大跨悬索桥箱形钢桁架梁的综合疲劳评定方法研究

Preliminary Investigation of Synthetic Fatigue Evaluation Method for Box-shaped Steel Trussed Girder of Long-span Suspension Bridge

根据大跨桥梁钢箱梁各类构件的受力特点建立了确定钢箱梁关键疲劳构件的评价模型,提出了基于结构有限元分析、应变监测信息、构件分级系统和桥梁结构人工检测等多方面信息综合评定关键疲劳构件的方法。以某大跨悬索桥钢箱梁结构为例,结合结构有限元数值计算和结构健康监测系统确定的关键钢箱梁截面,针对关键截面上的主要构件分布,利用应变传感器输出信息、结构有限元分析得到的应力分布信息、人工检测信息和桥梁主要构件的危险等级和易损等级信息,结合层次分析法和模糊综合评判理论确定了影响钢桥构件疲劳评定的各因素的权重,用综合隶属度评分法进行关键疲劳构件的等级评定。

An evaluation model of ascertaining critical fatigue members was established based on mechanical character of members of box girder of long span bridge, and a method to assess critical fatigue members was provided based on extensive information including structural finite element analysis, strain monitoring results, member classification system and close manual inspect reports. As an example of steel box girder of long-span suspension bridge, critical steel box girder sections were determined according to numerical computation of finite element and structural health monitoring system. Considering primary member distribution, fuzzy synthetic evaluation and analytic hierarchy process were used to obtain weights of all factors impacting on fatigue evaluation of bridge components and synthetic membership score was considered as classification criterion based on output information of strain sensors, stress distribution information of finite element model, general close visual inspection report and the criticality and vulnerability ratings of each member.