Fire resistance calculation of large span steel structure

In this paper, McCaffrey plume model is introduced to calculate convection heat flux to large span steel structure during fire, and a critical temperature is defined, below which the stress calculation could be omitted. It´s also suggested that the impact of the failure of a certain section on the whole structure should be considered. Such method is applied to the fire safety analysis of the large span steel structure of an airport. The results show that the temperature is sensitive to the height, thus the protection of the low position beams should draw special attention. While the column is too close to the fire source, it could get over heated, even if protected by fire retardant coating, so the accumulation of combustibles close to the column should be prevented during daily operation.