different construction for storey timber

ComparisonofDifferentConstructionMethodsforMulti‐StoreyTimberBuildings

LUCASBIENERT

SUPERVISORKatalinVertes

UniversityofAgder,2018FacultyofEngineeringandScienceDepartmentofEngineeringSciences

Abstract

MasterThesis‐LucasBienert I

AbstractInthismasterthesis,differenttimbermaterialsandconstructionmethodsareexaminedconcern‐ingtheapplicationinmulti‐storeytimberbuildings.

Althoughwoodasaconstructionmaterialhasmanyadvantages,itistodayonlyusedverylittleforlargerconstructions,concreteandsteeldominatethebuildingindustry.Plannersandengi‐neersareoftenlackingnecessaryexpertisetoutilisetimberinamodern,effectiveway.

Inordertopromotethedevelopmentofmodern,efficientmulti‐storeytimberbuildings,thegoalofthismasterthesisistocontributetoabetterunderstandingofthewood’scharacteristicprop‐ertiesandthebehaviouroftimberinlargerengineeringstructures.

For thispurpose, firsta literatureresearchhasbeenconductedtogather technicalknowledgeaboutmoderntimbermethods.Itcanbeconcludedthat,althoughwoodasanaturalmaterialhassome unfavourable properties,with an appropriate design, those problems can be overcome.Modernengineeredwoodproducts improvethebasicmaterial’spropertiesnoticeableandareimportantespeciallyformulti‐storeytimberbuildings.

Secondly,adesignhasbeencarriedoutforthreedifferentstructuralvariantsofthesameexistingmulti‐storeytimberbuilding.Bymeansof thisdesign,generalconclusionscouldbemadecon‐cerningthesuitabilityofthosedifferentconstructionmethods.Frameconstructionsareveryef‐fectiveforprovidingstabilityfortheoverallstructure.Prefabricatedmethodslikepanelconstruc‐tionshaveeconomicadvantages,should,however,onlybeusedincombinationwithothermeth‐odsforlargertimberstructures.Masstimbermethodsareverywellsuitedformulti‐storeytimberbuildingsandwillsupposedlyplayanimportantroleinthefuture.

Themainoutcomeofthismasterthesisisthattherearenolargehindrancesfortheuseofwoodinmulti‐storeybuildingstodayandthattimberstructuresstillhavemuchunusedpotential.

Declaration

MasterThesis‐LucasBienert II

Declaration

1. WiththisstatementIdeclarethatthismasterthesisismyownworkandthatIhavenotusedothersourcesorreceivedotherhelpthanwhatismarkedassuch.

☒

2. Furthermore,withthisstatementIdeclarethatthismasterthesis:

wasnotpreviouslysubmittedtoanotheracademicinstitutioninNor‐wayoranyothercountry.

doesnotrefertoexternalsourceswithoutthisbeingproperlymarked.

doesnotrefertoownearlierworkwithoutthisbeingproperlymarked.

includesabibliographywithallsources. isnocopyorduplicateofother’swork.

☒

3. IamawarethataviolationofthestatementsabovecancausenullificationoftheexaminationandexclusionfromuniversitiesinNorway,cf.Universitets‐oghøgskoleloven§§4‐7and4‐8andForskriftomeksamen§§31.

☒

4. Iamawarethatallsubmittedworkscanbecheckedforplagiarism. ☒

5. IamawarethattheUniversityofAgderwilltreatallcaseswithsuspicionforcheatingaccordingtotheuniversity’sguidelinesascheating.

☒

6. Ihavestudiedtherulesandguidelinesconcerningtheuseofsourcesandref‐erencesonthelibrary’swebpages.

☒

LucasBienert,30.11.2018

PublishingAgreement

MasterThesis‐LucasBienert III

PublishingAgreement

AuthorisationforElectronicPublishingoftheMasterThesis

Theauthorhasthecopyrightforthework.Thisincludesamongstotherthingstheexclusiverighttomaketheworkavailableforthepublic(Åndsverkloven.§2).

AllworksthatfulfiltherequirementswillberegisteredandpublishedinBrageAuraandonUiA’swebpageswiththeauthor’sapproval.

Worksthatareexcludedfromthepublicorsubjecttoprofessionalsecrecyorconfidentialitywillnotbepublished.

IherebygivetheUniversityofAgderthegratuitousright

tomakethismasterthesisavailableforelectronicpublishing: ☒YES ☐NO

Isthismasterthesisconfidential? ☐YES ☒NO

Ifyes:

Cantheworkbepublishedoncetheobligationfor

confidentialityhasended? ☐YES ☐NO

Isthismasterthesisexcludedfromthepublic? ☐YES ☒NO

LucasBienert,30.11.2018

Foreword

MasterThesis‐LucasBienert IV

ForewordDuringmystudiesofcivilengineeringattheLeibnizUniversitätHannover(LUH)inGermanyandtheUniversitetetiAgder(UiA)inNorway,therehadalwaysbeenonebuildingmaterialthatfasci‐natedmethemost,notonlybecauseofitsexcitingmechanicalproperties,butalsobecauseofitslonghistoryandtradition,itsarchitecturalvalueandlastbutnotleastbecauseofitsbeneficialenvironmentalproperties:wood.Thecoursesaboutwoodasaconstructionmaterial that Iat‐tendedwereinteresting,butIwantedtoworkmorewiththismaterial.Moreover,myexperiencesbothattheuniversityandworkingatanengineeringofficeatthesametimeshowedthatconcreteandsteelstilldominatethelargerengineeringstructurestoday.ThatwaswhyIdecidedtowritemymasterthesisaboutmulti‐storeytimberbuildings.

TheseconddecisionImadethenwastowritethemasterthesisinNorway,whichisknownforitsrichwoodenbuildingculture.IhadalreadybeenattheUiAinGrimstadduringbybachelor’sstud‐ies,thistimeIreturnedtofinishmymaster’studies.

Togetherwithmysupervisorat theUiA,KatalinVertes, Idevelopedthetaskandtheresearchquestionsforthemasterthesis.Theworkincludedanextensiveliteratureresearchtogetuptodateconcerningthemoderntimberengineering,aswellastheredesignofanexistingmulti‐storeytimberbuildingusingthreedifferentconstructionmethods.Thechoiceofthebuildingwasquitenatural–afterdoingsomeresearch,Idecidedtoworkwiththehighestwoodenbuildingoftoday,TreetinBergen,thesecondlargestcityinNorway(“Treet”istheNorwegianwordfor“thetree”).Especiallythedesignofthethreevariantsofthisbuildingwaschallenging,butithelpedmetomakesomeimportantexperiencesthatonedoesnotlearninanylecture,e.g.concerningthede‐velopmentofastructuralconcept.

Icouldnothavecompletedthisworkwithoutthehelpfromdifferentpeople.Mostofall,IwanttothankmysupervisorKatalinVertes.ShehadbeenthefirstpersontoteachmeaboutwoodwhenIhadbeenattheUiAforthefirsttimein2014and2015.Nowshewasthepersontoguidemewhileworkingatthismasterthesis.Inspiteofhavingtotravelalot,shewasalwaysreachableandassistedmewithhelpfuladviseorjustreassurancewhenIhaddoubts.

AnotherthankyouisalsomeantformyfriendsandmyfamilybothinNorwayandinGermany,fortheirsupportandforhelpingmetoclearmyheadwhenIneededit.

Finally,Ithankyou,thereader,forbeingopenmindedaboutthiswork,hopingtobeabletocon‐tributetoyourknowledgeabouttimberoratleasttogiveyouaninterestingreadingexperience.

LucasBienert

Grimstad,30.11.2018

TableofContents

MasterThesis‐LucasBienert V

TableofContentsAbstract...................................................................................................................................................................................I

Declaration...........................................................................................................................................................................II

PublishingAgreement....................................................................................................................................................III

Foreword.............................................................................................................................................................................IV

TableofContents..............................................................................................................................................................V

ListofFigures..................................................................................................................................................................VII

ListofTables......................................................................................................................................................................XI

AbbreviationsandSymbols.......................................................................................................................................XII

1. Introduction...........................................................................................................................................................1

2. SocietyPerspective.............................................................................................................................................3

2.1. HistoricalBackground..................................................................................................................................3

2.2. EvolutionofTimberTechnologies...........................................................................................................4

2.3. Today’sGlobalSituation..............................................................................................................................5

2.4. SummaryoftheSocietyPerspective......................................................................................................5

3. Theory......................................................................................................................................................................7

3.1. RulesandStandards......................................................................................................................................7

3.1.1. EuropeanStandards.............................................................................................................................7

3.1.2. NationalRulesandStandardsinNorwayandGermany.......................................................8

3.2. DesignBasis......................................................................................................................................................9

3.2.1. Parameters...............................................................................................................................................9

3.2.2. LoadCalculation.................................................................................................................................11

3.2.3. Software.................................................................................................................................................12

3.3. SummaryoftheTheory.............................................................................................................................12

4. ResearchQuestions.........................................................................................................................................13

5. Case/Materials...................................................................................................................................................14

5.1. TimberMaterials..........................................................................................................................................14

5.1.1. GeneralPropertiesofSolidWood...............................................................................................14

5.1.2. WoodinComparisontoOtherMaterials..................................................................................18

5.1.3. AspectsfromLifeCycleAssessment..........................................................................................20

5.1.4. EngineeredWoodProducts...........................................................................................................22

5.2. TimberConnections...................................................................................................................................25

5.3. TimberStructures.......................................................................................................................................31

5.3.1. TimberFraming..................................................................................................................................31

5.3.2. MassTimber.........................................................................................................................................34

5.4. NewDevelopments.....................................................................................................................................36

TableofContents

MasterThesis‐LucasBienert VI

5.5. SummaryoftheCase/Materials............................................................................................................38

6. Method..................................................................................................................................................................39

6.1. Procedure........................................................................................................................................................39

6.2. DesignVariants.............................................................................................................................................40

6.2.1. StructuralConcept.............................................................................................................................40

6.2.2. FrameConstruction..........................................................................................................................41

6.2.3. PanelConstruction............................................................................................................................43

6.2.4. CLTConstruction................................................................................................................................45

6.3. PreliminaryDesign.....................................................................................................................................46

6.4. EurocodeDesign..........................................................................................................................................49

6.5. FEMAnalysis.................................................................................................................................................50

6.5.1. GlobalFEMAnalysis..........................................................................................................................50

6.5.2. FEMConnectionAnalysis...............................................................................................................56

7. Results...................................................................................................................................................................60

7.1. ResultsfromtheDesignAnalysis..........................................................................................................60

7.2. Comparison....................................................................................................................................................66

8. Discussion............................................................................................................................................................69

9. Conclusions.........................................................................................................................................................71

10. Recommendations............................................................................................................................................72

Bibliography......................................................................................................................................................................73

Appendix.............................................................................................................................................................................75

A. Attachments........................................................................................................................................................75

B. SelectedRFEMResults...................................................................................................................................75

B.a) FrameConstruction...............................................................................................................................75

B.b) PanelConstruction.................................................................................................................................79

B.c) CLTConstruction....................................................................................................................................82

C. SelectedANSYSresults...................................................................................................................................87

ListofFigures

MasterThesis‐LucasBienert VII

ListofFiguresFigure5.1:Threeprincipalaxesofwoodwithrespecttograindirectionandgrowthrings

[16,5‐2]......................................................................................................................................................15

Figure5.2:Stress‐strain‐diagramforsolidwood[26,203]..........................................................................16

Figure5.3:Decreaseofthebendingstrengthoftimberdependingontheloadduration[26,135].....................................................................................................................................................17

Figure5.4:Meanmoisturecontentinwood(glulam90×100×600) versus time in a barn in Southern Sweden (Åsa)[26,155]......................................................................................................18

Figure5.5:Embodiedenergyandcarboncontentofdifferentbuildingmaterialsbasedon[24,415].....................................................................................................................................................21

Figure5.6:Comparisonofthefrequencydistributionofthestrengthofglulamandsolidwood[26,19].......................................................................................................................................................23

Figure5.7:Generalfailuremodesofatimberconnectionwitha)lowslenderness,b)mediumslendernessandc)highslenderness[17,68]............................................................................26

Figure5.8:ComparisonofexperimentallydeterminedstiffnessesofselectedtestswithcorrespondingdesignvaluesfromEC5forspecimenswithdifferentslenderness[17,77].......................................................................................................................................................27

Figure5.9:ComparisonofstrengthofselectedtestswithdesignvaluesfromEC5[17,77]..........27

Figure5.10:Examplesoftraditionaltimberjoints[21,58]..........................................................................28

Figure5.11:Examplesofnailedjoints[26,306]...............................................................................................28

Figure5.12:Steeldowelsandbolts[1,9.44].......................................................................................................29

Figure5.13:Examplesofjointsusingboltsordowels[26,308]................................................................29

Figure5.14:Examplesofapplicationsforfullythreadedscrews[1,9.55].............................................30

Figure5.15:Loadbearingbehaviourofareinforcedconnectionincomparisontoanon‐reinforcedconnection[26,324]......................................................................................................30

Figure5.16:Traditionalframeconstruction[21,56]......................................................................................32

Figure5.17:Panelconstruction(left)andballoonconstruction(right)[21,60‐61].........................32

Figure5.18:Exampleofamodernframeconstruction:schoolinWil,Switzerland[21,86]..........33

Figure5.19:Differentlogconstructionvariants[21,53]...............................................................................34

Figure5.20:Cornerdetailofastackedplankconstruction[21,122].......................................................35

Figure5.21:ExampleofaCLT‐construction:evangelicchurchinRegensburg,Germany[5]........36

Figure6.1:RFEMmodeloftheframeconstruction..........................................................................................41

Figure6.2:Sketchoftheconnectionbetweenthecolumnandthediagonal(nottoscale).............43

Figure6.3:RFEMmodelofthesecondstoreyofthepanelconstruction................................................43

Figure6.4:Sketchoftheconnectionbetweenthefloorandthewallinthepanelconstruction...44

Figure6.5:RFEMmodeloftheCLT‐construction.............................................................................................45

Figure6.6:SketchoftheconnectionbetweenwallandfloorintheCLT‐construction.....................46

ListofFigures

MasterThesis‐LucasBienert VIII

Figure6.7:Simplifiedsystemoftheframes.........................................................................................................47

Figure6.8:Convergenceanalysisoftheframeconstruction........................................................................51

Figure6.9:Convergenceanalysisofthepanelconstruction.........................................................................51

Figure6.10:ConvergenceanalysisoftheCLTconstruction.........................................................................52

Figure6.11:Conceptfordividingthepanelmodelintosub‐models........................................................53

Figure6.12:Sub‐modelinRFEMofthefirststoreyofthepanelconstructionwiththeloadsforLC1(self‐weight)....................................................................................................................................54

Figure6.13:Deformationuin[mm]oftheCLT‐constructionforLC3(windfromthefront),viewfromtheside............................................................................................................................................55

Figure6.14:Distributionoftheinternalnormalforcesin[kN/m]inwallx3forLC1(self‐weight).............................................................................................................................................56

Figure6.15:Distributionoftheinternalnormalforcesin[kN/m]inwallx21forLC3(windfromthefront)....................................................................................................................................................56

Figure6.16:GeometryoftheANSYSmodeloftheconnectionbetweendiagonalandcolumnintheframeconstruction.........................................................................................................................57

Figure7.1:InternalnormalforcesinthefrontframeoftheframeconstructionforLC4(windfromtheside)in[kN]...........................................................................................................................60

Figure7.2:DistributionoftheinternalnormalforcesinthestudsofthefirststoreyofthepanelconstructionforLC4(windfromtheside)..................................................................................61

Figure7.3:Exampleoftheassumptionoftheloaddistributionintheloadbearingstudsinawallinthepanelconstructionforwindfromtherightsideaccordingtothepreliminarydesign..........................................................................................................................................................61

Figure7.4:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC4(windfromtheside)in[kN/m]................................................................................................................................62

Figure6.17:VonMisesstressσVMoftheconnectionin[N/mm2]...........................................................63

Figure6.18:Shearstressτxyoftheconnectionin[N/mm2].......................................................................64

Figure6.19:DefinitionoftheforcesandgeometricdimensionsforthecheckagainsttensionperpendiculartothegrainaccordingtoEC5[2,8.1.4]...........................................................65

Figure6.20:Totalstrainεoftheconnectionin[‐]............................................................................................65

FigureB.1:DeformationoftheframeconstructionforLC1(self‐weight)in[mm]............................75

FigureB.2:DeformationoftheframeconstructionforLC3(windfromthefront)in[mm]...........76

FigureB.3:DeformationoftheframeconstructionforLC4(windfromtheside)in[mm].............76

FigureB.4:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC1(self‐weight)in[kN].....................................................................................................................77

FigureB.5:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC2(snow)in[kN]................................................................................................................................77

ListofFigures

MasterThesis‐LucasBienert IX

FigureB.6:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC3(windfromthefront)in[kN]...................................................................................................77

FigureB.7:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC4(windfromtheside)in[kN].....................................................................................................78

FigureB.8:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC5(lifeload)in[kN]...........................................................................................................................78

FigureB.9:InternalnormalforcesinthefrontframeoftheframeconstructionforLC1(self‐weight)in[kN]........................................................................................................................................79

FigureB.10:DeformationofthefirstfloorofthepanelconstructionforLC1(self‐weight)in[mm]............................................................................................................................................................79

FigureB.11:DeformationofthefirstfloorofthepanelconstructionforLC2(snow)in[mm].....80

FigureB.12:DeformationofthefirstfloorofthepanelconstructionforLC3(windfromthefront)in[mm]..........................................................................................................................................80

FigureB.13:DeformationofthefirstfloorofthepanelconstructionforLC4(windfromtheside)in[mm].......................................................................................................................................................80

FigureB.14:DeformationofthefirstfloorofthepanelconstructionforLC5(lifeload)in[mm]81

FigureB.15:DistributionoftheinternalnormalforcesinthestudsofthefirststoreyofthepanelconstructionforLC1(self‐weight)..................................................................................................81

FigureB.16:DistributionoftheinternalnormalforcesinthestudsofthefirststoreyofthepanelconstructionforLC3(windfromthefront)................................................................................81

FigureB.17:DeformationoftheCLTconstructionforLC1(self‐weight)in[mm]..............................82

FigureB.18:DeformationoftheCLTconstructionforLC3(windfromthefront)in[mm]............82

FigureB.19:DeformationoftheCLTconstructionforLC4(windfromthefront)in[mm]............83

FigureB.20:InternalnormalforcesintheCLTconstructionforLC1(self‐weight)in[kN/m]......83

FigureB.21:InternalnormalforcesintheCLTconstructionforLC3(windfromthefront)in[kN/m]........................................................................................................................................................84

FigureB.22:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC1(self‐weight)in[kN/m]..................................................................................................................................84

FigureB.23:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC2(snow)in[kN/m]........................................................................................................................................................85

FigureB.24:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC3(windfromthefront)in[kN/m]..............................................................................................................................85

FigureB.25:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC5(lifeload)in[kN/m]...................................................................................................................................................85

FigureB.26:InternalshearforcesinthefirststoreyoftheCLTconstructionforLC3(windfromthefront)in[kN/m]..............................................................................................................................86

FigureB.27:InternalshearforcesinthefirststoreyoftheCLTconstructionforLC4(windfromtheside)in[kN/m]................................................................................................................................86

FigureB.28:Stressinglobalxdirectionσxoftheconnectionin[N/mm2]...........................................87

ListofFigures

MasterThesis‐LucasBienert X

FigureB.29:Stressinglobalydirectionσyoftheconnectionin[N/mm2]...........................................87

FigureB.30:Firstprinciplestressσ1oftheconnectionin[N/mm2].......................................................88

FigureB.31:Straininglobalxdirectionεxoftheconnectionin[‐]...........................................................88

FigureB.32:Straininglobalydirectionεyoftheconnectionin[‐]...........................................................89

ListofTables

MasterThesis‐LucasBienert XI

ListofTablesTable3.1:OverviewoverEuropeanstandardsforthedesignoftimberconstructions.......................7

Table3.2:Selectedmaterialsafetyfactors[3,NA.2.4.1]...................................................................................9

Table3.3:PartialsafetyfactorsaccordingtoECandtheNorwegiannationalannex[4,NA.A1.3.1]...........................................................................................................................................10

Table3.4:SelectedcombinationfactorsaccordingtoECandtheNorwegiannationalannex[4,NA.A1.2.2]...........................................................................................................................................10

Table3.5:Loadcases.....................................................................................................................................................11

Table3.6:Loadcombinations....................................................................................................................................11

Table5.1:Mechanicalpropertiesofsteel,concreteandwoodincomparison[1]..............................19

Table5.2:Pricesofsomeselectedengineeredwoodproductsincomparisontosolidwood[20,51].......................................................................................................................................................24

Table5.3:Advantagesanddisadvantagesofgluedconnections[26,334].............................................25

Table6.1:MaterialpropertiesfortheANSYSmodel[12,table5][16,5‐3]...........................................58

Table7.1:Evaluationmatrixforthecomparisonofthethreeconstructionvariantsframeconstruction,panelconstructionandCLTconstruction........................................................67

AbbreviationsandSymbols

MasterThesis‐LucasBienert XII

AbbreviationsandSymbolsAbbreviations3D three‐dimensional

CAD computer‐aideddesign

CLT cross‐laminatedtimber

CNC computerisednumericalcontrol

CO loadcombination(followedbythecorrespondingnumber)

DIN “DeutschesInstitutfürNormung”(GermanInstituteforStandardization)

EC Eurocode

EN EuropeanStandard

EQU equilibriumlimitstate

FE finiteelement

FEM finiteelementmethod

FSC ForestStewardshipCouncil

GEO geotechnicallimitstate

GHG greenhousegases

glulam gluedlaminatedtimber

LC loadcase(followedbythecorrespondingnumber)

LCA lifecycleassessment

LVL laminatedveneerlumber

MBO “Musterbauordnung”(Germanbuildingregulation)

M‐HFHHolzR “Muster‐RichtlinieüberbrandschutztechnischeAnforderungenanhochfeu‐erhemmendeBauteile inHolzbauweise” (Germanregulation for firesafetyrequirementsontimberelements)

OSB orientedstrandboard

PEFC ProgrammefortheEndorsementofForestCertification

PSL parallelstrandlumber

SLS serviceabilitylimitstate

STR structurallimitstate

TMT thermallymodifiedtimber

ULS ultimatelimitstate

VOC volatileorganiccompounds

AbbreviationsandSymbols

MasterThesis‐LucasBienert XIII

LatinSymbolsa years

c compression

CO2 carbondioxide

E Young’smodulus

f strength

f compressionstrength

f tensilestrength

G permanentloads

h hours

k modificationfactorforthestrengthofwood

Q variableloads

SL stresslevel

t tension

T time,loadduration

u ultimate

y yieldpoint

GreekSymbolsγ specificweight

γ partialsafetyfactorforpermanentloads

γ materialsafetyfactor

γ partialsafetyfactorforvariableloads

ε strain

λ heatconductivity

σ stress

σ reducedpreliminarydesignstrength

ψ combinationfactor

Introduction

MasterThesis‐LucasBienert 1

1. IntroductionAlthoughwoodisoneoftheoldestmaterialsthathavebeenusedforbuildings,todayithasmostlybeenreplacedbyconcreteandsteel.Thismasterthesisdealswithdifferentconstructionmethodsthatcanbeusedformulti‐storeytimberbuildings1toanalysethewood’spotentialinthisfield,alsoincomparisontoconcreteandsteel.

Oneofthemainmotivationstousewoodisthatitisrenewableandenvironmentallysuperiortothoseothermaterials.Globally,theconstructionindustryisresponsiblefor40%ofthetotalde‐pletionofnaturalresources,40%oftheconsumptionofthetotalprimaryenergy,15%oftheusageoffreshwater,25%ofallwasteand40to50%ofallgreenhousegasemissions[24,39].Usingwoodinsteadofconcreteandsteelhasthereforegreatpotentialtopromoteamoresustain‐ablesociety.

