Fire performance of Tapered Concrete-Filled Steel Tubular Columns Protected by Intumescent Fire Coating

Tapered concrete-filled steel tubular (CFST) columns have been used in various structures due to their aesthetic appearance and excellent structural behaviour. However, the research on their fire performance is still insufficient at this stage. In this paper, fire tests of three tapered CFST columns under eccentric load are carried out, and all specimens are protected by intumescent fire coating (IFC). The test results show that the IFC and tapered CSFT specimen can reliably work together under fire. Under remarkable heat insulation effects of the IFC, the fire rating of the tapered CFST specimen can exceed 180min, even if the load ratio is up to 0.56. A verified finite element analysis (FEA) model to predict the fire performance of CFST tapered column was established, taking into account the passive confinement effect of steel tube on the infilled concrete. Combined with typical cases, the influence of tapered angle and slenderness ratio on the fire performance of tapered CFST column was discussed.