Research On The Flexural Behavior Of RC Beams Strengthened By CFRP Under Quadratic Loading

Carbon fiber reinforced polymer has advantages of light weight、high strength、corrosion resistance and plastic etc, so make use of CFRP reinforced concrete structurehas already become a hotspot in the field of civil engineering and has a broadapplication prospect. While during the practicing, most of the construction has beenunder a certain load,it will be under secondary stress when strengthening.This articlethrough using of finite element sofeware ANSYS to simulate and analyse the reinforcedconcrete beams,in order to convenient for comparing with the test results inreferences,the size and reinforcement ratio of beams are same with the relatedliterature,but there will be some small differences on CFRP strengthening layers andinitial load.Main contents of this paper are as follows:Analyse mechanism and failure pattern of carbon fibre reinforced concrete beam;analyse several kinds of commonly used methods at present to the lag of straincalculation and compare the differences between them. Through calculating primarystress and secondary stress under different breaking forms,if only for calculating theultimate bearing capacity of beams,it can ignore the influence of secondarystress.Through ANSYS to establish three-dimensional finite element model, to imitatethe bending resistance of beams under unreinforcement、primary stress and secondarystress,then come out a result that if more CFRP strengthening layers、 biggerreinforcement ratio and small initial bending moment, the beam carrying capacity willbe higher、the deflection will be smaller、steel and CFRP strain will be smaller.Contrastthe cracking load，ultimate load and deflection of ANSYS simulation with the testresults of literature，analysis the reason of producing gaps,when verifying the feasibilityof finite element analysis method,and it also can provide referable basis for practicalengineering application.