Experimental investigation on flexural behaviors of cyclic overloading PRC beams strengthened with prestressed CFRP fabric

In this study, the artificially damaged PRC beams strengthened with prestressed CFRP fabric were subjected to a four-point bending test to study the influence of the overloading amplitudes, the number of cyclic overloading, and the cyclic overloading after strengthening on mechanical properties of the beam. A prediction method of the shear stress between the beam and the FRP was given through theoretical analysis. The test results showed that the failure modes of the test beams were that the concrete crushed after the steel strands yielded, while the CFRP fabric separated before the concrete was crushed. Prestressed CFRP fabric external bonding had no obvious effect on improving the ultimate bearing capacity of the PRC beams while had a positive effect on improving the yield load of the beams, which was increased by 25.00%-31.90%. As the overloading amplitude increased, the stiffness and the ductility of the test beam decreased, but the yield load of the beam increased. The number of cyclic overloading had little effect on the stiffness, ductility, and yield load of the test beam. The stiffness, the yield load, and the ductility of the PRC beam were improved by cyclic overloading after the beam was strengthened with prestressed CFRP fabric. The debonding performance of CFRP fabric was not related to the overloading degree of the test beam, while was related to the performance of the adhesive and the bonding area.