Finite Element Study On Mechanical Properties Of T-shaped Multi-cavity CFST Columns

As a new type of column structure,concrete-filled steel tube(CFST)composite special-shaped column has been favored by many scholars because it gives full play to the advantages of CFST and CFST.The special-shaped column can be wrapped in the wall,which increases the room’s use space and greatly improves the comfort and aesthetic feeling of the room.The structure of the special-shaped column can be divided into three types:reinforced concrete special-shaped column,steel reinforced concrete special-shaped column and concrete-filled steel tube special-shaped column.As an indispensable part of the whole structural system,the t-shaped column is very important to study a kind of t-shaped column with high strength performance.In this paper,a new type of composite concrete-filled steel tubular column--t-shaped multi-cavity concrete-filled steel tubular column is proposed.The composite special-shaped column is composed of square steel tube,u-shaped steel plate and filled concrete.The axial compression,bending and seismic behavior of T-shaped multi-cavity concrete-filled steel tubular columns are studied.The finite element model of T-shaped multi-cavity CFST special-shaped column was established by using ABAQUS software.The numerical analysis of axial compression performance of seven composite special-shaped column members was carried out.The effects of aspect ratio,steel rate and material properties on the axial compression performance of the members were considered..As the steel rate is increased,the axial bearing capacity and rigidity of the special-shaped column also increase,and conversely,the ductility decreases.Compared with the steel rate,the strength grade of concrete has a more obvious influence on the axial bearing capacity.The numerical analysis of the bending and bending performance of three T-shaped multi-cavity CFST composite columns is carried out.The failure of the one-way compression and bending specimen is bending failure.The location of the failure occurs in the middle of the specimen,and the stress cloud of the steel shows a symmetric distribution.In the middle of the steel,there is a significant bulging and crushing state.This is mainly because the concrete in the internal compression zone has exceeded the stress limit state,and the concrete is crushed,resulting in the lifting and expansion of the middle part of the steel.The numerical analysis of seismic performance of 12 composite special-shaped column members is carried out,and the effects of different loading methods,concrete strength,steel thickness and aspect ratio on the seismic behavior of special-shaped column members are considered,and the whole process and working mechanism of the members are studied.The strength of the concrete,the thickness of the steel and the axial compression ratio are the main factors affecting the bearing capacity of the T-shaped multi-cavity concrete-filled steel tubular special-shaped columns,and the T-shaped multi-cavity concrete-filled steel tubular shaped columns have good bearing capacity and ductility.The finite element analysis of seismic behavior of 12 T-shaped multi-cavity CFST columns under horizontal reciprocating load.It is shown that the above parameter changes have a certain degree of influence on the seismic performance of the combined special-shaped column members,and the influence of the parameter aspect ratio and the thickness of the steel plate is particularly obvious.Finally,under the premise of considering the bearing capacity and economy of T-shaped multi-cavity CFST special-shaped column members,the reasonable values of relevant parameters are given.