1、Designation: D7469 16Standard Test Methods forEnd-Joints in Structural Wood Products1This standard is issued under the fixed designation D7469; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in
2、parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONAdhesive bonded end-joints are used in structural glued wood products. The bond performance ofthese end-joints is only one of several parameters
3、that influence the in-service performance of theseproducts. Evaluating the performance of these end-joints require specific tests.The testing regimen, which may consist of one or more of the test methods specified in thisstandard, is dependent on the type of product, the stage in the manufacturing o
4、f the product orsub-components when the testing is to be performed, and the objective of the evaluation. AppendixX1 Appendix X7 provide an overview of considerations for developing a testing regimen.1. Scope1.1 This standard provides test methods for evaluating thestructural capacity and integrity o
5、f end-joints in structuralwood products.1.2 End-joints are manufactured by adhesive bonding ofmachined, mated surfaces at the ends of two pieces of lumberto form a joint. Typical end-joint configurations include fingerjoints and scarf joints. The combination of one or moreend-joints and the adjoinin
6、g sections of the structural woodproduct within the assembly is considered to be the testspecimen.1.3 Off-line test methods include: (1) Axial Tension, (2)Bending, and (3) Cyclic Delamination.1.4 In-line test methods include: (1) Tension Proofload and(2) Bending Proofload.1.5 The values stated in in
7、ch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
8、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 Standards:2D9 Terminology Relating to Wood and Wood-Based Prod-uctsD198 Test Methods of Static
9、Tests of Lumber in StructuralSizesD1101 Test Methods for Integrity of Adhesive Joints inStructural Laminated Wood Products for Exterior UseD1151 Practice for Effect of Moisture and Temperature onAdhesive BondsD1183 Practices for Resistance of Adhesives to CyclicLaboratory Aging ConditionsD2559 Speci
10、fication for Adhesives for Bonded StructuralWood Products for Use Under Exterior Exposure Condi-tionsD2915 Practice for Sampling and Data-Analysis for Struc-tural Wood and Wood-Based ProductsD3434 Test Method for Multiple-Cycle Accelerated AgingTest (Automatic Boil Test) for Exterior Wet Use WoodAdh
11、esivesD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Based MaterialsD5456 Specification for Evaluation of Structural CompositeLumber ProductsD4688 Test Method for Evaluating Structural Adhesives forFinger Jointing LumberD4761 Test Methods for Mechanical Properties of Lu
12、mberand Wood-Base Structural MaterialD7247 Test Method for Evaluating the Shear Strength of1These test methods are under the jurisdiction of ASTM Committee D07 onWood and are the direct responsibility of Subcommittee D07.01 on FundamentalTest Methods and Properties.Current edition approved Aug. 1, 2
13、016. Published August 2016. Originallyapproved in 2008. Last previous edition approved in 2012 as D7469 12. DOI:10.1520/D7469-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informati
14、on, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Adhesive Bonds in Laminated Wood Products at ElevatedTemperaturesD7438 Practice for Field Calibration and Application
15、ofHand-Held Moisture MetersE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3. Terminology3.1 Terms used in these methods shall be as defined inTerminologies D9 and
16、E6 and Practices E4 and E177.3.2 Definitions of Terms Specific to This Standard:3.2.1 delaminationseparation of a bondline due to dimen-sional changes (swelling and shrinkage) of the wood aroundthe joint caused by extreme changes in the moisture content.3.2.2 finger jointa joint formed by bonding tw
17、o pieces oflumber with ends machined to a mated finger-like profile (Fig.1).3.2.3 finger joint specimenboard segments joined at oneor both ends by finger joints to form an assembly and obtainedfrom a finger joint production line for testing.3.2.4 finger lengthlength of machined finger along thelongi
