1、Designation: D6513 14Standard Practice forCalculating the Superimposed Load on Wood-frame Wallsfor Standard Fire-Resistance Tests1This standard is issued under the fixed designation D6513; 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 procedures for calculating thesuperimposed axial load required to be applied to
3、 load-bearingwood-frame walls throughout standard fire-resistance and fireand hose-stream tests.1.2 The calculations determine the maximum load allowedby design for wood-frame wall assemblies under nationallyrecognized structural design criteria.1.3 This practice is only applicable to those wood-fra
4、meassemblies for which the nationally recognized structuraldesign criteria is the National Design Specification for WoodConstruction (NDS).21.4 The system of units to be used is that of the nationallyrecognized structural design criteria. For the NDS, the units areinch-pound.1.5 The text of this sta
5、ndard references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
6、 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. Referenced Documents2.1 ASTM Standards:3D9 Terminology Relating to Wood and Wood-Based Prod-uctsE119 Test Methods for Fi
7、re Tests of Building Constructionand MaterialsE176 Terminology of Fire StandardsE1529 Test Methods for Determining Effects of Large Hy-drocarbon Pool Fires on Structural Members and Assem-blies2.2 Other Standards:NDSNational Design Specification for Wood Construc-tion2NDS SupplementDesign Values for
8、 Wood Construction23. Terminology3.1 DefinitionsDefinitions used in this practice are inaccordance with Terminology D9 and Terminology E176,unless otherwise indicated.3.2 Definitions of Terms Specific to This Standard:3.2.1 gross area, nsection area calculated from overallactual dimensions of member
9、.3.2.2 net section area, nsection area calculated by deduct-ing from the gross section area the projected area of allmaterials removed by boring, grooving, dapping, notching, orother means.3.2.3 superimposed load, nThe additional external loadneeded to be applied to the assembly to result in the cal
10、culatedstresses within the assembly when any dead load of theassembly itself is accounted for in the calculations.4. Significance and Use4.1 Test Methods E119 and E1529, and other standard fireresistance test methods specify that throughout exposures tofire and the hose stream, a constant superimpos
11、ed axial load beapplied to a load-bearing test specimen to simulate a maximumload condition. They specify that this superimposed load shallbe as nearly as practicable the maximum load allowed bydesign under nationally recognized structural design criteria.For this practice, the nationally recognized
12、 structural designcriteria is the National Design Specification for Wood Con-struction (NDS).4.1.1 Alternatively, the standard fire resistance test methodsshall be conducted by applying an axial load that is less thanthe maximum allowable axial load as addressed by the NDSand this practice, but thes
13、e tests shall be identified in the testreport as being conducted under restricted load conditions. The1This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility of Subcommittee D07.05 on Wood Assemblies.Current edition approved Oct. 1, 2014. Published Nove
14、mber 2014. Originallyapproved in 2000. Last previous edition approved in 2008 as D6513 08. DOI:10.1520/D6513-14.2Available from American Forest fire resistance; superimposed load; wallassembly; wood studsAPPENDIXESX1. Calculating the Superimposed Load on Wood-Frame Walls for E119 Standard Fire-Resis
15、tance TestsX1.1 ScopeX1.1.1 During an E119 standard fire resistance wall test, thewall assembly is required to be subjected to a superimposedload to simulate a maximum load condition per nationallyrecognized structural design criteria.NOTE X1.1In the United States, the nationally recognized structur
16、aldesign procedures for wood construction are contained in the NationalDesign Specification for Wood Construction (NDS). In accordancewith these standard design procedures, the superimposed load applied towood stud wall assemblies is typically limited by the adjusted compres-sion design stress paral
17、lel to grain of the wood stud.X1.1.2 The maximum superimposed load for a wall beingtested in accordance with E119 is the sum of the maximumallowable design loads for each stud in the wall assembly.X1.1.3 As an alternative, E119 permits testing at less thanthe maximum load, however, these tests must
18、be reported asbeing conducted under restricted load conditions.X1.2 Design ExampleX1.2.1 The following example calculations are based on2005 National Design Specification for Wood Construction(NDS) design procedures and the requirements of this stan-dard.X1.2.2 Example Construction (See Fig. X1.1):S
