Basic Analytical Study of CFRP Grid-Sprayed Mortar Behavior in Shear Strengthening of a RC Beam

抄録

The shear failure of reinforced concrete (RC) beams is extremely dangerous as it can occur suddenly and it is difficult to predict. Therefore, strengthening methods to prevent this failure in a RC beam are especially important. Recent years, CFRP material is promising alternatives for rehabilitation of deteriorated concrete members. In this study, it is assumed that, shear resistance of a RC beam decreases because of corroded stirrups, thus it need to be strengthened by using carbon fiber-reinforced polymer (CFRP) grid and sprayed mortar. Subsequently, the part where potentially appears diagonal crack in this beam would be taken out to analyze. The work of CFRP grid inside the mortar layer is modelled as a frame put on an elastic-brittle springs foundation. Simultaneously, bond behavior between mortar layer and substrate concrete is also modelled as the same type springs. A system of CFRP frame and springs is analyzed to investigate about the failure process and the influence of the strengthening layer. Lastly, case studies are presented by FEM analysis to compare with results of some previous tests. There is an appropriate good agreement between FEM and experimental approaches. It is suggested that the damage zone starts at the bottom of the specimen and spreads to the top during loading. In addition, the effect of CFRP and sprayed mortar on the resistance capacity of the structure was also clarified.