致损荷载信息缺失在役钢桥的疲劳损伤状态重构方法

大多数在役钢桥的致损荷载信息缺失,根据不完备监测检测信息重构结构的疲劳损伤状态,是确保结构服役安全的基本前提。基于部分疲劳开裂信息反向重建等效致损荷载信息,提出了致损荷载信息缺失条件下的在役钢桥疲劳损伤状态重构方法。首先通过线性损伤累积理论和等效结构应力评估方法计算不同荷载工况下的疲劳敏感构造细节疲劳损伤累积;以钢桥服役期间疲劳损伤监测检测获得的疲劳裂纹检测结果为约束条件,将荷载工况的线性组合作为等效荷载历程,实现了在役钢桥结构的疲劳损伤状态重构;通过模型试验对所提出的疲劳损伤状态重构方法进行了验证。研究结果表明:基于疲劳裂纹损伤信息,在致损荷载信息缺失条件下重构得到的疲劳敏感构造细节损伤状态重构结果与试验结果吻合,证明了致损荷载信息缺失条件下实现疲劳损伤状态重构的可行性和所提出方法的有效性,为在役钢桥的实际疲劳损伤状态评估提供了新思路和新方法。

Reconstruction Method for the Fatigue Damage State of Steel Bridges in Service with Missing Fatigue Load Information

The fatigue load information of most steel bridges in service is missing and the realization of structural fatigue damage state reconstruction based on incomplete monitoring and detection information is a fundamental prerequisite for ensuring the safety of structures in service. In this study, based on partial fatigue crack information, equivalent damage load information was reconstructed and a reconstruction method for the fatigue damage state of steel bridges in service was developed under conditions with missing fatigue load information. First, the fatigue damage accumulation of fatigue-sensitive structural components under different load conditions was determined using linear damage accumulation and equivalent structural stress evaluation methods. Then, the fatigue crack detection on steel bridges in service using the monitoring system were used as constraints. Considering the linear combination of load cases as an equivalent load history, the fatigue damage state of steel bridges in service was reconstructed and verified through a model test. The results show that based on fatigue crack damage information, fatigue-sensitive structural components damage reconstruction results obtained under conditions with a missing fatigue load history were consistent with the test results, which proves the feasibility of the proposed method for achieving fatigue damage state reconstruction under conditions with missing load history information. This study provides a novel method for evaluating fatigue damage in steel bridges in service.