Itistodaynotechnicalchallengetobuildsmalltwo‐orthree‐storeyhousesfromwood.Buttheglobalpopulation increases,andaconsiderablepart ismoving to the largecities,where livingspacegetsscarce.Therefore,themajorityofnewbuildingswillbeerectedinthecitiesandwillprobablybemulti‐storeyconstructions.Fortimbertoreallymakeachange,thechallengesregard‐ingmulti‐storeytimberbuildingsmustbeaddressed.

Thegoalofthismasterthesisistocontributetothisdevelopmentbydiscussingthepropertiesofmodernwoodproducts and structures andby analysing the suitability of timbermethods formulti‐storeybuildings.Asamethodfortheanalysis,adesignwillbeperformedofthreedifferentalternativetimberstructuresforanexistingmulti‐storeytimberbuilding.

Firstofall,thesocietyperspectiveshallbedescribedinchapter2,alsolookingatthedifferentsituationsinNorwayandGermany.Thiswillstartwithasummaryofthehistoricaldevelopmentofwoodenbuildingsandconstructionmethods.Afterthat,thesituationoftodayispresented.Inchapter3,thetheoreticalbackgroundshallbeestablished.Hereitisimportanttotakealookattherulesandstandardsthatmustbefollowedinthedesign.Basedonthat,thebasisforthefol‐lowingdesigncanbecreated.Afterdefiningthecentralresearchquestionsforthefollowingworkinchapter4,thedifferenttimberstructures,materialsandconnectionsthatareavailabletodayorarebeingdevelopedwillbeexaminedinchapter5.

Finally, the above mentioned method, the design analysis is presented in chapter 6. Today’sworld’shighesttimberbuilding,Treet2inBergen(Norway)willberedesignedtoevaluatethreedifferentconstructionmethods.Thosethreevariantswillbeamodernframeconstructionfeatur‐ingalargegrid,apanelconstructionrelyingheavilyonprefabrication,andamasstimbercon‐structionusingcross‐laminatedtimber(CLT).Apreliminarydesignisconductedforallthreecon‐structions.Thisincludesshapingthestructuralideaanddeterminingdimensionsofcross‐sectionandconnections.Thispartofthedesignwillbegiventhemostattention,becausethisiswherethemost engineeringproblemsmustbe solvedand thegeneral structure is shaped.Basedon the

1 Inthecontextofthismasterthesis,amulti‐storeybuildingisconsideredtobeabuildingwithat leastthree,butalsomorethantenstoreys.Thetermtimberbuildingreferstoabuildingwiththeload‐bearingstructuremadefromtimberorengineeredwoodproducts.Whilethewordwoodisamoregeneraltermthatdescribesthebasicmaterialextractedfromtrees,timberisanykindofwoodproductusedforbuildingpurposes.2TheconstructionofTreetwasfinishedin2015anditisbytoday(2018)with14storeysandaheightofabout51mstillthehighesttimberbuildingintheworld[10].However,thereisanothertimberbuildingunderconstructioninNorwaythatwillbeevenhigher,MjøstårnetinBrumundal.Aftertheprojectedcom‐pletionoftheprojectin2019,itwillhave18storeyswithatotalheightof81m[22].

Introduction


preliminarydesign,thefinaldesignaccordingtotheEurocodestandardsisperformed,includinga finiteelement(FE)analyses.The idea is todesignthreedifferentconstructions forthesamebuildingandtocomparethemafterwardsconsideringdifferentaspectssuchastheefficiencyoftheload‐bearingstructureorenvironmentalaspects,cf.chapter7.

Afteradiscussionoftheresultsinchapter8,thefinalconclusionsofthismasterthesisarepre‐sentedinchapter9,wheretheearlierstatedresearchquestionswillbeanswered.Basedonthoseconclusions, recommendations concerning the future of multi‐storey timber buildings can begiveninchapter10.

SocietyPerspective


2. SocietyPerspective2.1. HistoricalBackground

Inearlyhistory,timberwasthemostimportantbuildingmaterialforresidentialbuildings.Oneofthemainreasonsforthatisthatitwasreadilyavailableinlargequantities,althoughthisdifferedfromregiontoregion.Accordingly,somecountrieshavearichhistoryofbuildingwithtimbertoday,whileothersrelymoreonothermaterials.Moreover,woodisrelativelyeasytoshape,incontrasttoe.g.stone.

Theworld’soldeststillstandingtimberbuildingistheHōryūtempleinJapan,whichwasbuiltinthe7.century[7].TheoldesttimberbuildinginNorwayistheBorgundchurchfromthe12.cen‐tury[26,1].Theseexamplesprovethattimberbuildingsareverydurableandcanpersistforapracticallyunlimitedamountoftimeifplannedandmaintainedcorrectly.Importantelementsofagooddesignconcerningthedurabilityarethatwaterandmoisturearenothinderedfromleavingthebuildingandthatdamagedcomponentscanbereplacedeasily[26,2].

InNorway,woodhasbeenthemostimportantmaterialforallkindsoftools,includingshipsandbuildings,sincethetimeoftheVikings.ThatisbecauseofNorway’swide‐spreadforests.WoodenhousesareanimportantpartoftheNorwegianculture,onlyinafewcountriesliketheUSAandCanadaistheshareoftimberbuildinginallexistingbuildingscomparablyhigh.Today,75to80%ofallnewlybuiltresidentialbuildingsinNorwayaretimberbuildings[18,7].

ThefirstwoodenhousesinNorwaywereprobablypalisadebuildingsmadefromlogsdrivenintotheearthvertically,butthiskindofstructuredidnotprevailbecauseofthedecayofthewoodintheground.Furtherdevelopment leadtostavebuildings likethewell‐knownNorwegianstavechurches.Adifferentmethodthatwasusedfromearlyinthehistoryisthelogconstruction,whichwaswidelyuseduntilthe19.century.Overthetime,moremethodsweredeveloped,leadingtomoreefficientbuildingconstructionsthatneededlessmaterialandweremoredurable.Anexam‐pleisthetraditionalframeconstructionwhichwasintroducedaround1700notonlyinNorway,butalsoinotherEuropeancountries.Inthebeginning,thespacein‐betweentheframeswasfilledwithe.g.brickworktosealthehouseagainsttheweather.Around1900,thebuildingsgotsheath‐ingbothontheinsideandtheoutsideandthespacesintheframeworkwereleftfree,whichsavedmuchmaterial,i.e.unnecessaryweightandcosts.Inthemiddleofthe19.century,thosecavitieswerethenfilledwithinsulation,whichimprovedtheindoorclimate.Today,thedevelopmentofnewmethodsisstillongoing.Prefabricationbecomesmoreandmoreimportantandnewtechnol‐ogiesase.g.compoundmaterialsareused[18,7‐10].

Intheearlyhistory,Germanywasalsocoveredwithrichforests.IncontrasttoNorway,however,deforestationandindustrialisationdevelopedfasterandstronger,possiblereasonsforthatarethe easier topography andGermany’s central position inEurope.During the industrialisation,woodwasmoreandmorereplacedbysteelandlateralsoreinforcedconcrete,becausethewoodworkingprocessesweretooslowandthereforemoreexpensive[20,6].Thiswasmainlyduetolabour‐intensiveconnectionssuchasdovetailconnections.Furthermore,thetimberindustrywasmorefocusedontraditions,alsobecauseofitslonghistory[25,5],andcouldthereforenotcom‐petewiththemodernsteelandconcreteindustry.

Duringthistime,thewaypeopleregardedthedifferentbuildingmaterialschanged.Onlybrickhouseswereregardedassufficientlydurable,woodenhouseswereespeciallyshort‐livedandthefireriskwashigher[25,6].Manyoftheseviewsoftimbersurviveduntiltoday,althoughthetim‐bertechnologychangedfundamentally.

SocietyPerspective


In thebeginningof the20.century,during the firstworldwar, the timber industrydevelopedstronglyagain.Manyconstructionswereneededforthewar,manyhousesweredestroyed,andsteelwasneededotherwise[25,6].Fastpanelconstructionswerepreferred[25,9].Afterthefirstandsecondworldwar,againmostlybrickworkandconcretestructureswereused,whichwerefasterandcheapertobuildthanwoodenstructures.

Today,about10%oftheexistingconstructionsfeaturewoodasmainbuildingmaterialinGer‐many,intheNordiccountriestheshareamountsto80to85%[24,408],whichisprobablymainlyduetothedifferenthistoricdevelopment.Thetechnologiesthatareusedtoday,however,donotdifferasmuchbetweenthecountriesbecauseofeasyexchangeoftechnicalknowledge.

2.2. EvolutionofTimberTechnologiesWhile thepreviouschapter focusedonthegeneraldevelopment inGermanyandNorway, thischapter dealswith the development of the timber technologies themselves. It is important toknowhowthetimbertechnologieschangedovertimetohaveabetterunderstandingoftoday’stechnologies.Furthermore,itcanhelptobetterunderstandthedoubtsthatexistamongstboththeclientsandthearchitects,plannersandengineers.

Theoldestwoodproductis,ofcourse,timbermadefromsolidwood,whichwasusedalmostex‐clusivelyuntilthe20.century.Nonetheless,thereweresomeearlyinventionsthatcombinedin‐dividualwoodmemberstoformbiggercomponentsthatcouldspanlargerdistances.Whenthoseearlyengineeredwoodproductsweredeveloped,theindividualmemberswereconnectedusingmechanicalfastenerssuchasnails,boltsordowels.Oneoftheearliestexamplesisanarchcom‐ponentmadefromtwotothreecurvedplanksthatstanduprightandarelinkedtogetherbycross‐members,developedbyaFrencharchitectasearlyas1561.Itallowedforlongerspans,withatthesametimelowerhorizontalshearforcesatthesupports,comparedtothetraditionalcoupleroof.In1830,anotherFrenchengineerdevelopedabeammadefromstackedhorizontalplanksholdtogetherbybolds,whichcanbeseenasthepredecessorofthemoderngluedlaminatedtim‐ber(glulam)[20,10].

Themechanicalfastenersusedfortheengineeredwoodproductswerewidelyreplacedbysyn‐theticgluesintheearlytwentiethcentury[26,7],thoseallowedasuperiorstressdistributionandbetterload‐slip‐behaviour.ThefounderofmoderngluedwoodproductssuchasglulamwasOttoHetzer(1846–1911),whoobtainedhispatentongluedtimberconstructions in1906[26,67].Someoftheearlierinventionsthatusedsyntheticglues,developedinthefirsthalfofthe20.cen‐tury,includeplywood,apanelmadefromthinlayersofveneer,andparticleboard,apanelmadefromfinewoodchipsandsawmillshavings[26,84].Later,glulambecamecommerciallyavailable.Someoftheoldestbuildingsstillinusethataremadefeaturingglulamasthemainbearingele‐mentare therailwaystations inMalmø(built in1922)andStockholm(1925),both located inSweden[26,67].Morerecentlydevelopedproductsincludeorientedstrandboardaswellasthesolidwood‐likeparallel strand lumberand laminatedstrand lumber,allmade fromstrandsofwood[26,84].Thosedevelopmentsmadeitpossibleforwoodtobeusedinlargeandcomplicatedengineeringstructures.

Overthetime,theplanningwasmoreandmoremovedfromtheconstructionsitetotheoffice.Morecomplexandefficienttechnologiesrequiredmorepre‐planning.

Inthe21.century,thedevelopmentwascharacterisedbynewtechnologieslikeCAD(computer‐aideddesign),CNC(computerisednumericalcontrol)andtheso‐calledindustry2.0.Thisallowedforthewoodproductstobemanufacturedveryefficiently,evencostumerspecificproductscouldbeproducedeconomically.Thisagainhelpedtheplannerstodesignmoreefficientbuildingswith

SocietyPerspective


speciallytailoredwoodproducts.Additionally,makinguseofthemanifoldpossibilitiestoshapetimberandengineeredwoodproductsopenedupgreatnewpossibilitiesforarchitectsandengi‐neers.

Today’sresearchfocusesamongstotherthingsonimprovementsofthewood’sproperties,sincehereinstillliethebiggestproblemsandchallenges.Thisconcernse.g.thedecayofwoodanditscomparably lowstiffness.Moreabout today’s researchanddevelopmentswillbedescribed inchapter5.4.

2.3. Today’sGlobalSituationWiththedevelopmentofnewtechnologiesthatmakewoodcompetitiveagain,thedemandforwoodproductsrises.Thereis,however,agapbetweendemandand(sustainable)supplyofwood,oneofthemostimportantissuesoftodayisthereforetheuseofwoodfromsensitiveecosystems,e.g.rainforests,inanon‐sustainableway.Theworld’stotalforestareadecreasedinthetimebe‐tween1990and2000by8,3millionha/aandfrom2000to2010by5,2millionha/a,mostlosseswereobservedinthetropicalregionsinSouthAmericaandAfrica[24,314].

Anotherissueistheconflictbetweentheindustrialuseofforeststoproducewoodproductsandthevalueofforestsforrecreationandforahealthyecosystem.Forestsarenotonlyveryimportantforthehealthofthelocalecosystems,butalsofortheglobalenvironmentandclimate.

Todissolvethoseconflicts,measuresmustbetakenatdifferentpoints.Ontheproductionside,sustainablemethodsmustbeestablishedworldwide,reforestationandforestplantationareim‐portantpartsofthismeasure.Thedevelopmentofnewtechnologiesforharvestingandmanufac‐turingleadstoahigherefficiencyandthusareducedwooddemand.Finally,newproductsthatusesmallerdiameterandlowerqualitywoodcanslowdowntherisingdemandforwood[26,81‐82],someexamplesforthisapproachareaddressedinchapter5.1.4aboutengineeredwoodprod‐ucts.

Topromotesustainableforestry,certificationisneeded.Onaglobalscale,therearetwodifferentsystemsforcertificationofforests,theForestStewardshipCouncil(FSC)andtheProgrammefortheEndorsementofForestCertification(PEFC).Thelatteristoday’sbiggestcertificationsystem[27,18‐19].Additionally, thereare alsonational certification systems like theNorwegian “Le‐vendeSkog”,thiswillbetakenupagaininchapter3.1.2.

Inspiteofalltheissuesdescribedabove,woodwilldefinitelyplayanimportantroleinthefuture.Withappropriatemanagement,thoseproblemscanbeovercome,becausewoodisstillsufficientlyavailable.InEurope,thewoodgrowthexceedsthefellingeachyear,andconsequently,theforestareaincreasedby0,7millionha/aduringtheperiodfrom2000to2010[24,314].InGermany,onethirdofthecurrentannualyieldofwoodwouldsufficetousewoodforallnewlybuiltcon‐structions[23,43]andinNorway,thenewgrowthofwoodperyearismorethantwiceashighastheusage[27,25].

2.4. SummaryoftheSocietyPerspectiveThepurposeofthischapterwastogiveanintroductionintobuildingwithtimberfromasocietypointofview.Itstartedwithasummaryofthehistoricaldevelopment,whichshowedthatwoodhasbeenused forbuildingpurposes forcenturies, longer thane.g.concreteandsteel,but thetechnologieshavechangedsignificantly.Large‐scalestructureshavebecomepossible.Moreover,formerproblemsconcerningthecombustibilityandthedecayofwoodhavelargelybeenover‐come.OldwoodenbuildingsliketheNorwegianstavechurchesprovethatwoodenbuildingscanbeverydurable,providedgoodplanningandmaintenance.Still,therearewide‐spreadreserva‐

SocietyPerspective


tionsagainsttimberamongstboththeclientsandtheplanners,andthetimberindustryisonlynowstartingtodevelop.

Today’sglobalsituationwasdescribed,pointingattheenvironmentalissuesconnectedtothepro‐ductionofwoodproductsconcerningunsustainableforestry.

Beforedealingindetailwiththedifferenttimbertechnologies,someofwhichhavealreadybeenmentionedinthischapter,itisnecessarytofirsttakealookatthetheoreticalbackgroundinthenextchapter.Thisincludestheinternationalandnationalrulesandstandardsthatformthebasisforanytimberdesign.OfcentralimportanceforallEuropeancountriesaretheEuropeanstand‐ardsincludingtheEurocodes(EC).Afterthat,adescriptionofselectednationalrulesandstand‐ardsinNorwayandGermanywillbegiven.

Thedesignbasis,whichisbasedonthoserules,willcompletethetheoreticalbackgroundforthesubsequentexaminationsofthetimbertechnologiesandthedesignanalysis.

Theory


3. Theory3.1. RulesandStandards

3.1.1. EuropeanStandardsManydifferentstandardsplayaroleinthedesignoftimberbuildings.ThedesignisconductedaccordingtotheEurocode5(EC5),i.e.EN1995‐1‐1.Additionalstandardsregulatethedifferentmaterials, give requirements for manufacturers and define material properties. Furthermore,therearesomeproductsthatarenotornotyetstandardised,wherethecharacteristicpropertiesarespecifiedbythemanufactureroratestinglaboratorycommissionedbythemanufacturer.Ta‐ble3.1givesanoverviewovertheEuropeanstandardsthatareimportantforthedesignoftimberconstructions.

Table3.1:OverviewoverEuropeanstandardsforthedesignoftimberconstructions

product mainstandard

productstandard

propertiesstandard

designstandard

solidwood EN14081‐1 EN14081‐1 EN338 EN1995‐1‐1glulam EN14080 EN14080 EN14080laminatedve‐neerlumber

EN13986 EN14374EN14279

manufacturer

plywood EN636 EN12369‐2orientedstrandboard

EN300 EN12369‐1

particleboard EN312hardfibreboard EN622‐2mediumhardfi‐breboard

EN622‐3

mediumdensefibreboard

EN622‐5

solidwoodpan‐els3

EN13353 EN12369‐3 ‐

cross‐laminatedtimber CLT

EN16351 EN16351 manufacturer ‐

Ascanbeseenfromthistable,forsomeproductslikelaminatedveneerlumber(LVL)andcross‐laminatedtimber(CLT),nopropertiesstandardshavebeenworkedoutyet,sothatcharacteristicpropertiesmustbetakenfromtechnicalapprovalsprovidedbythemanufacturer.Moreover,theEC5doesnotmentioneithersolidwoodpanelsorCLT.ThedesignrulesoftheEC5mustthereforebeadaptedforthosematerials,thatconcernsmainlythechoiceofadequatesafetyfactors.Thiswillplayarolelateroninthismasterthesis,whenitcomestothedesigntheCLTconstructionofTreet.Itcanberevealedatthispointthat,basedonresearchresults,itisrecommendedtousethesamedesignfactorsforCLTasforglulam[19,934].

Inadditiontothosetimberspecificstandards,Eurocode0(EC0)describesthegeneraldesigncon‐cept,andinthedifferentpartsofEurocode1(EC1),allthetypesof loadsaredefined.It isnot

3Solidwoodpanelsarepanelsmadefromoneorseveralpliesofwoodplanks; theycanhavethesamecompositionasCLTpanels,butincontrasttoCLTtheplankshavenotbeensortedintostrengthclassesandthegluehasnotbeentested.

Theory


withinthescopeofthismasterthesistogointodetailconcerningthosebasicstandards.Atsomepoints,though,thestandardsallowe.g.theuseofdifferentformulae.Moreover,everycountrycanspecifytheirownsetofsafetyfactorsandcombinationfactorsandcanadaptthestandardswithinspecificboundariesinthecorrespondingnationalannexes.ToavoidmisunderstandingsandtohaveasolidfoundationfortheECdesign(cf.chapter6.4),designbasisisestablishedinchapter3.2.

Togivesomeexamplesofthedifferencesthatarisefromthedifferentnationalannexes,ashortcomparisonoftheNorwegianandtheGermannationaladjustmentsshallbepresented.

Quitenaturally,therearebigdifferencesconcerningthedeterminationoftheenvironmentalloadslikewindandsnowloads.Thisismostlyduetothefactthattheenvironmentalloadshighlyde‐pendonthegeographicalsituationinthedifferentcountries.TheNorwegiannationalannexestoEC1part1‐3(snowloads)andEC1part1‐4(windloads)featuredetailedtableswithfactorsforthecalculationoftheloadsatdifferentplaces.IntheGermannationalannextoEC1part1‐4,anaccidentalloadcase4forespeciallyhighwindloadsintheflatnorthernregionsisadded.

Concerningthetimberspecificstandard,EC5,theGermannationalannexfeaturesextensivead‐ditions,e.g.asimplifiedapproachforthedesignoftimberconnectionsusingγ 1,1aspartialsafetyfactorinsteadofγ 1,3.Furthermore,onecanfindadditionsfordifferentdetailsthatarenotcoveredbythemainstandard,e.g. forstrengtheningof transverseconnectionsusing fullythreadedscrewsandfortraditionalwoodworkingjoints.

3.1.2. NationalRulesandStandardsinNorwayandGermanyBesides the described standardswhich define the technical requirements, additional nationalrulesdefinefurtherrequirements,concerninge.g.thelayoutofthebuilding,firesafetymeasuresandtheexecutionofthebuildingproject.

InGermany,thatconcernsthe“Musterbauordnung”[9](MBO,Germanbuildingregulation)to‐getherwiththetimberspecific“Muster‐RichtlinieüberbrandschutztechnischeAnforderungenanhochfeuerhemmende Bauteile in Holzbauweise” [8] (M‐HFHHolzR, German regulation for firesafety requirementson timberelements).The fire safety requirements forwoodproductsarequitestrict,makingitnecessarytomakeadeviationrequestiftimberistobeusedvisiblyinbuild‐ingswithmorethanthreestoreys5.Thisleadstohighercostsfortimberconstructions.

InNorway,itisonlyallowedtousetimberinbuildingshigherthanthreestoreysatallsince1998.InaresearchdocumentcommissionedbytheNorwegiangovernmentin2013,itisfoundthat,asalong‐termeffectofthat,thetimberindustryisstillnotfullydevelopedandthatexpertiseismiss‐ing[13,4].Thismaysoundstrangeconsideringtherichhistoryofbuildingwithtimberwhichwasdescribedpreviously.Theproblem,however,isthatwoodisalmostexclusivelyusedforsmallerresidentialbuildings,butnot for largerstructures.Thestrategyof theNorwegiangovernmentaimsatusingmorewoodforpublicbuildings,therebysupportingthetimberindustry[13].ThismeasurecoulddefinitelyalsobetransferredtoGermany,wherethesituationofthetimberindus‐tryisapproximatelythesame,ifnotworse.Butacomparablestrategyhasnotyetbeenworkedout.

4ThedesignaccordingtotheECstandards isbasedontheanalysisofdifferent loadcaseswithspecificcombinationsof thedifferent loads.Accidental loadcasesarereserved forexceptional loads like fireorearthquakes.5Actually,therequirementsarelinkedtotheheightofthegroundfloorofthehighestinhabitedstoreyabovetheground.Thelimitissetto7m,whichcorrespondsapproximatelytoabuildingwiththreestoreys.

Theory


Adifferentaspect, thathasalreadybeenmentionedearlier inthedescriptionoftoday’sglobalsituation,isforestcertification.Norwayhasitsownforestcertificationsystem“LevendeSkog”,whichfulfilstherequirementsforthePEFCcertification.Itwasfoundedin1998andaimsatthepromotionofamoresustainableuseoftheforests,balancingthethreecentralaspectsindustrialandeconomicalinterests,environmentalissuesandsocialinterests(cf.chapter2.3).Inthe“Le‐vendeSkog”system,theforestindustry,labourunions,recreationorganisationsandenvironmentorganisationsworktogether.Today,allNorwegianforestsarecertifiedafterthisstandard[27,19].

3.2. DesignBasis3.2.1. Parameters

Thepreliminarydesignwasperformedusingsimplifiedloads(seenextchapter)andreducedma‐terialpropertiestoaccountforthenecessarysafetymargins,e.g.σ 5N/mm forthestrength

ofwoodparalleltothegrain(bothbending,compressionandtension).Thisallowsforarelativelyquickpreliminarydesignwithresultsthatgenerallyareonthesafeside.Thepreliminarymaterialpropertiesaresummarisedintheprefaceofthepreliminarydesigndocumentation,whichisat‐tachedtothisdocument(seeappendixA).

