Study Of Strengthening Reinforced Concrete Beam Using Prestressed Carbon Fiber Sheet

In the paper, the study of strengthening reinforced concrete beam using prestressed carbon fiber reinforced plastic is introduced, which is the subsystem of repairing and strengthening reinforeed concrete structure using carbon fiber reinforced plastic, undertaken by College of Civil engineering of Hunan University.First, the paper introduces current strengthening technology, and summarizes the application and development of carbon fiber reinforced plastic, discuss the advantages and disadvantages of repairing and strengthening reinforced concrete structure using carbon fiber reinforced plastic. Furthermore, the paper put forward the thought that the disadvantages can be overcome by prestressing technology, and introduce the conception of prestressing, history and application. At the end of introduction, the paper presents the study content.Nine rectangular beams were tested and the beams strengthened using prestressed carbon fiber sheet were compare with beams strengthened using non-prestressed carbon fiber sheet, in order to evaluate the effect of externally bonded prestressed carbon fiber reinforced plastic reinforcement on the cracking load, ultimate load and flexural stiffness of reinforced concrete beams. In addition, the different yield strength and deformation resulting from the different initial stress were discussed.At the theoretical study part of the paper, the paper presents the analytical model based on a strain compatibility and equilibrium of internal forces, and analysis all specimens using the model in order to compare the analytical result with experimental result. And the paper find out that traditional analytical model can predict the behavior of the specimens accurately.The paper discuss the design issue of repairing and strengthening reinforced concrete structure using prestressed carbon fiber sheet, presents the equations of brittle ratio, cracking load, ultimate load and vertical deflection, and come to a conclusion that the equation of vertical deflection can get quite accurate result. Finally, the strengthening technology using prestressed carbon fiber reinforced plastic was presented.