Fire resistance of eccentrically loaded slender concrete-filled steel tubular columns

• A numerical model is developed to simulate fire behavior of CFST slender columns.
• Effects of load eccentricity and reinforcement ratio have been investigated.
• Effects of concrete and steel strength have been investigated.
• Parametric study is performed to understand the effects of design parameters.
• The Rankine approach is extended to predict fire resistance of CFST columns.

Computational analysis was performed to study the behavior of concrete filled steel tubular (CFST) slender columns subjected to eccentric load under fire conditions. To simulate the destruction process of the CFST slender columns under ISO-834 standard fire, a sequentially nonlinear thermal-stress finite element analysis was performed. Concrete tensile strength and stirrup ratio were incorporated in the numerical model. Compared with the experimental results, it shows that the developed model can predict the fire resistance of CFST slender columns subjected to eccentric load with reasonable accuracy. Based on the developed model, parametric study was performed to investigate the effect of load eccentricity ratio, yield strength of steel, compressive strength of concrete and the reinforcement ratio on fire resistance of CFST columns. Based on the computational study, the conventional Rankine approach was extended to predict fire resistance of the CFST slender columns subjected to eccentric load. The theoretical predictions show good agreement compared with experimental results.