Analysis On Mechanical Behavior Of Concrete Beams Which Reinforced By Pre-tensioned CFRP And Bearing Capacity Calculation

In recent years, CFRP strengthening technology is widely used in the field ofreinforcement. For this method, the researchers used different methods to improve:reinforced with pre-tensioned CFRP can improve the whole stress performance of thestructure, However, there are questions about pre-tensioned whether can raise the bearingcapacity of components. Before reinforcement, structure is generally under certain load,this problem affects the performance of CFRP reinforcement. In a word, a lot of researchworks still need to be followed up.The finite element analysis software ANSYS to do the nonlinear numerical simulationin order to investigate the mechanical behavior of concrete beams which reinforced bypre-tensioned CFRP have been used in this paper, the analysis results are in goodagreement with experiment results and proved that the established3D finite element modelis effective. Using the right model, the secondary stress of prestressed carbon fiberreinforced beams under vertical displacement on both sides decreases from the beam wasfound. When prestressed CFRP first load co-bearing, vertical displacement of beam willhave a rebound, steel get to a certain extent reduce the tensile stress, compressivereinforcement and concrete compressive stress has been a certain degree of ease, thismeans that the stress of the whole structure is improved. Steel yield before, CFRP straingrowth is slow. However, after the steel yield, CFRP strain increase rapidly until failure.Carbon fiber cloth in force while can greatly improve the yield load and ultimate load ofreinforced beams, but for the ductility of the reinforced beam is greatly reduced, due to thebearing capacity of the carbon fiber cloth after the fracture structure fell sharply, this papersuggested to estimate the bearing capacity of the beam and the displacement limit, toensure the safety of the structure.By using finite element analysis software, and discusses the related parameters affectthe performance of this type of reinforcement beam stress, get the following conclusion:when the strength of concrete is low and the strengthening of carbon fiber cloth is large,the destruction of the beam will damage because of concrete crush, so can’t give full playto the strength of the carbon fiber cloth, should not appear this kind of situation in thedesign. As the concrete level, the destruction of the beam will be snaped into a carbon fibercloth, in the reinforcement design, designer wants to see is a carbon fiber blah to break thiskind of failure mode, so when cannot meet the demand of the compressive strength ofconcrete, increasing the reinforcement of the upper beam compressive ability should be considered, in order to make carbon fiber cloth can give full play to their strength. Carbonfiber cloth reinforcement amount of yield load and ultimate bearing capacity of beamreinforced a lot, but only the influences of CFRP prestressed beam reinforced yield loadsize, and the carbon fiber cloth prestrain of0.02is the best effect, to a little effects on theultimate load of the beam. Before reinforcement of beam with Dutch size had a greatinfluence on the effect of reinforcement, this paper concluded that hold a load afterunloading is more than40%of the ultimate load.In addition, referred to the existing related theory literature, took example bycalculation theory of the concrete beams which reinforced by pre-tensioned CFRP,respectively gave the two failure modes of flexural bearing capacity calculation formula.Based on beam theory, Validated by finite element data, the theoretical calculation showsthat the model is more close to the actual situation.