Comparison of Progressive Collapse Capacity of Steel Moment Resisting Frames and Dual Systems with Buckling Retrained Braces

Progressive collapse is a condition where local failure of a primary structural component leads to the collapse of neighboring members and the whole structure, consequently. In this paper, the progressive collapse potential of seismically designed steel dual systems with buckling restrained braces is investigated using the alternate path method, and their performances are compared with those of the conventional intermediate moment resisting frames. Static nonlinear Push-down and dynamic analyses under gravity loads specified in GSA guideline are conducted to capture the progressive collapse response of the structures due to column and adjacent BRBs removal, and their ability of absorbing the destructive effects of member loss is investigated. It was observed that, compared with the intermediate moment resisting frames, generally the dual systems with buckling restrained braces provided appropriate alternative path for redistributing the generated loads caused by member loss and the results varied more significantly depending on the variables such as location of column loss, or number of stories. Moreover, in the most column removal scenarios, steel dual systems are more capable to resist the progressive collapse loads and maintain the structural overall integrity.