AS/NZS 2878:2000 pdf – Timber-Classification into strength groups

AS/NZS 2878:2000 pdf – Timber-Classification into strength groups

AS/NZS 2878:2000 pdf – Timber-Classification into strength groups.
The test specimens to be used shall be 20 x 20 x 300 mm long. They shall be selected from boards of wood so as to he parallel to the longitudinal grain of the wood, and to have one face as near as possible to the radial direction.
The specimens shall he cut out of clear wood. i.e. wood clear of knots and other botanical features. For softwoods the specimens shall be clear of corewood, i.e. at least 50 mm from the centre of the pith: for hardwoods the specimens shall he clear of brittle heart.
Prior to testing, all specimens shall be conditioned so that the moisture content is constant throughout the specimen. i.e. a skin-effect’ caused by the occurrence of differential moisture contents within a specimen shall he avoided.
The specimen shall he tested in centre-point loading over a span of 280 mm. Orient the specimen so that the growth rings run vertically (or as close to the vertical as possible depending on how the specimen was cut). Load the specimens to failure and record the modulus of elasticity and bending strength.
After the specimen has failed, examine the ruptured surface to check that the specimen complies with the target requirements specified in Paragraph B I. Any non-compliance (such as the occurrence of hidden knots, corewood in softwoods, brittle heart in hardwoods or slope of grain greater than I in 10) shall cause the specimen to be rejected.
The moisture content of the timber at the time of test shall be measured.
NOTE: The methods used in Australia for the testing of small clear specimens of timber to determine mechanical strength properties arc described by Mack. J. J. (1979) Australian Methods for Mechanically Testing Small Clear Specimens of Timber. CSIRO Division of Building Research. Technical Paper (Second Series) No. 31. In the absence of an Australian Standard. BS 373. or ISO 3133 and ISO 3349 may be used following the procedure given in this Standard.