Ultimate Temperature of Steel Frames Exposed to Fire-Part 1 Stress Redistribution and Ultimate Temperature of Steel Frames-

The verification for the structural safety of frames exposed to fire heating was carried out by the estimating method for ultimate-temperature of partial frames in the present fire resistant design.[1] The thought of the fire resistance design that the ultimate state of a partial frame, a column or beam was regarded as the design limit was based on the estimation that the ultimate temperature of the partial frame obtained by disregarding the stress redistribution of the overall frame and thermal stress, showed the lowest limit of the ultimate temperature of a real frame. However, it was presumed to be not clear what the margin the design limit had against the collapse of the whole frame because the relation between the collapses of a member, the partial frame, and the overall frame was not sufficiently taken into consideration. In this research, focusing on the effect of the stress redistribution on the ultimate temperatures of the overall frame that seismic design was carried out, the relation between the collapse of the overall frame and the total buckling of heated columns was considered by analysis results.