ASTM D7147-2005 Standard Specification for Testing and Establishing Allowable Loads of Joist Hangers《检验和确定搁栅吊钩允许荷载的标准规范》.pdf

1、Designation: D 7147 05Standard Specification forTesting and Establishing Allowable Loads of Joist Hangers1This standard is issued under the fixed designation D 7147; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last

2、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 specification covers a procedure for evaluatingmetal devices used for wood-to-wood, wood-to-concrete,wood-to-concrete

3、 masonry, and wood-to-steel connections.This method is intended for use with devices used to connectjoists, beams, and girders together. These devices are com-monly described as joist hangers.1.2 This specification describes test methods for evaluatingthe capacities of joist hangers subject to verti

4、cal and torsionalloading.1.3 This specification provides a method of assigning allow-able loads to joist hangers based on measured strength anddeformation characteristics. Information obtained by the pro-visions of this specification is applicable to design when usingthe Allowable Stress Design meth

5、od.1.4 This standard does not 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. Reference

6、d Documents2.1 ASTM Standards:2C 31/C 31M Practice for Making and Curing Concrete TestSpecimens in the FieldC 39/C 39M Test Method for Compressive Strength of Cy-lindrical Concrete SpecimensC90 Specification for Hollow Load-Bearing Concrete Ma-sonry UnitsC 270 Specification for Mortar for Unit Mason

7、ryC 1314 Test Method for Compressive Strength of MasonryPrismsD9 Terminology Relating to WoodD 245 Practice for Establishing Structural Grades and Re-lated Allowable Properties for Visually Graded LumberD 2395 Test Methods for Specific Gravity of Wood andWood-Base MaterialsD 3737 Practice for Establ

8、ishing Stresses for StructuralGlued Laminated Timber (Glulam)D 4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base MaterialsD 4444 Test Methods for Use and Calibration of Hand-HeldMoisture MetersD 5055 Specification for Establishing and MonitoringStructural Capacities of

9、 Prefabricated Wood I-JoistsD 5456 Specification for Evaluation of Structural Compos-ite Lumber ProductsE4 Practices for Force Verification of Testing MachinesE8 Test Methods for Tension Testing of Metallic MaterialsE 575 Practice for Reporting Data from Structural Tests ofBuilding Constructions, El

10、ements, Connections, and As-sembliesF 606 Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,Washers, and RivetsF 1470 Guide for Fastener Sampling for Specified Mechani-cal Properties and Performance InspectionF 1575 Test Method for Determining Be

11、nding Yield Mo-ment of Nails2.2 Other Standards:ANSI/AF the measuredlength, diameter; and strength properties required in 7.4,12.1.5 A description of the concrete or masonry properties,including measured properties as required in 7.2, if concrete ormasonry was used,12.1.6 A description of the load t

12、ransfer block, other block-ing, low-friction materials, reinforcement, and any deviationsfrom the standard test setup shown in Figs. 3 and 4,12.1.7 Data on load-deflection, including the load at the0.125 in. (3.18 mm) deflection limit, and the maximum testload observed,12.1.8 Type and location of fa

13、ilure of the specimen,12.1.9 Number of replications including a description ofreplications not used as allowed in 11.7,12.1.10 Loading procedure details, including preload, loadrate, and time to maximum load, and12.1.11 Details of any deviations from the prescribed testsetup and test procedures as o

14、utlined in this specification.13. Allowable Joist Hanger Loads Limited by Test13.1 Joist hanger design values limited by test shall belimited to the materials tested, except as otherwise provided inSection 13. For application to materials used in construction,the construction materials shall satisfy

15、 13.1.1-13.1.4.13.1.1 WoodAll wood materials shall be of structuralquality with allowable values substantiated by accepted proce-dures, such as those found in Section 2.13.1.2 SteelAll production steel material shall meet orexceed a specified minimum yield strength, a specified mini-mum ultimate str

16、ength, and a specified minimum thickness.13.1.3 FastenersFasteners used for field installation shallmeet or exceed minimum specified cross-sectional dimensions(for example, diameter or width and thickness), length, otherrelevant dimensions, and relevant material properties.13.1.4 Concrete and Masonr

17、yAll concrete and masonrymaterials shall have structural properties that meet or exceed aminimum specified compression strength.13.2 Allowable loads for joist hangers based upon test shallbe the lesser of the values determined in 13.3 and 13.4.Adjustments to test results shall be made in accordance

