Theory Research On RC Beams Strengthened With NSM Prestressed CFRP Bars

Fiber reinforced plastics have been widely used in the field of the Civil Engineering.The current hot spot is that how to make full use of fiber reinforced plastics more effectively. This paper selected the initial prestress,the amount of reinforcement and the section size as the study parameters and studied the flexural performance of reinforced concrete beam strengthened by NSM-prestressing CFRP bars.The aims of this paper is to provide a basis for the actual engineering design.The major study works and results are as follows:(1)This paper summarized the development of FRP materials and analysed the current status and characteristics of the NSM-prestressing CFRP bars based on researching a large number of related literature at home and abroad,then pointed out the problems existing in the current reinforcement technology.(2)Basing on the test of our research group,this paper analysed the the stress progress of reinforced concrete beam strengthened with NSM-prestressing CFRP bars,summarized the calculation formulas of eliminating pressure stage, the cracking stage, yielding stage and failure stage,then summarized the calculation method of boundry amount of reinforcement.(3)The theoretical formula is calculated using the numerical calculation software, The calculation results and the experimental data are in good agreement.Combined with the bearing capacity of different reinforcement,this paper analysed the reinforcement effects by initial prestress,the amount of reinforcement and the section size,we concluded that with the section size changed,the optimal initial prestress value is not changed, but the optimal amount of reinforcement value is changed.