1、Designation: D 6513 08Standard Practice forCalculating the Superimposed Load on Wood-frame Wallsfor Standard Fire-Resistance Tests1This standard is issued under the fixed designation D 6513; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last 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 practice covers procedures for calculating thesuperimposed axial load required to be applied
3、 to 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-
4、frameassemblies 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
5、standard 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.
6、 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. Referenced Documents2.1 ASTM Standards:3D9 Terminology Relating to WoodE119 Test Methods for Fire Tests of Building C
7、onstructionand MaterialsE 176 Terminology Relating to Fire StandardsE 1529 Test Methods for Determining Effects of LargeHydrocarbon Pool Fires on Structural Members and As-semblies2.2 Other Standards:NDSNational Design Specification for Wood Construc-tion2NDS SupplementDesign Values for Wood Constru
8、ction23. Terminology3.1 DefinitionsDefinitions used in this practice are inaccordance with Terminology D9 and Terminology E 176,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.3.2.2 net s
9、ection 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 calculatedstres
10、ses within the assembly when any dead load of theassembly itself is accounted for in the calculations.4. Significance and Use4.1 Test Methods E119and E 1529, and other standard fireresistance test methods specify that throughout exposures tofire and the hose stream, a constant superimposed axial loa
11、d 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 structural
12、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 these tests shal
13、l be identified in the testreport as being conducted under restricted load conditions. Thesuperimposed axial load, as well as the superimposed axialload as a percentage of the maximum allowable axial design1This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct respon
14、sibility of Subcommittee D07.07 on Fire Performance of Wood.Current edition approved Feb. 1, 2008. Published March 2008. Originallyapproved in 2000. Last previous edition approved in 2000 as D 6513 00.2Available from American Forest fire resistance; superimposed load; wallassembly; wood studsD651308
15、2APPENDIXESX1. Calculating the Superimposed Load on Wood-Frame Walls for E119Standard Fire-Resistance TestsX1.1 ScopeX1.1.1 During an E119standard fire resistance wall test,the wall assembly is required to be subjected to a superimposedload to simulate a maximum load condition per nationallyrecogniz
16、ed structural design criteria.NOTE X1.1In the United States, the nationally recognized structuraldesign procedures for wood construction are contained in the NationalDesign Specification for Wood Constructiont (NDSt). In accordance withthese standard design procedures, the superimposed load applied
17、to woodstud wall assemblies is typically limited by the adjusted compressiondesign stress parallel to grain of the wood stud.X1.1.2 The maximum superimposed load for a wall beingtested in accordance with E119is the sum of the maximumallowable design loads for each stud in the wall assembly.X1.1.3 As
18、 an alternative, E119permits testing at less thanthe maximum load, however, these tests must 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 Constructiont(NDSt) design
19、procedures and the requirements of this stan-dard.X1.2.2 Example Construction (See Fig. X1.1):Studs: Douglas fir Larch (DFL) Select Structural (SS)grade 2 3 4 lumber (1.5 in. 3 3.5 in. 16 in. o.c., 115.5 in.long)Plates: DFL SS grade 2 3 4 lumber (1.5 in. 3 3.5 in.): onebottom plate 120 in. long, two
20、 top plates 120 in. long.Configuration: nine studs arranged symmetricallyInsulation: 3.5 in. thick Mineral Wool 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
