Numerical modeling and analytical predictions of high-performance CFDST columns

Concrete-filled double-steel tube (CFDST) columns are increasingly used in high-rise buildings and heavily loaded structures due to their excellent strength and deformation capabilities. The use of high-performance materials (ultra-high-strength steel and high-strength concrete) facilitates slender and material-efficient structural column designs. However, current design standards, e.g., Eurocode 4, do not explicitly account for the behavior of such advanced configurations, leading to uncertainties in stability assessment and structural design. This study develops and validates two numerical models, a 3D solid model in ABAQUS and a fiber-based model in OpenSees, using large-scale experimental data from slender CFDST columns for validation. The models reproduce load–deformation responses, strain distributions, and failure modes across a broad range of slenderness levels. Parametric studies highlight that high-performance materials significantly enhance load capacity in stocky columns, while their benefits diminish in slender column configurations due to global buckling. The post-peak behavior of concrete is shown to critically influence ultimate load predictions, particularly in stocky configurations. Comparisons between results obtained from OpenSees and ABAQUS demonstrate the importance of multiaxial stress states and confinement effects in advanced material systems. Furthermore, a statistical evaluation of a broad parametric finite element dataset indicates that homogeneous CFDST columns align well with existing buckling curve classifications, whereas hybrid configurations exhibit greater scatter. These findings support the reliable and efficient use of high-performance materials in CFDST systems, providing design-relevant insights for improving the applicability of current design standards. Future experimental investigations on stocky hybrid configurations are recommended to refine stability classifications and ensure reliable structural assessment. • ABAQUS and OpenSees models reproduce large-scale tests with ≤5 % mean error. • High-strength steel increases capacity in stocky columns; effect drops with slenderness. • Concrete post-peak modeling strongly affects stocky-column capacity. • Hybrid design (different steel grades) changes stiffness evolution; outer high-strength tube increases capacity the most. • Buckling-curve classification possible; hybrids show larger variability than homogeneous cases.