ASTM D5764-1997a(2007) Standard Test Method for Evaluating Dowel-Bearing Strength of Wood and Wood-Based Products《木和木制品的榫支承强度评估用标准试验方法》.pdf

《ASTM D5764-1997a(2007) Standard Test Method for Evaluating Dowel-Bearing Strength of Wood and Wood-Based Products《木和木制品的榫支承强度评估用标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM D5764-1997a(2007) Standard Test Method for Evaluating Dowel-Bearing Strength of Wood and Wood-Based Products《木和木制品的榫支承强度评估用标准试验方法》.pdf（5页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: D 5764 97a (Reapproved 2007)Standard Test Method forEvaluating Dowel-Bearing Strength of Wood and Wood-Based Products1This standard is issued under the fixed designation D 5764; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re

2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method provides the basic procedure forevaluating dowel-bearing strength of wood and wo

3、od-basedproducts. The bearing test results are used to determine thestatic load resistance and deformation characteristics of con-nections in wood and wood-base products resulting from theapplication of a load transmitted by a fastener inserted into apredrilled hole, or driven without drilling. Meth

4、ods are givenfor preparing specimens with predrilled holes larger than thefastener diameter and specimens with holes produced byinserting fasteners in holes smaller than the fastener diameter.The methods apply to fasteners such as dowels, bolts, nails,spikes, drift pins, screws, lag screws, and stap

5、les.1.2 This test method also provides the basis for determiningthe compression behavior of wood products beneath a laterallyloaded fastener where the thickness of the product and thediameter of the fastener are such that minimal bending of thefastener occurs during testing.1.3 This standard does no

6、t purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standard

7、s:2D 143 Test Methods for Small Clear Specimens of TimberD 2395 Test Methods for Specific Gravity of Wood andWood-Based MaterialsD 2915 Practice for Evaluating Allowable Properties forGrades of Structural LumberD 4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base Materi

8、alsE4 Practices for Force Verification of Testing Machines3. Terminology3.1 Definitions:3.1.1 dowel-bearing behaviorthe load-deformation be-havior of wood or wood-base products laterally loaded by afastener where the fastener does not bend during loading.3.1.2 dowel-bearing strengthyield load obtain

9、ed from theload-deformation curve of a dowel-bearing test divided by thedowel diameter and specimen thickness.4. Summary of Test Method4.1 Specimens consisting of a single rectangular parallele-piped member with a fastener hole perpendicular to the faces ofthe member are evaluated for the resistance

10、 to embedding thefastener into the fastener hole, so as not to bend the fastener.Tests are conducted on a testing machine at a uniformdeformation rate, while loads and deformation are measured atvarious intervals. Supplementary physical properties of thewood or wood-base member are also determined.5

11、. Significance and Use5.1 The localized crushing behavior of wood or wood-baseproducts beneath a fastener where the fastener does not bendprovides a material property that is used in theoretical modelsfor connections where crushing or fastener bending, or both,occur. These theoretical models are use

12、d to establish designvalues for wood and wood-base connections. The tests areappropriate when studying the effects of such variables asfastener diameter, fastener hole size, moisture content, specificgravity, and grain direction on the dowel-bearing strength.6. Apparatus6.1 Testing MachineAny suitab

13、le testing machine capableof operation at a constant rate of motion of its movable headand having an accuracy of 61 % when calibrated in accor-dance with Practices E4.1This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.05 on W

14、ood Assemblies.Current edition approved July 1, 2007. Published July 2007. Originally publishedas D 5764 95. Last previous edition D 5764 97a (2002).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda

15、rds volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Deformation GageA deformation-measuring device,with a least reading of 0.001 in. (0.025 mm) f

16、or measuring themovement of the fastener into the wood or wood-base speci-men.7. Sampling7.1 Sampling shall provide for selection of representativetest specimens which are appropriate to the objectives of thetesting program.7.2 Sample size shall be estimated using procedures inPractice D 2915.NOTE 1

17、The precision required, the manner of sampling, and thenumber of tests will depend upon the specific test objectives. Generalexperience indicates that the coefficient of variation from embedment testsranges from 15 to 30 %.8. Specimens8.1 Wood members shall be selected, and the dowel posi-tioned in