21、using Allowable Stress Design (ASD) procedures:Fc= reference compression design value parallel to grain= 1700 psiFc* = reference compression design value multiplied by allapplicable adjustment factors except CP= FcCDCMCtCFCi(Table 4.3.1, NDS 2005)= (1700 psi)(1.0)(1.0)(1.0)(1.15)(1.0) = 1955 psiWher
22、e:Fc= reference compression design value parallel to grain= 1700 psiCD= load duration factor = 1.0CM= wet service factor = 1.0Ct= temperature factor = 1.0CF= size factor = 1.15 (for 1.5 in. 3 3.5 in. studs, SSgrade DFL)Ci= incising factor = 1.0CP= column stability factorA = area of cross-section = (
23、3.5 in.)(1.5 in.) = 5.25 in2Due to the slenderness of the studs, the adjusted compressiondesign stress parallel to grain is affected by the bucklingresistance of each stud. For strong-axis buckling of the stud(perpendicular to the plane of wall):CP51 1 FcE/Fc*!2cF1 1 FcE/Fc*!2cG2FcE/Fc*c51 1 521/195
24、5!2!0.8!F1 1 521/1955!2!0.8!G2521/19550.8(X1.1)CP5 0.7915 =0.7915!2 0.3330 5 0.2498 (X1.2)Where:FcE= 0.822Eminle/d!250.822!690 000 psi!33!2= 521 psiEmin= reference minimum modulus of elasticity designvalue = 690 000 psiEmin = adjusted minimum modulus of elasticity designvalue for beam and column sta
25、bility multiplied byall applicable adjustment factors= EminCMCtCiCT(Table 4.3.1, NDS 2005)= (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 g
26、rain= Fc*CP= (1955 psi)(0.2498) = 488 psiPr= FcA = (488 psi)( 5.25 in2) = 2564 lb/studFIG. X1.1 Example of Calculation ConstructionD6513083X1.2.4 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
27、acts as a bracingpoint along the stud length.X1.2.5 Compressive resistance of wood plates loaded per-pendicular to grain, Qr, as determined in accordance with theNDS (ASD Method) for the Example construction:Fc= reference compression design value perpendicularto grain = 625 psiFc = adjusted compress
28、ion design value perpendicularto grain multiplied by all applicable adjustmentfactors= FcCMCtCiCb(Table 4.3.1, NDS 2005)= (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-secti
29、on = (3.5 in.)(1.5 in.) = 5.25 in2Qr= FcA = (625 psi)( 5.25 in2) = 3281 lb/studX1.2.6 Compression perpendicular 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 superimpo
30、sed load on wallassembly Construction:Ws5 PrNumber of studs!52564 lb/stud!9 studs!523.1 kips(X1.3)X2. Total Superimposed LoadsX2.1 Table X2.1 presents the results of using the calcula-tion procedure and the reference design stresses from the 2005NDS.TABLE X2.1 Total Superimposed Loads Obtained Using
31、 the D 6513 Calculation Procedure and the Reference Design Stresses from the2005 NDSSpecies Grade Size FcAFc-perpAEAEminAStud LoadBTotal LoadCpsi psi psi psi lb/stud lbDOUGLAS FIR-LARCH SS#1#2STANDARDSTUD2x42x42x42x42x417001500135014008506256256256256251 900 0001 700 0001 600 0001 400 0001 400 00069
32、0 000620 000580 000510 000510 0002564230021451890179723 07320 70319 30717 01116 176SOUTHERN PINE Dense SSSS#1 Dense#1#2 Dense#2STUDSTANDARD2x42x42x42x42x42x42x42x422502100200018501850165097515006605656605656605655655651 900 0001 800 0001 800 0001 700 0001 700 0001 600 0001 400 0001 300 000690 000660
33、 000660 000620 000620 000580 000510 000470 0002589247224642312231221561820176123 30122 25222 17920 81220 81219 40016 38115 850HEM-FIR SS#1#2STANDARDSTUD2x42x42x42x42x415001350130013008004054054054054051 600 0001 500 0001 300 0001 200 0001 200 000580 000550 000470 000440 000440 0002126204317611640157
34、019 13618 38615 84614 75914 130SPRUCE-PINE-FIR SS#1/#2STANDARDSTUD2x42x42x42x41400115011507254254254254251 500 0001 400 0001 200 0001 200 000550 000510 000440 000440 000204818811624154818 43616 93114 61713 931AReference design stresses from the 2005 NDS.BStud load is calculated based on Fc using a s
35、tud length of 115.5”, resulting in Le/d = 33, and plates of the same species as the studs.CThe total superimposed wall load values for a wall with nine studs.D6513084ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin thi
36、s standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be
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38、onsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D6513085
