Computational modeling and dynamic response of highway bridge columns subjected to combined vehicle collision and air blast

Vehicle impacts into supporting bridge columns can cause significant damage and, when combined with an air blast, could result in, at best, an unsafe situation for the bridge or, at worst, complete collapse. Limited studies have been conducted that investigate the response of bridge substructure units subjected to a combined collision and blast loading. This paper summarized results from a numerical study examining the response of highway bridge columns subjected to a combined vehicle collision and air blast using LS-DYNA, the computational tool used for this research. Numerical models consisting of a circular reinforced concrete (RC) bridge column, its pile cap and pile foundation system, and a surrounding soil volume were developed and validated. Validated models were then subjected to simulated impacts from a Ford F800 Single-Unit Truck (SUT) and air blasts represented using a Multi-Material Arbitrary Lagrangian-Eulerian (MM-ALE) formulation with applied blast loads being taken from the fluid-structure interaction (FSI) algorithm in LS-DYNA. The validated computational modeling technique presented in this study provides a vital source for producing information in the combined collision and blast design field and determining the combined impact-blast behavior of bridge columns. A detailed investigation was performed to determine a critical impact and blast sequence for this research study. Furthermore, numerical simulations of SUT collision with RC column coupled with air blast were conducted considering variations of vehicle velocity, blast scaled distance, and column diameter. The demand and performance of RC bridge columns were examined with representative damage categories identified in this study to provide insights on column design to withstand the collision and blast combination.