Study On The Flexural Behavior Of Steel Fiber Reinforced Concrete Beams With CFRP Bars

The durability of reinforced concrete structures are influenced by the corrosion of steel bars seriously.It is an effective approach to substitute for ordinary reinforcements with FRP bars,which are provided with high strength and better corrosion resistance.However,it will have large the deformation and crack width of FRP bar-reinforced concrete structures under bending.So,in order to meet the actual engineering needs,steel fiber reinforced concrete beams with FRP bars is formed by combining toughening and crack resistance of steel fiber with FRP bar-reinforced concrete.Therefore,it is very important to research on FRP steel fiber reinforced concrete structure.In this paper,the bending behavior of steel fiber reinforced concrete beams with CFRP bars under static load is studied by means of experimental research and theoretical analysis.(1)Through testing tensile property of CFRP bars and compressive property of concrete and obtaining the ultimate tensile strength,modulus of elasticity of CFRP bars and compressive strength of concrete.It provides data support for the later bending test analysis of steel fiber reinforced concrete beams with CFRP bars.(2)Through bending tests of three steel fiber reinforced concrete beams with CFRP bars and one CFRP bar-reinforced concrete beam,the crack load,crack development,crack width,ultimate load,deflection and failure mode of the members are observed and recorded.Based on the experimental phenomena and the test results,the plane section assumption is verified.The stress of CFRP bars,the deflection of beams and the variation of crack width with load are analyzed.(3)The test results of steel fiber reinforced concrete beams with CFRP bars with different reinforcement ratios are analyzed.The results show that the reinforcement ratio has little effect on the cracking load of the beams,and the ultimate bearing capacity increases with the reinforcement ratio.(4)The influence of steel fiber on the bearing capacity,crack width and deflection of CFRP bar-reinforced concrete beams and steel fiber reinforced concrete beams with CFRP bars is analyzed.The results show that the addition of steel fiber increases the ultimate bearing capacity of beams,reduces the deflection of CFRP bar-reinforced concrete beams and restrains the development of cracks.(5)According to the different failure modes of steel fiber reinforced concrete beams with CFRP bars,the design theory and calculation method of normal section bearing capacity of steel fiber reinforced concrete beams with CFRP bars are put forward.The calculated values are in good agreement with the experimental results.(6)Based on the test results,the deflection variation of steel fiber reinforced concrete beams with CFRP bars during bending failure is analyzed,and the deflection calculation model of steel fiber reinforced concrete beams with CFRP bars is established by modifying the relevant deflection calculation formula.