Progressive collapse of steel moment frame subjected to post-earthquake fire

Earthquake events and consequent structural damages can lead to occurrence of fire in parts of buildings. In this paper, the effects of the fire after earthquake on a steel moment frame building are investigated. For this, a two-dimensional model of such building is considered here as case study. The fire resulting from several earthquakes is applied in part of the ground floor.

For evaluating different performance levels (O, IO, LS and CP) of the mentioned frame, six lateral displacements are applied on the frame using nonlinear static analysis (push over). The acquired results of this study show that the time of instability of structures with lower performance level is different in case of a simple fire and a fire following an earthquake.

However, the difference is disputable for structure with performance levels LS and CP (containing most of the buildings). This paper presents a simple and effective method to investigate the influence of the fire following earthquake for unprotected steel structures by considering performance level for post-earthquake fire by structural designers.