A numerical investigation on the behaviour of concrete-filled steel tubular columns under initial stresses

In the practical construction of concrete-filled steel tubular (CFST) structures, the steel tubes usually have already had some initial stresses before they work together with the core-concrete. The initial stress should affect the behaviour of the whole member. In this paper, a comprehensive numerical investigation is presented on the behaviour of CFST columns under initial stresses by the non-linear finite element method. The investigation includes several parametrical studies such as initial stress ratio, slenderness ratio, eccentricity ratio, etc. Numerical analysis results are verified with published experimental ones. Recommendations on how to consider the effect in design formulae are also suggested.