Demand Model for Concrete Barriers Subject to Tractor Tanker-Trailer Impact

Test-level-6 (TL-6) barriers are specified for situations that involve a high percentage of truck traffic or unfavorable site conditions, where truck rollover or penetration beyond the railing could result in severe traffic consequences. Previous studies of TL-6 barriers impacted by tractor tanker-trailers (the truck category that creates the highest impact demands) assumed that the barriers behave rigidly. The rigid barrier assumption is investigated in this paper through simulation studies in which validated nonlinear models of the truck and barrier are employed. Parametric simulations are carried out to evaluate the effects of truck velocities, weights, and barrier heights on the impact force demands. The demand model in the current design guideline is critiqued based on the simulation results and discrepancy was found between the predicted performance of the barrier by AASHTO-LRFD loading and the truck impact. A revised demand model is proposed based on the simulation results.