To the contents of Vol. 49, issue 4
To full-text article (pdf)

An economic method to determine the strength class of wood species

G. Ravenshorst1, M. van der Linden1, A.C.W.M. Vrouwenvelder1, J.W. van de Kuilen2, 3
1 TNO Building and Construction Research, Delft, The Netherlands
2 Delft University of Technology, Delft, The Netherlands
3 CNR-Ivalsa, Italy

As a result of the demand for wood from forests that are managed in an environmentally sustainable manner, many unknown wood species are introduced into the market at the moment. To classify a wood species into a strength class and determine the accompanying grading parameters for visual grading in practice, the strength characteristics are traditionally determined by destructive tests, with a minimum of 40 test pieces.  To support a quick introduction of unknown wood species a method has been developed in which only 25% of the test sample that is investigated has to be tested destructively, and 75% can be tested non-destructively. This approach is more economic and faster than the present traditional method.  This method has been developed by obtaining general correlations that are species-independent between non-destructive measured timber characteristics and the timber strength.

Key words: timber strength, non-destructive measurements, timber strength modelling