| Square Concrete-filled steel tubular(CFST)column is a common composite structural member.However,due to the uneven confinement of square steel tube on concrete core,it is prone to cause local buckling of steel tube prematurally,so its application is limited.This paper proposes a new type of composite column,i.e.,high-strength steel wire mesh(SWM)reinforced high-strength concrete-filled square steel tube(SWMCFST).The use of high-strength concrete instead of ordinary concrete can effectively reduce the cross-sectional size of the member.At the same time,high-strength SWM is employed to laterally confine the concrete core,which improves the uneven confinement of the square steel tube on the concrete core,thereby improving the load-bearing capacity and ductility of the member.In order to study the axial compression mechanical properties of SWMCFST columns,this paper conducted investigation from three aspects: experiment,theoretical analysis and finite element numerical analysis.The main research contents are as follows :1)Axial compression tests were carried out on 13 specimens,including one square hollow steel tube(SHS)column,two square concrete columns confined by high-strength SWM(SWMRC),two ordinary square CFST columns and eight square SWMRCFST.By observing the failure modes of the specimens and analyzing their axial load-axial displacement curves,the influence of main parameters such as concrete strength,steel wire diameter,transverse spacing of steel wire mesh,longitudinal spacing of steel wire mesh,steel wire length and steel wire strength under the same volume stirrup ratio on the axial compressive mechanical behavior of the specimens was investigated.2)Based on the limit equilibrium theory,concrete strain compatibility condition and superposition principle,the calculation formula of axial compression load-bearing capacity of the SWMRCFST columns is derived.By comparing with the experimental data,it is found that the calculation value is in good agreement with the experimental value,which indicates that the formula can accurately predict the axial compression load-bearing capacity of the new composite column,and further proves the reliability and applicability of the formula.3)The ABAQUS finite element software was used to simulate the axial compression test of the SWMRCFST columns,and the reliability of the model was verified.In addition,using the verified finite element model for parameter analysis,the effects of concrete strength,steel wire diameter,transverse spacing of SWM,longitudinal spacing of SWM,steel wire yield strength,steel tube wall thickness,steel tube yield strength and volumetric ratio of stirrups on the axial compressive mechanical properties of the specimens were further explored. |