For theECdesign, thematerial propertieswere taken from the relevantEuropean standards,whichweresummarisedinTable3.1.SincethedesignedbuildingislocatedinNorway,theNor‐wegiannationalannexesoftheECwereused.

AccordingtotheNorwegianrules,everystructuremustbeassignedareliabilityclass.Residentialbuildingsgenerallybelonginreliabilityclass2.ThismeansthatthebuildinghastobeassignedtotheplanningcontrolclassPKK2andtheexecutioncontrolclassUKK2,whichrequireadetailedqualitycontrol[4,NA.A1.3.1(901)‐(904)].

BecauseofdifferencesbetweentherecommendationsinthemainECstandardsandtheNorwe‐giannationalannexes,Table3.2toTable3.4summarisethesafetyandcombinationfactorsthathavebeenusedinthismasterthesis,whichcorrespondtotheNorwegiannationalannexes.

Table3.2:Selectedmaterialsafetyfactors[3,NA.2.4.1]

material materialsafetyfactorγsolidwood 1,25glulam,CLT 1,15plywood 1,15connections 1,3

Theory


Table3.3:PartialsafetyfactorsaccordingtoECandtheNorwegiannationalannex[4,NA.A1.3.1]

load favourable/un‐favourable

partialsafetyfactor

EQU:basicloadcombinationforpermanentandtransientloadsG :permanentloads uf γ 1,20

f γ 0,90

Q :leadingvariableload i 1 uf γ , 1,50

f γ , 0

Q :furthervariableloads uf γ , 1,50

f γ , 0

STR,GEO:basicloadcombinationforpermanentandtransientloadsG :permanentloads uf γ 1,20

f γ 1,00

Q :leadingvariableload i 1 uf γ , 1,50

f γ , 0

Q :furthervariableloads uf γ , 1,50

f γ , 0

EQU equilibriumlimitstateSTR structurallimitstateGEO geotechnicallimitstate

Table3.4:SelectedcombinationfactorsaccordingtoECandtheNorwegiannationalannex[4,NA.A1.2.2]

load combinationfactorψ ψ ψ

liveloads A:residentialbuildings 0,7 0,5 0,3 H:roofs 0 0 0snowloads 0,7 0,5 0,2windloads 0,6 0,2 0

Itmustbenotedthat,sinceCLTisnotconsideredintheEC,assumptionshadtobemadefortheselectionofappropriatesafetyfactorsandotherparameters.Inaresearchprojectfrom2018,itisrecommendedtousethesamesafetyfactorsasforglulam(cf.Table3.2)[19,934].Accordingly,otherfactorslikethemodificationfactork toaccountforeffectsofmoistureandload‐dura‐tion,werealsotakenoverfromglulam.

Forthecalculationofthedeformations,EC5allowstwodifferentmethods,ageneralmethodandasimplifiedmethodforstructuresthatconsistofcomponentsthatallhavethesamecreepingbe‐haviour.Thethreedesignvariantsthatareanalysedinthismasterthesisfulfilthisrequirement(cf.chapter6.2.1),thereforethesimplifiedapproachisappliedfortheECdesign(see[3,2.2.3]).

AllotherparametersaredescribedinthedocumentationoftheECdesign,cf.appendixA.

Theory


3.2.2. LoadCalculationForthepreliminarydesign,simplifiedloadswereusedtogetaquickideaofthegeneralmagnitudeoftheresultingforces.Theself‐weightofthefloors,forexample,wasassumedtobe2kN/m ,thelifeloadandthesnowloadontheroofwerebothsetto2kN/m ,too.Onlythewindloadswerecalculatedinmoredetail,becausetheyhaveastronginfluenceonthesystemofamulti‐storeybuildingandhighlydependonthelocationofthespecificproject.

FortheECdeign,adetailedloadcalculationwasperformedaccordingtoEC1,usingtheNorwegiannationalannexes.Thedocumentationoftheloadcalculationcanbefoundattachedtothisdocu‐ment,cf.appendixA.Differentloadcases(LC)hadtobedistinguished,thosearesummarisedinTable3.5.

Table3.5:Loadcases

LC description loadduration1 self‐weight permanent2 snow short‐term3 windfromthefront instantaneous4 windfromtheside instantaneous5 liveload categoryA medium‐term

Theindividualloadcaseswerecombinedindifferentloadcombinations(CO).Becausetheloadbearingbehaviourofwoodistimedepended(seechapter5.1.1),differentloadcaseswithdiffer‐entloaddurationshadtobeconsidered,cf.Table3.6.

Table3.6:Loadcombinations

CO self‐weight leadingvariableload

accompanyingvariableload

loadduration

1 self‐weight ‐ ‐ permanent2 self‐weight liveload ‐ medium‐term3 self‐weight snow liveload short‐term4 self‐weight liveload snow short‐term5 self‐weight windfromthefront snow,liveload instantaneous6 self‐weight windfromtheside snow,liveload instantaneous7 self‐weight liveload snow,windfrom

thefrontinstantaneous

8 self‐weight live load snow,windfromtheside

instantaneous

9 self‐weight snow windfromthefront,liveload

instantaneous

10 self‐weight snow windfromtheside,liveload

instantaneous

11 self‐weight windfromthefront ‐ instantaneous12 self‐weight windfromthe side ‐ instantaneous

CombinationsCO1toCO10aremeant for thecalculationof themaximumcompressive forces.Sinceforcompression,incontrasttotension,bucklingmustbeconsidered,thesecombinationswillbedecisiveforthedeterminationoftherequiredcross‐sections.

Theory


CO11andCO12aremeantforthetensiondesign,whichise.g. importantforthedesignoftheanchorage6inthepanelandtheCLTconstruction.Thecorrespondinglowerpartialsafetyfactorfortheself‐weightwasused(γ 1,0insteadofγ 1,2).

3.2.3. SoftwareThepreliminarydesignwasmostlyperformedwithouttheuseofdesignsoftware.Stab2d,asim‐pleprogram for the analysis of two‐dimensional frameworks,wasused todetermine internalforcesanddeformations.MicrosoftEXCEL©wasusedforthestabilityanalysisofthepanelandtheCLT construction.The stability analysiswas conducted todetermine the shear forces andbendingmomentsintheindividualwallsduetotheglobalwindloads.

TheECdesignrequiredmoreaccuratecalculationmethods.TheFEMsoftwareRFEM©byDlubalSoftwareGmbHwasusedtomodelandanalysetheoverallstructureofallthreevariants.WithRFEM, both one‐dimensional members, two‐dimensional surfaces and three‐dimensional vol‐umescanbemodelled.OneofitsmajoradvantagesistheextensivelibraryofmaterialsandtheincorporationofmanystandardsincludingtheECanditsnationalannexes.RFEMcanautomati‐callycombineloadsaccordingtoloadcombinations.ThedetailsoftheFEManalysisusingRFEMareexplainedinchapter6.5.1.

Additionally,ananalysisofaselectedconnectiondetailwillbecarriedouttocomparewiththecalculationsaccordingtoEC.Thereasonsforthiswillbeexplainedinchapter5.2.Forthisanalysis,theFEMsoftwareANSYSwasused.ANSYS,incontrasttoRFEM,isaprogramthatfocusesmoreonin‐depthscientificcalculationsofdetailsinsteadofontheanalysisofwholeengineeringstruc‐tures.Italsoincludesanorthotropicmaterialmodelwhichisrequiredforwood.

3.3. SummaryoftheTheoryInthepreviouschapter,thetheoreticalbasisfortheexaminationsandthedesignanalysisthatwillfollowinthenextchaptershasbeenworkedout.Abriefoverviewoftherulesandstandardsthatdealwithtimberhasbeengiven.Somerulesarestillinfluencedbytheformerproblemsofwoodproducts like theGermanM‐HFHHolzRwhichdoes not allow visiblewoodmembers inbuildingswithmorethan3storeysduetofiresafetyreasons.InNorway,therewerecomparablerulesuntilrelativelyrecently,whichcanexplaintheweakpositionofthetimberindustrytoday.WiththenewstrategytosupportthetimberindustryinNorway,however,thesituationbeginstochange.

6Anchoragereferstotheconnectionsbetweenwallsaboveeachother,whichareresponsiblefortransfer‐ringtensileforces.Tensileforcesoccuratthebottomofthebuildingwheretheglobalbendingmomentduetothewindloadsissplitintocompressionandtensionforces.

ResearchQuestions


4. ResearchQuestionsThecentralresearchquestionforthefollowingexaminationsis:

1. Whichmaterialsandconstructionmethodsarebestusedforanefficientdesignofmulti‐storeytimberbuildingsfromastructuralpointofview?

Somesecondaryquestionshavealreadybeendealtwithinthepreviouswork:

2. Howdidthetimbertechnologydevelop,andwhichnewtechnologiesaredevelopedto‐day?

3. WhatarethemaindifferencesbetweenGermanyandNorwayconcerningthewaytocon‐structtimberbuildings?

4. Howdonationalrules influencethedevelopmentofthetimberbuildingindustryespe‐ciallyinGermanyandNorway?

Theanswerstothosequestionswillbesummarisedtogetherwiththeanswerstotheotherques‐tionsintheconclusionsinchapter9.

Furtherquestionsthatwillbediscussedinthefollowinginclude:

5. Whatarethemainadvantagesanddrawbacksoftimberincomparisontosteelandcon‐crete,alsoconsideringenvironmentalaspects?

6. Whichroledoconnectionplayinthedesignoftimberbuildings?7. Howcanfiniteelementsoftwarebeusedtoeffectivelydesigntimberconstructionsand

connections?8. Howwelldotheregulationsinthestandardsreflecttherealbearingbehaviouroftimber

constructionsandconnections?

Concerningthedesignanalysis,thismasterthesisfocusesonthestructuralaspectsofthetimbermaterials,whiletheconcreteandsteelmemberswillnotbetakenintoaccount.Fireprotectionandeconomicalaspectswillonlybediscussedbrieflyinthetext.

Inordertoanswerthosequestions,thenextchapterwilldealwiththepropertiesoftimbermate‐rialsandstructuresinmoredetail.Someoftheaspectsmentionedinthepreviouschapterswillbepickedupanddiscussed,liketheenvironmentalissuesandthenewdevelopmentsoftoday.

Themainmethodtofindanswerstothosequestion,however,isthedesignofthemulti‐storeytimberbuildingTreet,whichwillbepresentedinthefollowingchapter.

Case/Materials


5. Case/Materials5.1. TimberMaterials

5.1.1. GeneralPropertiesofSolidWoodAboveallelse,woodisanaturalmaterial.Thishassomegreatadvantagesbutalsoincludessomechallenges.Thischapterdealswithboth,describingimportantaspectstokeepinmindwhenplan‐ningatimberbuilding,andespeciallyoneaschallengingasamulti‐storeybuilding.Firstly,somegeneralpropertiesofwoodarepresented,followedbyanexaminationofitsmechanicalproper‐ties,whichareimportantforthelaterdesign.

Oneofthecharacteristicadvantagesofwoodisitsaestheticsurface,itdoesnotneedtobecoveredandisoftenusedforarchitecturalpurposes.Thisistrueforsolidwoodaswellasglulamandmostoftheengineeredwoodproducts.Moreover,withtoday’stechnologyitcanbeformedintoalmostanypossibleshape(agoodexampleforthatismasstimberlikeCLTwhichwillbedescribedlater).Besidesthat,woodstoresCO2,oneofthemaingreenhousegases(GHG).1m oftimbercontainsabout0,92tonnesCO2[27,26],therebyactivelycontributingtoslowingdowntheglobalwarming.Inadditiontothat,woodisarenewablematerialbecauseitalwaysregrows.

Acharacteristicdrawbackofwoodisthatitspropertiesvaryalot,dependingontheusedwoodspecies,butalsobetweensamplesofthesamespeciesbecauseofitsgeneralinhomogeneityanddefectslikeknotholes.Thismakesdesigningareliablestructuremoredifficult,largersafetyfac‐torsmustbeused.Ontheotherhand,differentspeciescanbeusedfordifferentpurposes,whichmakesdifferentstrengthclassesandeconomicadjustmentstothedesignpossible.Forstructuralelements, fastgrowingsoftwoods likespruceand firarepreferred. InNorway, theNorwegianspruceandpinearemainlyused.Hardwoodspecieslikeoakorbeechareusedforspecial,highlyloadedcomponentssuchaswooddowels[21,32].

Tocomebacktothegeneraldisadvantagesofwood,itisimportanttomentionthedecay.Thisismostofthetimeaconsequenceofmoistureinsidethewood.Measurestoenhancethewood’spropertiesconcerningdecaythereforefocusonsealingthewoodagainsttheinfiltrationwithwa‐ter.Today,manynaturalsubstancesandtechniquesareavailable,thereisnoneedforusingpoi‐sonous,environmentallydamagingchemicalwoodpreservatives.Oneoptionforthecoatingofthewoodarebiologicalsubstancesfromnaturalsources,examplesarechitosan,producedfromchitin,orpineoil[27,43].However,coatingisingeneralveryexpensive,smalldefectscandestroythepositiveeffectsandregularmaintenanceisnecessary[26,238].Acompletelydifferentpossi‐bilityisthebiological,chemicalorphysicalmodificationofthewood.Onerequirementforanysuchmethodisthatnopoisonisusedandnopoisonoussubstratesareemitted.Anexampleofchemicalwoodmodification is the furfurylation. Furfuryl alcohol is used, under heat it reactschemicallywiththewoodmolecules,thusrenderingthewoodsurfacemoreresistantagainstde‐cay.Furfurylalcoholisderivedfromfurfural,whichisproducedfrombiomasswaste,makingthefurfurylationarenewablemethod.Theprocessisstillquitecostlythough,sothatitisnotyeteco‐nomic inmostcases [24,319‐320].Anexampleofphysicalmodification is themanufactureofthermallymodifiedtimber(TMT)bymeansofaspecialheat treatment.All thosemodificationmethods,however,havethedrawbackthattheystillhaveanegativeinfluenceonthewood’sprop‐ertiesincludingtheloadbearingbehaviourandthetendencytocrack[20,26].

Anotherchallengefortimberstructuresisthecombustibilityofthewood.Buthereagain,withgoodplanning,anyproblemsconcerningthefiresafetycanberesolved.Whenexposedtofire,woodcreatesalayerofcoalonitssurface,whichprotectstheremainingpartofthecross‐section.Theratethatthethicknessofthecoallayerincreaseswithispracticallyconstantovertime,which

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makesitpossibletodeterminetheremainingcross‐sectionafteracertainamounttimeundertheinfluenceoffirequiteaccurately.EC5part1‐2forthefiredesignoftimberstructuresisbasedonthisprinciple.FromthoseexplanationsitalsofollowsthatmassivetimberelementslikeCLThaveadvantagescomparedtolighterframeworkstructureswhenitcomestofiresafety,becauseofthesmallersurfaceinrelationtothevolume.

Allthoseaspectsareimportanttokeepinmindwhendesigningbuildingsusingwoodproducts.Butofcourse,forthestructureitself,themechanicalpropertiesaremostimportant.

Firstofall,woodisanisotropic,morepreciselyorthotropic,thatmeansthatitsmechanicalprop‐ertiesaredifferentinthreeperpendiculardirections,paralleltothegrain,radialandtangential,cf.Figure5.1.Thisisduethewood’sinternalstructure,consistingoflonggrainsthatrunparalleltoeachotheralongthetrunkofatree.Additionally,thecross‐sectionofatreetrunkisbuiltupoutofrings,eachyearanewgrowthringisaddedtotheoutside,whichalltogetherleadstothethreedifferentdirections.

Figure5.1:Threeprincipalaxesofwoodwithrespecttograindirectionandgrowthrings[16,5‐2]

Indesignpractice,however,nodifferenceismadebetweentheradialandthetangentialdirection,onlyparallelandperpendiculartothegrainaredistinguished.Figure5.2showsthestress‐strain‐diagramofsolidwoodparalleltothegrain.Thetensionstrengthf ,thecompressionstrengthf andthestrainsεatthecorrespondingpointsarepointedout.

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Figure5.2:Stress‐strain‐diagramforsolidwood[26,203]

Thestrengthparalleltothegrainishighest,sincethisisthemaindirectionatreemustcarryloadsininthenature.Perpendiculartothegrain,woodhasalimitedbearingcapacityforcompression,but this can lead to large settlements.This is especially interesting formulti‐storeybuildings,whererathersmall settlementscanaddupoverall thestoreys toa considerabledeformationwhichcanendangerthestabilityoftheoverallstructure.Compressionperpendiculartothegrainshouldthereforegenerallybeavoidedinmulti‐storeybuildings.Thetensionstrengthperpendic‐ulartothegrainisevensmaller,about30to50timessmallerthanparalleltothegrain[26,19‐20].Asidefromthat,itisinterestingtonotethatahigherstrengthclassofwooddoesnotleadtoaconsiderablyhighertensilestrengthperpendiculartothegrain.Knotsinthewood,however,which leadtoagrading ina lesserstrengthclass,seemtohaveapositiveeffectonthetensilestrengthperpendiculartothegrain[26,112‐113].

Incompliancewiththosefindings,failureoftimberstructuresinpracticeisinmostcasesaresultoftensionperpendiculartothegrain.Thisoccurse.g.atconnectionswithmetalfasteners,atholesandnotchesandattheapexofgableroofbeams.Changesinmoisturecontentcanalsoleadtoeigenstressesandcrackswhich increasethedangerof fractureperpendiculartothegrain[26,153].Thebehaviourofwoodunderstressesperpendiculartothegrainisnotyetfullyunderstood.Empiricalmethodsarecommonlyused, likeminimumdistancesofmetal fasteners,orstressesperpendiculartothegrainareavoidedcompletely,e.g.byapplyingadditionalstrengtheninglikefullythreadedscrewsintheapexofgableroofbeams[26,19‐20].Thefailureitselfischaracterisedbyaratherbrittlebehaviour[20,15].

Anotherimportantfactorthatinfluencesthewood’spropertiesistime.Woodlosesitsstrengthandstiffnessunderlong‐termloads.Unlikemostothermaterials, thisbehaviourcannotbene‐glected,forsolidwoodthestrengthaftertenyearsofloadingcanbereducedbyupto40%[26,21].Thelong‐termbehaviourofwoodisstillapartoftheresearch.Testresultsshowalogarithmicrelationshipbetweentheloadingdurationandthestrengthforbending,cf.Figure5.3.

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Figure5.3:Decreaseofthebendingstrengthoftimberdependingontheloadduration[26,135]

Fortheteststhattheabovediagramisbasedon,specimenswereloadedwithaconstantbendingloadatdifferentstresslevelsandthetimeuntilfailurewasmeasured.Thelongertheloaddura‐tion,thelowertheacceptablestresslevel.Forotherfailuremodesthanpurebending,onlyverylittlestudiesexist.Thesesuggest,however,thatforanykindofloadingparalleltothegrain,thebehaviourfollowsapproximatelythecurvefromabove,whileloadingperpendiculartothegrainleadstoastrongerdecreaseinstrength[26,141].IntheEC5,theinfluenceoftheloaddurationisconsideredviathemodificationfactorforthewood’sstrengthk .

Moistureinwoodhasalreadybeenmentionedinconnectionwiththedecay.Italsoshortensthetimeto failure formemberssubjectedto long‐termloads[26,141].Moreover,with increasingmoisturecontent,boththestrengthandtheYoung’smodulusoftimberdecrease.Themoisturecontentinthewoodwilladapttothehumidityofthesurroundingair.Thatmeansthatdifferentclimaticconditionsleadtodifferentmoisturecontentinthewoodandthushaveadirecteffectonthebearingbehaviour.ThiseffectisincludedintheEC5viethesamemodificationfactorasfortheloadduration,k .

Besidesthestaticmoisturecontentinthewood,thechangesofthiscontentalsohaveanimpactonsomethewood’sproperties.Astheairhumiditygenerallychangesoverthetimeofayear(de‐pendingontheregion),atimbermemberthatisnotinaprotectedindoorclimate,willgothroughmanycyclesofmoisturechanges,cf.Figure5.4.

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Figure5.4:Meanmoisturecontentinwood(glulam90×100×600) versus time in a barn in Southern Sweden (Åsa)[26,155]

Those changes of moisture content will amongst other things lead to increased creep defor‐mations[26,141].

Avoidinghighmoisturecontentsandmoisturechanges is importanttoensurethatthewood’spropertiesdonotchangefortheworse.Furthermore,decayeffectsmustbeexcludedtoguaranteedurabilityandalonglifetimeofatimberstructure.Toachievethis,somemeasureshavealreadybeenmentionedinthebeginningofthischapter.Ageneraldesignruleistokeepwoodmembersindrysurroundingsorat least toallowwatercoming incontactwiththewoodtorunoffandevaporatewithouthindrances.Itisalsorecommendedtokeepdistancesbetweenwoodmembersandcomponentsmadefromdifferentmaterialstopreventmoisturefromgatheringinthegroovethatcandamagethewood.Averyeffectivemeasuretoprotectwoodencomponentsfromwaterisapplyingalayeronthecomponent(e.g.woodencladding)thatcaneasilybereplaced.

5.1.2. WoodinComparisontoOtherMaterialsNowthatageneralbasisiscreatedconcerningthecharacteristicpropertiesofwood,thisbasisshallbeextendedbycomparingwoodtoothermaterials,namelyreinforcedconcreteandsteel,whichareitsmostimportantcompetitors.

Oneaspectthathasalreadybeenmentionedisthewood’svariabilityandinhomogeneity,whichleads tohigheruncertaintiesconcerning itsmechanical (andother)properties.Both steel andconcretehavemuch lowerorpracticallynosuchvariabilityand inhomogeneity,althoughcon‐crete,becauseitisoftenproduceddirectlyonsite,alsohassomeuncertainties.ThisisdirectlyreflectedinthematerialsafetyfactorsthataredefinedinthedifferentEurocodesforthosethreematerials:γ 1,3forsolidwood7,γ 1,5forconcreteandγ 1,0forsteel.

7Someengineeredwoodproducts,becausetheyhavealowerinhomogeneity,havelowersafetyfactors,e.g.γ 1,2forlaminatedveneerlumber.

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Furthermore,theorthotropyofwoodhasbeenexplained.Whilesteelispurelyisotropic,i.e.itsmechanicalpropertiesarethesameinanydirection,reinforcedconcretefeaturesadifferentkindofanisotropy.Althoughbothitsbasicmaterials,concreteandsteel,areisotropic,thefinalproducthasadistinctiveanisotropydependingonthelayoutofthereinforcement.

Anotherimportantaspectisthefailurebehaviour.Whereaswoodhasaratherbrittlefailurebe‐haviour,concreteandespeciallysteelcandeveloplargeplasticdeformationsbeforefailure.Ontheotherhand,woodhasgoodstressdistributionproperties,whichareadvantageousforcom‐binedloadslikecompressionandbending.

Togiveanideaoftheoverallperformanceandcapacityofthethreematerials,someinterestingpropertiesaresummarisedinTable5.1.

Table5.1:Mechanicalpropertiesofsteel,concreteandwoodincomparison[1]

property steelS355 concreteC30/37 glulamGL24hyieldstrengthf 355N/mm 30 N/mm 24N/mm specificweightγ 78,5kN/m 25 kN/m 3,7kN/m heatconductivityλ 50W/ m ⋅ K 2,3 W/ m ⋅ K 0,12W/ m ⋅ K Young’smodulusE 210000N/mm 33000 N/mm 11600N/mm

Asonecouldalreadyguessfromthepreviousdescriptions,steelissuperiortowoodinmostme‐chanical properties. This canbepartly compensated, however, by thewood’s low self‐weight,whichmakesmore light‐weight,efficientstructurespossible.Thesmallweightcombinedwithgoodelasticityisalsoadvantageousforloadsfromearth‐quakes.Whatstillisachallengeespe‐ciallyinstructureswithlargespans,isthewood’slowYoung’smodulus,whichleadstolargede‐formations(evenifthematerialwouldnotfail).Insuchcases,specialstructuresareneededlikearchedbeamsorlatticegirders.Vibrationsandaninferiorsoundprotectionarefurtherproblemsconnectedtothewood’slowYoung’smodulusandweight.Steelbeams,ontheotherhand,canbeusedforlargerspanswithoutspecialmeasures,despitethesteel’slargeweight.

