Performance of concrete-filled stainless steel tubular stub columns with embedded steels after exposure to fire

This paper encompassed both experimental and theoretical studies into the structural performance of concrete- filled stainless steel tube (CFSST) stub columns with embedded H-shaped steels under axial compression, subsequent to exposure to fire. The main parameter in the fire tests was the duration of fire exposure. The thermal and mechanical models were developed, taking into account the heating and cooling effects. These validated numerical models facilitated the stress and strain analysis, as well as an examination of the load distribution and contact stress before and after fire. The study also explored the influence of critical parameters such as the fire duration, axial load level and confinement factor, etc. It was found that the residual resistance of CFSST column in axial compression decreased with the increase of fire duration and axial load level, yet increased with higher confinement factor and the yield strength of embedded steel. Finally, a simplified equation was proposed for the prediction of resistance in axial compression of such column after fire exposure.