Residual Axial Capacity Estimates for Bridge Columns Subjected to Combined Vehicle Collision and Air Blast

Abstract

Columns are the primary load-carrying components in the bridge, and column failure could initiate the collapse of the entire bridge. Estimates of residual axial capacity for round, bridge pier columns under combined vehicle collision and air blast were studied using high-fidelity, fully coupled finite-element computational models. The models included single reinforced concrete (RC) columns, pile foundation systems, and surrounding soil and air volumes. Modeling techniques were validated with existing full-scale, impact and blast experimental results. Validated column models were subsequently impacted by a Ford F800 Single-Unit Truck (SUT) and subjected to an air blast created by considering fluid–structure interaction (FSI) using a multimaterial arbitrary Lagrangian–Eulerian (MM-ALE) formulation. A parametric study was completed that examined effects of load parameters, column diameter and height, axial load ratio, longitudinal reinforcement ratio, and shear reinforcement spacing on column residual axial capacity to establish critical parameters influencing performance. An empirical equation estimating residual axial capacity was developed using multivariate regression analysis involving the critical parameters. Based on the proposed equation, the column residual axial capacity could be estimated to predict its resistance against failure and assess collapse risk for the bridge when subjected to collision and blast combination.