Fire Resistant Study for Long Span Beams Made of FR 490 Steels

Building could be severely influenced by fire and it can be demolished so that the major structural elements such as columns and beams required to be coated by fire protection materials according to each condition. Especially, a steel framed building regarded as a weaken structures when the building is engulfed with a severe fire condition. Therefore, the fire resistant steel (FR 490) has been developed to improve the structural properties of an ordinary structural steels at high temperature. Generally, the fire resistance of structural beam built with a structural steel can be measured by horizontal furnace using a standard testing method by each nation’s standard. However, the real length of the beam showed the tendency longer than that of the horizontal furnace. Therefore, it is considered more important to know the real fire resistant performance of structural beams. In this paper, to evaluate the fire resistant performance of long span beams made of the FR 490, the fire engineering method is done using not only materials properties at high temperatures but a heat transfer, a stress theory. The results showed that as the length of beams are longer, the maximum load bearing capacities at high temperatures are lower and the deflections are increased