Trrl Lr 884

The containment capability of post and rail parapets depends, inter alia, on the post spacing. To provide quantitative data on this behaviour, the increased containment obtained by halving the post spacing has been measured in dynamic tests using 5 tonne coaches impacting the parapet at 30 degrees. It was found that an aluminium PI aprapet with 3m post spacing did not contain a coach which struck it with the same severity as the PI car impact. When the post spacing of the aluminium parapet was halved to 1.5m it withstood a 2s x P1 impact from a coach, equivalent to the impact of a 20 tonne vehicle at 58 km/h and 15 degrees. Halving the post spacing of a steel P1 parapet from 3.66m to 1.83m increased its containment capability from from 1.6 x P1 impact to 3.2 x P1 impact, a high level of containment equivalent to the impact of a 20 tonne vehicle at 71 km/h and 15 degrees