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

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13.11 Design of Type 2 Screwed ConnectionsAs mentioned previously Type 2 screwed connections differ from nailed connections in onemajor aspect, i.e.:• Nails depend on friction between the shank and the wood fibres to resist withdrawal;• Screws depend upon a mechanical interlocking of wood fibre between threads thusenhancing the withdrawal capabilities of the screw over the nail.Equation 13.10 gives the design capacity (ΦN j ) for a Type 2 joint containing (n) screws.For the strength limit state to be satisfied:where ΦNjis the lesser of:ΦN j ≥ N* (13.10)ΦNj = Φk 13 . p.nQk (13.11)ORΦN j = n(ΦN ts ) (13.12)where:ΦN j= joint capacity of Type 2 screwed connection, i.e.along connector axis.and:N* = design action on a Type 2 nailed connection, alongconnector axis. due to factored loads applied to thejoints;Φk 13 pNQkΦN ts= capacity factor.= 1.0 for withdrawal from side grain;= 0.6 for withdrawal from end grain;= depth of screw penetration (mm) into primarymember.= total number of screws in joint.= characteristic screw capacity in withdrawal given inTables 4.6(A) and 4.6(B).strength group.= design tensile capacity of screw as per screwmanufacturers specificationNOTE:k 1 does not apply to screws subject to withdrawalDesign of Screwed Moment JointsScrewed moment connections are not common, the nailed option being preferred because of their lowerinstallation cost, and similar lateral load capabilities.In the event a screwed joint provides the desired solution to the connection problem the procedure presentedin Error! Reference source not found. of this Manual should be followed.201
Serviceability Requirements for Type 1 Screwed JointsAS 1720.1-1997 does not differentiate between nails and screws regarding joint deformations even thoughintuitively one may feel a screwed and nailed joint of identical construction would result in the screwed jointbeing stiffer.13.12 Design of Bolted ConnectionsAlthough the basic philosophy for the design of nailed and bolted joints is similar, there are somedifferences that need to be recognised, particularly with regard to the modification factors.In FIGURE 13.4 the importance of direction of load application relative to nominal grain direction hasalready been highlighted. In a nailed (or screwed) connection timber thickness is aligned with the depth ofnail penetration required to develop the full strength of the connector.In a bolted connection the bolt capacity is presented as a function of timber thickness, which in thetabulated data of AS 1720.1-1997, is referred to as the effective thickness (b eff ).FIGURE 13.8 defines (b eff ) for loads parallel and perpendicular to the grain in seasoned and unseasonedtimber.For Type 1 bolted connections the contents of FIGURE 13.8 can be summarized thus:• for loads parallel to grain (b eff ) is the smallest aggregate cross-section of members loaded parallelto grain:• for loads perpendicular to grain (b eff ) is the aggregate cross-section of the elements in themember with loads perpendicular to grain.The characteristic strength of a single bolt in a Type 1 timber connection is a function of a number ofvariables:• bolt diameter – M6 to M36.In seasoned timber the bolt hole is the nominal diameter of the bolt.In unseasoned timber the bolt hole is 10 to 15% oversize.• timber joint strength group – J1 to J6 and JD1 to JD6;• timber effective thickness – in AS 1720.1-1997 – 25 to 200mm unseasoned and 25 to 120mmseasoned;• moisture content;• angle between force application and the grain direction;• bolt spacings – edge, end, along and across grain to prevent splitting and allow development of thefull bolt capacity.Type 2 bolted connections do not depend on timber embedment of the bolt for load transfer and aretherefore largely independent of timber thickness. Type 2 joints depend upon:• bolt tensile strength;• crushing strength of the timber under the washers at each end of the bolt.13.13 Modification Factors – Bolted JointsModification factors applied to bolted connection design perform a similar function, and take the sameform, as those used in nailed connection design. However, a number of the factors relevant to nailedconnections are not relevant to bolted connection design, e.g. the factors k 13 and k 14 .202
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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
Page 160 and 161: FIGURE 11.6: Stressed skin panel tr
Page 162 and 163: Flexural Deflection Long Term Servi
Page 164 and 165: Compression SpliceUsing 17mm F11 st
Page 166 and 167: REFERENCES CITED:1. Design & Fabric
Page 168 and 169: 12 Exotic Structural Forms12.1 Intr
Page 170 and 171: displacement between diaphragms eac
Page 172 and 173: The section modulus (Z) is:ZZ=Iy1=1
Page 174 and 175: FIGURE 12.9: A parabolic arch (not
Page 176 and 177: F AFFFASS= (374.4 + 166.4)kN= 540.8
Page 178 and 179: 12.11 Hypar Design - GeometryTo dev
Page 180 and 181: FIGURE 12.16: Reactive force compon
Page 182 and 183: 12.14 Methodology - Principal Membr
Page 184 and 185: Many braced dome geometries exist b
Page 186 and 187: θasphere= is the angle subtended b
Page 188 and 189: AndNNNxyxyP=L21P=L12P=L33L2P3⎤+
Page 190 and 191: • whether or not to force the ply
Page 192 and 193: A12Chapter 12 AppendixEXAMPLES OF E
Page 194 and 195: EXOTIC STRUCTURAL FORMS DESIGN AIDS
Page 196 and 197: Type 1 joints referred to in AS 172
Page 198 and 199: FIGURE 13.3: Two and Three member T
Page 200 and 201: SECTION 4 : AS 1720.1-1997 : Clause
Page 202 and 203: connection load carrying capacity c
Page 204 and 205: 13.5 Design of Type 1 Nailed Connec
Page 206 and 207: The following unfactored loads are
Page 208 and 209: nnaa=nnr42=5= 9 rowsThe assumed val
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 258 and 259: FlooringConstructionLVL(Substrates
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as expressed in the BCA.Species Ave
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ClosurePlywood Thickness for:Dougla
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Borers are rarely a problem with st
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HazardClassH1Exposure Specific serv
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17.3 Durability and Finishing Appli
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EWPAA MembersPlywood and Laminated
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EWPAA Structural Plywood and LVL Design Manual - Engineered ...

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