Alternate Path Method in Progressive Collapse Analysis: Variation of Dynamic and Nonlinear Load Increase Factors
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Volume 17, Issue 4
Abstract
In performing alternative path analyses for checking the potential of a structure to progressive collapse, most designers often choose static procedures, which tend to be simpler and less labor demanding. As progressive collapse is a dynamic and nonlinear event, the load cases for the static procedures require the use of factors to account for inertial and nonlinear effects. A number of inconsistencies have been identified in the way the existing guidelines applied dynamic and nonlinear load factors to their static approaches. As part of an existing effort to update the existing guidelines, this study looked into the behavior of a variety of reinforced-concrete and steel moment-frame buildings to investigate the magnitude and variation of the dynamic and nonlinear load increase factors. The study concluded that the factors in the existing guidelines tend to yield overly conservative results, which often translate into expensive designs and retrofits. This study identified new load increase factors and proposes a new approach to utilize these factors when performing alternative path analyses for progressive collapse.
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Acknowledgments
The authors wish to express their gratitude and sincere appreciation to Naval Facilities Engineering Command (NAFVAC) for financing this research. Nonetheless, the conclusions of the paper reflect only the view of the authors.
References
American Concrete Institute (ACI). (2005). “Building code requirements for structural concrete and commentary. 318-05/318R-05, American Concrete Institute, Farmington Hills, MI.
ASCE. (2005). “Minimum design loads for buildings and other structures.” ASCE/SEI 7-05, Reston, VA.
ASCE. (2006). “Prestandard and commentary for the seismic rehabilitation of buildings.” ASCE/SEI 41-06, Reston, VA.
Department of Defense (DoD). (2005). “Design of buildings to resist progressive collapse.”Unified Facilities Criteria (UFC) 4-023-03, Washington, DC.
General Services Administration (GSA). (2003). Progressive collapse analysis and design guidelines for new federal office buildings and major modernization projects, Washington, DC.
McKay, A. (2008). “Alternate path method in progressive collapse analysis: Variation of dynamic and non-linear load increase factors.” M.S. thesis, Dept. of Civil Engineering, Univ. of Texas, San Antonio, TX.
McKay, A., Marchand, K., and Stevens, D. (2008). “Dynamic increase factors (DIF) and load increase factors (LIF) for alternate path procedures.” Rep. Prepared for UFC 4-023-03 Steering Group, Protection Engineering Consultants, Spring Branch, TX.
Ruth, P. (2004). “Dynamic considerations in progressive collapse guidelines.” M.S. thesis, Dept. of Civil Engineering, Univ. of Texas, Austin, TX.
SAP2000 [Computer software]. Berkeley, CA, Computers and Structures.
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© 2012 American Society of Civil Engineers.
History
Received: Feb 4, 2011
Accepted: Jan 26, 2012
Published online: Jan 28, 2012
Published in print: Nov 1, 2012
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