Abstract: The reliability of steel columns exposed to fire is analyzed, in which the capacity reduction and fire load factors are considered. A case study for evaluating the fire and steel column temperatures and the load capacity of the steel column is carried out to analyze the structural reliability of the column. The parameters affecting the structural reliability are treated as random variables, such as the fire load, dead load, live load, thermal absorptivity of structural boundaries, thickness, density and thermal conductivity of the insulation, ratio of floor area to the total area of the fire compartment, opening factor, and so on. The mechanical and geometric properties of the steel column (e.g. yield strength, elastic modulus, cross-section area, etc.) are also taken as random variables. The fire protection systems are related to the probability of fire occurrence. The retailed analysis results show that the capacity reduction and fire load factors should not be treated as constants in all design situations; they should be varied with fire protection system in the building and the compartment size.

Key words: engineering structure, fire load factor, capacity reduction factor, reliability, steel columns, temperature field