Nonlinear analysis of circular concrete-filled steel tube columns under eccentric loading

Abstract

In this paper, the mechanical behaviours of circular concrete-filled steel tube (CFST) columns were numerically investigated with the Abaqus/standard solver software. Based on the analysis of contact stress between the core concrete and the steel tube, it was found that the contact stress was non-uniformly distributed for CFST columns under eccentric loading, which is quite different from CFST columns under axial loading. A new concrete constitutive model, which considered the influence of eccentricity and depicted all loading stages, was developed. Existing experimental results were employed to validate the proposed constitutive model. It is concluded that the current model proposed in this paper is accurate in simulating the eccentric behaviour of CFST columns. Parameter study was also conducted to examine the effect of steel tube ratio (αs), yield strength of steel tube (fty) and compression strength of core concrete (fccu) on the mechanical behaviours of the CFST column under eccentric loading.