The effect of push-out of perimeter building columns on their survival in fire

There has been some concern that column distortion due to the expansion of beams exposed to fire may reduce the axial load capacity to such an extent that failure occurs in the column, even if it is protected from the fire. In this paper the structural analysis software VULCAN, which has been developed to perform non-linear analysis of three-dimensional frames and sub-frames subjected to fire, has been used to predict the behaviour of a range of column sub-frames in fire scenarios. The effect of thermal expansion of unprotected beams on the critical temperatures of edge columns has been studied for different levels of axial load. These preliminary results indicate that the reduction in column capacity is not critical, particularly when a composite frame is used.