Effectiveness of Progressive Collapse Resistance Criteria against Blast Loading

Current design standards provide methodologies to analyze and design structures against disproportionate collapse, colloquially referred to in instances as progressive collapse. While these standards generally improve the overall robustness of structures, it is not known with a high degree of certainty how these structures will perform directly against blast loading. There is a need for blast and structural engineers alike to incorporate disproportionate collapse mitigations that adequately address specific design basis threats (DBT), such as blast. This paper tests the tie-force collapse prevention methodology outlined in UFC 4-023-03 (2013), against a vehicle borne improvised explosive device (VBIED) detonated within an internal basement. Consideration is given to a typical multi-story structural steel building frame where the tie force method has been applied. Empirical methods are used to determine the applied blast loading and finite element analysis (FEA) is used to analyze the highly transient structural response under these loads. Expected levels of damage and the limitations of using a standardized approach to collapse prevention are summarized within this paper. The purpose of this paper is to provide blast engineering practitioners an understanding of considerations in applying general collapse prevention provisions in lieu of an assessment where a blast DBT is modeled explicitly.