Research On Seismic Performance Of Walled Concrete-filled Steel Tubular Columns With Binding Bars

The walled concrete-filled steel tubular columns with binding bars is new type of reinforced concrete-filled steel tube,which can solve the problem that the steel tube of conventional cross section with large aspect ratio rectangular concrete-filled steel tubular column prone to local buckling in the popularization and application and the confinement of the concrete is weak and so on.It obtains the advantages of simple structure,convenient construction,economical and reasonable,flexible layout and so on.It has a broad prospect of engineering application.In this paper,the seismic performance of double-cell concrete-filled steel tubular column is studied deeply.The main contents of this paper are as follows:(1)Two full-scale walled concrete-filled steel tubular columns with binding bars are subjected to horizontal cyclic loading under constant axial pressure,and the damage process and the horizontal load of each stage are recorded in detail.Through the deep analysis of the failure process and test results of the specimen,the failure modes,bearing capacity,energy absorption capacity and ductility of the walled concrete-filled steel tubular columns with binding bars with different arrangement mode under the horizontal cyclic load are obtained,and the influence of arrangement mode on the aseismic behavior of the full-scale walled concrete-filled steel tubular columns with binding bars is obtained by comparison and analysis.(2)Finite element analysis software ABAQUS is used to simulate the behavior of walled concrete-filled steel tubular columns with binding bars under monotonic loading and horizontal cyclic loading.The finite element model takes full account of the stress-strain relationship of steel and concrete under low cyclic reciprocating loads,the boundary conditions of components and the contact relationship between different materials.The finite element simulation results are compared with the experimental results,and the model results are in good agreement with the experimental results.(3)Based on the analysis of finite element models,the failure mode,material stress distribution and load-displacement relationship of walled concrete-filled steel tubular columns with binding bars under low cyclic reciprocating load is analyzed theoretically.The parametric studies are conducted to investigate the influence of axial compression ratio,concrete strength,steel strength,steel tube wall thickness,spacing of binding bars,diameter of binding bars.(4)Based on the experimental results and finite element results,a practical formula for calculating the ultimate bearing capacity of the walled concrete-filled steel tubular columns with binding bars is proposed,the results are compared with the experimental results and the finite element results,the result shows that the calculation results are more secure.Introducing the engineering practice and engineering application of walled concrete-filled steel tubular columns with binding bars,which can provide reference for engineering design.