Experimental and analytical investigation of square-shaped concrete-filled steel tube columns

Square-shaped concrete-filled steel tube (CFST) columns inherit the advantages of conventional steel and con-crete columns, and have been used in several super high-rise buildings. This paper presents a calculation model for square-shaped CFST columns. Based on the experimental results of a square-shaped CFST column and the application of a super high-rise building, numerical models are established to simulate the force-displacement curves of the CFST column and the stress-strain curves of square steel tubes and stiffeners, which show con-sistency with the experimental data. Meanwhile, the load-bearing capacity and ductility of CFST columns can be effectively increased by incorporating tensile plates, diaphragms, shear studs, and stiffeners. Considering the steel ratio, axial compression ratio, and concrete strength, nine finite element models are developed to evaluate the ductility and load-bearing capacity of the columns under the reversed-cyclic lateral load. The seismic and wind resistance properties of the structures are analyzed using a CFST column application.