疲劳失效概率的基本流程,编制用于铆接钢桥系统疲劳可靠性分析的大型程序RBSPFF。将铆接钢桥系统疲劳可靠性分析模型应用于京九线赣江桥的疲劳可靠度评估。由赣江桥概率剩余寿命评估结果可知,若按保证桥梁的正常使用功能,上、下游铁路桥面系的超声波探测间隔分别为1.7 a和0.6 a;若按保证主桁结构系统承载安全,则探测间隔为3.7 a。

Existing steel railway bridges are often required to carry an increasing volume of traffic, usually consisting of trucks heavier than those considered in the original design. Therefore, the service safety of such bridges is a topic of considerable importance. A double-angle probabilistic fracture failure model for riveted bridge members was developed based on an analysis of the fatigue failure mechanism of riveted steel bridges. The model is the basis for a systems fatigue reliability model for riveted steel bridges using the Monte-Carlo method in a large systems fatigue reliability analysis program to predict the system fatigue failure probability of existing riveted bridges. The systems fatigue reliability model was used to predicte the systems fatigue reliability of the Ganjiang Railway Bridge of the Jingiiu Railway in China. The probabilistic remaining fatigue life assessment was used to set the inspection intervals for the upriver railway deck systems for assuring normal service function at 1.7 years, with downriver inspection intervals of 0.6 year. The inspection intervals for assuring the load-carrying capacity of the main truss systems is 3.7 years.