19、tuds: Douglas fir Larch (DFL) Select Structural (SS)grade24lumber (1.5 in. 3.5 in. 16 in. o.c., 115.5 in.long)Plates: DFL SS grade24lumber (1.5 in. 3.5 in.): onebottom plate 120 in. long, two top plates 120 in. long.Configuration: nine studs arranged symmetricallyInsulation: 3.5 in. thick Mineral Wo
20、ol InsulationSheathing: 5/8 in. Type X gypsum wallboard each sideX1.2.3 Compressive resistance of the example wood studwall loaded parallel to grain, Pr, determined in accordance withthe NDS using Allowable Stress Design (ASD) procedures:Fc= reference compression design value parallel to grain =1700
21、 psiFc* = reference compression design value multiplied by allapplicable adjustment factors except CP= FcCDCMCtCFCi(Table 4.3.1, NDS 2015)= (1700 psi)(1.0)(1.0)(1.0)(1.15)(1.0) = 1955 psiWhere:Fc= reference compression design value parallel to grain =1700 psiCD= load duration factor = 1.0CM= wet ser
22、vice factor = 1.0Ct= temperature factor = 1.0CF= size factor = 1.15 (for 1.5 in. 3.5 in. studs, SS gradeDFL)Ci= incising factor = 1.0CP= column stability factorA = area of cross-section = (3.5 in.)(1.5 in.) = 5.25 in2Due to the slenderness of the studs, the adjusted compressiondesign stress parallel
23、 to grain is affected by the bucklingresistance of each stud. For strong-axis buckling of the stud(perpendicular to the plane of wall):CP511FcE/Fc*!2c2 F11FcE/Fc*!2cG22FcE/Fc*c511521/1955!2!0.8!2 F11521/1955!2!0.8!G22521/19550.8(X1.1)CP5 0.7915 2 =0.7915!22 0.3330 5 0.2498 (X1.2)Where:FcE=0.822Eminl
24、e/d!250.822!690 000 psi!33!25 521 psiEmin= reference minimum modulus of elasticity designvalue = 690 000 psiFIG. X1.1 Example of Calculation ConstructionD6513 143Emin = adjusted minimum modulus of elasticity designvalue for beam and column stability multiplied by allapplicable adjustment factors= Em
25、inCMCtCiCT(Table 4.3.1, NDS 2015)= (690 000 psi)(1.0)(1.0)(1.0)(1.0) = 690 000 psiCT= buckling stiffness factor = 1.0le/d = slenderness ratio = 115.5 in. / 3.5 in. = 33c = 0.8 for sawn lumberFc = adjusted compression design value parallel to grain= Fc*CP= (1955 psi)(0.2498) = 488 psiPr= FcA = (488 p
26、si)( 5.25 in2) = 2564 lb/studX1.2.4 In typical construction, weak-axis buckling of thestud (in the plane of the wall) is prevented by the gypsumwallboard fastened to the stud. Each fastener acts as a bracingpoint along the stud length.X1.2.5 Compressive resistance of wood plates loaded per-pendicula
27、r to grain, Qr, as determined in accordance with theNDS (ASD Method) for the Example construction:Fc= reference compression design value perpendicular tograin = 625 psiFc = adjusted compression design value perpendicular tograin multiplied by all applicable adjustment factors= FcCMCtCiCb(Table 4.3.1
28、, NDS 2015)= (625 psi)(1.0)(1.0)(1.0)(1.0) = 625 psiWhere:CM= wet service factor = 1.0Ct= temperature factor = 1.0Ci= incising factor = 1.0Cb= bearing area factor = 1.0A = area of cross-section = (3.5 in.)(1.5 in.) = 5.25 in2Qr= FcA = (625 psi)( 5.25 in2) = 3281 lb/studX1.2X1.2.6 Compression perpend
29、icular to grain resistance doesnot control (Qr Pr). Accordingly, the superimposed load islimited by compression parallel to grain resistance of 2564lb/stud.X1.2.7 Determine the required superimposed load on wallassembly Construction:Ws5 PrNumber of studs! 5 2564 lb/stud!9 studs! 5 23.1 kips(X1.3)X2.
30、 Total Superimposed LoadsX2.1 Table X2.1 presents the results of using the calculationprocedure and the reference design stresses from the 2015NDS.TABLE X2.1 Total Superimposed Loads Obtained Using the D6513 Calculation Procedure and the Reference Design Stresses from the2015 NDSSpecies Grade SizeFc
31、AFc-perpAEAEminAStud LoadBTotal LoadCpsi psi psi psi lb/stud lbDouglasFir-LarchSS#1#2StandardStud2x42x42x42x42x417001500135014008506256256256256251 900 0001 700 0001 600 0001 400 0001 400 000690 000620 000580 000510 000510 0002564230021451890179723 07320 70319 30717 01116 176SouthernPineDense SSSS#1
32、 Dense#1#2 Dense#2StudStandard2x42x42x42x42x42x42x42x420501900175016501500145085013006605656605656605655655651 900 0001 800 0001 800 0001 600 0001 600 0001 400 0001 300 0001 200 000690 000660 000660 000580 000580 000510 000470 000440 0002573245524392156213918951664164023 15422 09621 95219 40019 2501
33、7 05814 98014 759Hem-FirSS#1#2StandardStud2x42x42x42x42x415001350130013008004054054054054051 600 0001 500 0001 300 0001 200 0001 200 000580 000550 000470 000440 000440 0002126204317611640157019 13618 38615 84614 75914 130Spruce-Pine-FirSS#1/#2StandardStud2x42x42x42x41400115011507254254254254251 500
34、0001 400 0001 200 0001 200 000550 000510 000440 000440 000204818811624154818 43616 93114 61713 931AReference design stresses from the 2015 NDS.BStud load is calculated based on Fc using a stud length of 115.5”, resulting in Le/d = 33, and plates of the same species as the studs.CThe total superimpos
35、ed wall load values for a wall with nine studs.D6513 144ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent
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