Fragility analysis of the box-girder coastal bridge with different connections subjected to extreme random waves

Abstract

In the ocean environment, the coastal bridge is vulnerable to extreme waves caused by hurricane disasters, and the bridge superstructure is easily damaged during these events. Although there are a lot of studies on the vulnerability of coastal bridges subjected to extreme hurricane-induced waves, the literature still lacks a fragility model to study the fragility probability of the coastal bridge with a box-girder superstructure and determine the effect of the connection types on the fragility probability. This study presents a fragility framework to assess the failure probability of the box-girder superstructure experiencing the unseating or shifting failure with different connection types under extreme random wave actions. A developed method for calculating the random wave forces on the box-girder superstructure based on the potential flow theory is adopted to the probabilistic demand analysis, and the nonlinear dynamic analyses are conducted to calculate the structural responses. A comprehensive analysis of the influence of different connections and component parameters on the fragility curves of the coastal bridge with a box-girder superstructure is conducted using the proposed fragility framework. The results show that the failure probability of the coastal bridge with a box-girder superstructure can be reduced by increasing the number of bolted connections in the mitigation designs under extreme random wave risks.