Containment of Heavy Vehicles by Bridge Parapets of Post and Rail Type

摘要

The containment capability of post and rail parapets depends, iter alia, on the post spacing. To provide quantitative data on this behavior, the increased containment obtained by having the post spacing has been measured in dynamic tests using 5 ton coaches impacting the parapet at 30 degrees. It was found that an aluminum P1 parapet with 3m post spacing did not contain a coach which struck it with the same severity as the P1 car impact. When the post spacing of the aluminum parapet was halved to 1.5m it withstood a 2 x P1 impact from a coach equivalent to the impact of a 20 ton vehicle at 58 km/h and 15 degrees. Having the post spacing of a steel P1 parapet from 3.66m to 1.83m increased its containment capability from 1.6 x P1 impact to 3.2 x P1 impact, a high level of containment equivalent to the impact of a 20 ton vehicle at 71 km/h and 15 degrees. (Copyright (c) Crown Copyright 1979.)