Evaluation of AASHTO Suggested Design Values for Reinforced Concrete Bridge Piers Under Vehicle Collisions

Vehicle collisions with bridge piers result in a complex set of actions and reactions between the structural system and the vehicle. The design of these piers is very important as it can have an adverse effect on both the economy and the health and safety of users. Current design provisions, although simple to apply, do not account for the many variables that influence demand and capacity. The goal of this study was to analyze the behavior of bridge piers under vehicle collisions with respect to vehicle mass, velocity, pier diameter, and transverse reinforcement. The commercial finite element software LS-DYNA was used to simulate and analyze the vehicle collisions. The finite element models were first validated with available experimental data, then verified with the available finite element models to ensure accuracy and reliability of the results. Conservation of energy was continuously checked throughout the analyses to assure stability within each impact simulation. The results of the study show that the pier diameter governed the overall failure mode of the pier while the transverse reinforcement governed the degree of local failure. The results could be useful to bridge design engineers in ensuring that performance measures are acceptable.