Abstract

Fatigue is among the most critical forms of deterioration damage that occurs to steel bridges. The performance of steel bridges, which may be seriously affected due to fatigue, should be assessed and predicted. However, the code-based reliability assessment only provides a clear criterion for single details. The whole bridge or a splitting system from the bridge may contain many details which brings system impact on the fatigue assessment. In this paper the system reliability of steel bridges is addressed with focus on the influence of spatial correlations between similar fatigue sensitive details. The study is conducted on a typical riveted railway bridge, from which a subsystem is selected and modelled as a weakest link system. It is assumed that all details in the system are equicorrelated. An efficient modeling approach has been developed to quantify the correlation and help estimate the system reliability analytically. A parametric study was performed to determine the system effects on the fatigue reliability assessment and identify the decisive variables.

摘要

疲劳是钢桥最严重的劣化损坏形式之一。钢桥的性能可能因疲劳而受到严重影响，应进行评估和预测。然而，基于代码的可靠性评估只为单个细节提供了明确的标准。整座桥梁或桥梁的一个分裂系统可能包含许多细节，这些细节会给疲劳评估带来系统影响。本文讨论了钢桥的系统可靠性，重点关注相似疲劳敏感细节之间空间相关性的影响。该研究是在一个典型的铆接铁路桥上进行的，从中选择一个子系统并将其建模为最薄弱的连接系统。假设系统中的所有细节都是等相关的。已经开发了一种有效的建模方法来量化相关性并帮助分析估计系统可靠性。进行了参数研究以确定系统对疲劳可靠性评估的影响并确定决定性变量。