Reliability-Based Design Snow Loads. II: Reliability Assessment and Mapping Procedures
Publication: Journal of Structural Engineering
Volume 143, Issue 7
Abstract
This paper describes the development of reliability-targeted ground snow load maps for use in building (roof) design. The proposed procedures aim to ensure that structures designed achieve a target safety index, taken to be 3.0 as defined in ASCE 7 (ASCE 2010). When applied to the U.S. state of Colorado, the reliability-targeted mapping procedure shows that to achieve this target reliability index, design ground snow loads may need to be larger or smaller than the 50-year return period load that ASCE 7 currently stipulates for design, depending on the site and winter climate conditions at that site. Sites with larger coefficients of variation in the annual maximum snow load (in Colorado, lower-altitude sites) generally need design loads larger than the 50-year values. The paper also advances snow reliability assessment procedures through the proposal of a new model for the ground-to-roof conversion factor needed for quantifying roof snow loads as a function of ground snow loads. Spatial smoothing and altitude-dependent mapping procedures are described.
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Acknowledgments
This paper summarizes work done by the Structural Engineers Association of Colorado Snow Loads Committee. Other members of the committee have contributed extensively to the study, including Richard Cunningham and Robert Pattillo. Dania Hussain and Derek Kozak also contributed. Early analyses used in developing this research were supported in part by the National Science Foundation through Grant No. 0926680. Any opinions, findings, conclusions, or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of the National Science Foundation. Support for this work provided by J. R. Harris & Co. is also gratefully acknowledged.
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Published In
Journal of Structural Engineering
Volume 143 • Issue 7 • July 2017
Copyright
©2017 American Society of Civil Engineers.
History
Received: Jan 4, 2016
Accepted: Oct 24, 2016
Published online: Mar 3, 2017
Published in print: Jul 1, 2017
Discussion open until: Aug 3, 2017
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