Numerical simulation of FRP shear-strengthened reinforced concrete girders

The structural response of reinforced concrete (RC) girders strengthened with fiber reinforced polymer (FRP) composites in shear is investigated in this study, using a rationally-developed three-dimensional finite element model that was calibrated through comparison with test results. Analysis of reinforced concrete structures dominated by shear requires careful consideration in selecting the appropriate elements and material models. This task is more prominent in RC girders strengthened with FRP composites due to the difficulties of characterizing the corresponding properties and failure modes. Thus, the novel attributes of the proposed model is in the description of the three-dimensional constitutive material laws for each component. In the proposed model, the softening behavior of concrete under a triaxial state of stress was accounted for. The effect of the out-of-plane stress behavior of the FRP-concrete interface was carefully evaluated, which currently cannot be measured during experiments. In addition, the use of mechanical anchors to improve the bond behavior was properly simulated. Furthermore, the damage mechanism and progression of failure were carefully monitored. The model was shown to provide a good level of correlation with experimental data, and could therefore be used to conduct extensive parameter studies.