Oneinterestingpropertybesidesthemechanicalbehaviouristheinsulationcapability.Theheatconductivityofwoodisabout20timessmallerthanthatofconcreteandmorethan400timessmallerthanthatofsteel.Moreover,woodregulatestheclimateinsideabuildingbyadaptingitsmoisturecontent.Consequently,woodcanfulfilmultiplefunctionsinabuilding,notonlyload‐bearingbutalsobuildingphysicalones(and,additionally,architecturalones,asdescribedbefore).

Concerningthedecay,steelandconcretehaveadvantages.But,asexplainedearlier,ifdesignedproperly,decaycanbeprevented,andsteelandconcreterequirespecialmeasuresaswelltoavoidcorrosion,whichcanbeseenasthe“decay”ofsteel.Inreinforcedconcrete,theconcretecoverisnormallydimensionedtoprotectthesteelbarsfromcorrosionfor50years.Steelrequiresexpen‐sivecoatingorgalvanisingwhenexposedtotheweather.

Whenitcomestologisticsandtheerectionofabuilding,thewood’slowself‐weightisagainad‐vantageous.Thisalsomakesahighdegreeofprefabricationpossible,allowingforveryeconomicstructures.Inadditiontothat,woodproductscanrelativelyeasilybeadjustedontheconstructionsite.Here,steelhassomedisadvantages,while(non‐prefabricated)concreteallowsforthehighestdegreeofadaption.

Lookingatecologicalaspects,woodrevealsitsgreatestadvantages.Becauseofthelowweight,lessenergyisneededfortransportanderection.Woodisinfinitelyavailableanddoesnotdamagetheenvironmentifsustainableforestryisapplied.Incontrasttothat,whiletherawmaterialsfor

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steelandconcreteareabundantaswell,theirexploitationisoftenconnectedtoenvironmentaldamages.Whenmanufacturingtimber,thewastewoodcanbeusedtopowerthefactory.Noad‐ditionalenergyisneededwhenusingmodern,efficientpowerproductionwithheatrecovery.Andwhenitcomestotheproductionofthefinalbuildingproduct,timberusesingenerallessenergythanconcreteorsteel[27,26].

Recyclingattheendofthelifetimeofabuildingcaneffectivelyreducethedemandfortherawmaterialsandistodaypossibleforallthreematerials.Therecyclingofsteelismosteffective,whileconcretecanonlybecrushedandusedasaggregatefornewconcreteagain.Itis,however,alsopossibletouseby‐productsfromsteelandpowerproductionlikeslagandflyashfornewconcrete[24,412].Woodcanbereusedforengineeredwoodproductsor,asalastpossibility,burnedandusedasanenergysource.

Sinceecologicalaspectsplayamoreandmoreimportantroleinoursocietyandareoneofthecentralfactorswhenplannersdecidetousewoodforacertainproject,thoseaspectswillbead‐dressedinmoredetailinthenextchapter,focusingagainmoreonthewooditself.Asameanstoanalysetheecologicalaspects,lifecycleassessment(LCA)willbeused.

5.1.3. AspectsfromLifeCycleAssessmentBeforestartingtoanalyseaspectsfromLCA,aquickexplanationofLCAmethodsshallbegiven.“LCAisamethodologyusedtoanalysecomplexprocesseswhichfocusondealingwiththeinputandoutputflowsofmaterials,energyandpollutantstoandfromtheenvironmentfromalifecycleperspective”[24,49].Itsobjectivesare,ontheoneside,toquantifytheenvironmentalpropertiesofaproductorprocess,andontheotherside,toassesspotentialsforimprovingtheproductorprocess[24,49].WithoutknowingmuchmoreaboutLCA,itcanbeguessedthattoquantifyalltheenvironmentalinfluencesofaproductinonenumberoreveninseveralnumbersispracticallyimpossible.TheresultsofanLCAanalysisareneverexactlycorrectbecauseofthehighcomplexityoftheprocessesandbecauseitisnotpossibletopredictthefutureaccurately.ThismustbekeptinmindwheninterpretingLCAresults.Hence,LCAisespeciallysuitedtocomparedifferentalter‐nativesbymeansofrelativeresults,notsomuchtoobtainabsoluteresultsforoneproductorprocess.Lookingattherelativeresults,LCAgivescorrectresultsalmosteverytime[24,417‐418].

Astrongtoolfortheinterpretationoftheresultsisanevaluationmatrix,whichbalancesenviron‐mental,economicandsocialfactorse.g.fortheselectionofamaterialforaspecificproject[24,44].(Asimilarmatrixwillbeusedattheendofthismasterthesisinchapter7.2tocomparethethreedifferentconstructionmethodsthatwillbedesignedandanalysed,extendingthetoolbytechnicalaspects.)

ImportantaspectsinanLCAstudyforbuildingproductsare

resourceefficiency, energyefficiency, GHGemissions, pollutionpreventionand wastemanagementaftertheendofthelifetime[24,421].

Theresourceefficiencyincludestheexploitationoftherawmaterialsaswellasreuseandrecy‐cling.

Theenergyefficiencyisabigfactorwhichincludesalltherequiredenergyfromdepletingtherawmaterials,tomanufacturing,transportingandmaintainingtheproduct,alsocalledembodieden‐ergy. Influencing factors are amongst others the lifetime of a product and the amount of

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maintenancethatisrequired.Toensurealonglifetime,measuresmustbetakentopreservethewood,ashasalreadybeenexplained.Theembodiedenergyrepresentsnormallyaround10to60%ofthetotalenergyusedduringthewholelifetimeofabuilding,whichincludestheenergyforheatingandusingthebuilding.Asbuildingsbecomemoreenergy‐efficientconcerningheatingandtheuseofelectricity,theembodiedenergyinthematerialsbecomesproportionallymoreim‐portant[24,421].

GHGemissionsisanothercentralaspectforthewholelifetimeofabuilding.Woodasaconstruc‐tionmaterialcanbecarbonneutralorevencarbonnegativewithgoodrecycling[24,418],be‐causecarbonisstoredinthewood.However,takingintoconsiderationaspectsfromafullLCA,studiesshowedthatthetotalamountofavoidedcarbonisactually2,1timeshigherthanthecar‐bonstoredinthewooditself.Thisisduetolesscarbonemissionsintheindustrialprocessescom‐paredtoothermaterialsandusageofby‐productsfromthemanufacturingofwoodproductsasbiofueltoreplacefossilfuels[24,326].Concerningtheforestry,somestudiesfoundthatintensiveforestryhaslessCO2emissionsthantraditionalforestry.Thisisbecausetheproductivityismuchhigher,thereforemoreCO2canbestored.Nonetheless,itmustbekeptinmindthatCO2isnottheonlyfactorforLCAandanintensiveforestrycanproduceconflictswithotheraspects,e.g. thebiodiversity[27,27].

Figure5.5showsthecarboncontentandtheembodiedenergyofsomeselectedbuildingmateri‐als.Itmustbenotedthatthecarbonstoredinsidethewoodisnotconsideredinthepresentedvalues.Moreover,thevaluesaregivenrelatedto1kgofthecorrespondingmaterial,butdifferentamountsareneededfordifferentmaterialsinthesamestructure.Theratioofthetotalrequiredweightofmaterialbetweenawoodenstructureandacomparableconcretestructurecanbeupto1:5[24,413].

Figure5.5:Embodiedenergyandcarboncontentofdifferentbuildingmaterialsbasedon[24,415]

Pollutionpreventionconcernsthereleaseofpollutinggasesduringboththemanufacturingpro‐cessandtheuseofaproduct[24,45‐46].

Withthewastemanagement,potentiallyincludingrecycling,thecycleclosesagain.

Buildingsareverycomplexstructuressincematerialsandmembersgenerallyfulfilseveralfunc‐tions.Becauseofthatandbecausedifferentmaterialsrequiredifferentquantitiestofulfilaspecific

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function,thematerialscannotbedirectlycompared.Moreover,allthecomponentsinsideabuild‐inginfluenceeachotherinsomewayoranother.ThebestwaytoperformanLCAanalysisisthere‐foretocomparewholebuildingsthathavethesamefunctionality.Conclusionsfromvarioussuchstudiesshowthatwoodenconstructionshaveingenerallowerenvironmentalimpactthanequiv‐alentstructuresusingnon‐woodmaterials[24,321].

Besidesthechoiceofmaterial,structuresthatcaneasilybedisassembledareadvantageousfromanLCApointofview,becauseit improvesrecyclingcapabilities. Inwoodbuildingsthiscanbeachievedbypreferablyusingbolts insteadofadhesives.Monolithicconcretestructures,ontheotherhand,havetobedemolishedforrecycling[24,418].

Acontroversialpointconcerningmodernwoodproducts istherollofprefabrication.Prefabri‐catedproductshavealowerenvironmentalimpactduringthemanufacturing,theconstructionandattheendoftheirlife,butthetransportationhasamuchhigherimpact[24,438].Thedistancebetweenthebuildingsiteandthefactoryiscritical[24,452].Thedistancesaregenerallymuchlarger for specially manufactured products than for individual standard components. This ishighlydependentonthespecificproject.

Tosumup,anexampleofafullLCAstudyconductedin2000byBörjessonandGustavssonshallbegiven.ItcomparedthenetCO2emissionsoftwosimilarfour‐storeyapartmentbuildings,oneinSwedenfeaturingawoodframestructure,theotherinHelsinkimadefromaconcreteframestructure.Theresultsshowedthatthewoodconstructionreleased30to133kg/m²lessCO2intotheatmosphere.Lateradditionalresearchconfirmedthegeneralresultsandfoundthatconcretestructuresneed16to17%moretotalenergythanwoodenstructures.Thoseresultsare,however,onlytruefornorthernEurope,wherewoodisavailablelocally[24,414‐416].

Lookingintothefuture,woodstillhasunusedpotentials.Onepotentialistoincreaserecyclingandtousemorewastestoreplacefossilfuelsforenergyorheatproduction.E.g.inNorway,onlyabout5%ofthewoodfrombuildingsisrecycled,70%isusedforenergyproduction,9%issendtolandfills,2%iscompostedand17%isusedforunknownintentions[27,44].Toachieveim‐provements,differentindustriesliketheforestry,energy,buildingandthewasteindustrymustworktogether[27,26].Wastes,hithertolittleusedspeciesandrecycledmaterialcanwellbeusedfornewengineeredwoodproducts,whichisthetopicofthenextchapter.

5.1.4. EngineeredWoodProductsEngineeredwoodproductsare todayalreadyan importantpartof thesupportingstructure inmostbuildings.Theiradvantagesareobvious:Whereassolidwoodisonlyavailableintheformoflinearmembersandthecross‐sectionareaislimitedbythesizeofthetreetrunk,engineeredwoodproductsallowarbitrarycross‐sectionsandalsotwo‐dimensionalmemberslikeplates.Moreover,thepropertiesofthewoodcanbeimprovedpurposefully.

Engineeredwoodproductsareingeneralmadefromboards,veneers,strandsandflakesofwoodthatarejoinedtogetherwiththeuseofadhesives.Thefinalproductscanbeofvariableform,e.g.boardsortimber‐likebeams.Thefinalproductsaremuchmorehomogeneousthantheinitialsolidwood,knotsandotherdefectscanbeeliminatedoratleastevenlyarrangedoverthewholecom‐ponent[26,82‐83].

Themanufacturingofengineeredwoodproductsrisestheefficiencyofthetimberproductionbe‐causeitalsoallowstheuseofpartsfromtheinitiallogsthatcannotbeusedforsolidwoodbeams,likethebranchesandthewastefromtheproductionofsolidwood.Thisallowsforamoreefficientuseofthewood,comparedtothemanufacturingoftraditionalsolid‐woodmembers,whichhasarelativelyhighdegreeofwastebecauserectangularcross‐sectionsarecutfromaroundlog.

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Therearemanydifferentengineeredwoodproductsavailabletoday,andmorearebeingdevel‐oped.

Oneofthemostwidelyusedengineeredwoodproductsisgluedlaminatedtimber(glulam).Glu‐lamismadeofseveralplanksthataregluedtogetherontopofeachother,formingacross‐sectionthatcanbeashighas2m[26,7].Withglulamitispossibletoovercomeoneofthesolidwood’slimitingfactors,whichisthesize.Thebiggestpossibledimensionforsolidwoodisabout300mm,thusthemaximumpossiblespanofatimberbeaminpracticeisabout5to7m[26,7].Glulamallowspracticallyarbitrarycross‐sectionsforspansofupto100m[26,8].Usingfinger joints,beamsoftheoreticallyanylengthcanbeproduced.Duetotransportationlimitations,however,themaximum length in practice is limited to 16 to 20m [26, 68]. It can beproduced in bothstraightandcurvedforms,sothate.g.wholearchescanbeproducedasonesolidwoodcompo‐nent.

Aswithotherengineeredwoodproducts,glulamhasenhancedmaterialpropertiesincomparisontosolidwood,thestrengthandstiffnessareincreased,whilethevariabilityissmaller[26,69],thisisdepictedinFigure5.6.

Figure5.6:Comparisonofthefrequencydistributionofthestrengthofglulamandsolidwood[26,19]

Sincetheheightofthecross‐sectionisnormallymuchhigherthanitsthickness,stabilityfailuremodessuchaslateraltorsionalbucklingareofhigherimportanceforglulamthanforsolidwood.

Adifferentengineeredwoodproductisparallelstrandlumber(PSL),whichwasdevelopedwiththeideatoutiliseforestwastessuchasbranches.Itismadefromlong,thinstrandsofwoodwithalengthofupto2,4mandcanbemanufacturedwithcross‐sectionsofupto280×480mm,whichliesinthesamerangeasthepossiblecross‐sectionswithsolidwood.Itisthereforemainlyusedasasubstituteforsolidwood,withthebenefitsthatitmakestheforestrymoreefficientandhasahigherbendingstrengthaswellaslessshrinkageandsplittingcomparedtosolidwood[26,88‐91].

Laminatedveneerlumber(LVL)ismadefromlayersofwoodveneerthataregluedtogether,allwith the orientation of the grain along the long axis of the member. Cross‐sections of up to90×1200mmarepossible,thelengthcanbe25m.Itcanbeusedforbeamsinsmallandbigcon‐structionsandisalsocommonlyusedforflangesofI‐joists[26,93‐95].

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I‐joistsarebendingmemberswithamoreefficientstructuralshape,becausethematerialiscon‐centratedintheouterregionsofthecross‐section,theflanges.ThosearecommonlymadefromsolidwoodorLVL.Thewebistypicallymadefromorientedstrandboard(OSB)orplywoodpan‐els,i.e.woodenpanelswithahighshearcapacity[26,97].OnedrawbackofI‐joistsistheirvul‐nerabilitytofirebecauseofthethinweb.

Forplywood,layersofwoodveneeraregluedtogether,butunlikeforLVL,thoselayersarerotatedby90°toeachother,formingaboardthathasgoodbearingcapacityinbothdirectionsandamoreisotropicbehaviour.Orientedstrandboard (OSB) ismade fromsmall strandsofunderutilisedwoodspecies.Bothproductscanbeusedassheathingforwallsandfloors,wheretheyprovidestiffeningofthecomponentandactascoveratthesametime.OSB,however,hasthehighestemis‐sionsofvolatileorganiccompounds(VOC)ofallengineeredwoodproducts[27,35]andshouldthereforebeusedwithcareinresidentialbuildings.

Amorerecentlydevelopedengineeredwoodproductiscross‐laminatedtimber(CLT),whichisamasstimberproduct.Itconsistsoflayersofparallelboards,10to35mmthick,whicharethengluedtogetherat90°toeachothertoformbothmassiveplatesandmassivememberswithlargecross‐sections.Wherethebreadthofglulamcross‐sectionsislimitedbythebreadthoftheindi‐vidualboards,membersmadeofcross‐laminatedboardscanhavearbitrarydimensionsinbothdirections.Thecross‐laminationleadstoamorehomogenousbehaviourcomparedtosolidwood.Italsoreducestheshrinkageandswellingtoaninsignificantamount[20,52‐55].Furthermore,CLTpanelsareingeneralairtight(dependingonthespecificproduct)[21,115].Theyarethere‐foremainlyusedforfloorsandwalls,wheretheycanfulfilthefunctionofanairtightmembraneinadditiontotheloadbearingandthestiffening.CLTistodayreadilyavailableinpracticallyallpossibledimensions.

Besidesthemechanicalproperties,therearealsonoticeablepricedifferences.Althougheconomicaspectsarenotwithinthescopeofthismasterthesis,Table5.2givesanideaofthepricediffer‐ences,whichwillofcourseplayaroleintheplanningofatimberbuilding.

Table5.2:Pricesofsomeselectedengineeredwoodproductsincomparisontosolidwood[20,51]

material pricesolidwood 300–400 €/m³glulam 1000 €/m³parallelstrandlumber 1500 €/m³

Acentraldrawbackofalltheengineeredwoodproductsisthattheyusesyntheticaladhesives.Thosearetypicallyurea‐orphenol‐formaldehydewhicharemadefromnon‐renewablemineraloil.Moreover,theyemitformaldehydeduringtheirlifetime(indifferentamounts,dependingontheproduct).Newdevelopmentsaimatreducingtheuseofadhesivesorusingnaturalalternativessuchaslignin‐basedadhesives[24,317].

Inthefuture,whenenvironmentalrestrictionsmayleadtolessavailablelarge‐sizesolidwood,engineeredwoodproductswillbecomemore important[26,83].Today,solidwoodisalreadymeetingits limitswhenitcomestostructureslikemulti‐storeytimberbuildings.ProductslikeglulamandCLTopenupacompletelynewwayoftimberdesign.Itwillbeseeninchapter6.2thatnoneoftheanalysedstructuresusessolidwoodasacentralstructuralmaterialbecauselargercross‐sectionsarerequiredthanwhatispossiblewithsolidwood.Ithasalsobeenexplainedhowdeformationsduetocompressionperpendiculartothegrainormoisturechangescanbedecisive

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formulti‐storeybuildings.Inthisregard,thedescribedengineeredwoodproductsaresuperiortosolidwood,too.

5.2. TimberConnectionsThemissing linkbeforemovingon todiscussingentire timberstructuresare theconnections.Connections are ofmajor importance for timber constructions and especially formulti‐storeybuildingsbecauseofthehighloads.Evaluationofdamagedtimberbuildingsafterextremewindshowedthatconnectionsareoneofthemajorweakpoints[28,81].

Thereare,ingeneral,twopossibilitiestoformconnections:

gluedconnectionsor connectionswithdowel‐typefasteners(nails,bolts,screws,dowels,commonlymadeof

steel)[26,303].

Whilegluedconnectionsaremainlyappliedonprefabricatedcomponents,e.g.forfingerjointsinglulamelements,dowel‐typefastenersarewellsuitedforanyon‐siteassembly.Sincetheproper‐tiesofgluedconnectionsaremostofthetimealreadyincludedinthedescriptionofthepropertiesofthecorrespondingengineeredwoodproduct,thefollowingdiscussionswillfocusmoreoncon‐nectionsusingfasteners.Nonetheless,itshallbenotedthatnewtechniquesarebeingdevelopedthatalsoallowtheeconomicmanufactureofgluedjointson‐site.Table5.3summarisesthemainadvantagesanddisadvantagesofgluedconnections.

Table5.3:Advantagesanddisadvantagesofgluedconnections[26,334]

advantages disadvantages/problems higherrigidity canbehighlyautomated makesspecialconnectionspossible,

e.g.fingerjoints thecross‐sectionisonlyminimally

damaged,ornotatall

moresensitivetounskilledmanufac‐ture

lowerinherentredundancy ingeneral,noon‐sitemanufacture

possible oftenverybrittlebehaviour emissionofVOC complexmechanicalbehaviour,stress

peaks

Focusingonconnectionswithdowel‐typefastenersfromnowon,firstsomegeneralaspectswillbeexplainedbeforelookingatthedifferenttypesofconnectionsinmoredetail.

Resultsofexperimentsshowcorrelationsbetweenseveralparametersandthecapacityorfailurebehaviouroftheconnection.

Oneimportantparameteristheslenderness,i.e.therationbetweenthesidewidthofthewoodmemberandthedoweldiameter,whichleadstodifferentfailuremodesandthusverydifferentloadbearingcapacities,seeFigure5.7.Alowslendernessgenerallymeansthattherearenoplasticdeformationsinthedowel,onlyinthewood.Amediumslendernessleadstooneplastichingeinthedowel,whileforahighslendernesssecondaryplastichingesdevelop[17,68‐69].Largerwoodthicknessesgenerallyleadtoahighermaximumload,ahigherstiffnessandlargerdeformations.

Case/Materials


Figure5.7:Generalfailuremodesofatimberconnectionwitha)lowslenderness,b)mediumslendernessandc)highslenderness[17,68]

Moreover,thereisalinearcorrelationbetweenthedensityofthewoodandthemaximumloadandstiffnessoftheconnection.Aconnectionwithhighdensitywoodischaracterisedbyahighercapacity,lessdeformationsinthedirectionofthegrainandamorebrittlefailurebehaviourwithsplittingperpendiculartothegrain(aswasexplainedinchapter5.1.1,thetensilestrengthper‐pendiculartothegraindoesnotchangemuchevenforstrongwoodandthusbecomesdecisiveinanotherwisehighstrengthconnection).Thespacingbetweenthefasteners inamulti‐fastenerconnectionandtheirenddistancesalsohaveastronginfluenceonthecapacityofthewoodsincetoosmalldistancesprovoketheriskofsplitting[17,70‐74].

Johansendevelopedayieldtheorythatcanbeusedtodeterminethefailuremodeandtocalculatetheresistanceofawoodconnection,althoughitisnotsuitedtodeterminetheload‐slipbehaviour.Accordingtothistheory,therearethreemainaspectsthateffectthestrengthofaconnection:thebendingcapacityofthedowel,theembeddingcapacityofthewoodorengineeredwoodproductandthewithdrawalresistanceofthedowel.Theembeddingstrengthdependsmainlyontheden‐sityofthewood[26,316‐322]

Today’sdesignrulesforconnectionsine.g.theEC5standardaremainlybasedonempiricalin‐vestigationsandtheJohansen‐theory.ComparingthefindingsoftheexperimentswithcalculatedvaluesaccordingtoEC5revealsagoodaccordanceforthestiffnessandconservativevaluesforthestrengthformediumslendernessconnections.Forsmallslenderness,EC5overestimatesthestiffnessandthestrength,whileforhighslenderness,EC5underestimatesthestiffnessbutover‐estimatesthestrengthagain[17,76‐79],cf.Figure5.8andFigure5.9.

Case/Materials


Figure5.8:Comparisonofexperimentallydeterminedstiffnessesofselectedtestswithcorre‐spondingdesignvaluesfromEC5forspecimenswithdifferentslenderness[17,77]

Figure5.9:ComparisonofstrengthofselectedtestswithdesignvaluesfromEC5[17,77]

Becauseofthosediscrepancies,theapplicabilityoftheEC5rulesforconnectionsislimitedandanoptimiseddesignisdifficult[17,67].Sinceconnectionsareacentralpartofanytimberstructure,especiallyofmulti‐storeybuildings,onesectioninchapter6willbededicatedtoanalysingase‐lectedconnectioninoneoftheinvestigatedstructuresusingFEMtogainabetterunderstandingofitsbehaviour.

Therestofthischapterwillfocusonthecharacteristicsofthedifferentconnectionmethodsusingdowel‐typefasteners.

Thefirsttypeofconnectionthatwillbediscussedaretraditionaltimberjoints,someexamplesareshowninFigure5.10.

Case/Materials


Figure5.10:Examplesoftraditionaltimberjoints[21,58]

Theirmaincharacteristicisthattheydonotusemuchsteel,fastenersareonlyrequiredtosecurethe individual componentsagainstunwantedmovements.Those connections thereforehaveagoodfireresistance.Ontheotherhand,theycanhaveacomplicatedgeometry,especiallyiften‐sionforcesmustbetransferred.Withtoday’smodernCNCwood‐workingmachines,however,itispossibleagaintomanufacturesuchjointseconomically[26,304‐305].

