1、Designation: D3737 12D3737 18Standard 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 revi
2、sion, the 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.1. Scope1.1 This practice covers the procedures for establishing allowable properties for structural glued lamin
3、ated timber. Included arethe allowable stresses for bending, tension and compression parallel to the grain, horizontal shear, compression perpendicular tothe grain, and radial tension and compression in curved members.Also included are modulus of elasticity and modulus of rigidity.1.2 This practice
4、is limited to the calculation of allowable properties subject to the given procedures for the selection andarrangement of grades of lumber of the species considered.1.3 Requirements for production, inspection and certification are not included, but in order to justify the allowable propertiesdevelop
5、ed using procedures in this practice, manufacturers must conform to recognized manufacturing standards. Refer toANSI/AITC A190.1 ANSI A190.1 and CSA O122.1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units
6、that are provided for information only and are not considered standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironment
7、al practices and determine theapplicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides
8、 and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based ProductsD143 Test Methods for Small Clear Specimens of TimberD198 Test Methods of Static Tests of Lumber in
9、 Structural SizesD245 Practice for Establishing Structural Grades and Related Allowable Properties for Visually Graded LumberD2395 Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based MaterialsD2555 Practice for Establishing Clear Wood Strength ValuesD2915 Practice
10、 for Sampling and Data-Analysis for Structural Wood and Wood-Based ProductsD4761 Test Methods for Mechanical Properties of Lumber and Wood-Base Structural MaterialD5456 Specification for Evaluation of Structural Composite Lumber ProductsD6570 Practice for Assigning Allowable Properties for Mechanica
11、lly Graded LumberE105 Practice for Probability Sampling of Materials2.2 AITC Standards:3ANSI/AITC A190.1 Structural Glued Laminated Timber, 20071 This practice is under the jurisdiction of ASTM Committee D07 on Wood and is the direct responsibility of Subcommittee D07.02 on Lumber and Engineered Woo
12、dProducts.Current edition approved Nov. 1, 2012April 1, 2018. Published December 2012May 2018. Originally approved in 1978. Last previous edition approved in 20092012 asD3737 09D3737 12.E01. DOI: 10.1520/D3737-12.10.1520/D3737-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, o
13、r contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes ha
14、ve been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official do
15、cument.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 Other Standards:ANSI A190.1 Structural Glued Laminated Timber3ANSI/AF or solid-sawn lumber that is produced accordingto Practice D6570 and the grading rules of the applicable
16、grading or inspection agency.3.1.2 E-rated lumberlumber graded for use in manufacturing structural glued laminated timber by nondestructivemeasurement of a modulus of elasticity (E) and by visual inspection in accordance with the grading rules of the applicable gradingor inspection agency.3.1.3 glul
17、ama term used to denote structural glued laminated timber, which is a product made from suitably selected andprepared pieces of wood bonded together with an adhesive either in a straight or curved form with the grain of all pieces essentiallyparallel to the longitudinal axis of the member.3.1.4 hori
18、zontally laminated timbera member designed to resist bending loads applied perpendicularly to the wide faces ofthe laminations (referred to as bending about the x-x axis).3.1.5 laminationa layer of lumber within the glued laminated timber.3.1.6 modulus of elasticity (E)for laminating, E is designate
19、d in two categories to distinguish mode of measurement andapplication.3.1.6.1 Long-Span E (LSE)the modulus of elasticity calculated from deflection measured in a flat-wise static bending test oflumber with a center point loading and a span-to-depth ratio (1d) of approximately 100 or the E obtained f
