DESIGN STRATEGIES OF FIRE SAFETY FOR STEEL ROOF TRUSSES EXPOSED TO LOCALIZED FIRE

摘要

Steel trusses are usually employed to cover the large span buildings, and fire-resistance capacity is very important to ensure the fire safety for this type of roof structure within fire ultimate limit state.A series of steel roof truss models has been established by using ANSYS software and the behaviors of truss exposed to localized fire were under study.Then, the fire-resistance capacity of steel roof trusses under key factors has been developed by parametric method and proved by structural mechanical theory.The theoretical and numerical studies have indicated that the loading ratio, fire location, size of fire bed,fire temperature distribution and lateral bracing system for upper chords are key influencing parameters,for the fire load-bearing capacity of steel roof trusses.Finally, several strategies have been presented for the roof truss fire safety design.