1、Designation: D3737 181Standard Practice forEstablishing Allowable Properties for Structural GluedLaminated Timber (Glulam)1This standard is issued under the fixed designation D3737; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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.1NOTECorrected editorially in September 2018.1. Scope1.1 This practice covers the procedures for establishingallowable
3、properties for structural glued laminated timber.Included are the allowable stresses for bending, tension andcompression parallel to the grain, horizontal shear, compres-sion perpendicular to the grain, and radial tension and com-pression in curved members. Also included are modulus ofelasticity and
4、 modulus of rigidity.1.2 This practice is limited to the calculation of allowableproperties subject to the given procedures for the selection andarrangement of grades of lumber of the species considered.1.3 Requirements for production, inspection and certifica-tion are not included, but in order to
5、justify the allowableproperties developed using procedures in this practice, manu-facturers must conform to recognized manufacturing standards.Refer to ANSI A190.1 and CSA O122.1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalco
6、nversions to SI units that are provided for information onlyand are not considered standard.1.5 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, health, and env
7、ironmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Stand
8、ards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced 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 Test
9、s of Lumber in StructuralSizesD245 Practice for Establishing Structural Grades and Re-lated Allowable Properties for Visually Graded LumberD2395 Test Methods for Density and Specific Gravity (Rela-tive Density) of Wood and Wood-Based MaterialsD2555 Practice for Establishing Clear Wood Strength Value
10、sD2915 Practice for Sampling and Data-Analysis for Struc-tural Wood and Wood-Based ProductsD4761 Test Methods for Mechanical Properties of Lumberand Wood-Base Structural MaterialD5456 Specification for Evaluation of Structural CompositeLumber ProductsD6570 Practice for Assigning Allowable Properties
11、 for Me-chanically Graded LumberE105 Practice for Probability Sampling of Materials2.2 Other Standards:ANSI A190.1 Structural Glued Laminated Timber3ANSI/AWC National Design Specification for Wood Con-struction4CSA O122 Structural Glued Laminated Timber53. Terminology3.1 Definitions:3.1.1 alternativ
12、e lumberlaminated veneer lumber (LVL),laminated strand lumber (LSL), oriented strand lumber (OSL),1This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility of Subcommittee D07.02 on Lumber and EngineeredWood Products.Current edition approved April 1, 2018
13、. Published May 2018. Originallyapproved in 1978. Last previous edition approved in 2012 as D3737 12. DOI:10.1520/D3737-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re
14、fer to the standards Document Summary page onthe ASTM website.3Available from APA The Engineered Wood Association, Tacoma, WA 98466,http:/www.apawood.org.4Available fromAmerican Wood Council (AWC), 222 Catoctin Circle, SE, Suite201, Leesburg, VA 20175, http:/www.awc.org.5Available from Canadian Stan
15、dards Association (CSA), 5060 Spectrum Way,Mississauga, ON L4W 5N6, Canada, http:/www.csa.ca.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized princi
16、ples on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1or parallel strand lumber (PSL) meeting the requirements ofSpecification D54
17、56; or solid-sawn lumber that is producedaccording to Practice D6570 and the grading rules of theapplicable grading or inspection agency.3.1.2 E-rated lumberlumber graded for use in manufac-turing structural glued laminated timber by nondestructivemeasurement of a modulus of elasticity (E) and by vi
18、sualinspection in accordance with the grading rules of the appli-cable grading or inspection agency.3.1.3 glulama term used to denote structural glued lami-nated timber, which is a product made from suitably selectedand prepared pieces of wood bonded together with an adhesiveeither in a straight or
19、curved form with the grain of all piecesessentially parallel to the longitudinal axis of the member.3.1.4 horizontally laminated timbera member designed toresist bending loads applied perpendicularly to the wide facesof the laminations (referred to as bending about the x-x axis).3.1.5 laminationa la
