EWPAA Structural Plywood and LVL Design Manual - Engineered ...

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FlooringConstructionLVL(Substrates inTable 16.9)LVL(No substrate)MinimumThickness12mmApplicableSpeciesTable 16.6(a)andTable 16.6(b)PerformanceCritical Radiant Heat FluxBetween 2.2(kW/m 2 ) and 4.5 (kW/m 2 )SmokeDevelopmentRateBetween 2.2(kW/m 2 )12mm Table 16.52and 4.5(kW/m )Between 2.2(kW/m 2 )19mm Table 16.52 Less than 750and 4.5(kW/m )(%-min)19mm Table 16.6 More than 4.5(kW/m 2 )TABLE 16.10 : critical Radiant Heat Flux for LVL FlooringNOTE:Many of the timber species listed in Tables 16.4 through 16.8 are not used to manufacture plywood orLVL. Therefore, the Designer must check with the manufacturer before specifying a particular species as awall and ceiling lining or as flooring.16.5 Resistance to FireFire Resistance is the ability of a building component to resist a fully developed fire,while still performing its structural function. Fire resistance levels (FRL) are assignedas performance criteria, in minutes, for structural adequacy, integrity and insulation.This important parameter is defined by three numbers, e.g. 30/30/30 for which the:• first number relates to structural stability, i.e. the time to elapse before collapse;• second number is an integrity requirement, i.e. flames must not pass through thecomponent for this number of minutes;• third number is an insulation value, i.e. limits heat transfer through the component.Plywood is quite acceptable as a material used in fire resistant components provided it iscombined with other materials so as to meet the fire resistant requirements. This can beachieved by combining plywood with non-combustible materials such as fibrous cementor fire grade plasterboard. The FRL rating is evaluated in a Standard Fire Test as specifiedin AS 1530.4.LVL beam or column components can be assessed for fire resistance levels as per therequirements of AS 1720.4 Timber Structures – Fire-resistance of structural timbermembers. To ascertain the retained load carrying capabilities of a structural element isdone through a fire resistance test. This assesses how long a component can continueto perform when exposed to a fire. This ability is measured in terms of the elapsed time tofailure.When establishing the Fire Resistance Level (FRL) of structural untreated wood and woodbased products the charring rate of the surface is very important. As previously mentionedcharring produces a protective layer which slows down the charring process. The unburnttimber can then be used in calculations to determine the structural integrity of the loadbearing member.16.6 Steps in Establishing an FRLAfter a protective layer of char has developed the char rate slows considerably. Thecharring rate of dry wood has been shown to continue for several hours at a reasonablyconstant rate given in AS1720.4⎯2006 by:249
c = dh/dt = 0.4 + (280/ρ) 2 (16.1)where:c= dh/dt = notional charring rate (mm/minute);ρ = timber density (kg/m 3 ) at a moisture content of 12%.The charring rate of a typical softwood having a density of 500kg/m 3 is0.76mm/minute. During a fire a realistic assessment of structural response can bemade by neglecting 10mm of unburnt wood and assuming the remainder retainsits full strength and stiffness.• The effective depth of charring (d c ) for each exposed surface after a period of time (t)is given by:where:d c = ct + 7.5 (16.2)d cct= calculated effective depth of charring (mm);= notional charring rate;= period of time (minutes)NOTE:t can be taken as either the:(a) time taken for the FRL to be achieved;(b) fire resistance period determined by a series of successive iterations.• The effective residual section is determined by subtracting d csurfaces of the timber member as shown in FIGURE 16.3from all fire-exposedFIGURE 16.3: Shows loss of section due to charring• the design loads to be resisted by the structural elements/components are determinedfrom the application of Clause 4.2.4 and Section 6.1 of AS 1170.0.• a check of the strength of the residual section is done in accordance with therequirements of AS 1720.1-1997. The deflection limits can be:o set by the design engineero a maximum of span / 300.TABLE 16. provides a guide to selecting a minimum beam width for a FRL of 60/-/-,250
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Structural Plywood & LVL Design Man
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Table of Contents1 Plywood & LVL -
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11 Plywood Stressed Skin Panels ...
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Table of FiguresFIGURE 4.1: Plywood
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Part OneProduct Production & Proper
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PeelingAfter conditioning, the logs
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Sanding, Trimming and BrandingAfter
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through to applications where aesth
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2.7 Identification CodeThe plywood
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2.10 Non Structural PlywoodsInterio
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3.5 Veneer QualityVeneer quality us
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the hygroscopic movement of structu
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effective an insulator as the wood
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5 Structural Plywood - Design Princ
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12 - 13 40015 - 19 45020 - 25 52026
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TABLE 5.3: Standard Structural Plyw
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TABLE 5.5: Indicative Stiffness Val
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Strength Limit StateStrength LimitS
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Application of Structural memberAll
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FIGURE 5.5 shows an I-beam defining
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j 2- Duration of Load Factor for Cr
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Using the theory of parallel axes a
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6 Structural LVL - Design Principle
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I (neutral axis(NA)-stiffness= (bd
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Serviceability Limit State:Calculat
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Strength Limit State:Strength Limit
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Equilibrium Moisture Content (EMC)P
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(c) For shear k 11 = 1.0(d) For com
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Chapter 6 AppendixSlenderness Co-Ef
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FIGURE A6.3: Continuous restraint a
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Stability factor.The stability fact
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7.4 Structural Plywood Flooring - D
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5. Critical Load Action EffectsLoad
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5. Serviceability limit state - Des
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7.10 Structural Plywood Residential
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Because of the obvious difficulty a
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1.2 m roof load width)0.25 kPa x 1.
