An Experimental Study On The Flexural Performance Of Reinforced Concrete Beams Of Initial Load Strengthened With CFRP Sheets

The concrete structure are found be damaged and in need of strengthening or rehabilitation for all kinds of reasons. Strengthening RC member by bonding CFRP sheets externally is an important technique. Eighteen beams strengthened with epoxy-bonded carbon fiber reinforced plastic (CFRP) sheets were experimentally investigated. The flexural performance of the beams strengthened with pre-stressed CFRP sheets was studied. On the basis of experiments, the methods for calculating the flexural capacity of the repaired beams by pre-stressed CFRP were studied.1,The repaired beams with different reinforcement ratio, amount of CFRP, initial load were tested and some beams strengthened with pre-stressed CFRP by the installation made by ourselves. By measuring the diagnostic strength, deflection, width of cracks and stain of the concrete, reinforced bars, CFRP sheets of the repaired beams, observing the failure modes, the flexural performance of the repair beams was studied.2,The failure mechanism was analyzed and some parameters including amount of the CFRP sheets, reinforced ratio, and method of anchor, pre-stress and initial load were considered and the main rules were summarized. The rules of the crack load, yield load and ultimate load of the repaired beams change with the parameters above were detailed studied.3,The rules of the deflection and the crack of the repaired beams were studied and the effect of the parameters on the deflection and width of crack, space between crack were analyzed.4,Based on experimental research and flexural capacity calculation theory, a method for calculating the yield capacity and the ultimate capacity of member strengthened with CFRP sheets was proposed. The effect of pre-stressing force and initial load were considered when the formulas were put forward.Finally, this paper summarizes the ideas and raises some problems need to be further researched.