The Alternate Path Method is used to examine the vulnerability of a 5-story barracks building to progressive collapse based on DoD criteria UFC-4-023-03. The building is composed of composite deck floor system and steel roof trusses, all supported by cold-formed steel stud load bearing walls. Two different wall section removal scenarios at the first story of the building were considered for the analysis. The analysis was performed using the “Extreme Loading® for Structures” software, a 3-dimensional nonlinear dynamic analysis software.
The results show the ability of the composite deck floor slabs to bridge over the removed wall sections. The slabs were able to re-distribute the gravity loads to adjacent wall components, while some of the loads were picked up in tension by the stud walls above the slabs. The study provides a good understanding of the composite deck floor-cold-formed steel stud bearing walls building system in resisting progressive collapse.
Rahman, N., Elfouly, A., and Booth, M. “Alternate Path Progressive Collapse Analysis of Steel Stud Bearing Wall Structures,” Proceedings of the 2011 Structures Congress, Las Vegas, Nevada, ASCE, April 2011.