18、such a way that the results are not affected by knots,cross grain, or other natural or manufacturing characteristics,unless the objective of the study is to determine the effect ofsuch variables. Frequently, this will necessitate selecting mem-bers which are essentially clear and straight grained. F

19、orwood-based products, specimens shall be selected with regardto manufactured characteristics.8.2 Specimen Dimensions:8.2.1 Specimens shall consist of a rectangular parallele-piped member with half a dowel hole across one face (see Fig.1).8.2.2 For solid wood and wood composites, minimumdimensions s

20、hall be made large enough so splitting does notoccur during fabrication and not less than as follows (see Fig.1):Thickness $ the smaller of 112 in. (38 mm), or 2 dowel diametersWidth $ the larger of 2 in. (50 mm) or 4 dowel diametersLength $ the larger of 2 in. (50 mm) or 4 dowel diametersNOTE 2For

21、driven dowels in species that tend to split, larger thanminimum dimensions are recommended to prevent splitting duringspecimen preparation and testing.8.2.2.1 For specimens that tend to split before the comple-tion of the test, a full hole test configuration is allowed in Fig.2. Minimum dimensions s

22、hall be made large enough sosplitting does not occur during fabrication and not less than asfollows (see Fig. 3):Thickness $the smaller of 112 in. (38 mm) or 2 dowel diametersWidth $the larger of 2 in. (50 mm) or 4 dowel diametersLength:Loaded End $the larger of 2 in. (50 mm) or 4 dowel diametersUnl

23、oaded End $the larger of 1 in. (50 mm) or 2 dowel diameters8.2.3 For wood-base panel products, the minimum thicknessshall be the thickness of the panel. Minimum width and lengthshall be the same as for solid wood.NOTE 1Half of the fastener hole is produced by drilling oversizedhole or by the method

24、shown in Fig. 4.FIG. 1 Specimen Configuration FIG. 2 Schematic of Testing SetupFull HoleD 5764 97a (2007)28.2.4 Fastener holes for fasteners that are installed in drilledholes that are equal to or greater than the fastener diametershall be typical of those used in service. Drill the holeperpendicula

25、r and through the specimen and into an adjacentwood block to minimize splitting of the face where the drill bitexits. Then saw the specimen through the hole to produce aspecimen with a half hole. For bolts, the hole shall be116 in.(1.6 mm) larger than the bolt diameter. If other hole sizes arespecif

26、ied for the fastener, specimens shall have the specifiedhole size.8.2.5 Fastener holes for fasteners that are driven or insertedby other means in holes that are smaller than the fastenerdiameter shall be typical of those in service. Use a pilot hole ofthe size specified for service conditions for th

27、e fastener. Whenpilot holes are used with nails, they shall be less than 75 % ofthe nail diameter (except wood members with specific gravitygreater than 0.60 shall have lead holes less than 90 % of thenail diameter). The fastener shall be driven perpendicular toand through the test specimen and into

28、 an adjacent wood blockto minimize spalling of the face where the fastener exits. Ifwhen removed, the fastener does not affect the hole surface, ahalf hole shall be produced by removing the fastener andsawing through the hole. When removed, if the fastener affectsthe hole surface, a half hole shall

29、be produced by the procedureoutlined in Fig. 4.9. Conditioning9.1 The tests shall be made with material conditioned to theappropriate conditions for the objectives of the testing pro-gram. Care shall be taken to maintain the desired condition ofthe material prior to and during testing, unless specif

30、iedotherwise.10. Procedure10.1 Half-Hole Testing SetupPlace the dowel in the dowelhole. Place the specimen in the testing machine (see Fig. 5), sothat a compressive load can be uniformly applied to the dowelalong its length. A steel loading block of sufficient size toprevent bending of the dowel dur

31、ing loading shall be usedbetween the dowel and movable crosshead.NOTE 3It may be necessary to provide lateral support to thinspecimens loaded in compressions.10.2 Full-Hole Testing SetupPlace the dowel in the dowelhole. Place the specimen in the testing machine so that acompressive load can be appli

32、ed to the ends of the dowel usingan assembly as shown in Fig. 2.NOTE 4It may be necessary to provide lateral support to thinspecimens loaded in compression.NOTE 5If bending of the dowel is observed during loading, consid-eration of a half-hole test setup is recommended.FIG. 3 Specimen ConfigurationF

