4.1 The procedures described in this practice are intended to be used to establish allowable stress and modulus of elasticity values for solid sawn, visually graded dimension lumber from In-Grade type test data. These procedures apply to the tested and untested sizes and grades when an adequate data matrix of sizes and grades exists. In addition, the methodology for establishing allowable stress and modulus of elasticity values for combinations of species and species groups is covered. Allowable stress and modulus of elasticity values may also be developed for a single size or a single grade of lumber from test data.
4.2 Methods for establishing allowable stress and modulus of elasticity values for a single size/grade test cell are covered in Practice D2915. The appropriateness of these methods to establish allowable stress and modulus of elasticity values is directly dependent upon the quality and representativeness of the input test data.
4.3 A monitoring program shall be established to periodically review the continued applicability of allowable properties derived by this practice. A monitoring program will establish data sets that are either the same as, above, or below the data that was used to develop the current allowable properties. Upon detection of a statistically significant downward shift, evaluation of the data and confirmation of remedial actions shall be undertaken. When evaluation is not undertaken or the results of the evaluation indicate an adjustment to allowable properties is appropriate, a reassessment shall be conducted to re-establish allowable properties.
1.1 This practice covers the principles and procedures for establishing allowable stress values for bending, tension parallel to grain, compression parallel to grain and modulus of elasticity values for structural design from “In-Grade” tests of full-size visually graded solid sawn dimension lumber. This practice also covers procedures for periodic monitoring, and additional procedures, if needed, for evaluation and possible reassessment of assigned design values. This practice is focused on, but is not limited to, grades which used the concepts incorporated in Practice D245 and were developed and interpreted under American Softwood Lumber PS 20.
1.2 A basic assumption of the procedures used in this practice is that the samples selected and tested are representative of the entire global population being evaluated. This approach is consistent with the historical clear wood methodology of assigning an allowable property to visually-graded lumber which was representative of the entire growth range of a species or species group. Every effort shall be made to ensure the test......
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