Nonlinear failure analysis of bridge pier subjected to vessel impact combined with blast loads

The vulnerability of a reinforced concrete (RC) girder bridge pier is numerically assessed using high- and moderate-resolution finite element (FE) simulations in LS-DYNA under the combination of vessel collisions and blast loadings. The damage levels of the pier under combined loads are quantitatively assessed by proposing three different damage indices based on the residual axial load, shear, and flexural moment capacities of the pier column obtained through a series of multi-step loading procedures on the simplified FE-based model of the pier. In addition, the proposed simplified model of the pier is employed for sensitivity assessments of the damage indices of the pier to several loading-related parameters including the vessel type, the location of applied loads, the impact velocity, and the time lag between the initiations of loadings. From the FE simulations, it is found that the pier undergoes more severe localized failure when both impact and blast loads are applied at the same elevation on the pier column which is more likely to occur during barge collisions. Moreover, it is found that the pier experiences greater internal forces when the sequent blast loading is applied at the occurrence time of the peak impact force.