18、tudinal axis of the full-size member from the finger tip tothe base of the finger (Fig. 1).3.2.5 finger pitchwidest width of machined finger at thebase of the joint (Fig. 1).3.2.6 gauge lengththe clear distance between the grips fora specimen subjected to axial tensile loading.3.2.7 horizontal finge
19、r jointfinger joint where the fingerprofile appears only on the narrow face of the lumber.3.2.8 in-line testa test that is carried out on all productionfrom a continuous manufacturing process.3.2.9 joint misalignmentnon-zero slope between the lon-gitudinal axes of two adjoining pieces in the directi
20、on of depthor thickness, or both.3.2.10 joint offsetdistance between joint profile surfacesof two adjoining pieces in a cross-sectional direction perpen-dicular to the finger or scarf joint length.3.2.11 off-line testa test that is carried out on a sampletaken from a continuous manufacturing process
21、 or frominventory of the product.3.2.12 outer fingerthe finger at the edges of the faceshowing the finger profile (Fig. 1).3.2.13 proofload testinga test where a preselected load orstress level is applied to the specimen.3.2.14 scarf jointa joint formed by bonding two pieces oflumber with ends machi
22、ned with a single sloping profile. Thelength of the specimen cross-section occupied by the scarf jointis the run of the slope (Fig. 2).3.2.15 spanthe distance between the centerlines of endreactions on which the test specimen is supported to accom-modate a transverse bending load.3.2.16 standard dry
23、 dimensionsthe cross-sectional sizeused in design for sawn lumber, this is also known as thestandard dry size.3.2.17 tip gapdistance between the finger tip and the baseof the finger in the opposing segment (Fig. 1).3.2.18 tip thicknesssmallest width of machined finger(Fig. 1).FIG. 1 Finger Joint Pro
24、fileD7469 1623.2.19 vertical finger jointfinger joint where the fingerprofile appears only on the wide face of the lumber.4. Significance and Use4.1 These test methods are applicable to specimens with orwithout specific conditioning regimens. Tests are permitted tobe performed on specimens that are
25、not at moistureequilibrium, such as under production conditions in a plant, oron specimens that have been conditioned to specified moisturecontent or durability conditioning prior to testing.4.2 These test methods can be used as follows:4.2.1 To standardize the determination of strength propertiesfo
26、r the material and joint being tested.4.2.2 To investigate the effect of parameters that mayinfluence the structural capacity of the joint, such as jointprofile, adhesive type, moisture content, temperature, andstrength-reducing characteristics in the assembly.4.3 These test methods do not intend to
27、 address all possibleexposure or performance expectations of end-joints. The fol-lowing are some performance characteristics not considered:4.3.1 Long-term strength and permanence of the woodadhesive.4.3.2 Time dependent mechanical properties of the joint.4.3.3 Elevated temperature performance of th
28、e joint.AXIAL TENSION TEST METHOD (OFF-LINE)5. Scope5.1 This test method provides procedures for the determi-nation of the axial tensile capacity of full-size end-jointspecimen off-line.5.2 Applications of this test method include: end-jointqualification and daily quality control of production, and
29、otherpurposes where the strength of a full-size end-joint must beverified or determined.6. Summary of Test Method6.1 The test specimen is subjected to an axial tensile load.The length of the specimen is short enough such that failuresoccur primarily at or as a result of the joint, but long enoughsuc
30、h that the stresses around the joint are not affected by thegrips.6.2 Except as specified below, the specimens shall be testedin accordance with Test Methods D4761 for Axial Strength inTension.6.3 The specimen is loaded so that failure occurs or apreselected load is reached within the prescribed amo
31、unt oftime.NOTE 1It is preferred to apply load at a constant rate of increase.Either load or displacement control is acceptable. Apply load at a rate thatis as close to constant as is practical. Sudden increases in load should beavoided.7. Apparatus7.1 Test MachineAs specified in Test Methods D4761.
