Effects of mechanical quality of the concrete between steel and FRP in CFRP strengthening : theoretical analysis.

International audienceThere are many studies on the strengthening of works done with Fibre Reinforced Polymer (FRP). Most of these concern beams, techniques for bonding and effects of bonded fibre-reinforced composites in the strengthening of structural materials [1]. None of these studies considers the effect of the concrete, between the steel rods and the FRP, on the behaviour of the strengthened structure. This work aims to analyze the effects of mechanical quality of the concrete between steel and FRP. Therefore, a theoretical analysis is developed, simulating the bending behaviour of slabs reinforced by FRP strips. In this analysis, the concrete of the area between FRP strips and lower steel reinforcements is regarded as multi-layer non-linear concrete. The proposed model, based on commercially Finite Element Code Ansys [2], is used to analyse the effects of the layer of concrete covering the steel on the bending behaviour of FRP-strengthened slabs