Performance Evaluation of Highway Bridge Piers under Medium Truck Collision Combined with Air Blast

The extreme multihazardous event involving a truck collision and an air blast is a low-probability, high-consequence event for bridge piers. This study aimed to numerically investigate the performance and failure modes of multicolumn piers under a medium-sized truck collision combined with an air blast. Full-scale, finite-element models of multicolumn piers with three configurations were developed using LS-DYNA software with a soil domain restraining the foundations. The accuracy of modeling approaches was verified by comparing tested and simulated results. The collisions were simulated using a single-unit truck (SUT) at velocities ranging from 65 km/h to 120 km/h and combined with air blasts at different scaled distances. Analyses were completed to examine damage propagation and dynamic response during the extreme multihazards. The results showed that after the SUT collision compromised pier capacity, further deterioration occurred from the subsequent air blast, resulting in severe damage and even failure of the pier. In addition, parametric studies were conducted to assess the effects of several load and design parameters on pier performance and identify the controlling parameters. Representative failure modes of multicolumn piers under truck collisions combined with air blasts were assessed. The findings from this study provided a comprehensive understanding of multicolumn pier response to the extreme multihazards and developed recommendations for the practical design and analysis of the multicolumn pier.