Eccentrically loaded high-strength concrete filled high-strength steel tubular columns subjected to fire: Modelling, full-scale testing and design

High-strength concrete filled high-strength steel tubular (HCFHST) columns demonstrate excellent structural performance at ambient temperature but generally exhibit lower fire resistance compared to conventional normal-strength concrete filled steel tubular (CFST) columns. In light of this issue, this study investigated the fire behaviour of eccentrically loaded HCFHST columns through both numerical and experimental approaches, and subsequently developed practical fire resistance design methods. Sequentially coupled thermo-mechanical analysis models for eccentrically loaded HCFHST columns were developed using ABAQUS software, and full-scale standard fire tests were carried out on representative specimens with a total height of 3.64 m. Subsequently, an extensive parametric study was conducted to investigate the fire resistance of HCFHST columns under eccentric load, as well as of protected columns subjected to axial or eccentric loading. In addition, a simplified assessment method was proposed to estimate the fire resistances of HCFHST columns under eccentric compression, and an additional design approach was developed to support the fire safety design of protected columns.