Steel temperature calculations in performance based design, Advanced techniques for thermal response calculations with FE-analysis

Abstract

By using advanced FEA techniques, the predicted temperature in steel elements can be reduced significantly (see paper by Ulf Wickström). By in addition assuming a performance based fire exposure obtained with numerical fire models such as Fire Dynamics Simulator, FDS, the steel temperatures can be even further reduced.Most calculation methods assume the fire exposure of the steel sections to be uniform. By using section factors A/V, i.e. the circumference over the area, and the most onerous of the fire exposing temperatures from computer fluid dynamics, CFD, calculations, the temperatures is over-estimated which leads to very conservative and costly solutions.By considering the cooling effect of concrete structures and shadow effects, the temperatures can be reduced in the steel. By combining differentiated fire exposing temperatures from CFD calculations with consideration to shadow effects and the cooling of concrete, the temperature in the steel beam can be reduced even further