Behavioural analysis of concrete-filled double-skin tubular columns under axial and biaxial loads

In this study, the behaviour of concrete-filled double-skin tubular (CFDST) columns with square outer and circular inner tubes is evaluated under axial compression and cyclic biaxial bending loads. Finite-element modelling was conducted in Abaqus software to analyse parameters including internal and external steel strength, concrete strength, hollow ratio and wall thickness. The results reveal that reducing wall thickness and compressive load ratio enhances bearing capacity, while other parameters have limited impact. Furthermore, the inclusion of an internal steel tube significantly improves the columns’ load-bearing performance, increasing their capacity by 43% compared to single-walled columns. This study bridges the gap between theoretical and practical applications of CFDST columns, offering a framework for optimizing their design for high-rise buildings and critical infrastructure. The findings also highlight the importance of parameter selection in enhancing energy dissipation and overall structural stability under complex loading scenarios. This research provides a comprehensive understanding of CFDST behaviour, serving as a foundation for future experimental and numerical studies aimed at improving column performance.