Heat Actions Analysis of Actual Fire in Steel Structures

The paper presents the analysis of the influence of various types of actual fire loads upon the given industrial structure - steel hall. The simulation included several different fire loads with different quantities of combustible material and different floor surfaces of the structure covered with combustible material. By applying the approximate model of zones, for different fire loads, obtained by varying the surface of ventilation openings, it was possible to obtain the temperature curves as a function of time which were used as the temperature influence upon the supporting steel structure. The obtained temperature curves were compared to a Standard temperature-time curve. It was proved that for large compartments the action of actual fire loads cannot be computed by applying the standard curve but by determining actual temperature curves as a function of time. The heat transfer through a basic material of the supporting steel structure has been modelled according to the obtained values of the temperature curves by applying a transient, non-linear model and the necessity for the protection of the steel structure has been established. These investigations of the actual temperature-time parameter curves, for large compartments and different fire loads have been carried out within the National Application Documents in the field of fire action.