Effects of Post-to-Embankment Distance on Containment Capacity of a H1 Safety Barrier

The containment capacity of a road safety barrier is usually assessed by full-scale crash tests on level terrain. Unfortunately, this condition almost never corresponds to real situations because of the presence of steep embankments foreslope adjacent to the backside of guardrail posts. The presence of the foreslope adjacent to the posts both reduces the lateral load capacity of these - the “resistance” effect - and leads to the wheels penetration in it - the “geometrical” effect-. This paper describes a research aimed at evaluating the aforementioned effects of a 3:2 foreslope near to the backside of the posts of a real H1 (according to the EN 1317 standard) safety barrier which was successfully tested at level. The research has been carried out through a combined experimental and numerical approach. The crash test FE simulations have been performed with the Ls-Dyna 970 code version MPP. The results obtained put in evidence that the containment capacity of the considered barrier is affected only by the “resistance” effect, that is the reduction in the lateral load capacity of posts. The failure in the containment happens when the lateral load capacity of posts halves. This occurs for every distance from the top of the slope to the backside of the post.