1、Designation: D3737 091Standard 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.1NOTEAppendix X2 was editorially changed in April 2012.1. Scope1.1 This practice covers the procedures for establishing
3、allowable 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 ofelas
4、ticity and 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
5、 order to justify the allowableproperties developed using procedures in this practice, manu-facturers must conform to recognized manufacturing standards.Refer to ANSI/AITC 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
6、 mathematicalconversions 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 a
7、nd 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-uctsD143 Test Methods for Small Clear Specimens of TimberD198 Test Methods of Static Tests of Lumber in Structura
8、lSizesD245 Practice for Establishing Structural Grades and Re-lated Allowable Properties for Visually Graded LumberD2395 Test Methods for Specific Gravity of Wood andWood-Based MaterialsD2555 Practice for Establishing Clear Wood Strength Val-uesD2915 Practice for Sampling and Data-Analysis for Struc
9、-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 forMechanically Graded LumberE105 Practice for Probabil
10、ity Sampling of Materials2.2 AITC Standards:3AITC 117-71 Standard Specifications for Structural GluedLaminated Timber of Softwood Species, 1971AITC 117-74 Standard Specifications for Structural GluedLaminated Timber of Softwood Species, 1974AITC 117-79 Standard Specifications for Structural GluedLam
11、inated Timber of Softwood Species, 1979AITC “Brown Book” Determination of Design Values forStructural Glued Laminated, 1979AITC Standard 407 Standard for Alternate Lumber Gradesfor Use in Structural Glued Laminated Timber, 2005AITC Standard 500 Determination of Design Values forStructural Glued Lami
12、nated Timber in Accordance withASTM D3737-89a, 1991AITC Technical Note 21 Volume Factor for StructuralGlued Laminated Timber, 2005ANSI/AITC A190.1 Structural Glued Laminated Timber,20071This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility of Subcommit
13、tee D07.02 on Lumber and EngineeredWood Products.Current edition approved Sept. 1, 2009. Published December 2009. Originallyapproved in 1978. Last previous edition approved in 2008 as D3737 08. DOI:10.1520/D3737-09E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AS
14、TM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the American Institute of Timber Construction, 7012 S. RevereParkway, Suite 140, Centennial, CO 80112, https:/www.aitc-glulam.o
15、rg.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.3 Other Standards:ANSI/AF 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 lumberl
16、umber graded for use in manufac-turing structural glued laminated timber by nondestructivemeasurement of a modulus of elasticity (E) and by visualinspection 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-na
17、ted timber, which is a product made from suitably selectedand prepared pieces of wood bonded together with an adhesiveeither in a straight or curved form with the grain of all piecesessentially parallel to the longitudinal axis of the member.3.1.4 horizontally laminated timbera member designed tores
18、ist bending loads applied perpendicularly to the wide facesof the laminations (referred to as bending about the x-x axis).3.1.5 laminationa layer 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 meas
19、urementand application.3.1.6.1 Long-Span E (LSE)the modulus of elasticity cal-culated from deflection measured in a flat-wise static bendingtest 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 ap
20、propriate factorsfrom Table 1 and Table 6.3.1.6.2 Member E (Eaxial, Ex,Ey)the allowable modulus ofelasticity values of the structural glued laminated member asdefined in this practice.3.1.7 vertically laminated timbera member designed toresist bending loads applied parallel to the wide faces of thel
