woodworks presenta · woodworks presenta.on presented by norman scheel, p.e., s.e., secb, f.seaoc,...

Pleaseaddrelevantlogohere

WoodworksPresenta.on

PresentedbyNormanScheel,P.E.,S.E.,SECB,F.SEAOC,F.ASCE,LEEDAPBD+C,LEEDAPHOMES

Disclaimer:Thispresenta1onwasdevelopedbyathirdpartyandisnotfundedbyWoodWorksortheSo=woodLumberBoard.

WoodworksPresenta.on

PresentedbyNormanScheel,P.E.,S.E.,SECB,F.SEAOC,F.ASCE,LEEDAPBD+C,LEEDAPHOMES

“TheWoodProductsCouncil”isaRegisteredProviderwithTheAmericanInsKtuteofArchitectsConKnuingEducaKonSystems(AIA/CES),Provider#G516.Credit(s)earnedoncompleKonofthiscoursewillbereportedtoAIACESforAIAmembers.CerKficatesofCompleKonforbothAIAmembersandnon-AIAmembersareavailableuponrequest.

ThiscourseisregisteredwithAIACESforconKnuingprofessionaleducaKon.Assuch,itdoesnotincludecontentthatmaybedeemedorconstruedtobeanapprovalorendorsementbytheAIAofanymaterialofconstrucKonoranymethodormannerofhandling,using,distribuKng,ordealinginanymaterialorproduct.__________________________________

QuesKonsrelatedtospecificmaterials,methods,andserviceswillbeaddressedattheconclusionofthispresentaKon.

CourseDescrip.on

ThiscourseisintendedforengineersandarchitectswhospecifymetalplatedwoodtrussesforuseincommercialandmulK-familybuildingprojects.Metalplateconnectedwoodtrusses(MPCWT)havelongbeenusedasacosteffecKvemethodtoachievelongspansinroofandfloorapplicaKons.ThispresentaKonwillcoversharedresponsibiliKesbetweenthedesignprofessionalofrecordandthetrussdesigner:theproperspecificaKonofdesignloads,includingexamplesoftrussesusedasdiaphragmchords,andshopdrawingreviews.Bracing,largecanKlevers,over-framing,secKonaltrusses,andsheartransferscenarioswillalsobediscussed.

LearningObjec.ves

1.Reviewthestandard-of-pracKceforsharedresponsibilityoftrussdesignbetweenthedesignprofessionalofrecord,responsibleforthebuildingasawhole,andthetrussmanufactureranddesignerprovidingstructuralcomponentsusedinthebuilding.2.OutlinecriKcalandusefulinformaKontoincludeinbuildingconstrucKondocumentstoimprovetrussmanufacturersabilitytodeliverhighperformingcomponents.3.OverviewhowtoreadtrussshopdrawingstoverifyconformancewiththeintendedspecificaKons.4.ExaminedifferentconfiguraKonsandtrussdetailstodemonstratehowmetalplateconnectedwoodtrussescanmeettheneedsofavarietyofbuildingprojects.

A<endeeBreakdown

Engineers50%

Architects30%

BuildingOfficials&Others20%

•  DesignResponsibili.es

•  DesignLoads•  Ver.calLoads•  LateralLoads(wind&seismic)

•  Sheartransfer(collectors)•  Chords

•  Bracing•  Webs•  Chords(T.C.&B.C.)•  Overframing•  Sec.onalTrusses•  GableEndBracing

•  ShopDrawings•  Layouts•  TrussDrawings

•  SpecialUses•  TrussMyths

CourseOutline

DesignResponsibili.es

Construc.

on

Documents

CodeDefinedTerms

Contractor

TrussDesignDrawing

TrussDesignEngineer

TrussDesigner

RegisteredDesignProfessional

TrussManufacturer

TrussPlacementDiagram

TrussSubmi<alPackage DeferredSubmi<als

IndicatesLicensedPersons

* *

*

*

SimplifyTheProcess

•  LoadsappliedtoTrusses

•  TrussReac.ons

ImportantforEORReview

•  GableEndBracing

•  EndWallBracing

•  PermanentWebBracingRestraint

•  UpliWConnec.ons

•  LateralLoadConnec.onstoTopPlates

•  TrussHangerstoGirders

•  TrussHangerstoBeams

•  GirdertoGirderHangers

•  Overframing&TopChordBracing

References

SeeIBC/CBCSecKon2303.4forCodeRequirements

pertainingtoWoodTrusses.

References

References

References

SeeTPI1-2007,Chapter2forDesignResponsibiliKespertainingtoWoodTrusses.

References

References

References

References

References

DesignLoads Ver.cal

SimpleCase

EasyenoughStaKcallyDeterminate

WARNING:DoNotUsePinnedReac.ons

FORCE

MOVEMENT

0.85#

2508#

Addinteriorbearings,notsosimple.Ifdesigned,supportswillbeatajoint.

SimpleCase

Addinteriorbearings,notsosimple.Ifnotdesigned,supportsmaybeinthemiddleofpanelsornearajoint.

