Fatigue Reliability Assessment for Orthotropic Steel Deck Details Using Copulas: Application to Nan-Xi Yangtze River Bridge

Abstract

In this study, the correlation between the fatigue equivalent stress and the stress cycle was considered using the copula function in the fatigue reliability assessment. In most earlier studies, the variables for the fatigue reliability function were assumed to be independent. However, based on the structural health monitoring (SHM) data in this study, they show that there are correlation properties in part of the variables. Hence, using the traditional method, the calculated fatigue reliability index is not accurate. For this reason, a new calculation method that considers the correlation between the variables was developed. The Gaussian copula was used to solve this problem because of its powerful connect function and concise expression. The study shows that there is a correlation between the fatigue stress and the fatigue stress cycle in the Nan-Xi Yangtze River Bridge. The values of the fatigue reliability index that consider the correlation between the variables are smaller than those calculated by the traditional method.