FE analysis of fire resistance of concrete filled CHS columns

This paper is concerned with the FE method, used to calculate the fire resistance of concrete filled CHS columns. Concrete filled steel CHS structures are used widely all over the world, especially in high buildings and long span bridges. The current standards BS5990 and DD ENV 1994-1-2 confer the methods to calculate the fire resistance of these members, most of which are based on the experimental results and simplified methods. With the development of FE techniques and research on material mechanics in fire and high temperatures, it is possible for FE methods to predict more accurately the failure of concrete filled CHS columns under fire. In this paper, the behaviour of concrete filled CHS columns subjected to fire on all sides are investigated and the corresponding fire resistances are computed using FEA. The temperature distribution in the circular section during the fire is calculated by the two-dimensional nonlinear finite program FIRES-T, which depends on the thermal properties of materials. The results agree well with the current codes.