SimpleCase

PreliminaryDesign

Max.Span=60’

Min.Depth(in.)=Span(W.)–10

FlatTrusses

Examples:

40’span,min.30”deepaverage

50’span,min.40”deepaverage

60’span,min.50”deepaverage

SlopingFlatshaveheelheightover21”

PreliminaryDesign(Cont.)

GableTrusses

Min.Slopes:

40’for3/12

50’for4/12

60’for5/12(cap)

Es.ma.ngDeflec.ons&InteriorReac.ons

TreatasBearing–

UseMomentofIner.a(I)foreffec.vedepthfordeflec.on

Calcula.onforMomentofIner.a(I)

Calcula.onforMomentofIner.a(I)cont.

FlatTruss

Dbl.Howe(4/12pitch)Truss

Dbl.Howe(6/12pitch)Truss

Deflec.onvs.LoadGraph0 1.580 0.800 0.410 4166 8333

500 1.180 0.680 0.3501000 0.780 0.560 0.2901500 0.390 0.440 0.2302000 0.070 0.320 0.200

1250

K=STIFFNESS (LBS./IN.)

DBL. HOWE TRUSS (4/12)

DBL. HOWE TRUSS (6/12) FLAT TRUSS

DL+LL DEFLECTION (IN.)

LOAD (LBS.) DBL. HOWE TRUSS (6/12) FLAT TRUSS DBL. HOWE

TRUSS (4/12)

DEFLECTION VS. LOAD

1.580

1.180

0.780

0.390

0.070

0.800

0.680

0.560

0.440

0.320

0.4100.350

0.2900.230 0.200

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

1.600

1.800

0 500 1000 1500 2000

CONCENTRATED LOAD (LBS.)

DEF

LEC

TIO

N (L

L +

DL)

Flat Truss Dbl. Howe Truss (4/12 Pitch) Dbl. Howe Truss (6/12 Pitch)

ForGableTruss,usesameasFlatTrussanduse0.8overalleffec.vedepth

Example:

40’span,4/12pitch

0.8xdepth=0.8x4x20=64”

Resultsarewithin10%forDeflec.onsandReac.ons.ThisisOKforPreliminaryDesign.

Reasons:

•  Deflec.onsaresmall

•  BeamReac.onsareapproximateifTrussiscon.nuous

CODEREQUIREMENTS

OldvsNewCodeLoading

1.22.848

-0.48.4815

0.587.5814

1.46.6813

2.06.0812

2.05.0711

1.84.2610

1.53.559

0.82.237

0.41.626-0.21.215-0.80.804

DifferenceDeadLoadSlopeIncrease(14PSF)

LiveLoadDecrease

Slope/12

2006 IBC

MinimumRoofLiveLoads(TributaryAreaReduc.on)

2012IBC

DesignLoads Lateral

SimpleCollectorTruss

ComplicatedCollectorTruss

ShearTransfertoCenterCollectorTruss

BRAINBREAK

TrussHistory

ATRIBUTETOCEASER

NowBacktoSeriousStuff

Pre-EngineeredGangNailTrusses

ShearTransferPerpendiculartoTrusses

BlockingDetails

Pre-EngineeredGangNailTrussesFramingDetails

Bracing

ShopDrawings

TrussMyths

TrussMyths

•  Thetrusscompanyhandleseverythingfromthetopplateup.

•  Beamsbelowtrussesprovidetheinfinitelyrigidsupportasmodeledinthecomputeranalysis.

•  Axialforcesintrussmembersareatthemembercenterlines.

•  Thepin/rollermodeledinthecomputerisaccurate.

TrussMyths

•  Trussjointsareall“pin”connected.

•  Theengineerwhosealedthetrussdrawingshasseentheplans.

•  Thedesignprofessionalwillincorporatethetrussdesignsintothebuildingdesign.

•  Ifinteriorwallstouchthebo<omchorditwilloverstressthemembers.

TrussMyths

•  Collectortrusses(sheartransfertrusses)atthegableendneedtobestructural(withwebinsteadofver.calsonly)ifthetrusshasheelsateachend.

•  Scissortrussesimposelateralloadsontheexteriorwallsattheheels.

•  Alevelreturnwillsupporttheendofalongoverhang.

BRAINBREAK

SpecialUses

102

103

Six-Sided Roof

HorizontalThrust&TensionCalcsforOctagon

HorizontalThrust&TensionCalcsforOctagon

14

Applications

§ Concrete forming

68

Completed Arch Wall

69

Arch Truss Setup

70

Arch Truss Swing

71

Arch Walls

76

Arch Vault Section

77

Arched Girder Framing

78

Section Set

85

Vaulted Trusses

86

Girder-to-Girder

104

Compression Ring

12

Applications

§ Agricultural structures

Ques.ons?ThisconcludesTheAmericanInsKtuteofArchitectsConKnuingEducaKonSystemsCourse

NormanScheelNSSEnorm@nsse.com

REFERENCESTRUSSDETAILS