Steel structures may be exposed to localized heating by ignition of the fire source nearby. Flame impingement from localized fire may lead to high temperatures in the exposed steel members, which may lead to structural collapse. This paper numerically investigates the thermal and mechanical behaviors of restrained steel beams exposed to flame impinged localized fires. Four steel beams with different restraints were considered. Developing and steady burning fires were investigated. The standard ISO834 fire was also used for comparison. The study finds that the temperature distributions within the steel beams subjected to flame impinged localized fires are highly non-uniform both across and along the beams. Along the beam length, the temperatures near the fire source may be hundreds of degrees higher than those far from the fire source. Due to different temperature distribution, the deformation mode for restrained steel beam subjected to flame impinged localized fire may be significantly different to that subjected to the standard ISO834 fire. The failure temperatures for restrained steel beams subjected to flame impinged localized fires may be higher or lower than those subjected to the standard ISO834 fire. The standard fire may lead to unsafe design if the potential real fires are flame impinged localized fires.
Citation: Journal of Constructional Steel Research
Pub Type: Journals
Restrained steel beam, Flame impinged localized fire, Thermal and mechanical behavior, Numerical investigation