33、ull HoleNOTE 1The procedure is as follows:(1) Cut specimen at point where fastener is to be driven.(2) Clamp the two pieces together with sufficient pressure to maintaincontact between adjoining faces during nailing.(3) Drill lead hole in seam of abutting pieces.(4) Drive fastener in lead hole.(5) R

34、emove clamps and smaller piece.(6) The remaining piece is the test specimen with the fastener insertedin the hole.FIG. 4 Means of Producing a Half-Hole Specimen When theFastener Cannot Be Removed Without Affecting the Hole SurfaceFIG. 5 Schematic of Testing SetupD 5764 97a (2007)3NOTE 6For full-hole

35、 bolt embedment specimens, experience hasshown that a thickness of 2 to 3 bolt diameters (2 diameters # thickness# 3 diameters) and an end distance equal to or greater than seven boltdiameters will provide embedment displacements at failure greater thanthe 5 % offset limit.10.3 Deformation Measureme

36、ntThe deformation of thefastener shall be taken as the movement of the moveablecrosshead of the testing machine. Measure the movement witha linear variable differential transducer (LVDT), (see Fig. 5), orother suitable device.NOTE 7Equipment setup should be checked for tightness to ensurethat there

37、is no significant relaxation under load that would be erroneouslyrecorded as dowel deformation.10.4 Rate of TestingConduct the test to reach maximumload in 1 to 10 min. Record the rate of testing used.NOTE 8A constant rate of movement of the moveable crosshead ofthe testing machine of 0.04 in./min (

38、1.0 mm/min) 650 % usually permitsreaching maximum load in the prescribed time.10.5 TestingMeasure the deformation from the beginningof load application, and take readings at sufficiently frequentload intervals to permit establishment of a satisfactory load-deformation curve. Observe the general beha

39、vior of the speci-men, and record the observations. Record the first relaxation ofload indicated on the testing machine load scale, the mode offailure, maximum load, and other significant details. The testshall be terminated at an embedment of one half the fastenerdiameter or after maximum load has

40、been reached.10.6 Minor Tests:10.6.1 Determine the oven-dry specific gravity and moisturecontent of each specimen tested. Procedures for determiningthese properties are given in Test Methods D 2395 and D 4442.11. Interpretation of Results11.1 Yield LoadThe bearing yield load (see Fig. 6)isdetermined

41、 by the following procedure:11.1.1 Fit a straight line to the initial linear portion of theload-deformation curve.11.1.2 Offset this line by a deformation equal to 5 % of thefastener diameter.11.1.3 Select the load at which the offset line intersects theload-deformation curve. In those cases where t

42、he offset linedoes not intersect the load-deformation curve, the maximumload shall be used as the yield load.NOTE 9Compute the dowel-bearing strength by dividing the yieldload by the fastener diameter and the specimen thickness.11.2 Proportional Limit LoadThe proportional limit load(see Fig. 5) is t

43、he load at which the load-deformation curvedeviates from a straight line fitted to the initial portion of theload-deformation curve.12. Report12.1 Report the following information:12.1.1 Data on load deformation relationships, maximumload, and yield load,12.1.2 Mode of failure,12.1.3 Description of

44、the wood species or wood-base prod-uct being tested,12.1.4 Member dimensions, including length, width, thick-ness, and fastener hole diameter or lead hole diameter,12.1.5 Details of loading procedure and deformation mea-surement system,12.1.6 Number of replicate tests,12.1.7 Oven-dry specific gravit

45、y,12.1.8 Moisture content at time of test of each specimen,12.1.9 Moisture content at time of fabrication of eachspecimen if different than moisture content at time of test,12.1.10 Orientation of the wood grain with respect to thedirection of the applied load,12.1.11 Dimensions and other descriptive

46、 information aboutthe fastener, and12.1.12 Details of any deviation from the prescribed orrecommended methods as outlined in this test method.13. Precision and Bias13.1 The precision and bias of this test method has not yetbeen determined.14. Keywords14.1 dowel-bearing strength; wood-baseFIG. 6 Defi

47、nition of Loads Obtained from the Load-DeformationCurveD 5764 97a (2007)4ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity o

48、f any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments a

49、re invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Indi