ASTM International

Standard Practice for Establishing Clear Wood Strength Values
 N D2555

Annotation

This practice covers the determination of strength values for clear wood of different species in the unseaMEned condition, unadjusted for end use, applicable to the establishment of working stresses for different solid wood products such as lumber, laminated wood, plywood, and round timbers. Presented are:

Procedures by which test values obtained on small clear specimens may be combined with density data from extensive forest surveys to make them more representative,

Guidelines for the interpretation of the data in terms of assigned values for combinations of species or regional divisions within a species to meet special marketing needs, and

Information basic to the translation of the clear wood values into working stresses for different solid wood products for different end uses.

For species where density survey data are not as yet available for the re-evaluation of average strength properties, the presently available data from tests made under the sampling methods and procedures of Test Methods D143 or Practice E105 are provided with appropriate provision for their application and use. Because of the comprehensive manner in which the density survey is undertaken, it follows that the reevaluated strength data are intended to be representative of the forest stand, or rather large forest subdivisions.

Some useful mechanical properties (tensile strengths parallel and perpendicular to grain, modulus of rigidity for a longitudinal-transverse plane, and transverse modulus of elasticity) have not been extensively evaluated. Methods are described for estimating these properties by their relation to other properties.