Modelling of Reinforced Concrete Flexural Members Strengthened with Near-Surface Mounted FRP Reinforcement

Synopsis: This paper presents an analytical investigation conducted to study the flexural behavior of reinforced concrete beams strengthened with various Near-Surface Mounted (NSM) Fiber-Reinforced Polymers (FRP) reinforcements. The materials used in this investigation included carbon-fiber-reinforced-polymer (CFRP) rebars and strips, and glass fiber-reinforced-polymer (GFRP) rebars and strips. The analysis included the effects of strengthening on the serviceability and ultimate limit states as well the effect of tension stiffening. The effectiveness of NSM FRP rebars and strips was examined and compared to externally bonded (EB) FRP strips and sheets using the same material type and axial stiffness. Results from the analytical models were compared with those obtained from experimental studies. The analytical results agree very well with those obtained from the experimental results. It was found that the analytical model could effectively simulate the behaviour of the reinforced concrete beams strengthened with various NSM FRP and EB FRP reinforcements. Using the same axial stiffness of FRP to strengthen reinforced concrete beams, the beams strengthened with NSM FRP reinforcement achieved higher ultimate load than beams strengthened with EB FRP reinforcement. This result is due to the high utilization of the tensile strength of the FRP reinforcement.