Analysis of three-point bending tests for FRP-bonded notched concrete

Three-point bending tests on FRP-bonded concrete beams with notches have potential to become a conventional test method to evaluate the shear bond performance of FRP-to-concrete interfaces. This paper presents an analytical approach to predict the nonlinear response of FRP-bonded notched concret beams under three-point bending. The main objective is to simulate the mechanical interactions between the progressive shear debonding failure of the FRP-to-concrete interface and crack propagation in the concrete beams along the notch direction. The relationship between the tensile force in the FRP laminate and the relative slip of the FRP-to-concrete interface at the notched location is derived in an analytical manner, while the crack propagation in concrete is predicted using the weight function method. With a good understanding of the above interaction mechanism, it is possible to establish a quantitative relationship between the load (P)-crack mouth opending displacement (CMOD) curve of FRP-bonded notched concrete beams and the bond stress-slip relationship of the FRP-to-concrete interface. The derived analytical solutions are then validated through comparing with previous experimental results. Parametric analyses are also conducted to reveal how the bond parameters of FRP-to-concrete interface and the initial notch height in concrete influence the global P-CMOD curves of FRP-bonded notched concrete beams.