Numerical investigation and design of lightweight aggregate concrete-filled cold-formed built-up box section (CFBBS) stub columns under axial compression

Abstract

Cold-formed built-up box sections (CFBBS) have emerged as a promising solution for applications in light gauge steel framing systems and modular construction. However, they suffer from the inherent local buckling effect. Concrete infill has proven effective in mitigating this issue, yet existing codified provisions lack specific guidelines for the design of concrete-filled CFBBS stub columns. This paper proposed a design methodology that aims to predict the ultimate compressive strength of lightweight concrete-filled CFBBS stub columns. Leveraging finite element (FE) modelling techniques, this study augmented the existing test database and shed light on parametric influences, considering practical considerations, on the structural performances and axial compressive behaviour. The proposed design approach demonstrated superior prediction accuracy and consistency compared to other evaluated design approaches in this study.