Shear Properties of Eastern Hemlock with Respect to Fiber Orientation for Use in Cross Laminated Timber
Publication: Journal of Materials in Civil Engineering
Volume 32, Issue 7
Abstract
Shear properties of the cross layer in cross laminated timber (CLT) panels are critical for design purposes, especially for applications with high concentrated loads and low span-to-depth ratios. Understanding how the shear properties of CLT lamstock vary with respect to fiber orientation—from perpendicular-to-grain (90°) to parallel-to-grain (0°)—can lead to new and innovative panel layups with superior shear performance. In this study, two-plate shear specimens (per the relevant standard) were fabricated with fiber orientations of 0°, 30°, 45°,60°, and 90° with respect to the shear load direction using eastern hemlock lumber. Both shear modulus and shear strength were measured as a function of fiber orientation. The influence of fiber orientation and the interaction of resisting components on the shear properties are discussed concerning observations of the types of failure modes. The results indicate that the effective shear stiffness () and the characteristic shear strength () for a traditional (90°) CLT panel made from eastern hemlock would satisfy grade E3 CLT per the relevant standard. Moreover, the shear strength of the angled cross layers with 30° and 45° fiber orientation with respect to the major panel axis would be 98% and 59% higher, respectively, than CLT with a 90° cross layer orientation.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request, including the load-deflection response of the planar shear test for 0°, 30°, 45°, 60°, and 90° specimens.
Acknowledgments
This research was generously supported by the Massachusetts Executive Office of Energy and Environmental Affairs (EOEEA) Award No. 117-1855. The authors also thank technical laboratory assistant, Mr. Seth Lawrence, and research assistant, Mr. Eric Waterman, for their technical support.
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Published In
Journal of Materials in Civil Engineering
Volume 32 • Issue 7 • July 2020
Copyright
©2020 American Society of Civil Engineers.
History
Received: Mar 7, 2019
Accepted: Dec 16, 2019
Published online: Apr 22, 2020
Published in print: Jul 1, 2020
Discussion open until: Sep 22, 2020
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