Fire Resistances of Restrained Steel Beams Subjected to Fire Loads

Conventional fire loads and fire resistances of a steel beam still lack an adequate correlation. This paper has established the relationship between the responses of restrained steel beams and fire actions by using a new definition of fire resistances and a new expression of fire loads. By using reduction factors of elastic modulus and yield strengths, has presented three critical equations to predict the limit state of a restrained steel beam in a fire. Based on these equations and the heat transfer formula, the paper provided a new definition of fire resistances. By using the heat release rate and effective rate coefficient of thermal absorption, a new expression of fire loads has been argued. Compared with tests, the proposed approach in this paper is in good agreement with the measured values in tests. The results show that the new fire resistances could be able to reflect the facts of heat transfers and duration time. In contrast to conventional fire loads, the new fire loads are more efficient to indicate a fire load.