Stress field model for strengthening of shear-flexure critical RC beams

A model for the design of shear-flexure critical reinforced concrete elements strengthened with fiber-reinforced polymer (FRP) sheets and plates is presented. The model is based on the stress field approach and the equilibrium method and accounts for the different failure modes of FRP, focusing on the debonding of the FRP from the concrete surface. The efficiency of the model in the strength assessment of beams reinforced with FRP by the prediction of the shear-flexure capacity is checked by corroborating the results of several experimental tests found in the literature. Moreover, the presented model's capacity to reproduce experimental behavior is compared with the formulations suggested by some codes. Finally, to demonstrate the model's flexibility in evaluating the resistance domain for reinforced concrete beams strengthened with FRP and to investigate the influence of the shear-bending moment interaction, resistance domains with different arrangements of FRP reinforcement are presented.