Energy dissipated by concrete barriers in vehicle impact scenarios by combined numerical and analytical approaches

Abstract

The American Association of State Highway Transportation Officials (AASHTO) LRFD Bridge Design Specifications requires that bridge piers be capable of withstanding a lateral 600 kip static force. Older, bridge piers throughout Kansas, specifically those constructed before the requirement for the 600 kip force was established, often have insufficient load resistance. Any changes to a bridge require the piers to meet modern requirements in the AASHTO code so pavement replacement can require pier retrofits. Compared to a complete structural overhaul of the existing piers, protective concrete barriers may provide a cost, and time, effective approach to help piers meet current code requirements. Currently, no standards are available to reduce the magnitude of the lateral force requirement through the use of barriers. By combining yield line analysis and finite element analysis, this thesis establishes a baseline for the energy absorbed by a concrete barrier. A combination of various angles of impact, initial vehicle velocities and barrier boundary conditions are considered to build an envelope of scenarios. The results of this research show the vehicle’s kinetic energy and velocity may reduce by up to 57% and 35%, respectively, for a large truck.