21、aminations (referred to as bending about the y-y axis).3.1.8 visually graded lumberlumber graded by visualinspection in accordance with the grading rules 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 b
22、e 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-sectional 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 lumb
23、er (see Fig. 1).3.1.11 GDSthe projected sum of all GDE and GDCvalues within a one-foot length of lumber as defined in Fig. 1.3.1.12 KCthe ratio of the 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
24、 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 KEthe 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 re
25、quired strength ratio of the tension lami-nation at the outermost fiber.4. Materials Requirements4.1 Requirements for Laminations:4.1.1 Laminations of 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 wi
26、thstructural end joints to form long length laminations. End jointsshall be qualified and quality controlled with a recognizedmanufacturing standard.4.1.3 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
27、graded or E-rated according to established gradingrules.4.1.5 Alternate lumber material is permitted by demonstrat-ing equivalence to a dimension lumber grade in accordancewith Annex A1.4.1.6 For the analysis of a structural glued laminated timberlayup, all laminations in a single cross section shal
28、l be of equalthickness.4.1.7 The analytical procedures of this standard practice arebased on specific lamination characteristics.4.1.7.1 Lumber properties including knot size and fre-quency, physical properties such as specific gravity, andmechanical properties such as modulus of elasticity shall be
29、based on measurements of 2 3 6 lumber for definition of gradecharacteristics.4.1.7.2 The effect of decay or compression failures uponstrength cannot be readily determined, thus these defects shallbe prohibited from laminating grades insofar as existinginspection and grading technology permit. Firm w
30、hite 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 extent in combination with knots doesnot exceed that of the largest edge knot permitted. The4Available from American Forest and Paper Association (
31、AF graindeviations (with or without knots) are measured to the lateralextremes of the zone within which the local slope of grainexceeds the allowable slope of grain for the grade. Eq 8-11which follow yield the maximum allowable knot and graindeviation ratios in the outer 10 % of depth. It is suggest
32、ed theseratios be adjusted downward to the nearest 0.05 or to the nextnearest convenient fraction (such as13).4.3.2.3 Beams Greater than 15 in. (0.38 m) in Depth:6The boldface numbers in parentheses refer to a list of references at the end ofthis practice.(a) (b)GDC = y/b GDC = y/bGDE = z/b GDE = z/
33、bGDS = x/b where x=y+z GDS= x/b where x15in.A4.1.12 The required strength ratio of the tension lamina-tion (SRTL) shall be calculated using EqA4.15, and the tensionlamination grading requirements of 4.3 shall be determined, ifa tension lamination factor of 1.0 is used in Equation EqA4.14.SRTL5FbxS2d
34、TLDDSETLETDSIgITDBSITL(A4.15)where:dTL= distance from neutral axis to outer edge of tensionlamination,ETL= long-span modulus of elasticity of the lumber inthe outermost tension zone, andBSITL= bending stress index of the lumber in the outer-most tension zone.A4.2 ExampleGiven the 20-lamination beam
35、shown inFig. A4.1 and the lumber grade data in Table A4.1, determinethe allowable bending stress and tension lamination gradingrequirements for flexure with compression at the top of thesection.A4.2.1 The neutral axis is located relative to the bottom ofthe beam using Eq A4.1. For convenience, dista
36、nces aremeasured in number of laminations.y 5S2.12D22! 1S1.82D7222! 1S1.12D15272!1S1.82D192152! 1S2.12D202192!2.12! 1 1.872! 1 1.1157! 1 1.81915! 1 2.12019!y 5 9.740 laminations from the bottomD3737 09114A4.2.1.1 The core zone is split by the neutral axis into twozones for the analysis and the zones