Rightafterthetraditionaltimberjoints,nailshavebeenusedforalongwhileintimberbuildings.Todaytheyarerelativelycheap,oftennopre‐drillingisneeded,andmanydifferentconnectionsarepossible [26,306‐307],cf.Figure5.11.Onedisadvantage is that theyhavearelatively lowloadbearingcapacity,whichlimitstheirapplicabilityespeciallyinmulti‐storeytimberbuildings.

Figure5.11:Examplesofnailedjoints[26,306]

Thisiswhereboltsanddowelscomein,theycanbeusedforhigh‐strengthconnectionsinbigandcomplexstructures.Bothfastenersarenormallymadefrommetal,withmuchlargerdiametersthannails(acommonboltise.g.anM20‐boltwith20mmdiameter).Boltsarethreadedandhaveacounternutandwashers,whiledowelshaveasmoothsurfaceandarecompletelyhiddeninsidethewoodmember,cf.Figure5.12.

Case/Materials


Figure5.12:Steeldowelsandbolts[1,9.44]

Thelargediametersrequiresthewoodtobepre‐drilledwhichmakessuchconnectionsmorela‐bour‐intensive[26,307].Ontheotherhand,whenprefabricationisused,theholescanalreadybeproducedinthefactory.Thechoiceofdiametereffectstheloadbearingcapacityandbehaviour,largerdiametersleadtohigheracceptableloadsbutalsoabrittlebehaviourduetosplitting(cf.explanationsconcerningtheslendernessofaconnectionabove).ExamplesoftypicalapplicationsfordowelsorboltsareillustratedinFigure5.13.

Figure5.13:Examplesofjointsusingboltsordowels[26,308]

Arathernewdevelopmentarescrewjoints,withthescrewsbeingsubjectedtotensileloads.Thisisabigdifferencetoallothermethodsdescribedsofar,whichrelyontheshearcapacityofthefasteners.Modernhand‐heldtoolstoeasilydrivescrewsintothewoodhaveledtoscrewsmoreandmorereplacingnails.Atthesametime,theycanbedisassembledmoreeasily[26,307‐308].Moreover,modernfullythreaded,self‐tappingscrewsdonotrequirepre‐drilling[26,328].Theself‐tappingscrewsmakenew,effectiveconnectionspossible,someexamplesareshowninFigure5.14.

Case/Materials


Figure5.14:Examplesofapplicationsforfullythreadedscrews[1,9.55]

Adifferentpossibleapplicationoffullythreadedscrewsisthereinforcementofwoodenmembersperpendiculartothegrain.Thisensuresaductilebehaviouroftheconnectionandincreasestheloadbearingcapacity, sincea failureperpendicular to thegrain, i.e. splitting, isprevented [26,311‐313][26,317].ThepositiveeffectsofthisreinforcementarenotcoveredbytheJohansen‐theory,though,andarethereforenotconsideredintheEC5yet[17,79].

AnotherdrawbackoftheJohansen‐theoryandtheregulationsintheEC5isthatthetheoryhasbeendevelopedonlyforsinglefasteners.Thedesignofconnectionswithseveralfastenersisbasedonthepropertiesoftheconnectionwithonefastener,consideringaneffectivenumberoffasten‐ers,whichrespectsamongstotherthingsthespacingbetweenthefasteners.Formulti‐fastenerconnections,reinforcementperpendiculartothegrainisespeciallyinteresting.Withreinforce‐ment,groupeffectscanbeexcluded,sothattheload‐carryingcapacityoftheconnectioncanbeassumedtobethesumofthecapacitiesofallfasteners[26,322‐324].ProofforthevastlydifferentloadbearingbehaviourisdepictedinFigure5.15.Notonlyistheacceptableloadoftheconnectionhigher,buttheductilityisincreasedstrongly,too,whichcanbeseenfromthelargedeformationsthatoccurbeforetheconnectionfails.

Figure5.15:Loadbearingbehaviourofareinforcedconnectionincomparisontoanon‐reinforcedconnection[26,324]

Whenusing connectionswith several fasteners, it is important to allow formoisture inducedmovements.Connectionswherethewoodisrigidlyfixedatmorethanoneconnectorshouldbe

Case/Materials


avoidedbecausethiscanleadtocrackswhenshrinkageoccursduetochangesinthemoisturecontent[26,160].

Withthedescriptionofthebehaviourofmulti‐fastenerconnections,thechapteraboutconnec‐tionsiscompleted.Whilethedescriptionsanddiscussionssofardealtwithwoodingeneral,orspecificproductsandindividualcomponentsandconnections,thenextstepistolookatentiretimberstructuresthatconsistofthosecomponents.Inthenextchapter,thedifferencesbetweenthedifferentstructuralmethodsandtheirvariantsaredescribed,givinganideaofwhichmethodsarebestused inwhichcases.Basedonthose findings, thedesignanalysis inchapter6willbeplannedandconducted.

5.3. TimberStructures5.3.1. TimberFraming

Ingeneral,twomainconstructionmethodsaredistinguished.Timberframingstructures,featur‐ingone‐dimensionalelementsinthemainloadbearingstructure,willbeexaminedinthischapter.Masstimberstructures,whichusemasstimbermaterialslikeCLT,willbethetopicofthefollow‐ingchapter.

Structuresthatuseatimberframingmethodaregenerallycharacterisedbyanopenloadbearingstructure,aclearforcedistributionandacleardistinctionbetweentheloadbearingfunction,thestiffeningfunctionandtheroomseparation.Theloadsareconcentratedintheindividualmem‐bers,whichthuscanbeadaptedaccordingly,concerninge.g.thecross‐section.Connectionsaremorechallengingthanformasstimberstructuresbecauseofthehighconcentratedloadsandbe‐comethereforeoftendecisiveforthedimensioningofacomponent.

Thefollowingvariantswillbediscussedinthischapter:

traditionalframeconstruction, panelconstruction, balloonconstructionand modernframeconstruction.

ThetraditionalframeconstructionspreadinEuropearoundtheyear1700(cf.chapter2.1)andistodayoftenassociatedwithmedievaltimberhouses.Theframeworkconsistsofhorizontalandverticalbeamsaswellasdiagonalsforthestabilityandstiffening,seeFigure5.16.Theframeworkisoftenvisiblefromtheoutsidewiththecavitiesfilledwithe.g.brickwork.Thismethodismainlyusedforsmallone‐ortwo‐storeybuildings,theerectionoflargerbuildingsbecomesverycostly[21,55].

Case/Materials


Figure5.16:Traditionalframeconstruction[21,56]

ThepanelconstructionisanenhancementofthismethodandisillustratedinFigure5.17(left).

Figure5.17:Panelconstruction(left)andballoonconstruction(right)[21,60‐61]

ItreplacesthediagonalswithwoodenpanelsmadeofplywoodorOSBassheathing.Thisallowsinsulationtobeplaced in thesame layeras the loadbearingstructure, in‐betweenthecloselyspacedverticalmembers,thestuds.Thebigadvantageofthiskindofstructureisthebeneficialwaytheindividualelementsworktogether,becausethesheathingpreventsthestudsfrombuck‐linginthedirectionoftheirweakaxis.Thismakesveryslenderconstructionpossible,thepanelconstructionisthereforeprobablythemoststructurallyefficientsystem.

Thewallstudsareashighasonestorey,whichmakesthismethodhighlysuitableforprefabrica‐tion.Wallsandfloorsorevenentireroomsormodulescanbeprefabricated.Thisalsoleadstoasimpleerection,nospecialequipmentisrequired.Fromastructuralpointofview,prefabricatedwallpanelswithnailedsheathingarehighlyredundant.Arelativelylowgradeoftimbercanbeused[26,386].

Thepanel construction is commonlyused for smallerbuildingswithone to threestoreys.Formulti‐storeybuildings,thewallsneedhighershearresistanceandverticalloadbearingcapacitytowithstandthehighwindloadsandverticalloadsfromtheself‐weightaswellastheliveload.

Case/Materials


Newdevelopments to increase the shear capacityofwalls includebrace systemsbetween thestudsoradditionalsheathing[26,404].

Theballoonconstructionissimilartothepanelconstruction,withthemaindifferencethatthewallstudsgooverthewholeheightofthebuildingoratleastoverseveralstoreys(cf.Figure5.17(right)).Verticallycontinuousmembersarealwaysadvantageous inmulti‐storeybuildingsbe‐causetheyleadtolessdeformationsduetoshrinkageandgravityloads.Ontheotherhand,pre‐fabricationisnolongerpossibleinthesamedegreeasforthepanelconstruction[26,238][21,60‐61].

Finally,themodernframeconstructionisalsobasedonthetraditionalframeconstruction,buttakesthetimberframingtothenextlevel.AnexampleofamodernframeconstructionisdepictedinFigure5.18.

Figure5.18:Exampleofamodernframeconstruction:schoolinWil,Switzerland[21,86]

In contrast to the previously describedmethods, themodern frame construction features bigspans,withtheloadbearingcomponentsbeingwidelyspreadonalarge,regulargrid.Theload‐bearingstructureconsistsofasystemofcolumns,mainandsecondarybeams.Thewallsdonotcarryanyloads,thehorizontalloadsarerathertransferredbytheverticalmembersviabendingorvialarge‐spandiagonals.Thisopensupnewarchitecturalpossibilitieslikebigwindows.Italsooffersmaximumfreedomwhenitcomestosubdividingtheinteriorintorooms,changesarepos‐siblewithoutaffectingthestructure.Besides,theenclosingenvelopeformedbythewallscanbearrangedoutsideoftheloadcarryingstructure.Thishasthreemainadvantages:Firstly,theloadcarryingstructureandenclosingenvelopearecompletelyindependent,whichallowsforeasycon‐nections.Secondly,thewallsactasprotectionoftheloadcarryingstructurefromtheweather,andthirdly,theloadcarryingstructurestaysvisiblefromtheinside.

Forthemodernframeconstruction, largercross‐sectionsarerequired,therefore,glulamisthepreferredmaterial.Animportantpartoftheconstructionaretheconnectionsbetweenthecol‐umnsandthemainbeams.Therearedifferentpossibilities,thedecisionwilldependonproject‐specificstructuralrequirementsandarchitecturalaspects.Onecanusecontinuouscolumnswithtwo‐partcontinuousbeamsattachedtothesidesofthecolumns,orwithsimplysupportedbeamsin‐betweenthecolumns,attachedtothemwiththeirfrontends.Anotherpossibilityistousetwo‐

Case/Materials


partcolumnsorforkedcolumnswiththebeamsin‐between[21,86‐94].Tosumup,themodernframeconstructionishighlysuitedformulti‐storeybuildings.

5.3.2. MassTimberMasstimberconstructionsconsistoftwo‐dimensionalcomponents,i.e.wallsthatcarrytheverti‐calloadsandtheshear,andfloorswhichaccountforthehorizontalloaddistribution.Incompari‐sontoframeconstructions,masstimberconstructionshaveamorecomplexbehaviour.Thisisbecausethecomponentsperformdifferentfunctionsatonce,liketheloadbearing,thestiffeningandtheroomseparation.The loadsaremoredistributedandthereforegenerally lower.Asidefromthepurelystructuralproperties,masstimberisalsocharacterisedbyahigherweightwhichleadstoabettersoundprotection.Thefiresafety is increased,too,sincetwo‐dimensionalele‐mentsareonlyaffectedbythefireononeside,insteadofonuptoallfoursidesforone‐dimen‐sionalelements.

Thedifferentconstructionmethodsusingmasstimberthatwillbeexaminedinthischapterare

logconstructions, stackedplankconstructionsand CLT‐constructions.

Thelogconstructionhasalreadybeenmentionedinchapter2.1concerningthehistoricaldevel‐opmentinNorway.Itisoneoftheoldestmethodsandisstillinuse,althoughinmodifiedform.Anoverviewoverdifferentvariantsof the logconstructionareshowninFigure5.19,withtheoldestonesontheleftandmorerecentdevelopmentstotheright.Anyofthoselogconstructionsconsistsoflogsthatarehorizontallystackedontopofeachother.Thethirdonefromtherightshowsaprefabricatedsandwichelement.Thenexttwoarethermallyinsulatedlogwallswhichareassembledonsite.

Figure5.19:Differentlogconstructionvariants[21,53]

Thebiggestproblemwiththelogconstructionisthatlargecompressivestressesoccurperpen‐diculartothegrain.Asexplainedearlier,thisleadstohighsettling,about25mmperstorey,whichiswhylogconstructionarenotsuitedformulti‐storeybuildings[21,50‐53].

Adifferentmasstimbervariantisthestackedplankconstruction,whereplankswiththicknessesbetween20and50mmarestackedverticallynexttoeachothertoformwallsorhorizontallynexttoeachotherforfloors,cf.Figure5.20.Theplanksareconnectedwitheachotherontheflatsideswitheitheradhesivesorwithmetalfastenerssuchasnailsordowels.Woodenhardwooddowelscanalsobeused.Whiletheplanksthemselvesprovidethecompressionorbendingstrength,theconnection(eithertheglueorthefasteners)mustbedesignedfortheshear.Bothprefabrication

Case/Materials


or fabricationonsitearepossible.Thethicknessof thewallor floorequalsthebreadthof theplanksandiscommonlybetween80and240mm[21,122].

Figure5.20:Cornerdetailofastackedplankconstruction[21,122]

Inasimilarfashion,glulambeamscanbeusedtoformmassivewallsandfloors.Theindividualbeamsarethenjoinedusingatongueandgrooveconnection[21,176].

Finally,today’smostimportantmassivetimbermethodistheCLTconstruction.ThepropertiesofCLTanditsadvantagescomparedtosolidwoodhavealreadybeendiscussedinchapter5.1.4.Incontrasttotheothermassivetimbermethods,theCLTelementstakeonallnecessarystructuralfunctions inonesingleelement.As floorelements theyalsoallowbiaxial loadcarrying,whichmakesmoreeffectivestructurespossible.CLTelementsareexclusivelyprefabricatedandoftenadaptedtothespecificprojectconcerningopeningsforwindowsortechnicalinstallations.Theassemblyonsiteisthereforeverysimple,onlyaminimumofconnectionsisrequired.AnexampleofaCLT‐constructionisshowninFigure5.21.

Case/Materials


Figure5.21:ExampleofaCLT‐construction:evangelicchurchinRegensburg,Germany[5]

5.4. NewDevelopmentsInthepreviouschaptersaboutthetimberdesignbasics,boththebasictimbermaterialsandprod‐ucts,theconnectionstojointhoseproductsandfinallywholetimberstructureshavebeendis‐cussed.Tocompletethischapter,asmalloutlookintothefutureofthetimberdesignshallbegivenbyexaminingtoday’sresearchandnewdevelopments.

Inaccordancewiththestructureofthepreviouschapters,firstsomenewwoodenmaterialsorproductsshallbedescribed,followedbynewconnectiontechnologiesandnewlydevelopedstruc‐turalmethods.

Onenewmaterialismouldedwood,whichismadefromsolidwoodthatiscompressedbyabout30%,thencutintopoles,whichcanfinallybegluedtogetheragaintoformmanydifferentshapes.Withthistechnique,e.g.circularhollowtubecross‐sectionsbecomepossible.Thegoalistoman‐ufacturehighlyefficientshapesinthestyleofsteelcross‐sections[20,28].

Anothernewmaterialcanbemanufacturedbypressuretreatmentofsolidwoodand iscalledpressedwood.Thebasicsolidwoodisheatedto130°Candcompressedat5MPa.Thus,thecross‐sectionisreducedbyabout50%byeliminatingmostofthepores.Thetensileandcompressivestrengthsparallelwiththegrainaredoubled,thebendingstrengthincreasesbyafactorof2,5andtheshearstrengthbya factorof1,7.Someof thedisadvantagesthatarestillbeingworkedonincludeahigherriskofsplittingandlessbeneficialpropertiesconcerninggluedjoints[20,26‐28].

Connectionsaremaybethefieldoftimberdesignwheremostinnovationsaredevelopedtoday.Differentmanufacturersbringmanynewproductsontothemarket,aselectionshallbepresentedhere.Thewaysthatalreadyestablishedtimberconnectionsaredesignedandusedalsochange.

Diagonalscrewshavealreadybeenmentionedandareagoodexampleofhowalreadyestablishedconnectorsareusedinnewways.Sincetheyaresubjectedtotensioninsteadofshear,theload‐bearingismuchmoreeffective.Theycanevenbeusedtoconnecttwomembersthatdonottoucheachother,e.g.becausethereisathinlayerofinsulationbetweenthem[20,16].

Theenvironmentalproblemswithsyntheticadhesiveshavealsobeendiscussed.Theresearchfo‐cuses not only on usingmore natural substances but also on optimising the time it takes to

Case/Materials


manufacturesuchaconnection.Today’sstandardgluesneedabout20minutesopentime(thetimebetweentheapplicationoftheadhesiveandthejoiningofthetwocomponents),15minutespresstime(whenthecrampingpressureisapplied),andonlyaveryshortrestingtimeafterwards.Newpolyurethaneadhesivesonlyneed5minutesopentimeand2minutespresstime,whichal‐lowsforamoreproductivemanufacturingandmakesthemanufacturingofgluedjointsonsitepossible[20,17].Anexampleofaproductthatisalreadyavailableistheon‐sitefingerjointde‐velopedbyHESS[6].

Stillunderdevelopmentaregluedconnectionsthatdonotuseartificialadhesivesatall,butrathermakeuseofthewood’sownglue,thelignin.Thismethodiscalledwoodwelding.Applyingfric‐tionalheat,thelignininsidethewoodliquifiesattemperaturesabove200°Candcanthenbeusedtogluecomponentstogether.Ithardensinjustafewseconds[20,24‐25].

Glued‐insteeltubesandsteelplatesareconnectorsthatcanbeusedfornewkindsofjoints.Thesteeltubesarearound50mmindiameterand125mmlongandaregluedintothewoodparalleltothegrain,whichallowsforanoptimalloadtransferadaptedtothewoodscharacteristicstruc‐ture.Steelplatesworkliketongueandgroovejointsandcanbeassembledonsite,securedwithbolts[20,21].

Anothernewdevelopmentthatalsoconsidersenvironmentalaspectsaredowelsmadefromhard‐wood,tryingtominimisetheuseofenvironmentallyquestionablesteel.Hardwooddowelscanbeusedassubstitutes forsteeldowels,e.g. toconnectsecondarybeamstomainbeamsor inthestackedplankconstruction,asmentionedearlier.Hardwooddowelshavealreadybeenusedsuc‐cessfully,buttheyarenotyetincludedintheEC5.Itispossibletoreachthesameload‐carryingcapacityaswithsteeldowels,althoughthefailureisgenerallymorebrittle[20,22].

Whenitcomestowholetimberstructures,newdevelopmentsincludecompositestructuresthatfeaturebothwoodandanothermaterialasmainstructuralmaterials.Timberandconcretecanbecombinedtoformtimber‐concretecompositefloors,wherethewoodismainlyresponsibleforthetensilestresseswhiletheconcretetakesonthecompressionstresses.Incomparisontofloorsthatarepurelymadefromwood,thecompositefloorshavemuchbettersoundprotectionandahigherstiffness.Thehigherweightcancontributeto improvetheeigenfrequencyof thewholebuilding.That isparticularly interesting formulti‐storeybuildings,wherewind‐inducedvibra‐tionscanleadtodangerousresonanceeffects.Accordingtothebasicequationfortheeigenfre‐

quencyofastructure,f K/M,whereKisthestiffnessandMthemassofthesystem,ahighermasscanbeuseddirectlytodecreasetheeigenfrequencyandgetitoutoftherangeoftheexcita‐tionduetowindturbulences.Inadditiontothoseadvantages,theconcretealsoprovidesaverygoodfireprotection.

Concretecanbeusedfordifferentkindsoftimberfloors,e.g.joistfloorsorstackedplankfloors,hollow‐boxfloorswherethecavitiesarepartiallyfilledwithconcretearepossible,too[21,180‐181].

Thedisadvantagesofsuchhybridsystemsmostlycomefromthedifferentpropertiesandthedif‐ferentbehaviouroftheusedmaterials,e.g.concerningtemperaturedeformations,creepingandshrinkage.Thestructuremustbedesignedinawaythatallowsforrelativemovementsbetweencomponentswithdifferentmaterialstoavoidrestraintstresses.Ingeneral,hybridsystemsarealsomoreexpensivebecausedifferenttradesarerequiredontheconstructionsite.

Case/Materials


5.5. SummaryoftheCase/MaterialsThebasicpropertiesofwoodasa constructionalmaterialhavebeenexplained,mostof thosepropertiesareeitherdirectlyorindirectlylinkedtothefactthatwoodisanaturalmaterial.Incomparisontoconcreteandsteel,woodhasalowerstrength,whichcan,however,becompen‐satedbyitslowself‐weight,whichallowsforefficient,light‐weightstructures.AchallengewithtimberisitslowYoung’smodulusconcerningdeformationsandvibrations.IntermsofadesignbasedonEC5,theserviceabilitylimitstate,whichdealswiththoseaspects,oftenbecomesdeci‐sive.Thiswillbepickedupagaininthenextpart.

Furthercharacteristicsofwoodincludethatitsstrengthdependsontheloaddurationandmois‐turecontentinsidethewoodandthatitcandecay.Durabilityisthereforeimportanttoconsiderinthedesignfromanearlypointonwards.Thebiggestadvantagesoftimberbuildingsincompar‐isontothosemadefromsteelorconcreteareenvironmentalones,thishasbeendiscussedindetailconsideringaspectsfromLCA.

Modernstructuresandnewdevelopmentscarrythetimbertechnologiesfurtherandmakethemcompetitiveagain.Differentsolutionshavebeenpresented.Engineeredwoodproductslikeglu‐lam,plywoodorCLTplayacentralroleintoday’stimberconstructions.Concerningthedesignoftheoverallstructure,itcanbeconcludedthatmoderntimberframingstructures,CLTmasstimberconstructionsandpanelconstructionsarebestsuitedformulti‐storeybuildings.Ingeneral,andespeciallyforbuildingswithmanystoreys,clearloadpathsarehelpfulandallowforamoreeffi‐cientdesign.

Basedonthefindingsandconclusionsfromthischapter,thenextchapterwillbededicatedtothedesignandanalysisofthreedifferentvariantsofthetimberbuildingTreet.

Method


6. Method6.1. Procedure

Whilethepurposeofthepreviousworkwastocreateanobjective,up‐to‐datesummaryoftimbertechnologies,pointingoutaspectsthatareespeciallyinterestingformulti‐storeybuildings,thefurtherworkwillbemoreexperimental.Bymeansofthedesign,newinsightsintothedescribedconstructionmethodsshallbederived.Thegoalistomakesomesmallcontributionstotakethebuildingwithtimberintothenextstage.

Beforebeginningwiththedesign,firsttheprocedurethatwasfollowedduringthedesignshallbepresented.

Thefirstdecisionthathadtobemadewaswhichkindofstructuresshouldbeanalysed.Inthesummaryofthecase/materials(cf.chapter5.5),threestructureshavealreadybeenpointedout.Consequently,thefollowingthreedesignvariantsweredefined:

a) frameconstruction8b) panelconstructionc) CLTconstruction

Anotherdecision,whichiscloselyrelatedtothefirstone,wastoonlyanalysepurevariants,i.e.structuresthatuseonlyonesinglestructuralmethod.Attheendof thedesignof thedifferentvariants,oneofthemainconclusionswillbethatalltheconstructionmethodshaveadvantagesanddisadvantagesandthatthebestsolutionwillbeacombinationoftheabovethatmakesuseofeachmethod’scharacteristicadvantages.However,howthefinalresultwilllooklikeheavilyde‐pendsonthespecificproject,buttheintentistofindconclusionsandgiverecommendationsthatareasgeneralandapplyforasmanydifferentprojectsaspossible.Besides,analysingonlythepurevariantsmakesitmucheasiertocarveouteachmethod’sowncharacteristics.

