Best Practices for Reducing the Potential for Progressive Collapse in Buildings.
Best Practices for Reducing the Potential for
Progressive Collapse in Buildings.
(3813 K)
Ellingwood, B. R.; Smilowitz, R.; Dusenberry, D. O.;
Duthinh, D.; Lew, H. S.; Carino, N. J.
NISTIR 7396; 216 p. February 2007.
Keywords:
building collapse; structural design; risk reduction;
design applications; loads (forces); structural
materials; methodology; standards; risk assessment; risk
analysis; hazard analysis; hazard assessment; structural
systems; structural engineering; case histories; safety
engineering; alternate load path; blast loading;
progressive collapse; specific local resistance; damage;
failure
Abstract:
This document is intended to provide owners and
practicing engineers with current "best practices" to
reduce the likelihood of progressive collapse of
buildings in the event of abnormal loading. The report
includes a discussion of an acceptable risk approach to
progressive collapse, which involves defining the
threat, event control, and structural design to resist
postulated event. Practical means for reducing risk for
new and existing buildings are presented. An extensive
review is provided of the design methods used to enhance
a buildings resistance to progressive collapse. These
include the indirect method (providing sufficient tie
forces), the specific local resistance method (designing
key elements to withstand abnormal loads), and the
alternate load path method (allowing for redistribution
of load in the event of the loss of a
key member). Design considerations for different
structural materials are summarized. The methodology for
evaluating and mitigating progressive collapse potential
in existing buildings is also discussed. Three
appendices provide supporting information. Appendix A
presents a worldwide review of progressive collapse
provisions in various national design standards.
Appendix B identifies knowledge gaps related to
progressive collapse that require research. Appendix C
provides case studies of progressive collapses. This
document is not intended to provide step-by-step design
guidance for practicing engineers; however, applicable
design standards are referenced and summarized in
Appendix A.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899