Assigning Design Values to Four "Minor" Properties of MSR Lumber
William L. Galligan Consultant, Salem, Oregon, USA
Donald A. DeVisser Technical Director, West Coast Lumber Inspection Bureau, Portland, Oregon, USA
ABSTRACT
The commercial NDE of structural lumber in North America has used stiffness as a measurement parameter since 1963. Early emphasis was placed on assignment of design values for bending, tensile and compressive strength parallel to grain. Assignment of "minor" properties was based on species average clear wood data - the same procedure used for the visual grades. This traditional procedure granted no credit to the higher MSR grades and ignored a design MOE in a flatwise orientation. Design property assignments for shear, compression perpendicular to grain, specific gravity and MOE in a flatwise orientation can now be related to grade. A new ASTM standard on mechanically graded lumber contains some of these concepts; others are imbedded in the procedures of the agencies that write grading rules for American Standard Lumber.
Publication Source: Proceedings of the 12th International Symposium on Nondestructive Testing of Wood University of Western Hungary, Sopron, 13-15 September 2000, ISBN 963 7180 88 5 Publisher: University of Western Hungary, H 9400 Sopron, P.O.Box 132, FAX: +36 99 311 103
