Accounting for Ground-Motion Spectral Shape Characteristics in Structural Collapse Assessment through an Adjustment for Epsilon
Publication: Journal of Structural Engineering
Volume 137, Issue 3
Abstract
One of the challenges of assessing structural collapse performance is the appropriate selection of ground motions for use in the nonlinear dynamic collapse simulation. The ground motions should represent characteristics of extreme ground motions that exceed the ground-motion intensities considered in the original building design. For modern buildings in the western United States, ground motions that cause collapse are expected to be rare high-intensity motions associated with a large magnitude earthquake. Recent research has shown that rare high-intensity ground motions have a peaked spectral shape that should be considered in ground-motion selection and scaling. One method to account for this spectral shape effect is through the selection of a set of ground motions that is specific to the building’s fundamental period and the site hazard characteristics. This selection presents a significant challenge when assessing the collapse capacity of a large number of buildings or for developing systematic procedures because it implies the need to assemble specific ground-motion sets for each building. This paper proposes an alternative method, whereby a general set of far-field ground motions is used for collapse simulation, and the resulting collapse capacity is adjusted to account for the spectral shape effects that are not reflected in the ground-motion selection. The simplified method is compared with the more direct record selection strategy, and results of the two approaches show good agreement.
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Acknowledgments
This research was supported primarily by the Earthquake Engineering Research Centers Program of the National Science Foundation under award number NSFEEC-9701568 through the Pacific Earthquake Engineering Research Center (PEER). The research findings were also supported by related studies conducted for the “ATC-63 Project,” which is supported by the Federal Emergency Management Agency. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the writers and do not necessarily reflect those of the National Science Foundation or the Federal Emergency Management Agency.
The writers also acknowledge the contributions of Nico Luco, Stephen Harmsen, and Arthur Frankel of the USGS, who provided the mean data used in this research; the suggestions and advice of Dr. Charlie Kircher and other members of the “ATC-63 Project;” and the assistance of Jason Chou and Brian Dean in conducting the structural collapse analyses used in this study.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 137 • Issue 3 • March 2011
Pages: 332 - 344
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Oct 13, 2008
Accepted: Aug 31, 2009
Published online: Oct 2, 2009
Published in print: Mar 1, 2011
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