1、Designation: D1990 14D1990 16Standard Practice forEstablishing Allowable Properties for Visually-GradedDimension Lumber from In-Grade Tests of Full-SizeSpecimens1This standard is issued under the fixed designation D1990; the number immediately following the designation indicates the year oforiginal
2、adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONVisual stress-grades of lumber manufactured in North America have ev
3、olved from the proceduresof Practice D245. Allowable stress and modulus of elasticity values were determined for these gradesusing the procedures of Practice D245 and the appropriate clear wood values of Practice D2555. Theclear wood values of Practice D2555 were developed from tests of small clear
4、specimens.Development of allowable stress and modulus of elasticity values from tests of full-size structurallumber as commercially produced and marketed has become possible with the development of suitabletest equipment that permits rapid rates of loading to test large numbers of pieces from commer
5、ciallumber production. These tests can be carried out at the production sites or in a laboratory.1. Scope1.1 This practice covers the principles and procedures for establishing allowable stress values for bending, tension parallel tograin, compression parallel to grain and modulus of elasticity valu
6、es for structural design from “In-Grade” tests of full-size visuallygraded solid sawn dimension lumber. This practice also covers procedures for periodic monitoring, and additional procedures, ifneeded, for evaluation and possible reassessment of assigned design values.This practice is focused on, b
7、ut is not limited to, gradeswhich used the concepts incorporated in Practice D245 and were developed and interpreted underAmerican Softwood Lumber PS20.1.2 A basic assumption of the procedures used in this practice is that the samples selected and tested are representative of theentire global popula
8、tion being evaluated. This approach is consistent with the historical clear wood methodology of assigning anallowable 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 sample is represent
9、ative of population by grade and size (see 7.1.1 and 7.1.2).1.3 Due to the number of specimens involved and the number of mechanical properties to be evaluated, a methodology forevaluating the data and assigning allowable properties to both tested and untested grade/size cells is necessary. Sampling
10、 andanalysis of tested cells are covered in Practice D2915. The mechanical test methods are covered in Test Methods D198 and D4761.This practice covers the necessary procedures for assigning allowable stress and modulus of elasticity values to dimension lumberfrom In-Grade tests. The practice includ
11、es methods to permit assignment of allowable stress and modulus of elasticity values tountested sizes and grades, as well as some untested properties. The practice includes procedures for periodic monitoring of thespecies or species group to quantify potential changes in the product and verification
12、 of the assigned design values through,evaluation, and reassessment.NOTE 1In the implementation of the NorthAmerican In-Grade test program, allowable stress values for compression perpendicular to grain and shearparallel to grain for structural design were calculated using the procedures of Practice
13、 D245.1.4 This practice only covers dimension lumber.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of
14、 regulatorylimitations prior to use.1 This practice is under the jurisdiction of ASTM Committee D07 on Wood and is the direct responsibility of Subcommittee D07.02 on Lumber and Engineered WoodProducts.Current edition approved Feb. 15, 2014May 1, 2016. Published April 2014June 2016. Originally appro
15、ved in 1991. Last previous edition approved in 20072014 asD1990 07.D1990 14. DOI: 10.1520/D1990-14.10.1520/D1990-16.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may n
16、ot be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor
17、Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Referenced Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based ProductsD198 Test Methods of Static Tests of Lumber in Structural SizesD245 Practice for Establishing Structural Grades and Related Allowable
18、Properties for Visually Graded LumberD1165 Nomenclature of Commercial Hardwoods and SoftwoodsD2555 Practice for Establishing Clear Wood Strength ValuesD2915 Practice for Sampling and Data-Analysis for Structural Wood and Wood-Based ProductsD4442 Test Methods for Direct Moisture Content Measurement o
19、f Wood and Wood-Based MaterialsD4444 Test Method for Laboratory Standardization and Calibration of Hand-Held Moisture MetersD4761 Test Methods for Mechanical Properties of Lumber and Wood-Base Structural MaterialE380 Practice for Use of the International System of Units (SI) (the Modernized Metric S
20、ystem) (Withdrawn 1997)3IEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System2.2 American Softwood Lumber Standard:National Institute of Standards and Technology Voluntary Product Standard PS 20-9443. Terminology3.1 Definitions:3.1.1 For definitions of
21、terms related to wood, refer to Terminology D9.3.2 Definitions of Terms Specific to This Standard:3.2.1 characteristic sizethe standard dimensions of the piece at which the characteristic value is calculated (Note 2).NOTE 2In the NorthAmerican In-Grade program, the characteristic size used was 1.5 i
22、n. (38 mm) thick by 7.25 in. (184 mm) wide by 144 in. (3.658m) in length at 15 % moisture content.3.2.2 characteristic valuethe population mean, median or tolerance limit value estimated from the test data after it has beenadjusted to standardized conditions of temperature, moisture content and char
23、acteristic size.3.2.2.1 DiscussionThe characteristic value is an intermediate value in the development of allowable stress and modulus of elasticity values. Typicallyfor structural visual grades, standardized conditions are 73F (23C), and 15 % moisture content (Note 3). A nonparametricestimate of th
24、e characteristic value is the preferred estimate. If a distributional form is used to characterize the data at thestandardized conditions, its appropriateness shall be demonstrated. (See Practice D2915 for guidance on selection of distribution.)NOTE 3The described adjustment factors and allowable st
25、ress and modulus of elasticity value assignment procedures were developed based on testdata of visual grades of major volume, commercially available North American softwood species groups. For other species (see Nomenclature D1165)and for other grading methods, it may be necessary to verify that the
26、 listed adjustments are applicable. The commercial species groups and grading criteriaused in the development of these procedures were as described in the grading rules for Douglas Fir-Larch, Hem-Fir and Southern Pine from the UnitedStates, and Spruce-Pine-Fir, Douglas fir(N), and Hem-Fir(N) from Ca
