# Axial Compression Behavior of Steel Angle-Corrugated Steel Plate-Confined Concrete Columns
## 1 Introduction  
Concrete-filled steel tube (CFST) members have convenient manufacturing and construction properties, high bearing capacity, good seismic performance and ductility, and economic advantages. Square CFST columns are widely used in long-span and heavy-loaded structures due to the benefits of their flexible joint types, larger moment of inertia, and the ease of satisfying construction requirements [1; 2; 3]. Scholars have conducted a great deal of research on the performance of square CFST columns, including with regard to their static behaviors [4; 5], seismic behaviors [6], fire-resistant performance [7], and creep performance [8]. Compared with circular CFST columns, the confinement of square CFST columns to core concrete is reduced. The external steel tube of square CFST columns can suffer local buckling because of its low out-of-plane stiffness under axial compression, which reduces its bearing capacity. To improve the confinement effect of square CFST columns and tube wall-buckling resistance, scholars have proposed various new structures to enhance square CFST columns. [PERSON] et al. [9] presented a new type of stiffened square CFST column with diagonal binding ribs, which can increase the effectively confined regions of core concrete from the strengthened tube. A total of 21 stub columns were tested under axial compression to investigate the effect of the diagonal ribs on the mechanical properties of the new type column. [PERSON] et al. [10; 11] conducted a series of investigations of concrete-filled, stiffened thin-walled steel tubular columns under axial and eccentric compression through tests and finite element simulation. The results showed that the stiffened column has higher serviceability benefits than those unstiffened, and the carrying capacity of the stiffened column andconfinement of the core concrete increases with the stiffener number. [PERSON] et al. [12] introduced binding bars into square CFST columns to postpone the local buckling of steel tubes and conducted axial compressive tests. In addition, [PERSON] et al. [13] tested square CFST columns with binding bars under cyclic lateral loads to study their hysteretic behavior. The experimental results demonstrated that binding bars do not improve the bearing capacity of specimens significantly but can greatly improve their ductility and energy-dissipation capacity. In addition to these improvement schemes, some scholars used FRP [14] and steel fiber-reinforced concrete [15] to enhance the mechanical behaviors of square CFST columns. Currently, corrugated steel plates, a type of cold-formed steel plate, are chiefly used in the shear wall and composite beam for their excellent shear resistance [16; 17]. The vertical stiffness of corrugated steel plates is low, and it is difficult for them to bear a vertical load due to their particular corrugated form. However, several investigations have shown that corrugated steel plates are favorable for confining concrete and that composite concrete-filled columns with corrugated steel behave well [18; 19; 20]. [PERSON] et al. [19] tested a new kind of spiral concrete-filled corrugated steel tube (CFCST) column under axial compression and compared the mechanical properties of the CFCST and CFST columns. The test results demonstrated that the axial compression behavior of the CFCST column was greater than that of the CFST column under a similar steel ratio. [PERSON] et al. [21] performed experimental studies on concrete-filled double-skin steel tubular (CFDST) columns with galvanized corrugated steel tubes and CFCST columns embedded with structural steel (CFCST-S). The existing studies mainly focus on circular concrete-filled columns with corrugated steel tubes. However, like the circular CFST column, a circular concrete-filled column with a corrugated steel tube also suffers from the same problem of a difficult joint connection.