Abstract
Wood-composite I-joists are commonly used in residential and light commercial construction. I-joists are intended for use in dry-service environments, but rare situations exist in which I-joists may be subjected to environments that promote elevated moisture content levels. For example, flooding, poor construction practices or disaster situations leading to unprotected exposure, or abnormally long construction delays may arise. In these extreme situations it becomes necessary to characterize I-joist performance to determine if replacement is needed. This research subjects wood-composite I-joists (302 mm deep by 1.32 m long) to two extreme environments intended to assess moisture durability: laboratory-accelerated weathering and unprotected outdoor exposure. Joists are tested in short-span bending to assess shear capacity after conditioning back to the dry state. Shear capacity decreases as a result of exposure to high moisture conditions. All outdoor exposure intervals lead to greater losses in shear capacity than do any of the laboratory-accelerated weathering periods evaluated. In addition, the failure mode of I-joists changes with exposure type and duration.
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Acknowledgments
Financial support was provided by the Wood-Based Composites Center, a National Science Foundation Industry/University Cooperative Research Center (WBC I/UCRC Project Number F-01-KA). The laboratory assistance of Milo Clauson and Ian Morrell is greatly appreciated.
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Published In
Journal of Materials in Civil Engineering
Volume 30 • Issue 7 • July 2018
Copyright
©2018 American Society of Civil Engineers.
History
Received: Jul 19, 2017
Accepted: Jan 9, 2018
Published online: May 12, 2018
Published in print: Jul 1, 2018
Discussion open until: Oct 12, 2018
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