Study On Flexural Strength Of RC Beam Reinforced With Near Surface Mounted CFRP Strips

Because of aging ,change in use and accidental damages of the structures, the studies on strengthening and retrofitting structures were more and more concerned by countries of the world. In virtue of the advantages of fiber-reinforced plastic/polymer (FRP), light-weight, high-strength, nice environmental and fatigue resistibility, it has been broadly used in structural strengthening. Recently, a new technology of strengthening structures with near surface mounted FRP has been proposed. The beams are strengthened using FRP inserted into a groove cut at the tension surface of the beam. It's a promising technology for increasing flexural and shear strength of a deficient reinforced concrete (RC) member effectively.Based on the results of four-point bending tests of 14 RC test beams with different areas of CFRP strips, areas of steel tension bar and different lengths of CFRP, this thesis studies the flexural performance of the RC beams with near surface mounted CFRP strips. The test process and phenomenon, the failure modes, the flexural strength and the influence of the above three parameters are studied in detail. The failure machnism, the maximal CFRP strain of inter mediate debonding and a simple formula calculating the plate end debonding are proposed, leading to the flexural strength formular for each filure modes. After comparing with the results of experiment and theory, the validity of these formulas for practical engineering applications is made.