STRUCTURAL DESIGN OF ROADS WITH STEEL REINFORCING NETTINGS

It is well-known that classically used multi-layer design models are unable to describe the local stress concentrations encountered around cracks or discontinuities in roads. Earlier finite element simulations of cracked road structures in which interlayer systems are described as continuous homogeneous layers are also found not to be satisfactory to describe the real reinforcement effects of grids and steel reinforcing nettings. This paper describes the results of a structural design model which is based on a three-dimensional finite element analysis of a road structure containing a discontinuity or a crack and in which an exact modeling of the Bitufor steel reinforcing netting is introduced, with its real geometry and mechanical characteristics. The aim of this study was to compare the lifetime for crack initiation with the use of Bitufor steel reinforcing nettings to that of a system without interface system and to determine the gain in asphalt layer thickness with the use of these systems. Only the crack initiation phase was taken into account so far. Two types of loading were considered: thermal movements and traffic. The model has been applied for the simulation of asphalt overlays with steel reinforcing nettings on transversal cracks/joints in rigid pavements, in semi-rigid pavements and in flexible pavements and on longitudinal cracks in cement concrete structures. In the case of traffic loading, both the effect on the vertical differential displacements at slabs "slab rocking", as well as the effect on the bearing capacity, were studied. Several overlay thicknesses were considered. The efficiency of Bitufor could be demonstrated for these different cases and design charts were developed, which can then be used for practical applications. For the covering abstract see ITRD E109276.