Performance of RC Members under Impact Loads

Truck collisions with bridge piers can result in significant damage to the support pier and potentially lead to partial of full failure of the structure. This paper aims to study the structural response of reinforced concrete bridge piers subjected to vehicle collisions. Multiple parameters are known to affect the structural response such as pier diameter, transverse reinforcement spacing, vehicle impact velocity, pile cap height, and multi-pier configuration. This paper focuses on the effects of having single or multiple piers in the bent. Detailed finite element models of the single pier and multi-pier bent configurations have been developed. The truck models offered by the National Crash Analysis Center and the National Transportation Research Center are used to conduct this research. The finite element models are validated by comparing the results to available experimental tests. The bridge pier collision models are validated by comparing peak impact forces observed as well as checking the energy content of the whole system. The study suggests that a multi-pier bent changes the trend of absorption of kinetic energy, failure modes, and distribution of impact forces, especially for the lower impacting speeds. Although a multi-pier configuration results in higher impact forces but due to higher stiffness results in low lateral displacements, and higher resistance to shear and moment stress. The dynamic characteristics of the multi-pier bent also affects how the shear and moment forces are propagated within the pier.