Progressive Collapse Criteria and Design Approaches Improvement

Abstract

Methods for the assessment of structural designs or existing structural systems for susceptibility to disproportionate (progressive) collapse and prescriptive methods intended to mitigate or decrease the likelihood of progressive (disproportionate) collapse are approaching adolescence as compared to the age and maturity of other engineering design standards and approaches. U.S., British, and Eurocode standards such as ASCE–7, BS EN 1991–1–7, 2006, and Eurocode 1: Actions on structures first established design philosophies and some prescriptive approaches, while later U.S. guidelines and IBC code provisions have attempted to fill in the gaps with refined prescriptive methods or detailed static and dynamic analysis approaches. The U.S. Department of Defense (DoD) and the U.S. General Services Administration (GSA) have published design and analysis guidelines in recent years. The DoD guidelines have been updated three times since inception, and GSA guidance is currently being updated to take advantage of the DoD improvements through adaptation of DoD methods within GSA applicability requirements. Additionally, the Structural Engineering Institute (SEI) in the United States has focused on the efforts of several technical experts within their Disproportionate Collapse Mitigation Standards Committee. This paper provides updates on the steadily converging approaches and documents. Specifics of analysis approach updates as well as design philosophy and applicability direction are presented and discussed.