Compressive Behavior Of High Strength Steel Wire-mesh Reinforced Concrete Filled Steel Tubular Columns

Concrete-filled steel tubes(CFSTs)have been widely used in engineering practice due to their good mechanical performance.With the development of the industry,the building structure becomes more complex and the ordinary CFSTs could not fulfil the demand for higher strength.Set against this background,the present study proposed a new type of CFST: High Strength Steel Wire-Mesh(HSSWM)reinforced CFST.The HSSWM reinforced CFST neither increases the strengths of steel and concrete nor increases the cross-sectional area of CFST,but only provides high-strength steel wire meshes inside the CFST to form lateral confinement on the core concrete,thereby improving the overall compressive performance of the CFSTs.Different from ordinary CFSTs which employ confinement from outside to inside of concrete,the new type CFSTs develop confinement from inside to outside of concrete,which solves the problem of unconstrained effect of square steel tube concrete.In order to investigate the influence of HSSWM on the compressive performance of the new CFSTs,this paper used experimental verification,theoretical analysis and finite element simulation to study the axial compressive behaviour of said CFSTs,including:1)Axial compression tests were carried out on 6 square and 6 circular HSSWM reinforced CFSTs.The effects of steel mesh on the bearing capacity,axial stiffness and ductility of the CFSTs were investigated,and the different reinforcement parameters were compared;2)Internal load transfer mechanism of the HSSWM reinforced CFSTs under axial compression was firstly analyzed;then the analytical solution of axial compression capacity of said CFSTs was derived based on the theory of ultimate limit state equilibrium;and the analytical solution was finally verified through comparisons with test results.3)Finite element model was built by using ABAQUS and its validity was verified by the test results.The finite element model was used to simulate the internal load transferring and the influence of steel mesh on internal stress of the HSSWM reinforced CFSTs.Parametric analysis was conducted to investigate the effects of steel wire strength,steel wire diameter,concrete strength,wall thickness and outer diameter of the steel tube on the axial load bearing capacity of the new type CFSTs.It could be concluded in present study that the HSSWM reinforced CFSTs is superior to the ordinary CFSTs,in terms of load bearing capacity,axial stiffness and post-yield ductility.Meanwhile,it was found that the steel wire strength,steel wire diameter,concrete strength,steel pipe wall thickness and concrete tube outer diameter affected the axial bearing capacity of the HSSWM reinforced CFSTs.