20、rom Test Methods D2555and multiplying by the appropriate factors from Table 1Tables 1-6 and Table 6.3.1.6.2 Member E (Eaxial , Ex, Ey)the allowable modulus of elasticity values of the structural glued laminated member asdefined in this practice.3.1.7 vertically laminated timbera member designed to r
21、esist 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 visual inspection in accordance with the grading rules of the applicable gradingor inspection agency.3 Available from the American Institu
22、te of Timber Construction, 7012 S. Revere Parkway, Suite 140, Centennial, CO 80112, https:/www.aitc-glulam.org. APA TheEngineered Wood Association, Tacoma, WA 98466, http:/www.apawood.org.4 Available fromAmerican Forest and PaperAssociation (AF grain deviations (with or without knots) are measured t
23、o the lateral extremes of thezone within which the local slope of grain exceeds the allowable slope of grain for the grade. Eq 8-11 which follow yield themaximum allowable knot and grain deviation ratios in the outer 10 % of depth. It is suggested these ratios be adjusted downwardto the nearest 0.05
24、 or to the next nearest convenient fraction (such as 13).4.3.2.3 Beams Greater than 15 in. (0.38 m) in Depth:(1) Outer 5 %Grain deviation shall be limited in accordance with Eq 1 and 2.GDS#1.5512SRtl! (1)GDS#1.8212SRtl! (2)(a) (b)GDC = y/b GDC = y/bGDE = z/b GDE = z/bGDS = x/b where x = y + z GDS =
25、x/b where x 15 in.A4.1.12 The required strength ratio of the tension lamination (SRTL) shall be calculated using EqA4.15, and the tension laminationgrading requirements of 4.3 shall be determined, if a tension lamination factor of 1.0 is used in Equation Eq A4.14.SRTL5FbxS2dTLD DSETLETDS IgITDBSITL
26、(A4.15)where:dTL = distance from neutral axis to outer edge of tension lamination,ETL = long-span modulus of elasticity of the lumber in the outermost tension zone, andBSITL = bending stress index of the lumber in the outermost tension zone.A4.2 ExampleGiven the 20-lamination beam shown in Fig. A4.1
27、 and the lumber grade data in Table A4.1, determine theallowable bending stress and tension lamination grading requirements for flexure with compression at the top of the section.A4.2.1 The neutral axis is located relative to the bottom of the beam using Eq A4.1. For convenience, distances are measu
28、red innumber of laminations.y 5S2.12 D22!1S1.82 D72222!1S1.12 D152272!1S1.82 D1922152!1S2.12 D2022192!2.12!11.8722!11.11527!11.819215!12.120219!y 59.740 laminations from the bottomA4.2.1.1 The core zone is split by the neutral axis into two zones for the analysis and the zones are numbered from the
29、bottomof the beam. The distance from the neutral axis to the edges of each zone (Fig. A4.1) are determined using Eq A4.2 and A4.3.FIG. A4.1 Example of a 20-Lamination BeamD3737 1819N05s029.740d529.740N15s229.740d527.740N25s729.740d522.740N35s9.74029.740d50N45s1529.740d55.260N55s1929.740d59.260N65s20
30、29.740d510.260A4.2.1.2 Negative results indicate that the zone boundaries represented by N0, N1, and N2 are below the neutral axis. Positiveresults indicate that the zone boundaries represented by N4, N5, and N6 are above the neutral axis.A4.2.2 The transformed moment of inertia for each zone about
31、the neutral axis is calculated using Eq A4.4. For convenience, thewidth of the untransformed section, b, will be set equal to unity.I65S2.12.1Ds10.26329.2603d3 595.34I55S1.82.1Ds9.260325.2603d3 5185.3I45S1.12.1Ds5.2603203d3 525.41I35S1.12.1Ds032s22.740d3d3 53.592I25S1.82.1Dss22.740d32s27.740d3d3 512
32、6.6I15S2.12.1Dss27.740d32s29.740d3d3 5153.4A4.2.2.1 The moment of inertia of the transformed section is calculated using Eq A4.5.IT 5I11I21I31I41I51I65153.41126.613.592125.411185.3195.345589.6A4.2.3 The moment of inertia of the untransformed (gross) section is calculated using Eq A4.6.Ig 520312 5666
33、.7A4.2.4 Weighting factors, Oj and Pj are calculated for each zone using Eq A4.7 and A4.8.O65210.26329.2603!5572.0P6525910.26!52510.26!3110.26!299.260!5159.260!329.260!5163.6103!O5529.260325.2603!51297P552599.260!5259.260!319.260!295.260!5155.260!325.260!5229.3103!O4525.2603203!5291.1P452595.260!525
34、5.260!315.260!290!5150!320!514.21103!O35203222.740!3!541.14TABLE A4.1 Lumber Data for Analysis of Glulam Beam Bending Stress (see Ref (12)Grade and SpeciesA Modulus of ElasticityB Bending Stress IndexC Knot DataDSRbx minEx 99.5 Percentile hpsi MPa psi MPa % % %L1 Douglas fir 2 100 000 14 500 3500 24
35、.1 6.9 42.2 35.3 0.75L2 Douglas fir 1 800 000 12 400 3000 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 0.5A Graded 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.B Bas
