ced823 module 1a

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    CED823: Structural Design 3

    Timber Design

    BasicTimberDesignDefinitionandTheories

    RAUDENB.PANOTES,CE,MSSt

    CE Instructor

    Definitionof

    terms

    Diaphragm is ahorizontalornearlyhorizontalsystemactingtotransmit

    lateralforcestotheverticalresistingelements.Whendiaphragmisused,it

    Section602ofNSCP6th Edition,2010

    nc u es rac ngsys em.

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    Definitionofterms

    ConventionalLight

    Frame

    Construction is

    atype

    of

    construction

    whose

    primarystructuralelementsareformedbyasystemofrepetitivewood

    framingmembers.

    Definitionof

    terms

    Fiberboard isafibrousfelted,homogeneouspanelmadefrom

    lignocellulosic fibers(usuallywoodorcrane)havingdensityoflessthan

    497kg/cu.m butmorethan160kg/cu.m

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    Definitionofterms

    Hardboard is

    afibrous

    felted,

    homogeneous

    panel

    made

    from

    lignocellulosic fibers(usuallywoodorcrane)consolidatedunderheatand

    pressure inahotpressto497kg/cu.m

    Definitionof

    terms

    GluedBuiltUpMembers arestructuralelements,thesectionsofwhich

    arecomposedofbuiltuplumber,woodstructuralpanelsorwood

    structuralpanelsincombinationwithlumber,allpartsbondedtogether

    with adhesive..

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    Definitionofterms

    Grade theclassificationoflumberinregardtostrengthandutility in

    accordancewith

    the

    grading

    rules

    of

    an

    approved

    lumber

    agency.

    Stressgradeissimplysortingaproductionrunintogroupsthathave

    simi arproperties.T egroupingo t epropertiescan eany

    mixtureofappearanceandstructuralproperties.

    80%StressGrade

    63%StressGrade

    50%StressGrade

    UnseasonedWood

    SeasonedWood

    Unseasonedwoodmeanstimberhasnotyetdriedto

    moisturecontentmatchedtoitsintendedenvironment(12%

    Definitionof

    terms

    or n oor, ou oor .

    SeasoningisoftenperformedinKilnswhichinmostcasesare

    heatedbyfossilfuels.

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    StructuralPropertiesofTimber80% STRESSGRADE UNSEASONEDTIMBER

    StructuralProperties

    of

    Timber

    80% STRESSGRADE UNSEASONEDTIMBER

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    StructuralPropertiesofTimberUNSEASONEDTIMBER

    StructuralProperties

    of

    Timber

    UNSEASONEDTIMBER

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    Definitionofterms

    NominalSize

    the

    commercial

    size

    designation

    of

    width

    and

    depth,

    in

    the

    standardsawnlumbergrades;somewhatlargerthatthestandardnetsize

    ofdressedlumber,inaccordancetoPNS.

    Definitionof

    terms

    Woodstructuralpanel isastructuralpanelproductcomposedprimarily

    ofwoodandmeetingtherequirementsofthePNS.Woodstructuralpanels

    includeallveneerplywood,compositepanelscontainingacombinationof

    veneer and woodbased material and matformed anel such as oriented ,

    boardandwaferboard.

    waferboardItisastructuralmaterialmadefrom

    rectangularwoodflakesofcontrolledlengthand

    thicknessbondedtogetherwithwaterproof phenolic

    resin underextremeheatandpressure

    orientedboardisknownassterlingboard,

    sterlingOSB,aspenite,andsmartply inBritish

    English,isan engineeredwood particle

    boardformedbyaddingadhesives andthen

    compressinglayersof wood strands(flakes)in

    specificorientations.

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    Definitionofterms

    Plywood is

    an

    panel

    of

    laminated

    veneers

    conforming

    to

    PNS

    ConstructionandIndustrialPlywoodandUBCStandard233,Performance

    Standardforwoodbasedstructuralusepanels.

    veneer referstothin

    slicesofwood,

    usuallythinnerthan

    3 mm(1/8inch),

    thattypically

    are g ue on ocore

    panels

    Definitionof

    terms

    Treatedwood iswoodtreatedwithanapprovedpreservativeunder

    treatingandqualitycontrolprocedures.

    Woodtreatmentrefersto

    protectingwoodfromdamage

    causedbyinsects,moisture,and

    decayfungi.

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    TypicalStructuralComponentsBendingMembers

    Theseare

    structural

    elements

    that

    carry

    transverse

    loads

    loads

    that

    are

    perpendiculartothelongitudinalaxisoftheelementsubjectedtoloading.

    Rafters

    TypicalStructural

    Components

    BendingMembers

    Thesearestructuralelementsthatcarrytransverseloads loadsthatare

    perpendiculartothelongitudinalaxisoftheelementsubjectedtoloading.

    Joists

    BeamsandGirders

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    TypicalStructuralComponentsAXIALMEMBERS

    Theseare

    structural

    elements

    carrying

    axial

    or

    longitudinal

    loads

    loads

    thatareparalleltothelongitudinalaxisoftheelementbeingsubjectedto

    loading.

    ColumnsorPosts

    Verticalmembersthatcarry

    compressiveloads.Usuallymade

    ofsawnlumberorglulam and

    sometimescarrybendingloads

    duetolateralloadsoreccentricity

    ofaxialloads.Largerthanwall

    compressiveloadsfromgirders.

    WallStuds

    Axialmemberloadedincompressionspacedinfairlycloseintervals

    (typically,300,400,or600mm).

    TypicalStructural

    Components

    AXIALMEMBERS

    Thesearestructuralelementscarryingaxialorlongitudinalloads loads

    thatareparalleltothelongitudinalaxisoftheelementbeingsubjectedto

    loading.

    TrussElements

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    TypicalStructuralComponentsSTRUCTURALPANELS

    Sometimescalled

    shells

    or

    plates.

    Resist

    shear

    forces

    (from

    lateral

    loads)

    and/orbending(fromverticalloads).

    Thinstructuralelementloadedinitsplane.Makesuptheflooror

    roof.

    Shearwall

    Basicallynotastructuralelementsinceitscomposedofmore

    basiccomponents studsandsheathings.Resistsshearloadings

    duetolateralloads.Usedtopreventoverturning,rackingor

    slidingofstructures

    TypicalStructural

    Components

    STRUCTURALPANELS

    Sometimescalledshellsorplates.Resistshearforces(fromlateralloads)

    and/orbending(fromverticalloads).

    Shearwall

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    TypicalStructuralSystemsinWoodBuildings

    ROOFFRAMING

    TypicalStructuralSystemsinWoodBuildings

    ROOFFRAMING

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    TypicalStructuralSystemsinWoodBuildings

    ROOFFRAMING

    TypicalStructuralSystemsinWoodBuildings

    ROOFFRAMING

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    TypicalStructuralSystemsinWoodBuildings

    WALLFRAMING