ASTM D6570-2018a Standard Practice for Assigning Allowable Properties for Mechanically Graded Lumber.pdf

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1、Designation: D6570 18aStandard Practice forAssigning Allowable Properties for Mechanically GradedLumber1This standard is issued under the fixed designation D6570; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev

2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the methodology of gradequalification, assignment of design properties, and require-ments for the quality

3、 control of mechanically graded solidsawn lumber.1.2 This practice acknowledges alternative methods for theassignment of specific properties. These methods are assign-ment by test, relationship to other properties, and by proce-dures in other appropriate standards.1.3 This international standard was

4、 developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Reference

5、d Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based Prod-uctsD143 Test Methods for Small Clear Specimens of TimberD198 Test Methods of Static Tests of Lumber in StructuralSizesD245 Practice for Establishing Structural Grades and Re-lated Allowable Properties for Visually Gr

6、aded LumberD1165 Nomenclature of Commercial Hardwoods and Soft-woodsD1990 Practice for Establishing Allowable Properties forVisually-Graded Dimension Lumber from In-Grade Testsof Full-Size SpecimensD2395 Test Methods for Density and Specific Gravity (Rela-tive Density) of Wood and Wood-Based Materia

7、lsD2555 Practice for Establishing Clear Wood Strength ValuesD2915 Practice for Sampling and Data-Analysis for Struc-tural Wood and Wood-Based ProductsD3737 Practice for Establishing Allowable Properties forStructural Glued Laminated Timber (Glulam)D4442 Test Methods for Direct Moisture Content Measu

8、re-ment of Wood and Wood-Based MaterialsD4761 Test Methods for Mechanical Properties of Lumberand Wood-Base Structural MaterialD7438 Practice for Field Calibration and Application ofHand-Held Moisture Meters2.2 ANSI Standards:3ANSI A190.1 American National Standard for WoodProductsStructural Glued L

9、aminated TimberANSI/AWC NDS National Design Specification for WoodConstruction2.3 Canadian Standards Association Standard:4CSA O141 Softwood Lumber2.4 National Institute of Standards and Technology Stan-dard:5PS 20 Voluntary Product Standard, American SoftwoodLumber Standard3. Terminology3.1 Definit

10、ionsFor definitions of terms related to wood,refer to Terminology D9.3.2 Definitions of Terms Specific to This Standard:3.2.1 mechanical evaluation, nidentification and appraisalof one or more physical or mechanical lumber characteristicsas part of the lumber segregation process.3.2.2 mechanically g

11、raded lumber, nsolid sawn lumbergraded by mechanical evaluation. Visual evaluation also maybe required. The material has assigned design properties and ismanufactured for use as structural members.1This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility

12、of Subcommittee D07.02 on Lumber and EngineeredWood Products.Current edition approved Oct. 1, 2018. Published October 2018. Originallyapproved in 2000. Last previous edition approved in 2018 as D6570 18. DOI:10.1520/D6570-18A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orco

13、ntact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Availab

14、le from Canadian Standards Association (CSA), 5060 Spectrum Way,Mississauga, ON L4W 5N6, Canada, http:/www.csa.ca.5Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.Copyright ASTM International, 100 Barr Ha

15、rbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommenda

16、tions issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.3 qualified agency, nan organization, hereafter re-ferred to as the agency, that has trained personnel and proce-dures to ensure the system evaluations and grades comply withall applicable requirements of t

17、his practice.3.2.3.1 DiscussionThe agency shall have no financialinterest in, nor shall be financially dependent upon, any singlecompany manufacturing the product being inspected or tested;and shall not be owned, operated, or controlled by any suchcompany.3.2.3.2 DiscussionThe agency shall conform w

18、ith theprovisions for agency accreditation under the appropriateconsensus standard.3.2.4 visual evaluation, nidentification and appraisal oflumber growth and manufacturing characteristics by visualmeans as part of the lumber segregation process.NOTE 1In the United States and Canada, criteria for age

19、ncy accredi-tation are contained in PS 20, ANSI A190.1, and CSA O141.4. Significance and Use4.1 The procedures described in this practice are intended tobe used to establish appropriate allowable unit stresses, moduliof elasticity, and specific gravity for mechanically graded solidsawn lumber. An on

20、-going quality control program to monitorcompliance with the assigned grade properties is required.5. System Requirements5.1 Mechanical Device Requirements A mechanical de-vice used as part of the grading process shall demonstrate theability to measure the mechanical or physical wood propertyused to