Thesubsequentdesignfollowedthreemainsteps:

1. draftdesign2. preliminarydesign3. ECdesign

Thedraftdesignstartedoncethedesignvariantsweredefined,firstdraftsweremadetogetanideaoftheoverallstructuralsystem.Someimportantdetailswerealsoalreadyplannedtocheckthegeneralfeasibilityofthegeneralsystem.Thestructuralconceptsforthethreevariantswillbelaidoutinthenextchapter6.2.

Thepurposeofthepreliminarydesignistocalculatefirstestimatesofthedimensionsofthecom‐ponentsandchoosewhichmaterialsandconnectionsshallbeused.Thedocumentationofprelim‐inarydesigncanbefoundattachedtothisdocument,cf.appendixA,andisdiscussedinchapter6.3.

TheECdesign is required toprove the feasibilityof thewholeconstructionbasedon theEC5standard.ThedocumentationoftheECdesignisalsoattached(cf.appendixA).Somecommentsonthisphaseofthedesignaredescribedinchapter6.4.

Forthismasterthesis,moreemphasisisputonthegeneraldesign,i.e.designphases1and2,andlessonthefinaldetaileddesign.Thegoalisnottodesignabuildinginalldetails,butratherto

8Inaccordancewiththetermsusedbefore,varianta)isamodernframeconstruction.Forreasonsofbetterreadability,thisvariantwillinthefollowingchapterssimplybereferredtoasframeconstruction.

Method


checkiftheconstructionisfeasibleandtoanalysetheoverallcharacteristics.Forthosepurposes,averydetaileddesignisnotnecessaryandcouldevendistractfromthemoreimportantaspects.

Sinceamulti‐storeybuildingisacomplexstructure,FEMwasusedforboththedesignandthegeneralanalysisofthestructure.Moreover,asmentionedbefore,sinceconnectionsaresuchanimportantpartofany timberconstruction,aselectedconnectionshallbeexaminedalsousingFEM.TheFEMcalculationswillbedescribedinchapter6.5.

6.2. DesignVariants6.2.1. StructuralConcept

Treet,themulti‐storeytimberbuildingthatistheobjectofthisanalysis,hasalreadybeenpre‐sented in the introduction (cf. chapter 1). Here, first the original building shall be describedquicklytocreatethebasisforthedraftdesignofthethreevariants.

Treet has 14 storey and an underground car park, its ground dimensions are a/b20,65/22,34m,thehighestpointlies47,48mabovetheground(withoutthecarpark).Thebuild‐ingisexclusivelyusedforresidentialpurposes.Eachstoreyconsistsoffourtofiveapartmentsthatareconnectedbyacorridor.Abigstaircaseandaliftinthemiddleofthebuildingconnectthestoreysvertically.Asecondarystaircase isaddedat thesideof thecorridor.Thearchitecturalplansofthebuildingcanbefoundintheattachment(cf.appendixA).

Treetconsistsofrectangularmoduleswhichareplacednexttoandontopofeachother.Thosemodulesareprefabricatedandarefullyequippedincludingakitchenandabathroom.Aframe‐workmadeofglulamontheoutsideandin‐betweenthemodulesisresponsiblefortheoverallstability.Thefifthandthetenthstoreyareaso‐calledpowerstoreys,featuringadditionalglulambracingstoachieveahighstiffnesssothatthosestoreyscanactasaplatformonwhichthenextmodulesareplaced.Prefabricatedconcreteslabsontopofthepowerstoreysprovideextraweighttocontrolthewind‐inducedvibrationsbyadaptingtheeigenfrequencyofthebuilding.ThestairsaremadefromCLT[14].

Tobeabletoconcentratemoreonthegeneralstructurethanproject‐specificdetails,somesim‐plificationsofthelayoutofthebuildingwereaccepted(cf.architecturalplans):

The15.storeyisconsideredtobeafullstorey,onlytheareaofthecorridor,theliftsandthestaircasesprotrudesonestoreyhigher.

Thebalconiesareneglected. Thedoorsandwindows,alsothoseintheoutsidewalls,areconsideredtobeofthesame

heightasonestorey,thepartsofthewallsaboveandbelowthoseopeningsareneglected.ThisisespeciallyimportantfortheanalysisofthewallsforthepanelandtheCLTcon‐struction(thelengthofeachwalliscalculatedasthedistancebetweentwoopenings).

Thestaircasesandtheliftareneglectedandconsideredasfloorareawiththecorrespond‐ingliveload.

Aconstantheightforallstoreysisassumed.Itiscalculatedastheaverageheightpersto‐reyoftheoriginalbuilding.

Theroomfortheliftandstairwaysisleftopenfromtheside,sothattheliftcaneasilybeaddedattheend,afterthemainstructureisfinished.

Withthosesimplifications,thestructuralconceptsofthethreevariantswereworkedout.Generalimportantcriteriaforagooddesign,thatshouldbeconsideredfromthefirststageon,are(innospecialorder):

Method


intendedusage structuralsafety architecturalvalue economicalaspects environmentalaspects firesafety thermalprotection noiseprotection possibilityofprefabrication suitabilityforextensions layingofserviceinstallations requiredmaintenance erectionmethods deconstruction

Concerningthechoiceofmaterials,thesamebasicmaterialswereusedfortheframeandpanelvariants(glulamforthemainstructuralcomponentsandplywoodforthestructuralsheathing)tomakeadirectcomparisonmorevalid.PlywoodisusedinsteadofOSBbecauseoftheratherhighVOCemissionsofOSB(cf.chapter5.1.4).Themassivetimberconstructionusesadifferentmate‐rial(CLT),sincethematerialisinthiscaseoneoftheaspectsthatshallbecompared.

6.2.2. FrameConstruction

Figure6.1:RFEMmodeloftheframeconstruction

AsdepictedinFigure6.1,theframe’sload‐bearingstructureconsistsofcolumnsthatgocontinu‐ously throughall storeys, two‐partbeams thatareattached to thecolumnsoneithersideand

Method


diagonalsintheoutsidewallsin‐betweenthecolumns.Thus,largeframesarecreatedonallfoursidesofthebuildingthatcarrytheglobalbendingmomentduetothewindloads.

Inanearlierstageofthedesign,itwasfirstplannedtohavethediagonalsontheoutsideoftheload‐bearingstructure.Thiswouldhavehadahigherarchitecturalvaluebecausethediagonalswouldhavebeenvisiblefromtheoutside.However,duringthedesign,itbecameobviousthattherequiredconnectionbetweentheouterdiagonalandthecolumnwasnotpossible,mostlybecauseofthehighforcescombinedwiththeeccentricityofthediagonal.Thefirstdesignwasthereforechangedtohavethediagonalsinthesamelayerasthecolumns,whichisadvantageousfortheloadtransfer.

Thecolumnsareplacedonasixbysixgridwithanaveragedistanceofabout4,3m.Thecontinu‐ouscolumnswiththecompoundbeamsonthesidesmakeanoptimalload‐bearingbehaviourpos‐sible,becausenoholesarenecessaryforthebeams,whichwouldweakenthecross‐section.An‐otheradvantageofarrangingthebeamsonthesidesisthatthestressesperpendiculartothegrainareminimised.Asexplainedbefore,thisisofgreatimportanceformulti‐storeytimberbuildings.

Thebeamsrunparalleltothefrontofthebuilding,wherethegridlineshavesimilardistances.Continuousbeamswithequalspansarestaticallymoreeconomicthansingle‐spanbeamsorcon‐tinuousbeamswithvaryingspans.

Thefloorjoistsareplacedonthebeamsandgoperpendiculartothefront.Becauseofthevaryingdistancesinthisdirection,thejoistsaredesignedassingle‐spanbeams,whichcanbeadaptedtothecorrespondingspans.Thisalsoimprovesthenoiseprotectionbecausethefloorscanbedi‐videdbetweenapartments.

Attachedtothetopofthefloorjoists,astructuralsheathingmadeofplywoodaccountsfortheshearstiffnessofthefloorsanddistributestheliveloadsandtheself‐weightoftheflooroverthejoists.Thefloorsactashorizontalbeamsthattransferthewindloadsintotheframesonthesides.

Oneimportantfactorforthedesignwastohaveassimpleconnectionsaspossible.Formulti‐sto‐reybuildingswithaverylargenumberofconnections,costlyconnectionscanleadtoeconomicproblems.

Theconnectionofthebeamstothecolumnsisrealisedbyusingsteelbolts.Theboltsareloadedindoubleshearwhichmakesthemmoreefficient.Theholesfortheboltscanbepre‐drilledinthefactory,allowingforaquickassemblyonsite.Theconnectionofthediagonalstothecolumnswasmorecomplexdueto theexpected large forces.Theconnection isrealisedusing internalsteelplatesinsidethewoodmembersandsteeldowels,seeFigure6.2.Thebigadvantageoftheinternalsteelplatesisthatmultipleplatescanbeused,creatingtwoshearplaneseach,whichincreasesthecapacityper fastener.Toavoidconflictswithotherconnections (especially in the corners,where two diagonals from perpendicular directionsmeet at the same column), some specialmeasureshadtobetaken.Ontheonehand,thecross‐sectionofthecolumnmustbelargeenoughfortheconnectionstobenexttoeachother.Ontheotherhand,completelyhiddensteeldowelsarerequired,sothatthebeamscancontinuealongthesideoftheconnection.Atthemiddlecol‐umns,thesteelplatessimplygothroughthecolumn,directlyconnectingthetwodiagonalswitheachother.

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Figure6.2:Sketchoftheconnectionbetweenthecolumnandthediagonal(nottoscale)

Onechallengewasthattheforcefromthediagonalactsonthecolumnunderanangletothegrain.Topreventthewoodfromsplitting,fully‐threadedscrewsaredrivenintothecolumnperpendic‐ulartothegrainasreinforcement.

6.2.3. PanelConstruction

Figure6.3:RFEMmodelofthesecondstoreyofthepanelconstruction

ThecentralconceptofthepanelconstructionisinspiredbytheoriginalstructureofTreetusingmodules.Eachstoreyconsistsof12modulesthatarepremanufactured,transportedtothecon‐structionsiteandthenconnected.Themodulesconsistofthewallsandthegroundfloor,cf.Figure6.3,andcanthusbefullyequippedincludingserviceinstallations,thebathroomandthekitchen.Theuppersideisclosedwhenthenextmodulesareplacedontop.

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Theindividualelementsofthepanelconstructionincludethestuds,theblockingin‐betweenthestuds,thestructuralsheathingnailedtotheoutsideandinsideofthewalls,thefloorbeams,thefloorjoists,andthestructuralsheathingofthefloors,cf.Figure6.4.Thestudscarrytheverticalloads,at theouterwalls, theyarealsosubjectedtobending fromthewindpressure.The floorjoistscarry the load fromthe floorsand transfer themvia the floorbeams into thestuds.Theblockingstabilisesthewallsinthedirectionperpendiculartothestuds.Themainfunctionofthesheathingistocarrytheshearstressesinthewalls.Thefloorsactasdiaphragms,transferringhorizontalloadsasshearforcesintothewalls.Allmembersaresinglespanbeamsduetothena‐tureoftheindividualmodules.

Figure6.4:Sketchoftheconnectionbetweenthefloorandthewallinthepanelconstruction

Incontrast tothe frameconstruction,where loadsareconcentrated inthemainmembers, theforcesaremoredistributedwithinthepanelwalls.Thismakesitpossibletoachievesmallerdi‐mensions.Ontheotherhand,however,italsomakestheloadtransferlessclearandthedesignmuchmorecomplex.

Toensureloadtransferbetweenthemodules,theconnectionsbetweenadjoiningmodulesplayacrucialrole.Toachieveaclearloadtransfer,itwasdistinguishedbetweenshearstressesandnor‐malstresses.

Theshearstressesaretransferredbythestructuralsheathing.Toachievetheloadtransfer,theedgesofthemodulesareleftwithoutsheathingwhenmanufacturedinthefactory,themissingsheathingisaddedonthesite,thuseffectivelyconnectingadjoiningmodules.

Thecompressionstressesaretransferredviadirectcontactbetweentheendgrainsofthestuds,thusstressesperpendicular to thegrainareavoided.Theblocking isarranged in‐between thestudsandthefloorbeamisattachedtotheinsideofthewall,sothatthecross‐sectionofthestudsisnotweakened.

Totransfertensileforcesbetweenmodulesaboveeachother,specialhold‐downdevicesarenec‐essary,e.g.boltsthatconnectthemodulewalls.Whileforsmallerstructureswithlowerloads,itispossibletoonlyusethenailsofthesheathingtotransferallforces,forhightensileforces,astheynaturallyoccurinmulti‐storeybuildings,thisisnotrecommended.Aclearseparationbe‐tweenthetransferofshearandtensionisimportant.

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Thefourlargerapartmentsineachstoreyconsistoftwomodules.Attheopensidesofthosemod‐ules,beamsandcolumnsareaddedtocarrytheloadsfromthefloors.Thecolumnsofthetwomodulesareconnectedaftertheyhavebeenbroughtinplacetoreachahigherbucklingresistance.

Ascanalreadybeguessedfromthosedescriptions,thepanelconstructionturnedouttobethecostliestvariantconcerningtheload‐bearingstructure.Manydifferentcomponentsandconnec‐tionswerenecessaryandmultiple iterationstepswereneededto findastructure that isbothcapableofbearingtheloadsandaseconomicaspossibleatthesametime.However,themajorpartofworkcanbedoneinthefactory,whichmakesthisstructureeconomicagainconcerningtheexecutionoftheconstruction.

6.2.4. CLTConstruction

Figure6.5:RFEMmodeloftheCLT‐construction

Inthisdesign,CLTwasusedinformofplatesforboththewallsandthefloorslabs,themodelisshowninFigure6.5.Again, toavoidstressesperpendiculartothegrain, insteadofplacingtheslabsin‐betweenthewallsofthetwostoreysaboveandbeneath,asisnormallydoneinthedesignofsmallerbuildings,theslabsareattachedtothewallslaterally.Agrooveiscutintothewallele‐mentsinwhichtheslabsareplaced,cf.Figure6.6.

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Figure6.6:SketchoftheconnectionbetweenwallandfloorintheCLT‐construction

Similartotheloadbearingbehaviourofthepanelconstruction,theCLTwallscarrytheverticalloadsandtheshear,whilethefloorsactasdiaphragmsthattransferthehorizontalloadsintothewalls.

OneadvantageoftheCLTconstructionisitssimplicity,itonlyconsistsofCLTelementsandonekindofconnection.Thisconnectionisrequiredtotransferthetensileloadsbetweenwallsaboveeachother.

6.3. PreliminaryDesignThegoalof thepreliminarydesign is to findastructure that fulfils therequirements fromtheintendedusage,isabletobeartheactingloads,ispossibletobuildandaseconomicaspossible.Sincethedesignofacomplexstructurelikeamulti‐storeybuildingtakesseveraliterationsteps,thepreliminarydesigncanbeunderstoodasthefirststepinthisiteration(althoughtheprelimi‐narydesignitselfalreadytakesmorethanonestep,too).Aftereverystep,thestructuralelementsareadapted,thecorrespondingloadschanged,andtheloadtransferrecalculated.

Thefirststepinanyiterationalwaysusessomeassumptionsandestimates,thesameistrueforthepreliminarydesign.Someexampleshavealreadybeengiven inchapter3.2concerningthematerialpropertiesandthe loads.Anothersimplification is the formulaethatareused,e.g. toquicklycalculatethecapacityofaconnection,sincetheECformulaecanbeverycomplex(theformulaethathavebeenusedforthedesigninthismasterthesisaredescribedintheprefaceofthepreliminarydesigndocumentation,seeappendixA).Themotivationistofindafeasiblestruc‐tureasefficientlyaspossible.

Duringthepreliminarydesignphase,themostengineeringcompetenceisrequired.Concerningthetopicofthismasterthesis,themostimportantfindingsweremadeduringthisphase.Thosefindingsshallbedescribedinthefollowing.

Thepreliminarydesignoftheframeconstructionwasrelativelystraightforward,moststructuralelementscouldbedesignedindependently.Oneexceptionweretheframesintheouterwallsthatcarrytheglobalbendingmomentduetothewind.Sincetheframesarestaticallyindeterminate,thecross‐sectionsdirectlyaffecttheloaddistribution.Therefore,theforcesmustbeestimatedasafirstsub‐step.Asimplifiedsystemwasusedtodeterminethosefirstestimates,cf.Figure6.7.Thewholeframewasdividedintotwohalfframes,whichwereconsideredtoactlikeBernoulli‐beams.Thisallowedforthesimplecalculationofthereactionforcesinthecolumns,whichfunctionedasthe tension and compression chords of the beams. Based on the forces in the columns,

Method


approximate forces in thediagonalscouldbedetermined.Withthoseestimated forces, there‐quiredcross‐sectionswerecalculated,whichcouldthenbeusedtomodeltheframewiththecor‐rectstiffnesses.

Figure6.7:Simplifiedsystemoftheframes

Abigpartofthepreliminarydesignoftheframeconstructionweretheconnections.Thebeamsareconnectedtothecolumnswithbolts.Theconnectionbetweenthediagonalandthecolumnsfeaturesinternalsteelplatesanddowels.Tocarrythewindsuctionloadsthatactonthefaçade,fullythreadedscrewswereused.Thesheathing,thejoistsandthebeamswereconnectedtoeachothervianails.However,althoughtherearemanydifferentconnections,allofthemcouldbede‐signedrelativelyeasilyusingthesimplifiedpreliminarydesignformulae.

ForboththepanelconstructionandtheCLT‐construction,thestabilisationofthebuildingwasanimportantandnottrivialpartofthepreliminarydesign.Thefunctionoftheframesintheframeconstructionisheretakenoverbyaninteractionofthewalls.Inthestabilityanalysis,theshareofeverywallintheglobalhorizontalshearloadandtheglobalbendingmomentiscalculated.Bothhavetheirmaximumintheloweststorey.

Inthecontextofthepreliminarydesign,someassumptionsweremadeforthestabilityanalysis:

Thebuildingisidealisedasaverticalcantileverbeam. Thefloordiaphragmsareperfectlyrigid. Thestiffnessofeachwallisproportionaltoitslength,i.e.allwallshavethesameheight,

thicknessandshearmodulus.

Basedonthoseassumptions,theshearforceisdistributedoverallwallsaccordingtotheirbend‐ingstiffnesses,cf.formula(4.1).Iftheshearforceactsatadistancetotheshearcentre(whichitdoesforwindfromtheside),anadditionaltorsionalmomentmustbeconsideredaccordingtoformula(4.2).

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V V ⋅EI∑ EI

(4.1)

V M ⋅EI ⋅ e∑ EI ⋅ e

(4.2)

where V =shearforceofthecurrentwallk

V =globalactingshearforce

EI =stiffnessofawall

M = torsionalmoment due to eccentricity of the global actingshearforce

e =distanceofawalltotheshearcentre

Tocarrytheglobalbendingmoment,eachwallcarriesashareofthisbendingmomentdependingonitsbendingstiffness(cf.formula(4.3))andanormalforcedependingonitsextensionalstiff‐nessanddistancetothecentreofgravity(cf.formula(4.4)).

M M ⋅EIEI

(4.3)

N M ⋅EA ⋅ eEI

(4.4)

where M =bendingmomentofthecurrentwallk

M =globalactingbendingmoment

EI = total stiffness of all walls according to Steiner’s theoremwithrespecttothecentreofgravity

N =normalforceofthecurrentwallk

EA =extensionalstiffnessofawall

e =distanceofawalltothecentreofgravity

Finally,theverticalloadsduetotheself‐weightofthestructureandthelifeloadcouldbeaddedtoobtainthetotalloadsforwhichtodesignthewalls.

Concerningthepanelconstruction,duringthedesignofthewalls,somechallengeshadtobeover‐come.Ascouldbeexpected,theloadsinthewallswereveryhigh,buttheyalsovariedsignificantlybetweentheindividualwalls,whichwasduetotheirdifferentpositionsandlengths.Thosevari‐ationsmadeanefficientandeconomicdesigndifficult.Dimensioningallstudsaccordingtothehighestoccurringloadswouldhavebeenhighlyuneconomic,whileadaptingeverysinglestudtoitsindividualloadisnotpractical.Finally,asolutionin‐betweenthosetwoextremeswaschosen.Onlyaselectednumberofstudswasconsideredtobeloadbearingineverywallandthusgivenarespectivelargercross‐section(upto28/28cm),whilethenon‐loadbearingstudscouldhaveamuchsmallercross‐section(e.g.8/28cm).Thenumberandarrangementof loadbearingstudscouldbeadaptedaccordingtotheloaddistributionineachindividualwall.

Thismethodprovedtobemosteffective,becauseithelpedtoconvertthevastlydifferentloadsonthewallstomoreequalloadsonthestuds.Shortwallswithrelativelylowloadscoulde.g.only

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havetwoloadbearingstuds,oneateachend,whileinthewallswithveryhighloads,almosteverystudwasloadbearing(thespacingofthestudsis61cm).

Becausethisstillledtoconsiderableloaddifferencesbetweenthestuds,themethodwastakenonestepfurther,introducingtwodifferentwallthicknesses.Inthefirstfloor,theouterwallsrun‐ningparalleltothebearingdirectionofthefloorshaveathicknessof20cm(withthecross‐sectionoftheloadbearingstudsbeing20/20cmandtheoneofthenon‐loadbearingstuds8/20cm)whileallotherwallshaveathicknessof28cm(heretheloadbearingstudsare28/28cmandthenon‐loadbearingstuds8/28cm).

Anotherchallenge for thepaneldesignwas theanchorage.Theproblemwere thecomparablysmallcross‐sectionsofthestuds,whichdidnotallowmuchspacefortheconnections.Finally,thisproblemwassolvedbyusinginternalsteelplatesinthestudsinquestionwhich,togetherwithsteelbolts,formatensionresistantconnectionbetweenthestuds.Thesteelplatescanbepre‐attachedtothelowerstuds,includingthebolts.Whenthenextmoduleisplacedontop,there‐mainingboltsareadded.Theboltsarelocatedabovethefloor,sothatthisworkcanbedonein‐dependentlyfromtheassemblyoftheadditionalsheathing,whichislocatedunderneaththefloor.

TheanchoragewasalsoachallengefortheCLTdesign.Forthisconstruction,longsteelplatesareused,thatareplacedingrooveswhicharecutintothelongtopedgesofthewallelements.Equallyspaceddowelsensureacontinuousloadtransferalongthewholelengthofthewalls.Usingglueinsteadofdowelswouldalsohavebeenpossible(cf.chapter5.4),butEC5doesnotyetincluderulesforthedesignofthiskindofconnection.

Theshearinthewallsduetowindloadswasnotdecisiveincomparisontothenormalforces.

6.4. EurocodeDesignInthischapter,firstsomegeneralfindingsfromtheECdesignshallbepresented,afterthat,againtheexperienceswiththethreedifferentconstructionvariantsaredescribed.

Ifthepreliminarydesignwasthefirstiterationstep,onetotwomorestepswererequiredintheECdesign.

ThesecondstepincludedadetailedloadcalculationandthebuildingoftheFEMmodelsaccordingtothedimensionsthathadbeenfoundinthepreliminarydesign.Withthehelpofthosemodels,moreaccurateinternalforcescouldbecalculated.ThenecessaryECcheckswereperformedforallrelevantstructuralcomponents.Theevaluationoftheresultsshowedthatsomecomponentsdidnotfulfiltherequirements,whileothercomponentswereonlyusedtoasmallpartoftheircapacity.

Theadaptionofthosecomponentswasthethirditerationstep.Thecross‐sectionsandconnec‐tionswerechangedsothatallchecksweresatisfied.Butbecausethe internal forcesagainareinfluencedbythesechanges, themodelshadtobechanged, the loadsrecalculated,andtheECchecksrepeated.Thistime,allcomponentsstillfulfilledtherequirementsandthedesigncouldbefinished.

