Design Live-Load Factor Calibration for Michigan Highway Bridges
Publication: Journal of Bridge Engineering
Volume 21, Issue 6
Abstract
In this study, a reliability-based calibration of live-load factors for bridge design specific to the state of Michigan was conducted. Two years of high-frequency weigh-in-motion (WIM) data from 20 representative statewide sites were analyzed, and load effects were generated for bridge spans from 6 to 122 m (20 to 400 ft), considering simple and continuous moments and shears, and single-lane and two-lane effects. Seventy-five-year statistics for maximum live load were then estimated with probabilistic projection. Bridge girders considered for the calibration included composite steel, prestressed concrete, side-by-side and spread box beams, and special long-span structural members. In some cases, it was found that Michigan load effects were greater than those previously assumed, often requiring higher load factors than those in current use. Moreover, significant variation in the required load factor was found, potentially resulting in significant inconsistencies in reliability if a single load factor is used for the design of all bridge types and load effects considered.
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Acknowledgments
The authors thank the Michigan Department of Transportation Research Administration for support of this effort.
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Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 21 • Issue 6 • June 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Dec 19, 2014
Accepted: Nov 19, 2015
Published online: Feb 1, 2016
Published in print: Jun 1, 2016
Discussion open until: Jul 1, 2016
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