21、 segregate the lumber.5.2 Visual Requirements:5.2.1 Characteristics to be limited by visual evaluation, shallbe documented as part of the qualification and quality controlprocedures. Such limitations shall be part of the grade require-ments.5.2.2 Personnel conducting visual evaluations shall bequali

22、fied by the agency.6. Criteria for Grade Qualification6.1 General Requirements:6.1.1 A minimum of one assigned property of a grade shallbe qualified by test. The grade assignment for propertiesqualified by test is given in 7.2.6.1.1.1 If the modulus of elasticity (MOE) is the onlyproperty assigned t

23、o a grade, it shall be evaluated by test.6.1.1.2 If both strength and MOE properties are assigned toa grade, a minimum of one strength property and one MOEproperty shall be evaluated by test. If only one strengthproperty is tested, that property shall be either the modulus ofrupture (MOR) or ultimat

24、e tensile stress (UTS).6.1.2 Each grade shall be qualified at each size and for eachspecies/species group.6.1.3 Sampling, evaluation, and presentation of data shall bein accordance with Practice D2915.6.2 Qualification Samples:6.2.1 The criteria for selecting qualification samples shall bedocumented

25、 and shall be in accordance with 6.1.3.6.2.2 All qualification samples shall meet the visual require-ments established for the grade.6.2.3 The minimum sample size for estimation of strengthproperties, and MOE shall be 53 specimens.6.2.4 The minimum sample size for estimation of mean ormedian propert

26、y values, other than MOE, shall be 30 speci-mens.6.2.5 When the allowable shear stress parallel to grain (Fv)or the allowable compressive stress perpendicular to grain(Fc) are determined in accordance with 7.3.4 and 7.3.5,respectively, the specific gravity of a minimum of 30 qualifi-cation test spec

27、imens shall be measured and recorded.6.3 Qualification Test Methods:6.3.1 When mechanical and physical properties in Section 7are determined by tests, the appropriate ASTM standards shallbe used:6.3.1.1 The determination of the MOE by edgewise bendingshall be in accordance with Test Methods D4761 or

28、 D198.6.3.1.2 The determination of the MOR by edgewise bendingshall be in accordance with Test Methods D4761 or D198.6.3.1.3 The determination of the MOE by flat-wise bendingshall employ center-point loading in accordance with TestMethods D4761 or D198.6.3.1.4 The UTS of a sample shall be determined

29、 accordingto Test Methods D4761 or D198. Whenever possible, aminimum gage length of not less than 96 in. (2.44 m) shall beused. When determination of the tension parallel to the grainMOE is desired, testing shall be conducted according to theprovisions of Test Methods D198.6.3.1.5 The determination

30、of the ultimate shear strengthparallel to grain values shall be in accordance with TestMethods D143.6.3.1.6 The determination of the compression perpendicularto grain values shall be in accordance with Test Methods D143.6.3.1.7 Determination of the moisture content of the lumbersample shall be in ac

31、cordance with Test Methods D4442 orD7438.6.3.1.8 Specific gravity shall be based on weight and dimen-sions when oven dry as specified in Test Methods D2395.Measurements shall either be taken on oven-dried specimens,or at some other moisture content and the values adjusted to theoven-dry condition.7.

32、 Procedures for Assignment of Allowable MechanicalProperties and Specific Gravity7.1 Allowable mechanical properties and specific gravityshall be assigned using the qualification test procedures of 7.2,the property correlation procedures of 7.3, or the procedures of7.4. These alternative procedures

33、of 7.2 7.4 define themaximum property values, which are permitted to be assignedto a grade of mechanically graded lumber.7.1.1 Selection of the procedures specified in 7.1 to estab-lish a value for any particular property assigned to a grade isthe prerogative of the grade specification author.7.1.2

34、The factors used in 7.2 and 7.3 apply to softwoodlumber.7.1.3 If the Fb is to be an assigned property, it shall bedetermined by the test procedures of 7.2.D6570 18a27.1.4 Hardwood lumber species shall be reduced by theapplicable factors in Practice D245, Table 8.7.1.4.1 Species containing interlocke

35、d grain shall have Fb,Ft, and Fc evaluated by test procedures of 7.2. Sample sizeselection shall consider the evidence of interlocked grain andits representation in the sample.7.2 Assignment of Allowable Properties by QualificationTests:7.2.1 Assignment of allowable properties by test shallfollow th

36、e procedures of this section. Test results shall beevaluated according to Practice D2915.7.2.1.1 Qualification tests are used to either establish allow-able mechanical property values for new grades or to qualifyfor published grade categories.7.2.2 Extreme Fiber Stress in Bending (Fb)The fifthpercen

37、tile tolerance limit (75 % confidence) for the MOR ofthe qualification sample shall equal or exceed 2.1 times theassigned Fb value.7.2.3 Fiber Stress in Tension Parallel to Grain (Ft)Thefifth percentile tolerance limit (75 % confidence) for the UTSof the qualification sample shall equal or exceed 2.

