Stability of steel moment resisting frames under fire loading

The steel moment resisting frames (SMRF) are the most common type of structural systems for bearing the gravity and lateral loads while this system is one of the more vulnerable structural systems under fire loading due to rapid descent of stiffness and strength properties of steel with temperature. In this regards, many researchers experimentally investigated the behavior of steel structural elements (e.g. Column, Beam, Connections) when exposed to fire. Most of these researches are limited to a sole element. Therefore, in this paper the entire behavior of the Steel moment resisting frames with intermediate ductility under different fire scenarios and for several gravity load ratios are studied through the numerical models. Three steel moment resisting frame with different stories and gravity load ratios in this study are considered. The analytical models of the studied frames are modeled in ABAQUS software. The results show that in different cases depending on the ratio of the gravity loads, different failure modes occur. In cases with the normal gravity loads, progressive collapse does not occur while with increasing the gravity loads; the vulnerability of structures increases and the potential of progressive collapse are increased.Fire loading, Steel moment resistant frame, Progressive collapse, Numerical models