Heavy Truck Collision with Bridge Piers: Computational Simulation Study

The vast majority of research studies on vehicular collision with bridge piers have been carried out with single-unit trucks, which are typically classified as medium-duty vehicles weighing about 90 kN (20,000 lb). Yet, collision events that involve severe bridge damage are generally caused by heavy-duty trucks, generally tractor-semitrailers weighing 360 kN (80,000 lb). The handful of tests that were conducted to study heavy truck collisions used rigid piers, which means that the energy absorption potential of the piers, and their failure mechanisms, were neglected. In this study, validated, high-fidelity finite-element simulations of collisions between heavy-duty tractor-semitrailers and reinforced concrete bridge piers have been carried out to investigate the demands imposed upon, and the damage modes of, concrete piers. Trucks with three different weights and piers with six different configurations were used in the simulations. The approach speeds for the trucks ranged from 48 to 113 km/h. The simulation results showed that impact from the engine block usually delivered the highest peak force, which was closely associated with the impact velocity of the vehicle. Once the pier’s resistance has been compromised by this event, the subsequent trailer impact, which has a lower force demand but longer duration, causes further significant damage or even destroys the pier. The current provisions regarding vehicular impact demands in AASHTO requirements are critiqued based on the results of parametric simulations using the heavy truck model.