38、1 times theassigned Ft value.7.2.4 Fiber Stress in Compression Parallel to Grain (Fc)The fifth percentile tolerance limit (75 % confidence) forultimate compressive strength parallel to grain (UCS) of thequalification sample shall equal or exceed 1.9 times theassigned Fc value.7.2.5 Shear Stress Para

39、llel to Grain (Fv)The fifth percen-tile tolerance limit (75 % confidence) Fv for the qualificationsample shall equal or exceed 2.1 times the assigned Fv value.7.2.6 Modulus of Elasticity:7.2.6.1 The upper bound of the 95 % confidence interval ofthe qualification sample mean MOE shall meet or exceed

40、theassigned grade MOE.7.2.6.2 For grades that include a near-minimum MOEspecification, the sample parametric or non-parametric pointestimate as determined in accordance with Practice D2915shall equal or exceed the near-minimum MOE for the grade.7.2.7 Specific Gravity (SG)The upper bound of the 95 %c

41、onfidence interval of the qualification sample mean specificgravity shall meet or exceed the assigned specific gravityvalue.7.2.8 Fiber Stress in Compression Perpendicular to Grain(Fc)The Fc shall be determined by test in accordancewith Test Methods D143, and adjusted by the procedures ofPractice D2

42、45.7.3 Assignment of Allowable Properties Based on Relation-ships:7.3.1 The methods of 7.3 permit assignment of certainallowable properties based on recognized relationships be-tween the assigned properties. This assignment shall be inaccordance with the following procedures.7.3.2 Fiber Stress in Te

43、nsion Parallel to Grain:7.3.2.1 The maximum allowable Ft shall be assigned inaccordance with an established grade assignment model basedon the assigned Fb, which has been published by the agency.7.3.2.2 In the absence of corroborative data, a maximumFt/Fb ratio of 0.45 shall be used.7.3.3 Fiber Stre

44、ss in Compression Parallel to Grain:7.3.3.1 The maximum allowable Fc shall be calculated fromthe following equation:Fc 5 0.7098 Fb 1 2060.7!/1.9 (1)where:Fb = the assigned Fb for the grade.7.3.4 Shear Parallel to GrainThe Fv determined by aspecific gravity-based model (see Appendix X1) is permittedw

45、hen the specific gravity is assigned in accordance with 7.2.7or 7.3.6.7.3.5 Fiber Stress in Compression Perpendicular to Grain(Fc)The Fc determined by a specific gravity-basedmodel (see Appendix X1) is permitted when specific gravity isassigned in accordance with 7.2.7 or 7.3.6.7.3.6 Specific Gravit

46、yIt is permitted to assign specificgravity in accordance with a model that relates gradingmachine measurement to specific gravity. When such a modelis used, the agency shall develop corroborative data to supportthe appropriateness of the assigned specific gravity.7.4 Assignment of Allowable Properti

47、es by Other Stan-dards:7.4.1 The methods of 7.4 permit assignment of certainallowable properties based on procedures in the appropriateASTM and ANSI standards.7.4.2 Shear Parallel to Grain StressThe Fv shall beassigned in accordance with the procedures of Practice D245for visually graded solid sawn

48、lumber of the same species orspecies group.7.4.3 Fiber Stress in Compression Perpendicular to GrainThe Fc shall be assigned in accordance with the proceduresof Practice D245 for visually graded solid sawn lumber of thesame species or species group.7.4.4 Specific GravityThe specific gravity shall be

49、as-signed as reported in ANSI/AWC NDS for visually gradedsolid sawn lumber of the same species or species group.8. Minimum Allowable Property Increment8.1 Allowable properties shall be rounded in accordancewith Table 1.9. Quality Control9.1 A quality control program shall be developed for eachmechanical grading system. The quality control program shalldelineate the respective responsibilities of the producer and theagency.TABLE 1 Rounding Rules for Allowable Property ValuesMOE 100 000 psiFb 50 psi at 1000 psiand above25 psi below 1000 psiFt 25 psiFc