27、nada (1, 2, 3, and 4)5. The specific species groupings, together with botanical namesare given in Nomenclature D1165.3.2.3 grade quality index (GQI)A numerical assessment of the characteristics found in the sample specimens which areconsidered to be related to strength and are limited as part of the
28、 grade description. The grade quality index is a scaling parameterwhich allows modeling of strength and modulus of elasticity with respect to grade (Note 4).NOTE 4In the NorthAmerican In-Grade test program, lumber produced in accordance with visual stress grading rules (1, 2, 3, 4, 5, and 6) develop
29、edfrom the procedures of Practice D245 was sampled. For each test specimen a strength ratio was calculated for the particular type of failure indicated bythe failure code (see Test Methods D4761). Strength ratios were calculated according to the formulas given in the appendix of Practice D245 for be
30、ndingand compression parallel to grain test specimens. Strength ratios for lumber tested in tension were calculated as for bending. The sample grade qualityindex for each sample was calculated as the nonparametric five percentile point estimate of the distribution of strength ratios. Specimens which
31、 failedin clear wood were excluded from the sample for determining the sample GQI.3.2.4 In-Gradesamples collected from lumber grades as commercially produced.3.2.4.1 Discussion2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For
32、 Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.4 Available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., N
33、W, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.5 The boldface numbers in parentheses refer to the references listed at the end of this practice.D1990 162Samples collected in this manner are intended to represent the full range of strength and modulus of elasticity values normallyf
34、ound within a grade.3.2.5 monitoring, na periodic review of a subset of structural properties of a lumber cell to determine if a potential downwardshift from the assigned values indicates a need for an evaluation or reassessment, or both, of allowable properties developed withthis practice (Stage 1)
35、.3.2.6 evaluation, nThe process of examining data, including that collected over the course of a monitoring program that hasdetected a shift in cell properties, to determine the likely cause for the detected shift in cell properties, developing the best responseto the data, and establishing that the
36、 actions are sufficient (Stage 2).3.2.6.1 DiscussionThe response to the evaluation can include altering the grade description, or the input resource, or changing the method ofprocessing. Testing is conducted to confirm that the action taken corrected the affected properties.3.2.7 reassessment, nThe
37、recalculation of allowable properties derived by this practice because of a change in productproperties (Stage 3).3.2.8 statistically significant downward shift, nA statistically significant downward change in the monitored size grade cellproperty in relation to a single cell from the matrix used to
38、 derive the current allowable property for which further action is requiredin this Practice.3.2.8.1 DiscussionThe Wilcoxon nonparametric statistical test showing a change that is significant at the 0.05 level has been selected as the consensusstatistical method for determining when further action is
39、 required in this Standard.3.2.9 action levelThe lower property boundary, representing a statistically significant downward shift, used in monitoring todefine the property level at which additional confirmation testing during monitoring, or further action beyond monitoring isnecessary.3.2.10 samplin
40、g matrixthe collective designation used to describe all of the individual test cells. The sampling matrix isintended to characterize the property trends for a range of grades for a single size or a range of sizes for a single grade or acombination of both sizes and grades for a species or species gr
41、oup.3.2.10.1 DiscussionThe sampling matrix is intended to characterize the property trends for a range of grades for a single size or a range of sizes fora single grade or a combination of both sizes and grades for a species or species group.3.2.11 test cellthe combined test data for a single size/g
42、rade/species/property which is intended to characterize that samplingunit.3.2.12 thicknessthe lesser dimension perpendicular to the long axis of lumber.3.2.13 tolerance limit (TL)refers to the tolerance limit with 95 % content and 75 % confidence.3.2.14 widththe greater dimension perpendicular to th
43、e long axis of lumber.4. Significance and Use4.1 The procedures described in this practice are intended to be used to establish allowable stress and modulus of elasticityvalues for solid sawn, visually graded dimension lumber from In-Grade type test data. These procedures apply to the tested andunte
44、sted sizes and grades when an adequate data matrix of sizes and grades exists. In addition, the methodology for establishingallowable stress and modulus of elasticity values for combinations of species and species groups is covered. Allowable stress andmodulus of elasticity values may also be develo
45、ped 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 inPractice D2915. The appropriateness of these methods to establish allowable stress and modulus of elasticity
46、 values is directlydependent upon the quality and representativeness of the input test data.4.3 Amonitoring program shall be established to periodically review the continued applicability of allowable properties derivedby this practice. A monitoring program will establish data sets that are either t
47、he same as, above, or below the data that was usedto develop the current allowable properties. Upon detection of a statistically significant downward shift, evaluation of the data andconfirmation of remedial actions shall be undertaken. When evaluation is not undertaken or the results of the evaluat
48、ion indicatean adjustment to allowable properties is appropriate, a reassessment shall be conducted to re-establish allowable properties.NOTE 5It is recognized that over time there is the potential for changes in the raw material or product mix. In response to this a monitoring programD1990 163must
49、be conducted to ensure design values derived by this practice are not invalidated by such changes. If the data collected with a monitoring providesevidence of an statistically significant downward shift in lumber properties an evaluation program in accordance with the procedures of this practice isneeded to detect and confirm that responses to such changes are appropriate. Evaluation, if undertaken, provides a means for responding to the data andassessing if the actions taken are sufficient. Following the confirmation of a statistically significant d
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