Dynamic response of guardrail systems encased in pavement mow strips

Pavement mow strips are being used to combat vegetation growth around guardrail posts. However, the effect of pavement post encasement on the crashworthiness of strong post guardrail systems has not been investigated. In this paper, the authors examined the performance of these systems using experimental testing and numerical simulation. Mow strip dimensions, materials, and depths are considered in addition to the presence of leave-out sections around posts. Seventeen configurations of wood and steel guardrail posts embedded in various mow strip systems and confinement conditions were subjected to dynamic impact testing with a bogie vehicle. The dynamic impact tests were numerically simulated, and full-scale mow strip system models were assembled using the validated subcomponent models. Based on predictive numerical simulations, the authors selected a concrete mow strip with grout-filled leave-outs for full-scale crash testing. Crash tests of a steel post guardrail system and wood post guardrail system encased in the selected mow strip configuration were successful, and implementation recommendations are provided.