18、with13.5.13.2.1 The results of all load tests except those testsexcluded per 11.7 shall be used to determine the allowable loadcapacity of the joist hanger.13.3 Test Strength Limit:13.3.1 The ultimate load rating shall be the lowest ultimateload per joist hanger divided by 3.0 if less than six repli

19、catesare tested. The ultimate load rating shall be the averageultimate load per joist hanger divided by 3.0 when six or morereplicates are tested. See 13.5 for adjustments to test results.13.4 Test Deflection Limit:13.4.1 For all vertical load tests, the load at 0.125-in.deflection shall be recorded

20、 for each hanger. The test deflectionlimit load shall be the average of all of these loads. The load atthe specified deflection limit shall be permitted to be interpo-lated from the test data.13.5 Adjustments to Test Strength Limit:13.5.1 When the specific gravity of any member is greaterthan the av

21、erage specific gravity for that species as listed in the“National Design Specification for Wood Construction”(NDS), or other approved source, the resulting test values shallbe multiplied by the lowest of the adjustment factors deter-mined in 13.5.2-13.5.4.NOTE 2Many evaluation reports for SCL list a

22、n “equivalent” specificgravity for connections as a convenience for design. This should not beconsidered the actual specific gravity of the product. The actual specificgravity of SCL should be obtained from the manufacturer.13.5.1.1 The following definitions apply to adjustment fac-tors in 13.5.2-13

23、.5.4.Ajoist= bearing area between the joist and the joisthanger, in.2.Aheader= the measured area on the header subject tocompression perpendicular-to-grain fromthe hanger.Fc, nominal= 2250 x Gnominal 480, psi.Fc, tested= 2250 x Gtested 480, psi.Fu, spec= ultimate strength of the connector steelfrom

24、the manufacturers specifications, psi(# Fu, tested).Fu, tested= measured ultimate strength of the connec-tor steel used in the test specimens, psi.D7147055Fyb, nominal= bending yield strength of the connectorfasteners published in the NDS or otherapproved document, psi (# Fyb, tested).Fyb, tested= m

25、easured bending yield strength of theconnector fasteners used in the test speci-mens, psi.Gnominal= published specific gravity of the test speci-men header material.NOTE 3Many evaluation reports for SCL list an “equivalent” specificgravity for connections as a convenience for design. This should not

26、 beconsidered the actual specific gravity of the product. The actual specificgravity of SCL should be obtained from the manufacturer.Gtested= actual specific gravity of the test specimenheader material as determined by 7.1.MClimit= moisture content (%) lower limit for wood typeas shown in Section 10

27、.MCtest= moisture content (%) in test samples.RJ= adjustment factor (#1.0) applied to test resultswhen joist test materials are stronger thanmaterials used in field applications.RHF= adjustment factor (#1.0) applied to test resultsof face mount hangers when header test mate-rials are stronger than m

28、aterials used in fieldapplications.RHT= adjustment factor (#1.0) applied to test resultsof top flange hangers when header test materi-als are stronger than materials used in fieldapplications.RMC= adjustment factor (#1.0) applied to test resultswhen the tested moisture content (MC) is lessthan the l

29、owest allowed moisture content listedin this specification in Section 10.RS= adjustment factor (#1.0) applied to test resultswhen the tested hanger steel is stronger thanspecified steel for hanger.tspec= specified minimum steel thickness joist hanger.ttested= measured steel thickness of tested joist

30、 hang-ers.Znominal= sum of all the lateral fastener resistance valuesaccording to the NDS or other approved docu-ment and based on the following: (1) headermaterial specified for the installation, (2) fas-tener quantity, type, and size specified for theinstallation of the hanger to the header andpub

31、lished Fybvalues, and (3) hanger steelspecified for production.Ztested= sum of all the lateral fastener resistance valuescalculated according to the NDS or otherapproved documents and based on the follow-ing: (1) header material tested, (2) fastenerquantity, type, and measured size for installa-tion

32、 of the hanger to the header and tested Fybvalues, and (3) hanger steel tested. Also see13.6.NOTE 4The values for Zpublishedand Ztestedare not accurate to use fornail design on structural composite lumber. However, in Eq 1-3 theyprovide an approximation suitable for the reduction factors in this sec

33、tion.13.5.2 Joist Specific Gravity AdjustmentsIf the publishedspecific gravity of the joist for the intended application is lessthan the specific gravity of the joist tested, then test values shallbe multiplied by the factor RJto account for fastener andcompression perpendicular-to-grain strength in

34、creases. Whenthe joist consists of multiple components, such as an I-joistwith flanges, a web, and blocking at the hanger, RJshall becalculated for the joist setup. The adjustment factor shall bedetermined and applied for each joist hanger connectionseparately using the material properties specific