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Concentrated Imposed Load (Q)M max
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5. Serviceability Limit Stateand [A
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8 Structural Plywood Webbed Box Bea
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AdhesivesBeams relying only on an a
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5. Check Beam Stiffness:Check beam
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1. Initial beam trial size:(a)(b)Fr
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Required nail spacing s = øN j / q
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Figure 8.5 shows a discontinuous pl
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A8Chapter 8 AppendixBending / Compr
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where:A= h3.5 3D .1032 N. mJ12.440.
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FIGURE A8.2: Guide for Selecting In
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Table A8.6: Unit-Load Deflection Sp
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9 Structural Plywood Diaphragms & S
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FIGURE 9.3 shows a plywood panel na
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The following are the design steps
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Wind force, w on diaphragm w = 1.86
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Converted to Limit States CapacityC
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4. Chord Size and SplicesThe chords
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Load/Nail (N)Nail Deformation (mm)2
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• The horizontal force is 1.9 x 2
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= 5 kN/m v oR = 15/5 = 3 kN/m107
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ELEVATIONFIGURE 9.12: Shows shear f
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As previously mentioned the shearwa
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Assuming the applied racking load t
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In this instance let the two panels
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A9 CHAPTER 9 APPENDIXPlate 1Plate 2
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Plate 7Plate 8Plate 9119
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REFERENCES CITED:1. Timber Shearwal
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“nailability” by increasing res
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(a) (b) (c)FIGURE 10.3: Actual and
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Re-arranging the torsion equation r
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The polar moment of area (I p ) of
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Design Example - Plywood Gusseted P
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• assuming width of lines paralle
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hence:where:ΦMj⎡ Ip⎤= (0.8 x1.
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A10 Chapter 10 AppendixPhotographs
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MOMENT JOINTSPlate 7Plate 8Plate 9(
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REFERENCES CITED:1. Investigation o
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11.2 MaterialsPlywoodPlywood used i
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FIGURE 11.3: Effective widths of pl
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Transformed SectionSince the plywoo
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FIGURE 11.5: Bending stresses in st
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FIGURE 11.6: Stressed skin panel tr
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Flexural Deflection Long Term Servi
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Compression SpliceUsing 17mm F11 st
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REFERENCES CITED:1. Design & Fabric
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12 Exotic Structural Forms12.1 Intr
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displacement between diaphragms eac
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The section modulus (Z) is:ZZ=Iy1=1
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FIGURE 12.9: A parabolic arch (not
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F AFFFASS= (374.4 + 166.4)kN= 540.8
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12.11 Hypar Design - GeometryTo dev
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FIGURE 12.16: Reactive force compon
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12.14 Methodology - Principal Membr
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Many braced dome geometries exist b
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θasphere= is the angle subtended b
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AndNNNxyxyP=L21P=L12P=L33L2P3⎤+
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• whether or not to force the ply
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A12Chapter 12 AppendixEXAMPLES OF E
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EXOTIC STRUCTURAL FORMS DESIGN AIDS
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Type 1 joints referred to in AS 172
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FIGURE 13.3: Two and Three member T
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SECTION 4 : AS 1720.1-1997 : Clause
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connection load carrying capacity c
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13.5 Design of Type 1 Nailed Connec
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The following unfactored loads are
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Page 210 and 211: 13.11 Design of Type 2 Screwed Conn
Page 212 and 213: The reasons k 13 and k 14 are not c
Page 214 and 215: Type of JointSeasoned TimberUnseaso
Page 216 and 217: 13.16 Design of Type 2 Bolted Conne
Page 218 and 219: where:Δ = Δi +h33j14xh35Q *Qkpfor
Page 220 and 221: The exploded view in Figure 13.11 s
Page 222 and 223: FIGURE 13.12: Edge, end and bolt sp
Page 224 and 225: 13.21 Design of Type 2 Coach Screwe
Page 226 and 227: REFERENCES CITED:1. AS 1720.1-1997,
Page 228 and 229: Plate 3Plate 4219
Page 230 and 231: Plate 7Plate 8221
Page 232 and 233: 14 Noise Control14.1 IntroductionTh
Page 234 and 235: The absorption process of a single
Page 236 and 237: When it is required to add more tha
Page 238 and 239: FIGURE 14.5: Types of cavity wallsT
Page 240 and 241: 15 Condensation & Thermal Transmiss
Page 242 and 243: 15.4 Thermal TransmissionThermal tr
Page 244 and 245: 15.5 Thermal Transmission - Design
Page 246 and 247: REFERENCES CITED:1. Condensation, C
Page 248 and 249: The early fire hazard test indices
Page 250 and 251: ISO 9705 AND AS/NZS 3837These tests
Page 252 and 253: General InformationDesign of struct
Page 254 and 255: SpeciesAsh, Alpine - Eucalyptus del
Page 256 and 257: Results of recent tests organised b
Page 260 and 261: as expressed in the BCA.Species Ave
Page 262 and 263: ClosurePlywood Thickness for:Dougla
Page 264 and 265: Borers are rarely a problem with st
Page 266 and 267: HazardClassH1Exposure Specific serv
Page 268 and 269: 17.3 Durability and Finishing Appli
Page 270: EWPAA MembersPlywood and Laminated
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