Behaviour and design calculations on very slender thin-walled CFST columns

This paper studies the behavior of very slender thin-walled concrete filled steel tubular (CFST) columns under axial compression. A finite element analysis (FEA) was developed to carry out the behavior of compressive columns. Initial out-of-straightness imperfection was discussed. Generally good agreement was obtained between the predicted and measured results. The FEA model was then used to perform mechanism analysis on very slender circular CFST columns. Parametric studies were carried out and the ultimate strengths from tested results and design codes were compared and discussed. The reliability analysis method was used to calibrate the existing design formulas given in DBJ/T13-51-2010, ANSI/AISC 360-05 and Eurocode 4.