Structural Fire Engineering of columns and space frames using Vulcan and Safir

Some large structures can be very sensitive to localised heating cases and the introduction of large compression forces due to restrained thermal expansion. These additional compression forces can eventually induce buckling of individual space frame members, potentially leading to progressive collapse of the structure at relatively low temperatures - often below those that are commonly assumed as their failure temperatures. In order to safeguard against progressive collapse, as is a requirement of some building regulations, 3D structural behaviour - including the post-local failure stage - should be analysed. In this paper, the results obtained from analyses carried out in two structural behavioural modelling programs - SAFIR and VULCAN - have been compared in order to carry out a benchmark study. The study is divided into two parts: • Initially a range of columns were uniformly heated by a linearly increasing temperature profile in order to establish how close the agreement between the results obtained in the two models is for simple cases; and • Subsequently, a thermo-mechanical analysis was carried out where a space frame roof was exposed to both localised and global heating regimes to evaluate the ability of the software packages to analyse the structural behaviour after the buckling of a single element - the post- local failure stage.