20、yer of lumber within the glued lami-nated timber.3.1.6 modulus of elasticity (E)for laminating, E is desig-nated in two categories to distinguish mode of measurementand application.3.1.6.1 Long-Span E (LSE)the modulus of elasticity cal-culated from deflection measured in a flat-wise static bendingte
21、st of lumber with a center point loading and a span-to-depthratio (1d) of approximately 100 or the E obtained from TestMethods D2555 and multiplying by the appropriate factorsfrom Tables 1-6.3.1.6.2 Member E (Eaxial, Ex,Ey)the allowable modulus ofelasticity values of the structural glued laminated m
22、ember asdefined in this practice.3.1.7 vertically laminated timbera member designed toresist bending loads applied parallel to the wide faces of thelaminations (referred to as bending about the y-y axis).3.1.8 visually graded lumberlumber graded by visualinspection in accordance with the grading rul
23、es of the appli-cable grading or inspection agency.3.1.9 GDCthe ratio of the cross-sectional area of the localgrain deviation (which may or may not be associated with aknot) away from the edge of the lumber to the cross sectionalarea of the lumber (see Fig. 1).3.1.10 GDEthe ratio of the cross-sectio
24、nal area of thelocal grain deviation (which may or may not be associated witha knot) at the edge of the lumber to the cross sectional area ofthe lumber (see Fig. 1).3.1.11 GDSthe projected sum of all GDE and GDC valueswithin a one-foot length of lumber as defined in Fig. 1.3.1.12 KCthe ratio of the
25、cross-sectional area of a knotlocated away from the edge of the lumber to the cross-sectionalarea of lumber. When a knot at the edge of the wide face anda knot located away from the edge are in the same cross-section, the combination of the two shall be used in determin-ing KC (see Fig. 2).3.1.13 KE
26、the ratio of cross-sectional area of a knot at theedge of wide face of lumber to the cross-sectional area of thelumber (see Fig. 2).3.1.14 SRtlthe required strength ratio of the tension lami-nation at the outermost fiber.4. Materials Requirements4.1 Requirements for Laminations:4.1.1 Laminations of
27、structural glued laminated timber shallbe of lumber with net thickness of 2 in. (0.05 m) or less.4.1.2 Lumber is permitted to be joined end to end withstructural end joints to form long length laminations. End jointsshall be qualified and quality controlled with a recognizedmanufacturing standard.4.
28、1.3 Lumber is permitted to be placed or joined side to sideto form wide laminations.4.1.4 Dimension lumber used to form laminations shall bevisually graded or E-rated according to established gradingrules.4.1.5 Alternate lumber material is permitted by demonstrat-ing equivalence to a dimension lumbe
29、r grade in accordancewith Annex A1.4.1.6 For the analysis of a structural glued laminated timberlayup, all laminations in a single cross section shall be of equalthickness.4.1.7 The analytical procedures of this standard practice arebased on specific lamination characteristics.4.1.7.1 Lumber propert
30、ies including knot size andfrequency, physical properties such as specific gravity, andmechanical properties such as modulus of elasticity shall bebased on measurements of 2 6 lumber for definition of gradecharacteristics.4.1.7.2 The effect of decay or compression failures uponstrength cannot be rea
31、dily determined, thus these defects shallbe prohibited from laminating grades insofar as existinginspection and grading technology permit. Firm white speck orlight white pocket is permissible in grades of lumber thatpermit knots to occupy up to one third or more of the crosssection provided their ex
32、tent in combination with knots doesnot exceed that of the largest edge knot permitted. Theexception is that firm white speck and light white pocket shallTABLE 1 Adjustment Factors for Clear Wood Stresses(Test Methods D2555)PropertyMultipliers for Averageor 5th PercentileSeasoningFactor for a12 %Aver
33、ageMoistureContentSoftwoods HardwoodsBending 0.476(12.1)0.435(12.3)1.35Compressionparallel to grain0.526(11.9)0.476(12.1)1.75Modulus of elas-ticity1.095(10.913)1.095(10.913)1.20Horizontal shear 0.244(14.1)0.222(14.5)1.13D3737 1812be excluded from end joints in tension members and the outer10 % of th
34、e total depth on the tension side of bendingmembers.4.1.7.3 Compression wood (as defined in Terminology D9)in readily identifiable and damaging form shall be limited inaccordance with 4.1.7.3 (1) and 4.1.7.3 (2).(1) For dry service conditions, grades permitting knots upto one half of the cross secti
35、on may contain streaks ofcompression wood occupying as much as 20 % of the crosssection. Streaks of compression wood up to one eighth of thecross section may be permitted in other grades.(2) For wet service conditions, or for pressure-treatedmembers, the conditions of 4.1.7.3 (1) apply except thatco
