Bond failure of steel beams strengthened with FRP laminates – Part 2: Verification

The application of the new bond failure model developed in Part 1 to predict the bond failure load of fiber reinforced polymer (FRP) strengthened steel beam is presented in this paper. Full-scale experiments on FRP strengthened steel beams under four-point bending were first carried out. The effects of different strengthening parameters including laminate thickness, bond length and adhesive thickness on the bond strength were investigated experimentally. Finite element analyses (FEA) were then conducted on the FRP strengthened steel beams. By incorporating the proposed bond failure model into the FEA, the equivalent strain energy density in the bondline was calculated for bond strength prediction. The validity of the model is assessed by comparing the bond strengths obtained from numerical analyses against the experimental results. The advantages of this model are proven by comparing its results against those predicted by the maximum value based model. Finally, a parametric study was conducted to investigate the effects of the thickness of FRP laminate, the tensile modulus of FRP laminate, the thickness of epoxy adhesive and the bond length on bond strength.