Research On Flexural Performance Of Concrete Beams Reinforced By Partial-prestressed Partial-bonded CFRP Tendon

To resolve the problem of rebar corrosion, after many years'study experts have found the application of fiber reinforced plastic(FRP) tendons proved to be the dependable measure in present time. fiber reinforced plastic (FRP) tendon, a new advanced composite material, is formed through pultrusion of epoxy-impregnated reinforced fibers. FRP tendons have many advantages such as lightweight, high strength, corrosive resistance, fatigue resistance, and so on. When used in concrete structure ,it is not very safe and do not make full use of materials strength result in over-reinforced failure .so we pay attention on the application of prestressing FRP tendon using in the partial-prestressed concrete structures.Although, there are many differences between partial-prestressed concrete components with partial-prestressing CFRP tendons and common prestressed concrete components because of tensile stress-strain curve and low young's modulus of FRP tendons, so does the difference between partial-bonded beam and full-bonded, unbonded ones. so make research on design calculation method and ductility property of the partial-prestressing and partial-bonded CFRP beams.Based on theory and experimental study foundation, has carried on the research to CFRP partial-prestressed partial-bonded concrete number in bending conditioning, the paper focused on following items: (1) six partial bonded concrete beams prestressed with CFRP tendons are tested under monotonic loads. The failure modes, ultimate stresses of prestressing tendons, ultimate load-carrying capacity, ductility, deformation and crack width of this kind of beams with varying unbonded length are systematically investigated.(2) based on the experiments of partial-prestressed partial-bonding concrete beam including CFRP at home and abroad and indignity model in the paper, study on the load-bearing capacity including ultimate stress and ultimate moment-resist capacity. and study on deform capacity including short-time rigid, deflection and width of crack. and offer some design advices.(3) study on influences factors on ductility property of CFRP partial-prestressed partial-bonded concrete beam including the facts such as unbonded length , concrete strength ,PPR, comprehensive reinforcing index, steel fixed in the compressed section and so on.(4) using commercial finite element software, ANSYS, nonlinear finite element simulation of partial-prestressed concrete beams with partial-bonded prestressing CFRP tendons is accomplished. modeling method, selecting element, defining constitutive relationship of materials and solution method that are elaborated on in this paper, and then reliability of methods as mentioned above is testified by comparing with experiment results.