Estimation of Vehicular Collision Force on Bridge Piers in the Presence of Sub-Standard Intervening Concrete Barriers

Critical infrastructures such as bridges should be resilient to extreme loading events. Among the potential hazardous events, vehicle collisions are becoming increasingly common. Modern American Association for State Highway Transportation Officials (AASHTO) bridge design specifications consider a limit state to account for vehicular Collision Force (VCF) and require addressing it when bridge piers are within the clear zone defined by AASHTO’s Roadside Design Guide. AASHTO specifies two methods to address this limit state: either by providing an intervening structure that is capable of absorbing the VCF and/or redirecting the colliding vehicle, or designing the piers to resist a lateral load equivalent to 2,670 kN (600 kips). Many old bridges that were designed before recognizing the VCF as a limit state fail to meet the modern specifications because either the piers were designed to resist a lower lateral load than the specified limit or the installed intervening concrete barrier is not a standard one that qualifies to solely protect the piers against VCF. This paper introduces a new approach to address the requirements of the modern standards. The approach is based on blended contribution between the available sub-standard barrier and the under-designed bridge pier. The proposed approach is based on a matrix of dynamic simulations using LS-DYNA and considering different crash scenarios. The results showed that in the presence of the sub-standard barrier, the estimated VCF can be at least reduced by about 25%, leaving 75% to be resisted by the existing pier.