Study And Numerical Analysis Of Bonding Anchorage Performance Of High Strength Corrosion Resistant Rebar

High strength corrosion resistant rebar in this paper is a new type of rebar.This kind of rebar’s material has high content of Cr and Ni,which causes its advantages of low cost,corrosion resistance and high strength.One of the key foundation problems of corrosion-resisting reinforced concrete structure is the bond and anchorage property between rebar and concrete.Because the change of the reinforcing bar leads to the change of bond relation,this paper analyses the bond property of the low-cost high strength corrosion resisting rebar and concrete in this paper.The conclusion of this study include:(1)First this paper obtains this kind of rebar mechanical performance and the mechanical performance appraisal by carrying on the steel material performance test.In addition,test proves that the constitutive relation of the rebar satisfies the modified R-O model proposed by Rasmussen,which can provide reference for engineering application.(2)In this paper,the influence of concrete strength,hoop ratio,cover thickness,anchorage length and rebar diameter on the bond strength of high strength corrosion resisting reinforced concrete is obtained by 24 specimens tests.Test show that the influence law is the same as that of ordinary rebar.In addition,the formula for calculating the bond strength of this kind of high strength corrosion resisting rebar is obtained by regression statistics of the test results.And it is conservative to think that the traditional formula proposed by the bond anchorage group is still applicable to this kind of rebar.At the same time,the parameters of the constitutive model are regressed by using the short anchor test data,and the bonding constitutive relationship of the short anchor specimen is obtained.Then the experimental data are used to verify that the model is suitable for short anchor specimens.(3)First,the finite element simulation of short anchor test is used to verify that the nonlinear spring element is suitable for the interface simulation of the reinforced concrete.Then the former parameters and the bond strength of the long anchor are put into the former model to obtain the long anchor constitutive model,and using finite element model and long anchor test data to verify the applicability of constitutive model and finite element model.In addition,using the spring element to simulate the interfacial relationship between fine-grained steel and concrete and carry on the analysis of bending bearing capacity.Then the correctness of the model is verified by comparing existing tests with simulation values.At the same time,the model is used to analyze the flexural bearing capacity of the reinforced concrete beams with high strength corrosion resistance,and it is concluded that the formula of bearing capacity in the norm still applies to this kind of reinforcing bar by comparing norm calculation values with simulation values.Finally,the influence of section height,concrete strength and reinforcing ratio on bending stiffness,crack moment and limit moment of reinforced concrete beams with high strength corrosion resistance was obtained by parametric analysis.(4)Through the reliability analysis of the critical anchorage length of high strength corrosion resistant reinforcement by the center point method,it is obtained that the reliability analysis value and approximate value are less than the norm value.Therefore,the norm value is biased towards safety.It is suggested that the critical anchorage length is based on the norm value.