A three-dimensional analysis of CFRP–concrete bond behaviour

In order to characterise the bond between FRP and concrete, several studies have been developed using two-dimensional tools. A considerable dispersion of the parameter values which characterise the bond behaviour has been found in the literature. The main purpose of this study is to investigate whether the non-uniform stress distribution across the width of the FRP–concrete interface can contribute to the dispersion of the shear strength found in the literature. For this purpose, a 3D numerical analysis is performed using the finite element method. Pure shear models are defined to describe the bond behaviour between concrete and externally glued sheets of carbon FRP. A comparison between the results obtained with the 3D numerical analysis and a 2D numerical analysis is made. These results are also compared to experimental data obtained from the literature. From this study, an analytical approach is proposed to estimate the ultimate load value, in which an innovative concept of effective bond width is introduced.