Study On Shear Behaviors Of Reinforced Concrete Beam Strengthened With Laterally Bonded CFRP Sheets

Recently, an advanced composite material named carbon fiber reinforced polymer(CFRP)has emerged as an alternative to traditional strengthening materials. The existing reinforced concrete structures can be strengthened by externally bonding CFRP to improve their mechanical behaviors. Many advantages of CFRP make it getting good effects in shear strengthening of RC beams, and make it widely used in strengthening field. But the researches about shear behaviors of RC beam strengthened with CFRP sheets are not sufficient, partly because of the complicacy of such shear failure.Based on the experiment of supported beams strengthened in shear with laterally bonded CFRP sheets, the failure process is observed; meanwhile the shear capacity and the failure modes are analyzed. In this paper, the writer summarizes all failure modes of beams strengthened in shear with externally bonded CFRP sheets, and proposes revising shear capacity design method of"Technical specification for strengthening concrete structures with carbon fiber reinforced polymer laminate"in China. Calculation error, applicability and reliability of revised shear capacity design method are examined last.Some conclusions of study on Shear Behaviors of Reinforced Concrete Beam strengthened with laterally bonded CFRP sheets are concluded as following:(1)The results indicate that CFRP can evidently increase the shear-bearing capacity of these specimens. Pre-load has no influence on effect of strengthening with CFRP sheets. Strengthening with externally bonded CFRP sheets and pressure grouting, seriously damaged shear-bearing capacity of RC beam can regain.(2)Shear-bearing action of CFRP sheets is similar to stirrup, but there is distinction between them(.3)Failure mode of strengthened specimens is the most important influence factor to shear strengthening effect CFRP sheets. There are mainly eight types of failure mode.(4)Shear capacity design method should establish based on the experiment results and the working mechanism of beams strengthened in shear with externally bonded CFRP sheets.(5)Compared with the experimental values, the results calculated by the revised shear capacity design formula give good agreement.