35、to that connec-tion.RJ5Fc, nominalxA! 1 ZnominalFc, testedxA! 1 Ztested#1.0 (1)13.5.3 Header Specific Gravity AdjustmentFace MountHangersIf the published specific gravity of the header for theintended application is less than the specific gravity of theheader tested, then test values shall be multip

36、lied by the factorRHFto account for fastener strength increases. When the headerconsists of multiple wood components, such as multiple pliesof the same wood type, the specific gravity of the criticalcomponent shall be used as specific gravity for the entireheader. The critical component is the compo

37、nent onto whichthe hanger is directly mounted.13.5.3.1 Test values shall be multiplied by the followingfactor, RHF, to account for increased fastener perpendicular-to-grain strength used in the test:RHF5ZnominalZtested#1.0 (2)13.5.4 Header Specific Gravity AdjustmentTop MountHangersIf the published

38、specific gravity of the header for theintended application is less than the specific gravity of theheader tested, then test values shall be multiplied by the factorRHTto account for fastener and compression perpendicular-to-grain strength increases. When the header consists of multiplewood component

39、, such as multiple plies of the same woodtype, the specific gravity of the critical component shall beused as specific gravity for the entire header. For verticallyoriented plies, the critical component is the component thatcontacts the vertical face of the hanger. For horizontallyoriented plies, th

40、e critical component is the component thatcontacts the top flange of the hanger.13.5.4.1 The adjustment to account for fastener and com-pression perpendicular-to-grain strength increases due tohigher specific gravity(ies) shall be made by multiplying theultimate test loads by the factor RHTshown bel

41、ow:RHT5SFcnominalx12AD1 ZnominalSFctestedx12AD1 Ztested#1.0 (3)13.5.5 If an approved design standard (other than the NDS)is used that does not provide calculated fastener values usingmaterial properties Fu, Fyb, and G, then Ztestedshall be thelower of the three following equations:Ztested5Fu2testedF

42、u2specxZnominal#Znominal(4)Ztested5Fyb2testedFyb2nominalxZnominal#Znominal(5)D7147056Ztested5GtestedGnominalxZnominal$Znominal(6)13.5.6 Linear interpolation of test results between testedjoist hanger fastener quantities shall be permitted for otherwiseidentical face-mount joist hangers with varying

43、heights. Linearinterpolation of test results between tested joist hanger widthsshall be permitted. Other interpolation and extrapolation toother sizes shall not be permitted.13.5.7 The design value determined in 13.3.1 shall bereduced by multiplying it by a steel ratio (Rs) as defined below.Rs5S3.02

44、.5DSFu2specFu2testedDStspecttestedD#1.0 (7)13.5.8 For joist hanger test specimens tested at moisturecontents less than the limit specified in Section 10, the resultingtest loads shall be reduced by multiplying by RMC.RMC5 1 2 MCLimit2 MCtest! x 0.015#1.0 (8)13.5.9 If the compressive strength of the

45、concrete or ma-sonry as determined in 7.2 and used in the test exceeds thespecified compressive strength of concrete, masonry, grout, ormortar to be used with that connector by more than 10 %, theallowable load as determined in 14.4.1 must be reduced bymultiplying it by:fc, specifiedfc, tested#1.0 f

46、or concrete, or (9)fm, specifiedfm, tested#1.0 for masonry. (10)No increase in design load is permitted if the measuredcompressive strength is less than the specified compressivestrength.13.6 Permitted Substitutions Without Adjustments:13.6.1 Load test results obtained from a joist hanger usingone f

47、astener size and quantity are applicable to the same joisthanger using a larger fastener size or quantity, provided thelarger fastener does not cause splitting of the wood membersand locations of existing fasteners are not changed.13.6.2 Test results from top-mount hangers shall be permit-ted to be

48、applied without change to deeper but otherwiseidentical top-mount joist hangers.13.6.3 Test results from top-mount and face-mount hangersshall be permitted to applied without change to narrower butotherwise identical hangers provided it can be shown thatadequate joist support is present in the narro

49、wer configuration.13.6.4 Load test results obtained from a joist hanger sup-porting a dimension lumber joist by dimension lumber headersare applicable to untested dimension lumber or structural gluedlaminated timber provided both of the following conditions aremet: (1) the untested dimension lumber has a published specificgravity equal to or greater than the tested material, and (2) theuntested dimension lumber headers have a net thickness equalto or greater than the tested headers.13.6.5 Load test results obtained from a joist hanger sup-porting a wood I-jois