Engineering Progressive Collapse in Cold-Formed Steel Buildings

Progressive collapse guidelines for DoD buildings were first introduced in 2001 to provide design requirements to reduce the potential of disproportionate collapse for new and existing DoD facilities in an extreme blast event. The guidelines are published in the Unified Facilities Criteria UFC 4-023-03, Design of Buildings to Resist Progressive Collapse, and are applicable to buildings three (3) stories and taller. Since cold-formed steel (CFS) framing is a potential construction material in mid-rise load-bearing wall structures for DoD facilities, it is essential for CFS engineers to learn practical methods to analyze and design CFS framing to resist progressive collapse.

This presentation will introduce the main concepts of structural design to mitigate the effects of progressive collapse in buildings, then will discuss the differences between the direct and the indirect methods of design. Focusing on CFS load-bearing wall buildings, the presentation will discuss how to qualify the structural components of the building (walls, floors and roof) for the progressive collapse analysis. A worked design example for a multi-story building will be presented and discussed with a focus on how to deal with sizing framing members and connection details.

Nabil Rahman, Ph.D., P.E.
FDR Engineers, PLLC

Nabil Rahman, Ph.D.,P.E., is a Principal at FDR Engineers in Raleigh, NC. Dr. Rahman is a past chairman of the Cold-Formed Steel Engineers Institute (CFSEI) and was the 1st recipient of John P. Masten Distinguished Service Award from CFSEI. He is also a past chairman of ASCE-SEI Committee on Cold-Formed Steel and a member of the CFS Committee on Specification and Committee on Framing.

Dr. Rahman has a vast experience in design and fabrication of CFS framing, as well as product development and software development. Dr. Rahman has been a blast consultant on several CFS projects, including load bearing barracks buildings and roof structures. He is also a named inventor on seven US patents and the author of over 50 research papers and technical notes.