Study On Mechanical Behavior Of Special-Shaped Columns Composed Of Concrete-Filled Steel Tube Connected By H-Shaped Steel

The special-shaped columns composed of concrete filled steel tube have the characteristics of good anti-seismic performance,fast construction speed,high economic benefit,and flexible section form,so as to be hidden in the wall,avoid the protruding angle of the indoor column and increase the room area,therefore,as a new force of green residential structure,The special-shaped columns composed of concrete filled steel tube has a broad application prospect in the field of architecture.At present,the special-shaped columns composed of concrete filled steel tube can be divided into the combination special-shaped columns of bain-connected concrete-filled steel tube,the combination special-shaped columns of concrete-filled steel tube with perforated steel plates and the combination special-shaped columns of concrete-filled steel tubes with steel plates,in view of the shortcomings of steel plate connected concrete filled steel tube combined the special-shaped column in processing and manufacturing,this paper proposes a new special-shaped columns composed of concrete filled steel tube connected by h-shaped steel,through experimental study and finite element analysis,the mechanical properties and simulation calculation methods are studied.The following is the main contents:(1)The axial compression experiment of special-shaped columns composed of concrete filled steel tube connected by h-shaped steel was carried out to analyze its failure form,bearing capacity,stiffness,ductility,strain characteristics and deflection.The research results show that the special-shaped columns composed of concrete filled steel tube connected by h-shaped steel shows overall bending instability under the axial pressure.On basis of verifying the correctness of ABAQUS finite element model through experiments,influence of parameters such as the thickness of h-shaped steel flange,thickness of h-shaped steel web,the width of h-shaped steel,the size of single-limb steel tube and height of column was taken into consideration for parametric analysis.(2)The bias compression experiment of special-shaped columns composed of concrete filled steel tube connected by h-shaped steel was carried out to analyze its failure form,bearing capacity,stiffness,ductility,strain characteristics and deflection.The research results show that the special-shaped columns composed of concrete filled steel tube connected by h-shaped steel shows overall bending instability and local failure under the bias pressure.On the basis of verifying the correctness of ABAQUS finite element model through experiments,influence of parameters such as the thickness of h-shaped steel flange,thickness of h-shaped steel web,the width of h-shaped steel,the size of single-limb steel tube,steel pipe thickness,the height of column and material strength was taken into consideration for parametric analysis.(3)In view of the lack of theoretical basis for the simplified simulation method of the special-shaped columns composed of concrete filled steel tube(SCFT columns)in the practical engineering design and calculation,a simplified simulation method of double beam single shell element based on the equivalent stiffness is proposed.The solid model and the single beam-single shell element model and the double beam-single shell element model by equivalent stiffness conversion are respectively adopted,and the general analysis and design software Midas is adopted to establish the calculation model of typical SCFT column frame structure,the responses of the three models under different loads are compared,and the feasibility of using the stiffness equivalent simulation method to calculate the overall structure with SCFT columns is verified.(4)YJK and MIDAS software are used to establish the model of special-shaped columns composed of concrete filled steel tube connected by h-shaped structure based on the equivalent stiffness.The comparison of large indexes such as period,mode shape and displacement shows its feasibility in the actual project.