A parametric study of SHS steel columns protected with gypsum-based mortars under fire load using finite element modelling

This paper presents a study on the thermal performance of gypsum-based mortars as a coating layer on the surface of tubular steel columns. Thermal properties of the fire protection mortars as a function of temperature were determined from the previous studies carried out by the authors and collected from the literature. Based on the measured thermal properties, numerical models were developed for heat transfer and thermo-mechanical analysis. The proposed analysis models were verified based on a set of experimental tests on square hollow section (SHS) steel columns protected with gypsum-based mortars. Finally, a parametric sensitivity study was carried out and the effect of different parameters, including fire protection type and thickness, cross-section width-to-depth ratio, and load level on the fire performance, critical temperature, and failure modes of the protected steel tubular columns under the ISO 834 standard fire curve was investigated.