Dynamic Actions on Bridge Slabs due to Heavy Vehicle Impact on Roadside Barriers

Abstract

The use of roadside safety barriers in Italy has changed in recent years: the number of installed devices has increased, and so have their stiffness and resistance. These changes were necessary because early barrier design was inadequate to contain and redirect heavy vehicles. The change in barrier design led to an increase in stiffness and resistance; consequently, the action transferred to the structure by the device increased. The need for resistance on the bridge slabs can be too high because the peculiar action of the roadside barriers was not adequately taken into account in the oldest bridge design codes. In addition, characterizing the actions transferred to the bridge slab is difficult because of the dynamic nature of vehicle impacts on roadside barriers. Given the impossibility of performing a full-scale laboratory test for every bridge deck, the use of computational mechanics applied to dynamic impact/interaction problems is one of the best ways to establish these actions in the project phase. Research was conducted into the use of a three-dimensional finite element model of the bridge slab-barrier-vehicle system to perform a numerical simulation of the impact, according to the procedure used for the roadside barrier homologation crash test, described in the European Standard EN 1317.

Improvement of Portable Concrete Barrier Design Using Computational Mechanics

“…For this and for other reasons, researchers of the Autostrade of the University of Rome La Sapienza began the development of a new FE model of a heavy vehicle (10, 11) (Figure 6). It is to be used in sim- ulations of crash tests with roadside safety devices (12)(13)(14), vehicle-to-vehicle impacts (15) and other road devices ( 16). This FE model has 24,311 elements (54% shell elements, 44% solid elements, 2% beam elements, eight dampers, and eight springs for the suspensions) and reproduces a four-axle vehicle (FIAT IVECO 180 NC) with a total mass of 30,000 kg (net mass 10,500 kg).…”