ABSTRACT
During the accidental fire events at the Plasco building in Tehran (2017) and the World Trade Centre Towers (WTC) 1, 2 & 7 in New York (2001) flames were observed to travel horizontally across the floor plate and vertically to different floors. Following the WTC fires a number of studies have been carried out on the effects of vertically travelling fires to structures. However, most of them have been limited to the structures with long span composite truss system as in WTC Towers. In this work the response of a substantially different structural system, i.e. a generic multi-storey steel frame, subjected to travelling fires in multiple floors is examined. A 2D 10-storey 5-bay steel frame is modelled in the finite element software LS-DYNA. In total, 51 fire simulations are considered. We find that both the fire type (travelling or a standard fire) and number of fire floors have a significant effect on the failure time and type of collapse mechanism. One single worst case fire scenario cannot be readily identified, especially considering the uncertainty in the number of fire floors likely to occur in a real fire.