Duringtheevaluationof theresultsof thechecks, itcouldbeconfirmedthattheserviceabilitylimitstate,i.e.thedeformations,becamedecisiveinsomecases.Concerningtheserviceability,itisimportanttoclearlydefinethecriterionfortheECverification.Forthefloorsinallthreecon‐structionvariants,thedeformationsaremainlyconnectedtothecomfortoftheresidents.Thereisalsoariskofdamageofothercomponentslikenon‐loadbearingwallsinsidetheapartments.IncompliancewiththeNorwegiannationalannextoEC5,thelimitvaluesforthedeformationswere

Method


definedasl/300fortheinstantaneousdeformationandl/150forthefinaldeformation(includingcreepandothertime‐dependenteffects),cf.[3,NA.7.2].

Asindicatedbefore,onlythemostrelevantelementsfromeachconstructionwerecheckedintheECdesign,somedetailsareonlyconsideredinthepreliminarydesign.Anexampleistheconnec‐tionofthesheathingofthefloorstothejoistsintheframeconstruction.Becauseofthelowloads,thisconnectionisclearlynotdecisiveandhasthereforealsonoinfluenceontheremainingstruc‐ture.

Thedesignoftheframeconstructioncouldbeperformedwithoutthehelpoffiniteelementpro‐grams,merelythesimpletwo‐dimensionalframeworkanalysisprogramStab2dwasusedtosolvestaticallyindeterminedsub‐systemsliketheframesonthesides.Asidefromthat,thechecksdur‐ingthesecond iterationsteprevealedthat thepreliminarydesignhadalreadyproducedquiteaccurateresults.Bothfactsdemonstratewelltheclearload‐transferviamainlyone‐dimensionalmembers,whichmakesiteasiertointerpretthestructureandallowsforaflexibledesign.Onlyforsomecomponents(e.g.thecolumns),thedimensionscouldbedecreasedinordertoachieveahigherdegreeofefficiency.

Inthepanelconstruction,theconnectionofthefloorjoiststothefloorbeamhadtobechanged.Thefullythreadedscrews,whichwerechoseninthepreliminarydesign,werenotabletotransfertheloadsbecauseofthelargerequireddistancetotheendgrain.Instead,joisthangerswereusedthatcouldtransfertheloadswithoutproblems.Adisadvantageofthissolutionistheprice,be‐causeitcanbeexpectedthatsuchmanufacturer‐specificproductsaremoreexpensivethanstand‐ardwoodscrews.Moreover,thedimensionsofsomecomponentsthatallhadthesamedimen‐sionsbefore,werechangedtodifferentdimensionstomakethedesignmoreeconomic.E.g.thejoistswiththesmallestspanwereadaptedtohaveasmallercross‐sectionthantheotherjoists.Thesolutionwiththedifferentiationbetweenloadbearingandnon‐loadbearingstudswasveryeffectivealsowiththemoreaccuratecalculations,sothatthecross‐sectionsofthestudsdidnothavetobechanged.

FortheCLTconstruction,becauseofthemorecomplicatedloaddistribution,anFEManalysiswasinevitable.Thisanalysisshowed,however,thattheestimationoftheforcesactingonthewallsinthepreliminarydesignhadbeenfaulty(thedetailswillbediscussedinchapter6.5.1).Therefore,thedimensionsofthewallshadtobeincreased.ThiscanbeseenasanindicationforthemorecomplexbehaviourofmassivetimberconstructionsandespeciallytheCLTmaterial.

6.5. FEMAnalysis6.5.1. GlobalFEMAnalysis

FEManalyseshavealreadybeenmentionedseveraltimes,mostmodernstructurescannotbede‐signedanymorewithoutthehelpofFEM.Italsowasanimportantpartofthedesignperformedinthecontextofthismasterthesis.Therefore,oneentirechapterisdedicatedtothistopictobeabletolookatsomeimportantaspectsoftheFEManalysisinmoredetail.

Besideshelpingtoverifytheloadbearingcapabilityoftheoverallstructures,thecreationofthedifferentmodelsalsoalreadygaveanideaofhowcomplexandcostlyconcerningtherealerectionthestructuresare.

Beforesolvingthemodels,aconvergenceanalysiswasconductedforeachmodeltofindasuitablesizeforthefiniteelements.Thisisofcentralimportancesinceanelementsizethatistoolargecanleadtoconsiderabledeviationsofthesolution,whiletoosmallelementsleadtoahighcomputa‐tiontime.InFigure6.8toFigure6.10,theresultsoftheconvergenceanalysisofallthreestructures

Method


arevisualised.Theselectedelementsizeforthesubsequentmainanalysisismarkedineachdia‐gram.Fortheconvergenceanalysis,asforallsubsequentcalculations,alinearfirstordertheorywasused.

Figure6.8:Convergenceanalysisoftheframeconstruction

Figure6.9:Convergenceanalysisofthepanelconstruction

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Figure6.10:ConvergenceanalysisoftheCLTconstruction

FortheCLTconstruction,thenumberoffiniteelementshadasignificanteffect,whereasfortheframeconstruction,theinfluenceofthenumberofelementsontheresultwasneglectable.Apos‐sibleexplanationforthisisthattheframeconstruction’smainload‐bearingstructureconsistsofone‐dimensionalmembers,theinfluenceofthesheathingofthefloorsisonlysecondary.Thecal‐culationoftheinternalforcesforthisframeworkiscomparablesimpleanddoesnotdependonthenumberoffiniteelements.Indeed,thisstructurecouldalsobesolvedasathree‐dimensionalframeworkwithouttheneedforFEM.TheCLTconstructionontheotherhandconsistssolelyoftwo‐dimensionalsurfaceelements,whichcanonlybesolvedusingFEM.

Asmentionedbefore,theFEMmodelwasnotstrictlynecessaryforthedesignoftheframecon‐struction, theECcheckscouldalsobeperformedusingsimplersub‐models.But the3Dmodelallowstotakeacloserlookattheglobalbehaviourandgivesanimpressionoftheoverallstruc‐ture.AcomparisonoftheresultsfromthedesignwiththosefromtheFEM‐modelshowedthatthedesigngenerallywasonthesafeside.

WhiletheframeandtheCLTconstructionscouldbemodelledinonepiece,thepanelconstructionconsistedoftoomanystructuralelementssothatthewholemodelcouldnotbesolvedinaprac‐ticalmanner.Somesmallerchangesweremadetoavoidnodesthatlieclosetoeachother,result‐inginanunnecessaryfinemeshatthosepoints.Still,thenumberoffiniteelementsexceededthenumberthatcouldbesolvedinareasonabletime.Tobeabletosolvethemodel,ithadtobedi‐videdintosmallersub‐models.Thebestsizeforthesub‐modelswasthatofonestorey,thecon‐sistentnumberingofthemodelnodesallowedforastraight‐forwardloadtransferbetweentheindividualsub‐models.Theconvergenceanalysiscouldbeconductedforthehigheststorey(cf.Figure6.9).

Sincethemodulesconsistofthewallsandthefloor(cf.chapter6.2.3),thesamecompositionwastakenfortheindividualsub‐models.Especiallyforthehorizontalwindloads,however,theupperfloorwasneededfortheloadtransfer.Becauseofthat,theupperfloorwasaddedtoeachsub‐model(withoutaddingthecorrespondingloadsagain).TheconceptforsubdivisionofthepanelmodelisillustratedinFigure6.11.

Method


Figure6.11:Conceptfordividingthepanelmodelintosub‐models

Someadditionalconsiderationwasnecessarytodeterminethecorrectconditionsatthetransi‐tionsofthesub‐models.Thebuildingasawholewasidealisedasacantileverbeam.Performingcutsthroughthisbeam,equivalenttodividingthemodelintosub‐models,willreleasebothmo‐ments,shearforcesandnormalforces.Sincethestudsareconsideredtobeconnectedtoeachotherbetweenstoreysviahinges(i.e.withouttransferringbendingmoments),eachsub‐modelissupportedatitslowerend,i.e.thelowercut,withhingedsupports.Thesupportreactions(whichareequaltotheinternalforcesinthestuds)couldthenbetransferredtothesub‐modelofthenextstoreyassingleloads.Becausetheupperfloorhadbeenaddedtothesub‐models,theuppercutwent throughthestudsthemselves(insteadof throughtheconnectionbetweenthestuds).Toassurecorrectboundaryconditions,supportswereneededattheupperendsoftheelementsofeachsub‐modelthatpreventrotationperpendiculartotheirverticalaxis,butallowingfor freedisplacementinalldirections.Asanexample,Figure6.12showsthemodelofthefirststoreywiththe loads forLC1(self‐weight) includingthesingle forces thatare transferred fromthestoreyabove.

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Figure6.12:Sub‐modelinRFEMofthefirststoreyofthepanelconstructionwiththeloadsforLC1(self‐weight)

Withthismethod,itwasfinallypossibletocalculatereliableresults.

FortheCLTconstruction,itwaspossibleinRFEMtodefinethecompositionoftheCLTelementsusingtheadd‐onRF‐LAMINATEandthedatafromthetechnicalapprovaloftheselectedmanu‐facturer(see[11]).Theadd‐onallowedforadetaileddefinitionofthecompositionoftheCLT‐elements,itcoulde.g.alsobespecifiedthattheindividualplanksarenotgluedtogetheralongthenarrowedges.

ToavoidFEM‐relatedsingularitiesduetosurfacesthatintersecteachother,themodelhadtobeadaptedtoleavesmallgapsbetweenthewallsinordertoassurethattheoverallloadbearingbe‐haviourcorrelatedwiththerealbehaviouraswellaspossible.

ConcerningtheresultsoftheCLTmodel,ithasalreadybeenmentionedthatthoseresultsdifferedsignificantlyfromtheresultsofthepreliminarydesign.Someoftheassumptionsforthestabilityanalysishadnotbeencorrect.Firstly,thebuildingdoesnotbehavelikeabeambasedontheBer‐noulli‐theory.Sheardeformationhasalargeinfluence,whichisprobablyalsobeaneffectoftheCLT‐material.ThiscanbeseenfromthedeformationinFigure6.13,whichisnotcurvedasonewouldexpectforthewindloads(foraBernoulli‐beam,constantdistributedloadsleadtoadefor‐mationintheshapeofathirdorderpolynomialfunction).Thefloordiaphragmsarealsonotrigid,especiallybecauseeachdiaphragmconsistsofseveralCLT‐slabswhichhavehingedsupports.

Method


Figure6.13:Deformationuin[mm]oftheCLT‐constructionforLC3(windfromthefront),viewfromtheside

WhenevaluatingtheresultsoftheFEManalysis,precautionshadtobetakenbecauseofunrealis‐ticstressconcentrations,whichoccurredespeciallyatthefoundationwherethesupportsatthebottomlinesofthesurfacescreatedrigidboundaryconditions.Theresultshadtobecorrectedtoexcludesuchstressconcentrations.

Ingeneral,theminimuminternalforceperwallwasselectedforthedesign(i.e.thehighestcom‐pression force).Todetect stressconcentrations, thedifferencebetween theminimumand themaximuminternalforce,themiddlein‐betweenthetwo,themedianandthestandarddeviationwerecalculatedforeachwall.Ahighstandarddeviationmeansthattheindividualvaluesononewalldeviatefromeachother,thisismainlythecaseatwallsthatcarryapartofthebendingmo‐mentfromthewindloads.Themiddlebetweenthetwoextremevaluesis,togetherwiththeme‐dian,bestsuitedtodetectthestressconcentrations.Iftherearestressconcentrationsinawall,onlyafewvalueswilldifferfromtherest,sothatthemedianisonlyslightlyaffected,whilethemiddle valuewill changeproportionally. Assuming negative values for compression, amiddlevaluethatismuchhigherthanthemedianwillmeanthattherearetensilestressconcentrations.

Asanexample,wallx3hadforLC1(self‐weight)amedianverticalinternalforceof 87,8kN/m,withtheextremevaluesbeing32,9and 121,1kN/m,whichmeansthemiddlevaluewas 44,1kN/m9.Thelargedifferencebetweenmedianandmiddlevaluesuggeststhattherearetensilestressconcentrations.AlookatthediagraminFigure6.14provesthishypothesis,thereasonforthestressconcentrationsisprobablythesupportwhichdoesnotallowanydeformationsalongthebottomline.Inthiscase,theminimumvalue( 121,1kN/m)wasselectedforthedesign.

9Theevaluationof the internal forceswasconductedatspecificgridpointsonthesurface,whichwereevenlydistributed.Sincethepositionsofthosepointswerestatic,theresultsdonotnecessarilycoverthewholerangeofinternalforcesandslightdeviationscanoccurincomparisontothediagrams.Thisisbene‐ficial,becauseitalreadyhelpstobalancestressconcentrations.

Method


Figure6.14:Distributionoftheinternalnormalforcesin[kN/m]inwallx3forLC1(self‐weight)

Adifferentexample iswallx21forLC3(windfromthefront).Here, thetheminimumandthemaximumvalueare 98,1and 33,7kN/mrespectively,themedianwas 41,7kN/mandandthemiddlevalue 65,9kN/m,whichshowedthepossibilityofcompressionstressconcentrations.ThiscanagainbeprovedbylookingatFigure6.15.Consequently,forthiswallthevalueofthedesign force had to be reduced to exclude the unrealistic concentrations. A factor of 0,5waschosentointerpolatebetweentheextremevalues, leadingtothefinaldesignvalueof 33,70,5 ⋅ 98,1 33,7 65,9kN/m.

Figure6.15:Distributionoftheinternalnormalforcesin[kN/m]inwallx21forLC3(windfromthefront)

Thisprocedurewasusedforallwalls,adaptingthecorrectionfactoraccordingtohowstrongtheconcentrationswere(measuredbymeansofcomparingthemedianandmiddlevalue).

ThemainresultsoftheglobalFEManalysiswillbepresentedinchapter7.1.

6.5.2. FEMConnectionAnalysisInadditiontotheanalysisoftheoverallstructure,oneselectedconnectionwasexaminedtoim‐prove theunderstandingof the loaddistribution inconnectiondetails. Ithasalreadybeenex‐

Method


plainedthatconnectionsplayanimportantroleintimberstructures,andthattherulesintheEC5areonlybasedonsingle‐fastenerconnections,usinganeffectivenumberoffastenerstoaccountforgroupeffects.Inlargemulti‐storeytimberbuildings,though,connectionsgenerallyconsistofmultiplefastenersbecauseofthecomparablyhighloads.Inordertoaddressthisaspect,thecon‐nectionbetweenthediagonalandthecolumnintheframeconstructionwasselectedtobeana‐lysedusingFEM. Itconsistsof the twowoodenmembersaswellas three internalsteelplatestogetherwithtensteeldowelsinboththecolumnandthediagonal(cf.chapter6.2.2).TheFEM‐softwareANSYSwasusedforthispurpose.

ThegeometryofthemodelisshowninFigure6.16,incomparisontotheoriginalconnection,thegeometrywassimplifiedtomakeamoreefficientFE‐solutionpossible,makinguseofthesym‐metryoftheconnection.Togetaclearviewofthedistributionoftheinternalstresses,oneofthemiddlelayersofthewoodcomponentsbetweentwosteelplateswasmodelled.

Figure6.16:GeometryoftheANSYSmodeloftheconnectionbetweendiagonalandcolumnintheframeconstruction

Thewood and steel partsweremodelled using the solid 8‐node brick element SOLID185. Tomodelthedowels,springelementsoftypeCOMBIN14wereapplied.

Sincewoodisanorthotropicmaterial,thecorrespondingorthotropicmaterialmodelhadtobeused.ThevaluesfortheelasticitymoduliweretakenfromEN14080forglulamGL24h.Thepois‐son’sratiosfordifferentwoodspeciescanbefoundintheliterature.Forthisapplication,theprop‐ertiesoftheDouglasfirwereused,whichisalsocultivatedinEurope.Thelongitudinaldirection

Method


ofthegrainwasassumedtocoincidewiththex‐axis,theradialdirectionwiththey‐axisandthetransversaldirectionwiththez‐axis.AllmaterialpropertiesaresummarisedinTable6.1.

Table6.1:MaterialpropertiesfortheANSYSmodel[12,table5][16,5‐3]

woodE 11500 N/mmE 300 N/mm

E 300 N/mmG ,G ,G 650 N/mm

ν 0,292

ν 0,449 ν 0,390

ρ 420 kg/msteelE 210000 N/mmν 0,3

Toobtainthecorrectstiffnessforthesprings,theslipmodulusofthedowelswascalculatedac‐cordingtoEC5[2,7.1],seeequation(6.1).

Kρ , ⋅ d

23⋅ 2 (6.1)

where ρ =meandensityofthewoodin[kg/m ]

d =diameterofthedowelin[mm]

Thefactor2inequation(6.1)isduetothesteelplatesthatareusedintheconnection.ForM20dowels(cf.preliminarydesign,seeappendixA)theslipmodulusperfastenerandpershearplaneresultsin:

K420 , ⋅ 20

23⋅ 2 14969N/mm

SinceonespringintheANSYSmodelrepresentstheactionofonedowelinoneshearplane,thisvaluecouldbeuseddirectlyasthespringstiffnessofthoseelements.

The tensile load in the diagonal was determined in the preliminary design and amounts to530,9kN.Distributedoverthecross‐sectionofthediagonalofb/h 40/40cm,theresultantten‐silestressis:

p530900400

3,318N/mm

Becausethewoodmembersforthemodelwerecutoutofthewholestructure,boundarycondi‐tionshadtobeappliedatthecuts.Forthecolumn,whichtransfersbothnormalandshearforcesaswellasbendingmoments,arigidsupportwasmodelled.Thediagonal,ontheotherhand,trans‐fersmostlynormalforces,shearforcesandbendingmomentcanbeneglected,thereforeonlythenormalpressurepisappliedtorepresenttheactionoftheinternalnormalforce.Additionally,tosupportthemodelagainstlateralmovement,supportsinthelateraldirections, i.e. inglobalz‐directionandperpendiculartothediagonal,hadtobeapplied.Thiswasnecessarybecausethe

Method


springelementsonlytransferforcesinthedirectionoftheirlocalx‐axis,whichmeansthatmove‐mentsperpendiculartothisaxisarenotconstraint.Withoutadditionalsupport,thiscausesthecalculationofthemodeltofailbecauseofrigidbodymovements.

Basedonthoseconsiderations,themodelcouldfinallybesolved.Butitisimportanttokeepthementionedassumptionsinmind,becausethemodeldoesnotrepresenttheconnectionaccuratelyenoughtoe.g.replacetheECcheckbythisFEanalysis.Theintentionisrathertogainabetterunderstandingofthedistributionoftheinternalstressesofarealisticconnectiondetail.

Theresultswillbepresentedinthenextchapter.

Results


7. Results7.1. ResultsfromtheDesignAnalysis

Theresultofthedesignshowedthatitistechnicallypossibletouseallthreeanalysedstructuralmethodsfortheconstructionofmulti‐storeybuildings.Thedesigndocumentationsandthetech‐nicalplansthatshowthefinaloutcomeofthedesignareattachedtothismasterthesis,cf.appen‐dixA. There are, however, important differences between the three variants concerning bothstructural,othertechnical,architecturalandenvironmentalaspects.Adetaileddiscussionofthoseresultswillfollowinchapter8.Inthischapter,theresultsfromtheFEManalyseswillbepresentedinrelationtothedesign.

TheglobalFEManalysishelpedtoverifytheoverallstabilityandloadbearingbehaviourofthethreestructures.Asanexample,theinternalnormalforcesinthefrontframeoftheframecon‐structionareshowninFigure7.1.Thisresultprovestheclearloaddistributionofthisconstruc‐tionwhichmakesitaveryefficientmethod.Theoverallstabilityisachievedrelativelyeasilywhichallowsforaflexibleinteriordesign.

Figure7.1:InternalnormalforcesinthefrontframeoftheframeconstructionforLC4(windfromtheside)in[kN]

Results


ThedistributionoftheinternalforcesforthepanelconstructionisdepictedinFigure7.2forthefirststorey.Althoughitisnotpossibletoreadindividualvalues,thefigurestillgivesagoodim‐pressionoftheloaddistribution.

Figure7.2:DistributionoftheinternalnormalforcesinthestudsofthefirststoreyofthepanelconstructionforLC4(windfromtheside)

Thefigureshowsthatforpurewindloads(withoutself‐weightorliveload),thenormalforcesaremostlyconcentratedintheendstudsofeachwall.Incontrasttothat,forthepreliminarydesign,thewindloadsweredistributedoverthestudswiththewallmodelledasabeamsupportedtheloadbearingstuds,cf.Figure7.3,whichresultedinmoreevenlydistributedloads,orratherhigherloadsinthemiddlestuds.Whilethismethodismorevalidfortheconstantverticalloadsfromtheself‐weightandtheliveload,itisapparentlynotacorrectassumptionforthewindloads.

Figure7.3:Exampleoftheassumptionoftheloaddistributionintheloadbearingstudsinawallinthepanelconstructionforwindfromtherightsideaccordingtothepreliminarydesign

Thedesignofthepanelconstructionwasnonethelesssuccessfulbecausethestudsthatwerecon‐siderednon‐loadbearingprovideadditionalloadcarryingcapacity.Thismakesthedesignmoreredundant.Nevertheless,theeffectoftheconcentratedwindloadsshouldbeconsideredforthedesignofpanelconstructionsinmulti‐storeybuildingswithhighwindloads.

Results


TogiveanexampleoftheloaddistributionintheCLTconstruction,Figure7.4depictsthenormalforcesinthewallsofthefirststoreyforwindfromtheside.

Figure7.4:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC4(windfromtheside)in[kN/m]

Itcanbeseenclearlythatallthewallsparalleltothedirectionofthewindcarryapartoftheglobalbendingmoment.Theloaddistributionineachwall is linearaccordingtotheequationforthenormalstressesσ M/I ⋅ z,whereσisthenormalstresses(or,inthiscase,thedistributednormalforces),Mistheactingmoment,Ithesecondmomentofinertiaandzthecoordinatethroughthecross‐section(inthiscasealongthewall).However,unliketheassumptionsthathadbeenmadeinthepreliminarydesign,thewallsperpendiculartothewinddirectioncarrypracticallynoloads.Theloadsintheparallelwallsareaccordinglyhigher.ThisisprobablyanotherreasonwhytheECdesignhadtobereworkedratherextensivelyfortheCLTconstructioninrelationtotheprelimi‐narydesign.

FurtherresultsforallthreeconstructionvariantscanbefoundinappendixB.TheelectronicfilesoftheRFEM‐analysisarealsoattached,seeappendixA.

Anotherpartofthedesignanalysiswastheexaminationoftheconnectiondetailasdescribedinchapter6.5.2.Togetafirstimpressionofthestressdistribution,theequivalentvonMisesstressisshowninFigure7.510.

10ThedeformationinallfigureswithANSYSresultsisscaledbyafactorof100.Thesteelplatesarenotshown.

Results


Figure7.5:VonMisesstressσVMoftheconnectionin[N/mm2]

Itcanbeseenthatthestressintheupperpartofthediagonalismainlyinfluencedbythetensileload,thevonMisesstressthereamountsapproximatelyto3,318N/mm .Goingdownthediago‐nal,thestressesgraduallydecreaseastheloadsaretransferredviathedowelstothesteelplatesandthenintothecolumn.However,stressconcentrationsoccurintheupperrangeoftheconnec‐tion,themaximumstressthereisaround1,5timeshigherthanthetensileload.Thisismostprob‐ablyduetothefactthatthedowelsaredistributedlaterallyalongverticallinesinsteadofperpen‐diculartothegrainofthediagonal.Thatleadstothefirstdowelintheupperrightcorneroftheconnectiontakingovermostoftheloads,whilethedowelsinthelowerregionscarrymuchlessloads.Thestressesinthewooddevelopaccordingly.

ThedistributionoftheshearstressesdepictedinFigure7.6yieldsthesamegeneralresult.Theshearstressesarealsoconcentratedaroundtheupperdowels.

