Timber Frame Moment Joints with Glued-In Steel Rods. II: Experimental Investigation of Long-Term Performance
Publication: Journal of Structural Engineering
Volume 138, Issue 6
Abstract
The pull-out performance of steel rods glued into timber is well-documented, and short-term tests by many researchers have demonstrated reliable strength. The behavior of glued-in steel rods in moment-resisting beam-column joints is much more complex because of anisotropy of wood in the connection region, discontinuity of material at the interface, and the possible effects of creep of timber and stress concentrations on the joint performance. This paper describes the results of a series of long-term load tests on moment-resisting joints between glulam members and separate load tests on the various joint components, including the epoxy itself and the timber stressed perpendicular to the grain. Different types of knee joints, with rods fully epoxied along their length or epoxied only in one member and tensioned in the other, and with different geometries (with the beam extended over the column or with the column extended past the beam) were tested. Measurements were recorded to identify time-dependent stress redistribution within the test joints, creep of the joint as a whole, and possible crushing of the timber-to-timber bearing surfaces. Local deformation of timber loaded in compression perpendicular to the grain was found to contribute to excessive joint deformations in tests in which the steel rods were not glued over their full length. The test results confirm the possibility to use the transformed section method in design as presented in the first companion paper, and address a number of issues pointed out in the same paper.
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Acknowledgments
Special thanks are due to Chris Wallington for performing all of the tests during his research project as an undergraduate student at the University of Canterbury, and to Prof. Andy Buchanan for his useful suggestions and contributions to this research. The authors thank John Duncan of BRANZ for a research grant with the University of Canterbury. Thanks to Owen Griffiths and McIntosh Laminates for supplying material and financial help. Thanks also to all the technicians for their support, particularly John Maley, Alan Poynter, Peter Coursey, Mike Weavers, Richard Newton, and Stuart Toase.
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Information & Authors
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Published In
Journal of Structural Engineering
Volume 138 • Issue 6 • June 2012
Pages: 802 - 811
Copyright
© 2012. American Society of Civil Engineers.
History
Received: Oct 6, 2010
Accepted: Oct 14, 2011
Published online: Oct 18, 2011
Published in print: Jun 1, 2012
Published ahead of production: Jun 15, 2012
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