Simple design procedure for concrete filled steel tubular columns in fire

Over the past 36 years, 238 experimental tests have been reported in the literature on concrete filled steel tubular (CFST) columns; different types of concrete infill have been considered: plain, steel fibre and bar reinforced concrete. In these tests, the columns were loaded axially under either concentric or eccentric load, and subjected to the standard ISO 834 fire or its equivalent in a furnace. In this paper, the experimental tests reported in the literature have been used to propose simple design equations to determine the axial capacity of CFST columns. The proposed equations are compared with that presented in DR AS/NZS 2327 and Albero et al.; it is shown that the proposed equations are more accurate. The proposed design procedure has been used for the Auckland International Airport Phase 4 Pier B Extension Project's structural fire design, brief details of which are presented.