Numerical finite element study of strengthening of damaged reinforced concrete members with carbon and glass FRP wraps

Concrete spalling is considered as one of the most common weaknesses phenomena in concrete members. In this article, reinforced concrete (RC) column and beam members are subject to a variety of loads under damaged and strengthened conditions using carbon and glass fiber reinforced polymer (FRP) wraps. The main parameters in this study include the number of the FRP layers, the materials of the strengthening FRP layers, and the loading types. The imposed loads include pure bending moment, shear, and pure torsional moment, to enable studying the structural elements' behaviors under such states. The numerical finite element (FE) model was verified using experimental results, and 10 different case numerical FE models were analyzed. The analysis results demonstrated that using an FRP layer increases the shearing and torsional capacities. Adding another FRP layer does not significantly affect the models' behavioral specifications. In both RC beam and column, this strengthening method did not affect the torsional capacity, while managed to prevent sudden capacity loss and enhance ductility.