The Experimental Study On The Flexural Behavior Of Beams Strengthened With Prestressed Carbon Fiber Reinforced Polymer Sheets

The technique of strengthening existing structures in flexure with FRP laminates is widely applied in engineering, but there are still some limitations. For instance, the amelioration of member's performances in serviceability state is limited, the high-strength quality of FRP material is employed inadequately, which causes great wastes. The disadvantages of reinforcing in flexural resistance with FRP laminates can be compensated by prestressing FRP laminates, the service performance and reinforcing efficiency can be improved, the applicable field can be extended as well.At present, the researches into the theory and technique of flexural reinforcing with prestressed FRP laminates both at home and abroad are still at the preliminary stage. So neither mature theories for analysis and design nor practical on-site construction technique and apparatus are available. In addition, there are no common recognitions on some critical issues of the technique. The existence of these issues has restricted the application and generalization of this emerging reinforcing technique.In this paper, systemic theoretic analysis and experimental study on strengthening concrete beams in flexure with prestressed CFRP laminates have been performed. First, this paper presents systemic summarization and review for the research achievements on strengthening existing structures with prestressed FRP laminates, which was both at home and abroad in the past decade; second, four rectangular section RC beams whose dimension is 300x500x6500mm have been strengthened under different conditions then subjected to static load; Afterwards, the theoretical failure modes of beams strengthened in flexure with prestressed CFRP laminates have been presented, based on which, in view of different construction techniques, the methods for bending capacity analysis and design in every loading phase for beams strengthened with prestressed CFRP laminates have been proposed; Besides, the influence factors of effects on flexural strengthing have been analyzed and the parameter study has also been...