36、mpression wood is limited to 5 % of the cross section of thelaminations in tension members and in the outer 10 % of thetotal depth on the tension side of bending members.4.1.7.4 Lumber shall be free of shakes and splits that makean angle of less than 45 with the wide face of the piece. Pitchpockets
37、shall be limited in size to the area of the largest knotpermitted, and pitch streaks shall be limited to one sixth of thewidth of the lumber.4.2 Requirements for Adhesives:4.2.1 Adhesives for use in structural glued laminated timbershall be rigid (non-elastomeric) to ensure composite action ofthe la
38、minations and shall be sufficiently strong to transferstresses required by the intended use of the member.4.2.2 Adhesives shall be sufficiently durable to providebond for the life of the glued laminated member in its expectedservice environment.TABLE 2 Bending Stress Index Based on Large Beam Tests
39、and Modulus of Elasticity Values for Visually Graded LumberNOTE 1Appendix X1 provides one method of developing new data.Species Growth ClassificationABending Stress IndexBModulus of Elasticitypsi MPa million psi MPaDouglas Fir-Larch medium grain 3000 20.7 1.9 13 100close grain 3250 22.4 2.0 13 800de
40、nse 3500 24.1 2.1 14 500Southern Pine coarse grainC2000 13.8 1.5 10 300medium grain 3000 20.7 1.8 12 400dense 3500 24.1 2.0 13 800Hem-Fir medium grain 2560 17.7 1.7 11 700denseD3000 20.7 1.8 12 400AClassification for “dense” wood shall follow Practice D245.BValues shown are based on full-size beam t
41、ests.As a result, these values incorporate the effects of some features such as grain deviations in lumber along with influencesof end and face bonding influences. Beams designed using these values and tested in accordance with Test Methods D198 will yield strength values such that the lower5th perc
42、entile will exceed the design bending stress by a factor of 2.1 with 75 % confidence. Analysis of test data assumed a log normal distribution. For unsymmetriccombinations, tests have shown that values up to 40 % higher than those listed may be applied to the compression side of bending members.CAlso
43、 applicable to minor species of southern pine regardless of growth rate.DSpecific gravity, based on oven-dry weight and volume at 12 % moisture content, must equal or exceed 0.39.TABLE 3 Bending Stress Indexes and Compression Stress IndexParallel to Grain for E-Rated Lumber Used in LaminatingALongSp
44、an,E, psiBending StressIndexACompression StressIndex Parallelto GrainB,Cpsi MPa psi MPa1 600 000 2560 17.7 1900 13.11 900 000 3000 20.7 2400 16.52 100 000 3500 24.1 2800 19.32 300 000 4000 27.6 3100 21.4AValues shall be not higher than obtained by interpolation for intermediate Evalues.BValues are f
45、or 12-in. deep members at 12 % moisture content (dry).CValues are for members at 12 % moisture content (dry) values.TABLE 4 Parallel to Grain Stress Modification Factors Associatedwith Slope of Grain for DesigningGlulam CombinationsSlope of GrainStress Modification FactorTension Compression1:4 0.27
46、0.461:6 0.40 0.561:8 0.53 0.661:10 0.61 0.741:12 0.69 0.821:14 0.74 0.871:15 0.76 1.001:16 0.80 1.001:18 0.85 1.001:20 1.00 1.00TABLE 5 Constant Used to Adjust Vertically Laminated BendingStrength RatioStrength Ratio (SR1) C10.45 or greater 1.2380.40 1.2920.35 1.3460.30 1.4000.26 or less 1.444TABLE
47、6 Grade Adjustment Factors for Modulus of ElasticityBending Strength RatioAAdjustment Factor0.55 or greater 1.000.45 to 0.54 0.900.44 or less 0.80ADetermined in accordance with Practice D245.D3737 18134.3 Tension Laminationsfor horizontally laminated bend-ing members shall meet the requirements here
48、in.4.3.1 The results of full-size beam tests reported in Refs(1-3)6have yielded an empirical relationship between the sizeof knots in the tension zone and bending strength. Thisrelationship dictates that special grading considerations beapplied to the laminations used in the outer 10 % of the beamde
49、pth on the tension side.This tension side may exist on the topor bottom of the beam, or both, depending upon loading andsupport conditions. If horizontally laminated timbers are manu-factured without applying these special tension laminationgrading considerations, the allowable bending stress shall bereduced by multiplying the allowable stress calculated in7.2.1.1 by 0.85 if the depth is 15 in. (0.38 m) or less or by 0.75if the depth exceeds 15 in. (0.38 m).4.3.2 Visually Graded Lumber:4.3.2.1 Definitions of terms required for calculation of
