Vehicle Impact Tests on Frangible and Yielding Post Designs of Bridge Parapets,

摘要

Two designs of post and rail bridge parapets were developed which provide more positive containment of vehicles and better vehicle response after impact than conventional parapets. In one design the posts fracture at their bases at a predetermined transverse loading thereby minimising the rolling motion of a large vehicle towards the parapet. In the tests both a car striking at 116km/h and 20deg and a coach striking at 82km/h and 20deg exhibited the same steer back response towards the parapet after impact. The car weighed 1488kg and the coach 5194kg. Maximum wheel penetration of the coach was 0.79 m. In the second design the posts yield,bending at their bases under impact from a large vehicle but are not damaged by car impacts. In the tests a coach striking at 86km/h and 20deg was redirected at 13deg to the parapet with a maximum wheel penetration of 0.36 m. A car striking at 109km/h and 20deg was steered back to the parapet after impact. (Author)