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Workshops Address How to Avoid Progressive Collapse

The 1995 bombing that triggered the collapse of the Alfred P. Murrah Federal Building in Oklahoma City, Okla., first raised concerns in the United States about the safety of public buildings from "progressive collapse" (the spread of an initial local failure in a structure until it results in the collapse of the entire building or a disproportionately large part of it). Since that event and the subsequent terrorist attacks of Sept. 11, 2001, both private and public groups have begun to address progressive collapse as a design requirement for new buildings.

Working with experts in the design, construction and operation of buildings, the National Institute of Standards and Technology (NIST) has prepared a comprehensive set of best practices guidelines for reducing the likelihood of progressive collapse of structures, and is participating in a series of technical workshops to spread the word.

Development, publication and dissemination of the report, Best Practices for Reducing the Potential for Progressive Collapse in Buildings, responds to one of the 30 recommendations for improvements to building codes, standards and practices in the final report of NIST's investigation into the WTC disaster. Among the items featured in the document are: an acceptable risk approach to progressive collapse, a review of design methods used to enhance a building's resistance to progressive collapse, a look at progressive collapse provisions in building standards around the world, and case studies of progressive collapse events triggered by abnormal loading (where building integrity is compromised by unexpected hazards from explosions, aircraft or vehicle impacts, foundation failures, construction errors, etc.).

To aid the understanding and use of the guidelines, and to provide an opportunity for technical exchange with the lead authors of the report, NIST and the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE) has organized a series of four workshops across the nation. The workshop dates and locations are: Sept. 7, Denver; Sept. 14, New York City; Sept. 28, San Francisco; and Oct. 19, Chicago (as part of the 2006 ASCE Annual Conference).

All pre-registered attendees will receive a draft copy of the NIST document in advance of the workshop. To register online, select a date and location under "Progressive Collapse Workshops" at the SEI Web site,

For more information on the guidelines, contact H.S. Lew, (301) 975-6060, hsl [at] (hsl[at]nist[dot]gov). For details on the NIST/SEI workshops, contact Mary Ellen Saville, (703) 295-6195, mesaville [at] (mesaville[at]asce[dot]org).

Released August 31, 2006, Updated January 12, 2023