Study On Bond-Slip Performance Of Concrete Filled Steel Tube And Numerical Analysis

As a concrete-filled steel tube many advantages,it gets more and more applications in engineering. Most of the concrete-filled steel tube study has focused on the capacity and it's seismic behavior in the engineering study. Now the studies of concrete-filled steel tube bond-slip performance relation are few both at home and abroad. Some of them are not deep enough. This paper is by test and numerical analysis of steel concrete tube bond-slip performance.By the 13 concrete-filled steel tube's short columns test, the first is that we get the load-slip relation curve of specimen tests launched by nine short columns, and we get the load-slip relation curve of specimen tests lauched by four columns,so we can get the limit bond load and the limit bond strength of specimen tests launched and we can get some factors of influence to bond strength.Based on the axial compression tests on nine specimens of the non-linear finite element analysis, obtained bond failure load and corresponding slip value, most of the results lower than the experimental value, calculated on the difference between experimental values and analysis the reasons, but the ratio of all specimens test results and calculation results is very regular. Overall, the finite element method gives more accurate results in this paper.By the nonlinear finite element analysis of the four client, the load on the bond-slip displacement is the biggest, along the concrete-filled steel tube,it longitudinal gradually decreases.In A type load, the deformation of concrete filled steel tube concrete is obviously better than the concrete stress deformation in steel, deformation along the longitudinal gradually becomes small, and the yield to appear.In the model introduced by the non-linear finite element analysis,the steel tube-axial stress along the axial load is beginning gradually increasing,the change law along the axial line is close to the straight line change; Concrete axial stress from the maximum loading terminal along the axial began gradually decreasing. Change rules along the axial are nearly a straight line,a steel pipe and concrete change rules of the axial stress are close to the change rules of test results.In bonding surface,the bond stress of the concrete,when the load is small,in the specimen loading terminal certain length(the length of the shear transfer)within the framework of the law changes on a straight-line,and then in the longer remain within the framework of the basic constants do not change.