Fire resistance of circular concrete-filled steel tubular (CFST) column protected by intumescent coating

For structural components with specific requirement of fire resistance rating for safety reasons, additional fire protection is usually necessary. Intumescent fire coating (IFC) is one of the well-used materials to protect steel structures, and it has advantages such as light weight, simple construction, aesthetic appearance, easy maintenance, etc. In this study, a group of eccentrically loaded concrete-filled steel tubular (CFST) columns with and without IFC protection was tested in standard fire circumstance up to 180 min. Three types of intumescent materials were adopted and different dry film thicknesses of the fire coating were designed. Temperature field of each CFST column and the load bearing behaviour were measured and analysed. Finite element modelling of the columns was also established for heat transfer analysis and fire resisting capacity analysis. The modelling was validated by the test data. This study expands the related experimental database with large scale column specimens. The investigation results provide further evidence that CFST column protected by intumescent fire coating could achieve excellent fire resistance. A technical process to determine intumescent fire coating for CFST columns coupling with experimental verification and FE modelling analysis is presented.