Rectangular concrete-filled double-skin steel tubular (CFDST) columns consisting of stainless-carbon steel tubes are high-performance composite columns that offer high corrosion resistance in harsh environments and have a wide range of applications in the construction industry. However, the buckling resistance of CFDST short and slender columns has not been properly investigated and design models for such columns need to be developed. In this paper, an extensive study on their performance is undertaken by employing the cost-effective fiber-based computation model. An accurate new confinement model for the confined concrete is suggested and implemented in the numerical modeling. The computational analysis procedures, which simulate the complete load-axial strain (P−ɛ) curves, load-lateral deflection (P−um) curves, and interaction diagrams of CFDST columns, are presented. The experimental data available is employed to validate the numerical predictions. The fundamental behavior of C
This article investigates the axial compressive performance of concrete-filled double steel tubular (CFDST) short columns composed of circular section loaded concentrically. An experimental program comprised of compression tests on short columns is carried out to examine their structural performance. Axial compression tests on conventional concrete-filled steel tubular (CFST) columns and double-skin concrete-filled steel tubular (DCFST) columns are also performed for comparison purposes. The test parameters include the diameter-to-thickness of the outer and inner steel tubes, concrete strength, and diameter ratio. The test results exhibit that CFDST short columns composed of the circular section have improved structural performance compared to its CFST and DCFST counterparts. A theoretical model is also presented to simulate the test ultimate strengths and load-axial strain relationships of CFDST columns. The existing design models proposed including the codified design specifications