Research Report RR:D07-1005
This research report provides information about the ASTM interlaboratory study (ILS) of precision of ASTM D198 test method for the flexural or bending modulus of elasticity (MOE) of lumber under third-pointing loading. The study was conducted during 2006-2007 in sixteen laboratories in the USA and Canada in accordance with Practice E691. The scope of the ILS was limited to determination of the apparent MOE of 2x4 size materials using the deflection of the beam’s neutral axis at the mid-span measurements of the load head displacement, similar to the D4761 edgewise bending test method under third-point loading. The test materials involved a limited sample from three product families: machine stress rated (MSR) lumber, laminated veneer lumber (LVL) and laminated strand lumber (LSL). Five specimens of each material were tested in a round robin fashion in each laboratory. Four test results were obtained for each piece of material and orientation, edgewise and flatwise. Span-to-depth ratios of 18 and 21were used in the edgewise and flatwise orientations, respectively. In addition, a steel reference bar (RHS) of comparable stiffness was tested to help tracking any possible changes in the stiffness of the wood materials from repeated loading and to serve as a reference for tracking potential changes in the specimen mass from moisture content changes.
D198-14 Standard Test Methods of Static Tests of Lumber in Structural Sizes
Committee D07 on Wood