Study On Mechanical Properties Of Cross-shaped Multi-cavity Concrete-filled Steel Tubular Columns

The concrete filled steel tubular column has the advantages of high bearing capacity,good plastic deformation ability and good seismic performance.The internal space utilization of the special-shaped column structure is high and the layout is flexible.In order to meet the needs of national development and meet the requirements of high-quality residential buildings,it is necessary to develop high-capacity,high-energy,high-ductility,fast construction and industrialized production of fabricated special-shaped concrete filled steel tubular columns.Aiming at the above problems and background,this paper proposes the fabricated cross-shaped multi-cavity concrete filled steel tubular column,which is studied by theoretical calculation and finite element simulation.The details are as follows:The axial compression performance of the cross-shaped multi-cavity concrete filled steel tubular column is analyzed by theoretical calculation and numerical simulation.The results show that the cross-shaped multi-cavity steel tubular concrete column has good axial compression performance.The theoretical calculation formula of axial compression bearing capacity of cross-shaped multi-cavity steel tubular concrete columns based on superposition principle is proposed.A suitable finite element model is established to compare with them.The finite element model established in this paper can well simulate the mechanical properties of cross-shaped multi-cavity concrete filled steel tubular columns.The finite element simulation is used to analyze the stress process of cross-shaped multi-cavity concrete-filled steel tubular columns under compression-bending,and the influence of different parameters on its compression-bending performance.The results show that the cross-shaped multi-cavity concrete-filled steel tube column has high bearing capacity and good ductility,and the thickness and height to width ratio of the steel tube have great influence on it.Moreover,based on the calculation formula of the bearing capacity of the normal section,the calculation formula of the simplified calculation formula of compression-bending bearing capacity is obtained,which provides a reference for the subsequent engineering application.The finite element software——ABAQUS is used to analyze the seismic performance of the cross-shaped multi-cavity concrete filled steel tubular column with different influence parameters.Under the action of low-cycle reciprocating load,different influencing factors,such as axial compression ratio,concrete strength,steel tube thickness,height to width ratio and load angle,are analyzed by comparing the hysteresis curve,skeleton curve,stiffness degradation curve,ductility analysis and energy consumption of each model.The results show that the hysteresis curve of the cross-shaped multi-cavity concrete filled steel tubular column is smooth and full,and the energy-consuming performance and deformation capacity of the special-shaped column are good,and the seismic performance is good.The different parameters have certain influence on the seismic performance of the cross-shaped multi-cavity concrete filled steel tubular column.The height to width ratio and the thickness of the steel tube are the main influencing factors.