Redistribution of bending moment in continuous reinforced concrete beams strengthened with fiber-reinforced polymer

The main aim of the paper is the analysis of the moment redistribution capacity of continuous reinforced concrete beams strengthened with fiber-reinforced polymer (FRP) sheets. The interest of the topic lies in the well-known aspect related to the reduction of ductility, very often exhibited by FRP-strengthened structures. This lack of ductility can strongly affect or even prevent the redistribution of bending moments in continuous FRP-strengthened structures. To study this problem, an analytical model, developed by the authors, is adopted, which is able to simulate the nonlinear behavior of reinforced concrete beams with external reinforcement. The obtained results are validated with numerical outcomes and experimental data available in the literature. A wide parametric survey allows the authors to point out the influence of the amount of FRP and its arrangement on the bending moment redistribution capacity of different continuous beams. Finally, a simplified formulation for the evaluation of the redistribution ratio is proposed and its effectiveness is highlighted