32、7.2 Grips or Clamping DevicesAs specified in Test Meth-ods D4761.NOTE 2Grip designs that do not minimize damage from clampingmay result in a high frequency of failure at the edge of the grips.Generally, if a specimen fails at the edge of the grips, the result should bedisregarded unless the load lev
33、el attains a load level that is sufficient todemonstrate a minimum end-joint capacity. When a high frequency of griprelated failure occurs at or below the load levels of interest, the gripsshould be redesigned as excessive culling of specimens for this reasonmay impact the representativeness of the
34、tensile strength for the sampletested.7.3 Distance Between GripsThe gauge length for finger-joint testing shall be selected such that the edges of the gripsare 2 ft (610 mm) apart. The gauge length for scarf joint testingshall be set to the nearest 1 ft (305 mm) increment greater thanthe length of t
35、he joint plus 2 ft (610 mm). With either jointtype, the tolerance for gauge length shall be 62 in. (51mm).NOTE 3The gauge length used for the test is intended to be longenough to result in uniform tensile stress across the joint and short enoughto minimize the number of failures that occur away from
36、 the joint. Thespecification outlined in 7.3 has proven reasonable for testing commonlyfingerjointed dimension lumber sizes. larger cross-sections may requirelonger gauge lengths.7.4 AccuracyAs specified in Test Methods D4761.8. Test Specimens and Conditioning8.1 Cross-SectionThe specimen shall be t
37、ested withoutmodifying the dimensions of the commercial cross-section.The use of reduced cross-section test specimens is permissibleaccording to considerations and guidelines for developing testprocedures provided in Appendix X5.8.2 LengthThe minimum specimen length shall be thegauge length, determi
38、ned in accordance with 7.3, plus anyrequired length to achieve contact along the full length of thegrips.8.3 ConditioningSpecimens are permitted to be tested asproduced or following a specified conditioning regimen de-pending on the purpose of the test program. The specimenconditions and details of
39、the conditioning regimen, ifapplicable, shall be reported.9. Procedure9.1 Specimen Measurements:9.1.1 Cross-Sectional DimensionsThe cross-sectional di-mensions of each specimen for which the tensile strength is tobe determined shall be measured to the nearest 0.01 in. (0.25FIG. 2 Scarf Joint Profile
40、D7469 163mm) and recorded. Where the cross-sectional dimensions differon either side of the joint, such as when testing samples beforethey are planed to a standard size, the cross-sectional dimen-sions used to calculate the tensile strength shall be reported.The width and thickness should be measure
41、d at the leastdimensional plane of the adjoining segment.NOTE 4When testing for end-joint quality control at a productionfacility, it may be acceptable to determine the tensile strength using thestandard dry cross-sectional dimensions.9.1.2 Moisture ContentUnless otherwise specified by adurability c
42、onditioning protocol or product standard, measureand record the moisture content of the specimens following atest on each side of the joint and as close to the failure zone aspractical in accordance with the procedures outlined in TestMethods D4442 or using a calibrated moisture meter accordingto Pr
43、actice D7438 guidelines. For specimens tested as pro-duced from a manufacturing process in which lumber moisturecontent is controlled or where all specimens are pre-conditioned to a uniform moisture content prior to mechanicaltesting, moisture content measurements for each specimen arenot required.
44、In those instances, the reduced number ofspecimens from the sample shall be determined in accordancewith the guidelines in Practice D2915.9.2 Test SetupThe end-joint shall be centered between thetwo grips. The specimen shall also be centered in the grips sothat the longitudinal axis of the specimen
45、coincides with thedirection of the load application. Load shall be applied to thespecimen at a rate determined in accordance with 9.3.NOTE 5Centering the joint in the grip span minimizes the biasbetween joint tests due to bending moments induced by grip head balance.It is recognized that bending mom
46、ents caused by non-homogeneity in thespecimens mechanical properties cannot be eliminated.9.3 Speed of TestingA constant test rate shall be selectedfor testing the sample such that the specimen failure load isachieved between 1 and 10 min.9.4 Maximum LoadThe maximum load attained in the testshall be
47、 recorded.9.5 Record of Test RateAdescription of the rate of loadingand method of application shall be recorded.9.6 Record of FailureFor all specimens tested to failure, adescription of the failure mode in accordance with Annex A1shall be recorded. Any specimen irregularities or the presenceof stren
48、gth reducing defects within the joint shall also berecorded.BENDING TEST METHOD (OFF-LINE)10. Scope10.1 This test method provides off-line test procedures forthe determination of the capacity of the end-joint in bending onshort spans when subjected to either three-point or four-pointloading.10.2 App
49、lications of this test method include: end-jointqualification and daily quality control, and other purposeswhere the strength of a full-size end-joint are to be verified ordetermined.11. Summary of Test Method11.1 The test specimen is simply supported and transverselyloaded in bending. Depending upon the test objectives andend-joint type, the test specimen may be loaded by two equal,concentrated forces spaced equidistant from the center of thesupports (four-point load configuration) or by a single concen-trated force centered within the tes
