Bridges are fitted with safety barriers for ensuring the traffic safety and the safety of persons who live, work or stay in direct environment of a bridge. The safety barriers usually installed on German bridges are able to protect lorries up to a weight of 13 t from breaking through the barrier and falling down the bridge. But in case of accidents with heavier vehicles conventional safety barriers reach the edge of their capability. These accidents may cause an undue hazard to a third party under the bridge. Therefore a research project was initiated in order to obtain safety barriers which are able to protect even heavy lorries from breaking through and falling down, without causing unacceptable bridge damages. Within the research project crash tests on different safety barriers in accordance with EN 1317 were performed - for the first time inclusive measuring the forces acting on the bridge construction. The measurements show the dimension of actions and forces caused by a vehicle impact on the bridge. As a main result it can be shown for the first time that safety barriers on bridges are able to avoid the fall of a heavy lorry from the bridge without causing unacceptable damages to the bridge construction. (Author/publisher)
Abstract