Study On Bond-Slip Behavior Of High Strength Concrete Planting Bars

In this paper,on the basis of the existing domestic and foreign research on the structure theory of concrete planting bars and the experimental research of concrete planting bars,the bond slip constitutive relationship of the interface bond failure of concrete planting bars is comprehensively studied,and the bond slip performance of the adhesive mixed adhesive bar interface is tested,and the finite element analysis considering the double interface bond slip performance is carried out.In order to study the bond slip constitutive relationship of the adhesive concrete interface of the reinforced concrete structure,a perfect unconstrained push out test of the reinforced concrete was designed.Based on the average bond strength theory,the bond slip constitutive curve and the four segment expression of the adhesive concrete interface of the reinforced concrete structure under the influence of various relevant parameters are regressed by comparing six concrete specimens.The main analysis parameters are embedded depth,adhesive layer thickness and surface type of reinforcement.In order to study the distribution of the bond stress on the interface between the adhesive and the concrete with the embedded depth of the embedded steel bar,a group of experiments on the embedded steel bar are designed,and the bond slip constitutive relationship on the interface between the adhesive and the concrete is studied.In order to study the bond slip constitutive relationship of the interface between the adhesive and the rebar,a steel sleeve pull-out test was designed.Three groups of 9 steel sleeve tests were designed based on the thickness of the adhesive layer,and the bond slip constitutive relationship between the adhesive and the steel bar was studied.In this paper,the finite element analysis software ABAQUS is used to establish an unconstrained finite element calculation model of bond slip nonlinear spring element considering the interface of glue bar and glue concrete.The spring element is edited by using the bond slip constitutive relation of the bond concrete interface obtained from the unconstrained push-out test and the bond slip constitutive relation of the bond steel interface obtained from the steel sleeve pull-out test.The definition of bond and slip between two interfaces in ABAQUS is completed.By comparing the test results with the finite element simulation results under the same parameters,the comparison results show that the finite element calculation model can be used for the stress analysis of the reinforced concrete structure.Through the finite element model,the distribution law of the bond stress along the embedded depth of the reinforced bar on the concrete interface is obtained.Based on the bond slip constitutive relation of the bond concrete interface obtained from the experimental regression and the bond stress location function of the bond concrete interface calculated by the finite element method,the expression of the bond slip constitutive relation of the bond concrete interface of the reinforced structure considering the nonuniformity of the bond stress is proposed.