37、 are numbered from thebottom of the beam. The distance from the neutral axis to theedges of each zone (Fig. A4.1) are determined using Eq A4.2and A4.3.N05 09.740! 5 9.740N15 29.740! 5 7.740N25 79.740! 5 2.740N35 9.740 9.740! 5 0N45 15 9.740! 5 5.260N55 19 9.740! 5 9.260N65 20 9.740! 5 10.260A4.2.1.2
38、 Negative results indicate that the zone boundariesrepresented by N0, N1, and N2are below the neutral axis.Positive results indicate that the zone boundaries representedby N4, N5, and N6are above the neutral axis.A4.2.2 The transformed moment of inertia for each zoneabout the neutral axis is calcula
39、ted using Eq A4.4. Forconvenience, the width of the untransformed section, b, will beset equal to unity.I65S2.12.1D10.263 9.2603!35 95.34I55S1.82.1D9.2603 5.2603!35 185.3I45S1.12.1D5.260303!35 25.41I35S1.12.1D03 2.740!3!35 3.592I25S1.82.1D2.740!3 7.740!3!35 126.6I15S2.12.1D7.740!3 9.740!3!35 153.4A4
40、.2.2.1 The moment of inertia of the transformed sectionis calculated using Eq A4.5.IT5 I11 I21 I31 I41 I51 I65 153.4 1 126.6 1 3.592 1 25.41 1 185.3 1 95.345 589.6A4.2.3 The moment of inertia of the untransformed (gross)section is calculated using Eq A4.6.Ig5203125 666.7A4.2.4 Weighting factors, Oja
41、nd Pjare calculated for eachzone using Eq A4.7 and A4.8.O65 210.263 9.2603! 5 572.0P6525910.26!5510.26!31 10.26! 99.260!51 59.260!3 9.260!5 163.6103!O55 29.2603 5.2603! 5 1297P552599.260!559.260!31 9.260! 95.260!51 55.260!3 5.260!5 229.3103!O45 25.260303! 5 291.1FIG. A4.1 Example of a 20-Lamination
42、BeamTABLE A4.1 Lumber Data for Analysis of Glulam Beam Bending Stress (see Ref (12)Grade and SpeciesAModulus of ElasticityBBending Stress IndexCKnot DataDSRbx minEx 99.5 Percentile hpsi MPa psi MPa % % %L1 Douglas fir 2 100 000 14 500 3500 24.1 6.9 42.2 35.3 0.75L2 Douglas fir 1 800 000 12 400 3000
43、20.7 10.9 54.9 44.0 0.67L3 Lodgepole pine 1 100 000 7 600 1933 13.3 23.0 78.8 55.8 0.5AGraded in accordance with WWPA and WCLIB rules under the American Lumber Standard (5 and 6). L3 lodgepole pine graded under rules for L3 Douglas fir.BBased on 6.1.4 for Douglas fir and 6.1.4 and 7.5 for lodgepole
44、pine.CBased on 6.1.1.1 for Douglas fir and 6.1.1 for lodgepole pine.DBased on knot surveys and analysis in accordance with Annex A3 and Annex A6.EAs determined by formula X1.2 of Practice D245, in accordance with 7.2.1.1 (1).D3737 09115P452595.260!555.260!31 5.260! 90!51 50!3 0!5 14.21103!O35 203 2.
45、740!3! 5 41.14P352590!550!31 0! 92.740!51 52.740!3 2.740!5 515.9O25 22.740!3 7.740!3! 5 443.1P252592.740!552.740!31 2.740! 97.740!51 57.740!3 7.740!5 98.56103!O15 27.740!3 9.740!3! 5 920.7P152597.740!557.740!31 7.740! 99.740!51 59.740!3 9.740!5 214.6103!A4.2.5 An Ik/Igratio is calculated for each zo
46、ne using EqA4.9.SIkIgD650.069!S2.12.1D572.0! 1 0.109!S1.82.1D1297! 1 0.230!S1.12.1D291.1!210.26!31!0.353!2S2.12.1D2163.3103! 1 0.440!2S1.82.1D2229.3103!1 0.558!2S1.12.1D214.21103!210.26!3SIkIgD65 0.198SIkIgD550.109!S1.81.8D1297! 1 0.230!S1.11.8D291.1!29.260!310.440!2S1.81.8D2229.3103! 1 0.558!2S1.11
47、.8D214.21103!29.260!3SIkIgD55 0.2499SIkIgD450.230!S1.11.1D291.1! 10.558!2S1.11.1D214.21103!25.260!3SIkIgD45 0.4585SIkIgD350.230!S1.11.1D41.14! 10.558!2S1.11.1D2515.9!22.740!3SIkIgD35 0.5381SIkIgD250.109!S1.81.8D443.1! 1 0.230!S1.11.8D41.14!27.740!310.440!2S1.81.8D298.56103! 1 0.558!2S1.11.8D2515.9!2
48、7.740!3SIkIgD25 0.2075SIkIgD150.069!S2.12.1D920.7! 1 0.109!S1.82.1D443.1! 1 0.230!S1.12.1D41.14!29.740!31!0.353!2S2.12.1D2214.6103! 1 0.440!2S1.82.1D298.56103!1 0.558!2S1.12.1D2515.9!29.740!3SIkIgD15 0.1688A4.2.6 The stress modification factor for knots is calculatedfor each zone using EqA4.10, subject to the minimum strengthratio from 7.2.1.1 (1) (Table A4.1).SMFbx knots 65 1 1 30.1980!10.1980!3S1S0.19802DD$ 0.75SMFbx knots 65 0.741 $ 0.75SMFbx knots 65 0.75SMFbx knots 55 1 1 30.2499!10.2499!3S1S0.24992DD$ 0.67SMFbx knots 55 0.646 $ 0.67SMFbx knots 55 0.67SMFbx knots 45 1 1 30.458
