Mechanical Properties Study On Special-Shaped Concrete-Filled Steel Tube Compound Column

Special-shaped concrete-filled steel tube compound columns developed from the special-shaped concrete columns and steel pipe concrete columns. It not only meets the need of erect, long-span and heavy load for high-rise and super-high-rise buildings, which makes up for the lack of bearing capacity of special-shaped reinforced concrete columns, but also satisfies people's aesthetic demands of interior decoration. It can fully avoid the weaknesses of appearing column corner indoors for using traditional rectangular reinforced concrete columns, which can bring great unconvenience for the interior decoration and furniture arrangement. There are three kinds of cross-section for special-shaped concrete-filled steel tube compound columns. They are cross-shaped, T-shaped and L-shaped. All of them can be used in central column, side columns, and corner columns. They are made up of special-shaped reinforced concrete columns and steel pipe column. The concrete-filled steel tube column is located in the vertical and horizontal cross point of cross-section column. The combination is known as the special-shaped concrete-filled steel tube compound column. Compared with the special-shaped concrete columns under the conditions of the same section, Special-shaped concrete-filled steel tube compound columns can greatly enhance its bearing capacity and ductility because of its compound concrete-filled steel tube column. It has the advantages of both special-shaped concrete columns and steel pipe concrete columns, and can effectively expand the scope of application of special-shaped columns. It has opened up a new system of special-shaped columns of residential areas.In this paper, we designed three kinds of special-shaped concrete-filled steel tube compound columns, in order to study the mechanical properties for this new component deeply. We analysed the finite element simulationthe of the cross-shaped, T-shaped and L-section specimens, we researched the axial load mechanical properties for three kinds of specimens, calculated the bearing capacity and displacement of three specimens with ABAQUS finite element simulation software, and elaborate on the failure mechanism of three specimens in detail. At the same time, in order to checking the accuracy of the simulation, we tested and analised the cross-section. This paper describes the production process of the specimen in detail, loading equipment and loading methods, and methods of displacement measurement. We compare the cross-section specimens with different pipe diameters. The results showed that as the pipe diameter increased, the bearing capacity and ductility of the specimens increased accordingly, but their displacements were almost the same which under the peak loads. The results agreed well with the simulation results. In this paper, we also analysed the cross-section concrete-filled steel tube compound columns according to different slenderness ratio, eccentric loads and ductility. We obtained the bearing capacity and displacement values of the specimens under different slenderness ratios, the failure modes under eccentric loads, as well as the change of the ultimate bearing capacity and the displacement. The simulation result is in good agreement with the theoretical analysis. We analysed the ductility of the specimens under the unidirectional loads and calculated the ductility factor. The conclusion is that each part of cross-shaped concrete-filled steel tube compound columns can work together to make specimen has good ductility so that this new special-shaped column can be widely used in engineering.