Reliability analysis of girder bridge piers subjected to barge collisions

This paper aims to probabilistically assess the multiple failure modes of the piers of St. George Island Bridge subjected to barge collisions using the correlation analyses of failure limit states at various section zones. Structural capacities and demands for internal shear forces and flexural moments are calculated using the finite element modelling software, LS-DYNA, and the reliability assessments are performed using Monte Carlo simulations against flexural and shear failures. From the results of reliability analysis, the base and impact zones for the isolated cases, and the top zone of impacted piers in the multiple-pier systems are recognized as the critical zones for localized failures of the piers. In addition, from the statistical correlation analysis, it is found that a shear failure mode is predominant on the relatively stiffer pier, a flexural failure mode on the more flexible pier in the isolated cases, and a combined shear-flexural failure mode on the response of the piers in multiple-pier systems. Moreover, from a series of sensitivity analyses of reliability indices to both shear and flexural failures by varying impact loading parameters, it is found that the shear failure is more sensitive to the impact variables rather than flexural failure.