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Thinking beyond the usual strength grades – with examples of British spruce and larch

Ridley-Ellis, Dan; Adams, Steven; Lehneke, Stefan



This paper summarises the processes and normative requirements involved in grading of structural timber, and outlines a number of areas in which matters may be improved, so as to make better use of the true properties of the timber resource used. The activities of resource segregation and timber grading are well researched, but what is not commonly realised is that there are opportunities to do things more efficiently. This is especially true when the structural timber is produced with a specific customer, project, or end use in mind. The paper uses data from research projects, and development of machine grading settings, to illustrate how assignment of timber to a limited set of strength grades can, in exchange for convenience in trade, involve considerable compromise in design properties. In some cases, this trade convenience is not necessary or can still be obtained while also permitting less of a compromise in design properties. The paper also explains why, in research, knowledge of the timber grade is not all that useful and why it is necessary to take other steps to characterise the material. The focus of the paper is strength grading in Europe, but many of the aspects are also applicable elsewhere.


Ridley-Ellis, D., Adams, S., & Lehneke, S. (2016, August). Thinking beyond the usual strength grades – with examples of British spruce and larch. Presented at World Conference on Timber Engineering (WCTE 2016)

Presentation Conference Type Conference Paper (Published)
Conference Name World Conference on Timber Engineering (WCTE 2016)
Start Date Aug 22, 2016
End Date Aug 25, 2016
Acceptance Date Aug 22, 2016
Publication Date Aug 22, 2016
Deposit Date Jan 11, 2017
Publicly Available Date Jan 11, 2017
Book Title Proceedings of the World Conference on Timber Engineering (WCTE 2016), August 22-25, 2016, Vienna, Austria, Eds.: J. Eberhardsteiner, W. Winter, A. Fadai, M. Pöll, Publisher: Vienna University of Technology
ISBN 978-3-903039-00-1
Keywords Strength grading; Strength classes; Sawn timber; Characterisation; Prediction
Public URL
Contract Date Jan 11, 2017


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