Concrete-filled steel tubular (CFST) columns have been extensively studied and widely used in practice. Existing research has shown that non-circular CFST columns is much less ductile than their circular counterparts, particularly when thin/high strength steel (HSS) tubes and high-strength concrete are used. To address this problem, a new form of CFST columns has recently been proposed by the first author. The new column consists of a steel tube filled with concrete that is confined with HSS spiral reinforcement typically with a yield stress exceeding 1000 MPa. These columns, referred to as confined concrete-filled steel tubular (CCFST) columns, also maintain the ease for connection to CFST or steel beams. This paper presents the results of a series of concentric axial compression tests on such columns of square cross-section to demonstrate their advantages. The experimental program included 13 CCFST columns, four CFST columns without internal spiral confinement, two hollow steel tube (HST) columns, and 11 circular HSS spiral-confined concrete columns. Three different compressive strengths and three HSS spiral pitches were examined in the experimental program. The CFST columns, HST columns, and HSS spiral-confined concrete columns were all tested under axial compression to gain a good understanding of the confinement mechanism in a CCFST column. The test results show that the new columns possess much greater ductility than those without internal spiral confinement, although the use of HSS spirals increases the steel volume by only a small percentage. It is also shown that the axial load-axial strain curve of a CCFST column can be conservatively predicted by summing the axial load-axial strain curves of the hollow steel tube without local buckling, the HSS spiral-confined concrete core, and the sandwiched concrete between the two.

钢管混凝土（CFST）柱已被广泛研究并在实践中得到广泛应用。现有研究表明，非圆形CFST柱的延性远低于圆形柱，特别是在使用薄/高强度钢管（HSS）和高强度混凝土时。为了解决这个问题，第一作者最近提出了一种新形式的CFST柱。新的立柱由钢管填充，钢管内填充有HSS螺旋钢筋，其屈服应力通常超过1000 MPa。这些立柱被称为钢管混凝土（CCFST）承压柱，也易于连接CFST或钢梁。本文介绍了在此类方形截面柱上进行的一系列同心轴向压缩试验的结果，以证明其优势。实验程序包括13根CCFST柱，四根没有内部螺旋约束的CFST柱，两根空心钢管（HST）柱和11根圆形HSS螺旋约束混凝土柱。在实验程序中检查了三种不同的抗压强度和三种HSS螺旋螺距。CFST柱，HST柱和HSS螺旋约束混凝土柱均在轴向压缩下进行了测试，以更好地理解CCFST柱的约束机理。测试结果表明，与没有内部螺旋约束的新柱相比，新柱具有更大的延展性，尽管使用高速钢螺旋仅使钢的体积增加了很小的百分比。通过对无局部屈曲的空心钢管，HSS螺旋约束混凝土芯和夹心混凝土的轴向载荷-轴向应变曲线求和，可以保守地预测CCFST柱的轴向载荷-轴向应变曲线。两者之间。