Numerical Investigation of Progressive Collapse of a Multispan Continuous Bridge Subjected to Vessel Collision

Abstract

Multispan continuous bridges have been widely used in navigable waterways. However, their susceptibility to progressive collapse as a result of vessel collision is not yet fully understood. Experimental studies of bridge collapses induced by vessel collision are costly, time-consuming, and often not feasible. This paper presents a numerical study on the progressive collapse of a multispan continuous bridge subjected to vessel collision. A high-fidelity finite-element model of a 14-span continuous bridge, including its prestressed concrete (PC) superstructures and reinforced concrete (RC) pier columns/piles, and the colliding barge was developed to investigate the bridge failure mechanism. The validation was carried out for PC superstructures and RC structural members of the bridge piers by using available drop-weight impact tests of PC and RC beams. Furthermore, evaluation of available forensic investigation data, such as photographs and a survey of collapsed spans/piers, indicated that the progressive collapse was well predicted by the numerical analysis. Results show that the bridge pier directly impacted by a vessel will fail in the lateral direction of the bridge span, whereas nonimpacted piers will fail in the longitudinal direction of the bridge span. Results also show that the number of collapsed spans/piers depends on underwater terrain conditions and that the failure of the slender pier columns and piles results from plastic-hinge bending.