36、ed on 6.1.4 for Douglas fir and 6.1.4 and 7.5 for lodgepole pine.C Based on 6.1.1.1 for Douglas fir and 6.1.1 for lodgepole pine.D Based on knot surveys and analysis in accordance with Annex A3 and Annex A6.E As determined by formula X1.2 of Practice D245, in accordance with 7.2.1.1 (1).D3737 1820P3
37、52590!5250!310!2922.740!51522.740!3222.740!5515.9O25222.740!3227.740!3!5443.1P2525922.740!52522.740!3122.740!2927.740!51527.740!3227.740!598.56103!O15227.740!3229.740!3!5920.7P1525927.740!52527.740!3127.740!2929.740!51529.740!3229.740!5214.6103!A4.2.5 An Ik/Ig ratio is calculated for each zone using
38、 Eq A4.9.SIkIgD650.069!S2.12.1D572.0!10.109!S1.82.1D1297!10.230!S1.12.1D291.1!210.26!31!0.353!2S2.12.1D2163.3103!10.440!2S1.82.1D2229.3103!10.558!2S1.12.1D214.21103!210.26!3SIkIgD650.198SIkIgD550.109!S1.81.8D1297!10.230!S1.11.8D291.1!29.260!310.440!2S1.81.8D2229.3103!10.558!2S1.11.8D214.21103!29.260
39、!3SIkIgD550.2499SIkIgD450.230!S1.11.1D291.1!10.558!2S1.11.1D214.21103!25.260!3SIkIgD450.4585SIkIgD350.230!S1.11.1D41.14!10.558!2S1.11.1D2515.9!22.740!3SIkIgD350.5381SIkIgD250.109!S1.81.8D443.1!10.230!S1.11.8D41.14!27.740!310.440!2S1.81.8D298.56103!10.558!2S1.11.8D2515.9!27.740!3SIkIgD250.2075SIkIgD1
40、5D3737 18210.069!S2.12.1D920.7!10.109!S1.82.1D443.1!10.230!S1.12.1D41.14!29.740!31!0.353!2S2.12.1D2214.6103!10.440!2S1.82.1D298.56103!10.558!2S1.12.1D2515.9!29.740!3SIkIgD150.1688A4.2.6 The stress modification factor for knots is calculated for each zone using Eq A4.10, subject to the minimum streng
41、th ratiofrom 7.2.1.1 (1) (Table A4.1).SMFbx knots 65s113s0.1980dds12s0.1980dd3S12S0.19802 DD$0.75SMFbx knots 650.741$0.75SMFbx knots 650.75SMFbx knots 55s113s0.2499dds12s0.2499dd3S12S0.24992 DD$0.67SMFbx knots 550.646$0.67SMFbx knots 550.67SMFbx knots 45s113s0.4585dds12s0.4585dd3S12S0.45852 DD$0.50S
42、MFbx knots 450.291$0.50SMFbx knots 450.50SMFbx knots 35s113s0.5381dds12s0.5381dd3S12S0.53812 DD$0.50SMFbx knots 350.211$0.50SMFbx knots 350.50SMFbx knots 25s113s0.2075dds12s0.2075dd3S12S0.20752 DD$0.67SMFbx knots 250.724$0.67SMFbx knots 250.724SMFbx knots 15s113s0.1688dds12s0.1688dd3S12S0.16882 DD$0
43、.75SMFbx knots 150.792$0.75SMFbx knots 150.792A4.2.7 The stress modification factor for slope of grain is determined for each zone from Table 4, using the factors forcompression for the zones above the neutral axis and the factors for tension for the zones below the neutral axis.SMFbx SOG6 = 0.87SMF
44、bx SOG5 = 0.82SMFbx SOG4 = 0.66SMFbx SOG3 = 0.53SMFbx SOG2 = 0.69SMFbx SOG1 = 0.74A4.2.8 The stress modification factor for each zone is determined using Eq A4.11.SMFbx6 = min0.75, 0.87 = 0.75SMFbx5 = min0.67, 0.82 = 0.67SMFbx4 = min0.5, 0.66 = 0.5SMFbx3 = min0.5, 0.53 = 0.5SMFbx2 = min0.724, 0.69 =
45、 0.69SMFbx1 = min0.792, 0.74 = 0.74A4.2.9 The maximum stress permitted on each zone is calculated using Eq A4.12.D3737 1822Fmax,6 = 1.4 (3500 psi) (0.75) = 3675 psiFmax,5 = 1.4 (3000 psi) (0.67) = 2814 psiFmax,4 = 1.4 (1930 psi) (0.50) = 1351 psiFmax,3 = 1.0 (1930 psi) (0.50) = 965 psiFmax,2 = 1.0 (
46、3000 psi) (0.69) = 2070 psiFmax,1 = 1.0 (3500 psi) (0.74) = 2590 psiA4.2.10 The apparent outer fiber stress on the beam corresponding to Fmax, j for each zone is calculated using Eq A4.13.apparent,653675 psiS 1010.26DS2.12.1DS589.6666.7D53168 psiapparent,552814 psiS 109.26DS2.11.8DS589.6666.7D53135
47、psiapparent,451351 psiS 105.26DS2.11.1DS589.6666.7D54336 psiapparent,35965 psiS 102.74DS2.11.1DS589.6666.7D55946 psiapparent,252070 psiS 107.74DS2.11.8DS589.6666.7D52759 psiapparent,152590 psiS 109.74DS2.12.1DS589.6666.7D52352 psiA4.2.11 The allowable flexural design stress (Fbx) is determined using
48、 Eq A4.14 and rounded according to the rules given in 5.2.Fbx5min$3168,3135,4336,5946,2759,2352%psi!1.0!52352 psi(1) Rounding in accordance with 5.2 gives:Fbx52400 psiA4.2.12 The required strength ratio of the tension lamination (SRTL) is calculated using Eq A4.15.SRTL52400 psiS29.74!20 DS2.12.1DS66
49、6.7589.6D3500 psi 50.755(1) The maximum permitted grain deviations in the tension laminations for the outermost 5 % of the depth on the bottom ofthe beam are determined as follows:GDSC 51.82120.755!50.446GDSE 51.55120.755!50.380(2) Because the required strength ratio of the tension lamination is greater than 0.60, the general slope of grain must not exceed1:16.SOG#1:16(3) The m