Results


Figure7.6:Shearstressτxyoftheconnectionin[N/mm2]

Inadditiontothat,however,shearstressesalsodevelopinthediagonalinsomedistancefromtheconnection,wherethelocaleffectsofthedowelshavenoinfluenceanymore.This isprobablyagainduetothearrangementofthedowels,sincethediagonal,asapartoftheframeintheframeconstruction,isapuretensionmember.Onepossibleexplanationistheasymmetricalloadtrans‐ferfromthewoodintothedowels.Becausehigherloadsaretransferredintheupperregionoftheconnectioncomparedtothelowerregion,theinternalforcesareunbalanced.Tosatisfytheequi‐libriumofforces,additionalshearforcesarerequired.

Shearstressesalongthegrainarepotentiallydangerousbecausetheycanleadtocracks.IntheEC,thecheckagainstcracks,i.e.thecheckfortensionperpendiculartothegrain,isbasedontheshearforceinthememberinquestion.Thecapacityagainsttensionperpendiculartothegrainiscalculatedusingformula(6.2)withthegeometricdimensionsaccordingtoFigure7.7.

F , 14 ⋅ b ⋅ w ⋅h

1 h /h (6.2)

where w =modificationfactor,w 1forallconnectionsexceptfornailplates

b,h ,h =geometricdimension,seeFigure7.7

Results


Figure7.7:Definitionoftheforcesandgeometricdimensionsforthecheckagainsttensionperpen‐diculartothegrainaccordingtoEC5[2,8.1.4]

Sincethischeckisonlynecessaryforaforcethatactsatanangletothegrain,itisonlyrequiredforthecolumnandnotthediagonal(seeEurocodedesignfortheexecutionofthischeck,cf.ap‐pendixA).TheFEresultsontheotherhandsuggestthattheshearforcesarelargerinthediagonal,duetotheasymmetricarrangementofthedowels.Thisaspectis,however,notconsideredintheEC.

Lastly,Figure7.8showsthetotalstraininsidethewoodmembers.Theresultsreinforcethesug‐gestionsthathavebeenmadesofar.SincethestrainandthestressaredirectlylinkedviaHooke’slawσ E ⋅ ε,withthestressesσ,thestrainsεandtheYoung’smodulusE,theplaceswiththehigheststressesalsoshowthehigheststrains.Thesheardeformationinthediagonalcanalsobeseenrelativelyclearlywhenlookingatthedeformedshapeofthemodel.

Figure7.8:Totalstrainεoftheconnectionin[‐]

FurtherfigurescanbefoundinappendixC,whichshowthesameoverallresults.TheelectronicfiecontainingtheANSYSmodelisalsoattached,seeappendixA.

Tosumup,themostimportantinsightfromtheANSYSanalysisisthatthearrangementofthefasteners in amulti‐fastener connection has a significant influence on the distribution of thestressesandthustheloadbearingbehaviourandpotentiallyalsothecapacityoftheconnection.It

Results


appearstobedisadvantageoustoarrangethefastenerswithanoffsetparalleltothegrain.Asaresultofthat,theloadtransferisunbalancedandadditionalshearstressesdevelop.Theshearstressesraisetheriskforsplitting,thestressconcentrationsaroundthefrontdowelscanalsoleadtocracks.Butitisimportanttorememberthatthisanalysiswascarriedoutwithoutconsideringthesplittingitselforrelatedeffects.

TheEurocodedoesconsiderthedistancesbetweenthefastenerstodetermineaneffectivenum‐beroffasteners,buttheoffsetalongthegrainisnotincluded.AccordingtoEC,theeffectivenum‐beroffastenersforthecolumnn 6,74islowerthanforthediagonalwithn 7,93(seeEu‐rocodedesign,cf.appendixA),whiletheaboveresultssuggestalessbeneficialstressdistributionforthediagonal. InadditiontothechecksfromtheEC,thedescribedeffectsshouldbekept inmindforthedesignofmulti‐storeytimberbuildingsandthelayoutofsuchconnectionsadjustedaccordingly.

7.2. ComparisonToelaboratethecentralresultsfromallpreviouschapters,ashortcomparisonofthethreevari‐antsshallbemadeinthischapter.Asatoolforthecomparison,anevaluationmatrixshallbeused,aswasdescribedinthecontextoftheLCAinchapter5.1.3.Forthiscomparisonhowever,amoregeneralevaluationmatrixisestablished,consideringalltheabovementionedaspects.TheresultispresentedinTable7.1.

First,allcriteriawereweightedtoaccountfortheirimportance.Inthenextstep,allthreevariantswereassignedvaluesbetween1and5foreachcriterion,were1istheworstratingand5thebestrating,thatmeansthate.g.alowdifficultyoftheconstructionwouldberatedwithahighvalue.Thescalefrom1to5isfineenoughtoclearlybringoutthedifferencesbetweenthethreecon‐structions,butnottoofine,forwhichthereisnosufficientbasis.Theresultswerecalculatedbymultiplyingthevaluewiththeweightingofthecorrespondingcriterion.

Results


Table7.1:Evaluationmatrixforthecomparisonofthethreeconstructionvariantsframeconstruction,panelconstructionandCLTconstruction

criteria weighting frameconstruction panelconstruction CLTconstructionvalue result value result value result

complexityofthestructure

10% 3 30 1 10 5 50

difficultyoftheerection

20% 2 40 5 100 4 80

difficultyofthetransport

10% 5 50 1 10 3 30

deconstructionandreuse

5% 5 25 1 5 2 10

suitabilityforprefabrication

10% 2 20 5 50 3 30

firesafety

15% 2 30 3 45 5 75

noiseprotec‐tion

5% 1 5 2 10 5 25

environmentalaspectsofthematerials

15% 4 60 4 60 2 30

difficultyofad‐justmentsoftheinterior

5% 5 25 1 5 3 15

architecturalvalue

5% 4 20 1 5 5 25

sum 100 % 305 300 370

TheresultsrevealthattheCLTconstructionisbestsuitedfromthisall‐integratingpointofview.Itdidnotgetthelowestvalue1foranycriterion,theworstratingswereattainedfordeconstruc‐tionandreuse,sincetheCLTelementsareengineeredwoodproductsthatarehighlyadjustedtothespecificproject,andenvironmentalaspects,becausemostsyntheticadhesivesarerequiredforthemanufacturing.Theframeconstructionandthepanelconstructionhavealmostthesameresult,althoughthescoringat the individualcriteria isoftenopposite.For thedifficultyof thetransport,forexample,theframeconstructionscoreshighbecausethebasiccomponentsarerel‐ativelyeasilyavailableandcanbetransportedefficiently.Thepanelelements,however,prefabri‐catedwallsandfloorsorevenwholeprefabricatedmodules,aremoredifficulttotransportandthedistancebetweenthefactoryandtheconstructionsiteispresumablymuchbigger.Forthedifficultyoftheerectionontheotherhand,thepanelconstructiongetsahighvaluebecausetheprefabricatedelementsonlyhavetobeconnectedonsite,whiletheerectionoftheframeismorecostly.

Itisimportanttoremindthatthisevaluationwillnotvalidforeverycase,itisonlyintendedtogiveageneralideaofthedifferences,theadvantagesanddrawbacksofthethreestructuralmeth‐ods.Thedecisionforoneoranotherofthemethodswillinadditiontothoseresultshighlydependonproject‐specificaspects,whichcannotbeconsideredhere.Moreover,theabovevalueswereonlydeterminedqualitativelybasedonthefindingsofthismasterthesis.Foramorethorough

Results


evaluation,especiallywhenappliedtoarealbuildingproject,inputfromexpertsfromdifferentfieldsshouldbeconsidered.

Discussion


8. DiscussionApartfromtheaspectsofthepreviouschapter,somemoredetailedresultsconcerningtheout‐comeofthedesignandtheexperienceswiththethreevariantswillbediscussedinthischapter.

Theframeconstruction isveryeffectiveto transferthewind loadswhichcreatea largeglobalbendingmomentatthefootofbuilding.Thisisnaturallyabigchallengeforallmulti‐storeybuild‐ings.Lookingatexistingmulti‐storeytimberbuildingstoday,liketheoriginalTreetconstructionortheMjøstårnet(cf.chapter1),mostofthemfeaturesomekindofframeconstructionontheoutsideofthebuilding.

Lookingattheconnectiondetailintheframeconstruction,onecanconcludethatitwouldhavebeenmoreappropriatetoseparatetheconnectionofthetwodiagonalsthatmeetatthecornercolumn.Thisconnectionisquitecomplex,ascouldbeillustratedintheFEManalysisofthecon‐nectioninchapter6.5.2.Muchspaceisneededtosecurelytransfertheveryhighloads.Thetwo‐dimensionalconnectionmakesthistaskevenmorecomplicated.Basedonthoseexperiences,itcanberecommendedtoalwayspreferone‐dimensionalconnections,althoughagain,thecondi‐tionscanbedifferentinaspecificproject.

Ofallthreevariants,thepanelconstructionisleastsuitableformulti‐storeybuildings.Thepanelconstructionisanefficientandlightweightconstructionmethodforsmallerbuildings,whichhasmanyadvantageslikethegoodsuitabilityforprefabricationanditssmallweight.Itis,however,notefficientforbuildingswithmanystoreysbecauseoftheveryhighloadsthatoccurinmulti‐storeybuildings.Theextensivepreliminarydesignandthe issueswithcreatinganFEMmodelillustratethecomplexityoftheconstruction.Theloaddistributionisnotclear,whichmakesanoptimisationofthedesigndifficult.

Incontrasttothat,themainadvantageofthemasstimbervariantisitssimpleconstruction.Es‐peciallycomparedtothepanelconstruction,butalsotheframeconstruction,lessdifferentstruc‐turalelementsandthereforealsolessconnectionsarenecessary.Themasstimberelementscom‐binethedifferentstructuralfunctionsinaneffectiveway.

However,thepreliminarydesignhadtobereworkedcomparablystronglyfortheCLTconstruc‐tion.Thisisobviouslyduetoinadequateassumptionsforthepreliminarydesign,e.g.concerningthestrengthortheYoung’smodulus.Inthepreliminarydesign,itwasnotaccountedforthedif‐ferentmaterialparametersinthedifferentdirectionsoftheplates,althoughthoseactuallydiffersignificantly.

Onereasonforthoseproblemsisthelackofexperiencewiththismaterial.Adequateassumptions(whicharealwaysbasedonexperience)arenotavailableyetasextensivelyasfortheothercon‐structionmethods.AnotherissueforthedesignoftheCLTconstructionisthatstandardisedrulesforthedesignofCLTarestillmissing.IntheEC,CLTisnotmentionedatall.Assumptionshadtobemade,butbecauseoftheadvantagesofCLTthatwerepointedoutearlier(aboveallthesupe‐riorhomogeneity),thereispotential fore.g.highermodificationfactorsk whichwouldin‐creasetheefficiencyofthismaterial(seealso[19]).

Ontheotherhand,however,itwascomparativelyeasytoadjustthedimensionsofthemembersinquestion.Inspiteoftheconsiderablechangesthathadtobemade,theloaddistributiononlychangedrelativelylittle.Thisprovesagainthesimplicityofthestructure.Thestructuralelementsarequiteindependentofeachotherconcerningtheloadtransfer.Thesimplicityoftheconnec‐tionswasalsobeneficial,becauseconnectionsoftenrepresentfixedpointsforthedesign,formingboundaryconditionsthatlimitthefreedomofthedesignperceptibly.

Discussion


Tocomebacktothereasonforthosenecessaryadjustments,thereisstillsomeworkandresearchtobedonetogainmoreexpertiseaboutthismaterial.ExtensionstothestandardsarenecessarytoincludeCLT,especiallybecauseitisusedmoreandmoreandwillverylikelyplayanimportantroleinthefutureofmulti‐storeytimberbuildings,aswasdiscussedearlier.TheFEM‐softwareRFEMalreadyincludedanadd‐ontomodelCLT‐materialsrealistically.Thiscanbeseenasasignthattheindustryhasalreadyunderstoodtheimportanceofthismaterialandisusingit,whiletheresearchandstandardisationstillhavetocatchup.CLThasalsobeenusedindifferentextendforthemulti‐storeytimberbuildingsTreetandMjøstårnet.

Itcanbeseenfromtheoutcomeofthismasterthesis,thatallthreevariantshaveadvantagesanddrawbacks.Thisisnotsurprisingandhadalreadybeenindicatedinchapter6.1.Torounduptheconclusionsofthedesignanalysis,ashortlookwillbetakenathowtocombinethedifferentvar‐iantseffectively.

Sincetheframeisverywellsuitedtotakeoverthewindloads,itmakessensetousethisstructureontheoutsideofthebuildingfortheglobalstability.Ontheinside,modulesinpanelconstructioncanbeused.Tominimisetheloadsonthepanelwalls,itispossibletoconnectthemodulestotheframestotransfertheverticalforcesthere.Thiscaneitherbedonewitheverystoreyorwithsev‐eralstoreys,creatingplatformsatequalintervals,verymuchliketheoriginalstructureofTreetwascarriedout.Thismakesitpossibletomakeuseofthepanelconstruction’sadvantages.None‐theless,higherloadswillprobablyoccurinthepanelwallscomparedtosmallerbuildings.Con‐cerningthis,thesolutionwithadistinctionbetweenloadbearingandnon‐loadbearingstudshasprovedtobeveryeffective.

ACLTconstructionisverywellsuitedformulti‐storeytimberbuildingswithoutadditionalstruc‐tures. For even bigger buildings, constructions in the style of traditionalmonolithic concretestructurescanbeimagined,withaninternalmassivecore,providingthestability.Inthisway,CLTcanalsobecombinedwithothermaterials,e.g.alightweightpanelconstructiontoformtheouterwalls.Furthermore,floorslabsmadefromCLTarewellsuitedtobeusedindifferentconstruc‐tions,oneoftheiradvantagescomparedtoe.g.joistfloorsiftheircapabilityofbearingloadsinbothdirections,whichmakesthemmuchmoreefficient.Becauseoftheirmassivestructureandhighweight,theyalsoaddagoodfireandnoiseprotection.

Conclusions


9. ConclusionsInthismasterthesis,anextensivebasisformoderntimberdesignwasestablishedandcouldsuc‐cessfullybeusedtoperformadesignanalysisofthreevariantsofthemulti‐storeytimberbuildingTreet.Onevariantwasaframeconstruction,oneapanelconstructionandoneaCLTconstruction.Fromtheexperiencesduringthedesignandfromthefinaloutcome,conclusionscouldbemadeconcerning thesuitabilityof those threevariants, thusgivingaversatileanswer to thecentralresearchquestion(questionnumber1)thatwasformulatedinchapter4.Someofthemostim‐portantfindingsare:

Aframeconstructioniswellsuitedtoprovidestabilityinmulti‐storeytimberbuildings. Apanelconstructionshouldonlybeusedincombinationwithotherconstructionmeth‐

ods,butthenithassomegreatadvantages,aboveallthegoodsuitabilityforprefabrica‐tion.

CLTcanbeusedforvariouspurposesinmulti‐storeytimberbuildings,eitheronitsownorincombinationwithothermaterialsandstructuralmethods.

Aclearloadtransferisbeneficial,especiallyfortheoptimisationofthedesign. EngineeredwoodproductslikeglulamandCLTarepracticallyinevitableformulti‐storey

timberbuildings. Stressesperpendiculartothegrainshouldbeavoided.

Togiveanswerstothesecondaryquestions,herearethefurtherimportantpoints,gatheredfromallchaptersofthemasterthesis:

2. Woodistheoldestmaterialusedforbuildingpurposes.Muchexperienceexistsfortimberconstructions,buttoday’stechnologiesdifferconsiderablyfromthoseusedearlierinhis‐tory.Therearestillmanyreservationsamongstbothclientsandplannersinthebuildingindustry, which are connected to the disadvantages of the traditional technologies,althoughthenewtechnologiessolvedmostofthosedisadvantages.

3. Inspiteofthedifferenthistoricaldevelopments,inbothNorwayandGermany,asinmanyothercountries,thetimberindustrylacksexpertiseforthosenewtechnologies.

4. SupportedbyprogramsliketheNorwegianstrategytopromotetheuseofwoodinpublicbuildings,however,thetimberindustryisdeveloping.

5. Woodisanaturalmaterialwithalltheadvantagesanddrawbacksthatareconnectedtothisfact.Itsgreatestadvantagecomparedtosteelandconcreteisprobablyitsenviron‐mentalproperties.Butwoodhasstructuraladvantages,too,likethelowself‐weight.

6. Theroleconnectionsplayinthedesignoftimberbuildingsdependsontheconstructionmethod.Fortheframeandthepanelconstruction,theconnectionsplayanimportantrole,a largepartofthedesigndocumentationisdedicatedtotheconnections.TheCLTcon‐structionontheotherhandonlyrequiresaminimumofconnections.

7. ThedesignofthepanelandtheCLTconstruction,likemostmodernengineeringconstruc‐tions,requiredtheuseofFEM‐software.Specialcautionisrequiredwhenevaluatingtheresultsbecauseofmodel‐relatedeffectsthatcaninfluencetheresultsunrealistically.Theframeconstructioncouldbedesignedonlymakinguseofasimple frameworkanalysisprogram.

8. TheFEM‐analysisoftheconnectionsshowedthatthelayoutofthefastenersinmulti‐fas‐tenerconnectionshasanimportanteffectonthestressdistributionandisnotcompletelyconsideredintheEC.Generally, itcanberecommendedtoarrangethefastenersonanorthogonalgridparallelandperpendiculartothegraintoachieveanevenloadtransfer.

Recommendations


10. RecommendationsAsdescribedintheintroductioninchapter1,today’shighesttimberbuilding,Treet,hasaheightof51m,whentheMjøstårnetwillbefinishedin2019,itwillhaveaheightof81m.Thinkingfur‐ther into the future, it canwellbe imagined that there soonwillbewoodenskyscraperswithheightsfarabove100m.Theaspectsdiscussedinthismasterthesiswillstillbeabletobeusedinageneralsenseforsuchbuildings,butthestructuresmustofcoursebeadapted.Toobtainthenecessarycross‐sections,CLTwilldefinitelyplayanimportantrole.Newproductslikemouldedwoodimprovethewood’spropertiesandwillmakesuchnewstructurespossible.Tomakethosenewproductsapplicable,furtherresearchisneeded.

Toeconomicallydesignnewconstructions,improvementsmustbemadetothecurrentstandards,e.g.toincludeCLTintheEC.

Apartfromthat,withthismasterthesisitcouldbedemonstratedthattherearetodaynotechnicalhindrancestoconstructmulti‐storeybuildingsusingtimber.Itisnowthetaskofthelegislativeorgantoprovidemodern,contemporaryrulesthatsupporttimberstructures,especiallyconsid‐eringthebigenvironmentaladvantagesthathavebeendiscussed.Atthesametime,theresponsi‐bleplannersinthebuildingindustryshouldbemoreawareofthetechnicalpossibilitiesthathavebeenpresented,andridthemselvesofthereservationsconnectedtoearlierweaknessesoftimber.

Allinall,thismasterthesisshowedthattimberconstructionsstillhavemuchunusedpotential,alsofortomorrow’sbuildings.

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Appendix


AppendixA. Attachments architecturalplansoftheoriginalbuildingTreetP01–P06(PDF)[15] loadcalculation(PDF) preliminarydesign(PDF) Eurocodedesign(PDF) technicalplans(PDF) EXCELdesignfiles(XLSX) RFEMmodels(RF5) ANSYSmodel(DB)

B. SelectedRFEMResultsB.a) FrameConstruction

FigureB.1:DeformationoftheframeconstructionforLC1(self‐weight)in[mm]

Appendix


FigureB.2:DeformationoftheframeconstructionforLC3(windfromthefront)in[mm]

FigureB.3:DeformationoftheframeconstructionforLC4(windfromtheside)in[mm]

Appendix


FigureB.4:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC1(self‐weight)in[kN]

FigureB.5:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC2(snow)in[kN]

FigureB.6:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC3(windfromthefront)in[kN]

Appendix


FigureB.7:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC4(windfromtheside)in[kN]

FigureB.8:InternalnormalforcesinthecolumnsoftheframeconstructioninthefirststoreyforLC5(lifeload)in[kN]

Appendix


FigureB.9:InternalnormalforcesinthefrontframeoftheframeconstructionforLC1(self‐weight)in[kN]

B.b) PanelConstruction

FigureB.10:DeformationofthefirstfloorofthepanelconstructionforLC1(self‐weight)in[mm]

Appendix


FigureB.11:DeformationofthefirstfloorofthepanelconstructionforLC2(snow)in[mm]

FigureB.12:DeformationofthefirstfloorofthepanelconstructionforLC3(windfromthefront)in[mm]

FigureB.13:DeformationofthefirstfloorofthepanelconstructionforLC4(windfromtheside)in[mm]

Appendix


FigureB.14:DeformationofthefirstfloorofthepanelconstructionforLC5(lifeload)in[mm]

FigureB.15:DistributionoftheinternalnormalforcesinthestudsofthefirststoreyofthepanelconstructionforLC1(self‐weight)

FigureB.16:DistributionoftheinternalnormalforcesinthestudsofthefirststoreyofthepanelconstructionforLC3(windfromthefront)

Appendix


B.c) CLTConstruction

FigureB.17:DeformationoftheCLTconstructionforLC1(self‐weight)in[mm]

FigureB.18:DeformationoftheCLTconstructionforLC3(windfromthefront)in[mm]

Appendix


FigureB.19:DeformationoftheCLTconstructionforLC4(windfromthefront)in[mm]

FigureB.20:InternalnormalforcesintheCLTconstructionforLC1(self‐weight)in[kN/m]

Appendix


FigureB.21:InternalnormalforcesintheCLTconstructionforLC3(windfromthefront)in[kN/m]

FigureB.22:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC1(self‐weight)in[kN/m]

Appendix


FigureB.23:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC2(snow)in[kN/m]

FigureB.24:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC3(windfromthefront)in[kN/m]

FigureB.25:InternalnormalforcesinthefirststoreyoftheCLTconstructionforLC5(lifeload)in[kN/m]

Appendix


FigureB.26:InternalshearforcesinthefirststoreyoftheCLTconstructionforLC3(windfromthefront)in[kN/m]

FigureB.27:InternalshearforcesinthefirststoreyoftheCLTconstructionforLC4(windfromtheside)in[kN/m]

Appendix


C. SelectedANSYSresults

FigureB.28:Stressinglobalxdirectionσxoftheconnectionin[N/mm2]

FigureB.29:Stressinglobalydirectionσyoftheconnectionin[N/mm2]

Appendix


FigureB.30:Firstprinciplestressσ1oftheconnectionin[N/mm2]

FigureB.31:Straininglobalxdirectionεxoftheconnectionin[‐]

Appendix


FigureB.32:Straininglobalydirectionεyoftheconnectionin[‐]

LoadCalculation

TableofContents

LoadCalculation‐LucasBienert 2

TableofContentsTableofContents...............................................................................................................................................................2

Self‐weight............................................................................................................................................................................3

Liveloads............................................................................................................................................................................10

Snowloads.........................................................................................................................................................................10

WindLoads........................................................................................................................................................................12

Appendix.............................................................................................................................................................................18

Self‐weight


Self‐weightTechnicaldrawingsofthewall,floorandroofconstructionscanbefoundintheappendix.

a)FrameConstruction

roof characteristicweight dimensions spacing load γ b h a g gravel,protectivelayer 0,2 kN/m2/cm 5 cm 1 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2ventilation+counterbattens,C24 4,2 kN/m3 4 cm 3 cm 30 cm 0,02 kN/m2airtightinsulation,wood‐fibre 0,026 kN/m2/cm 2 cm 0,047 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2horizontalcarriers,C24 4,2 kN/m3 6 cm 16 cm 30 cm 0,13 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2 1,458 kN/m2roofjoists,glulamGL24h 3,7 kN/m3 14 cm 24 cm 65 cm 0,19 kN/m2

1,65 kN/m2

floor characteristicweight dimensions spacing load γ b h a g floortilesincl.mortar 0,3 kN/m2/cm 1 cm 0,30 kN/m2cementscreed 0,22 kN/m2/cm 3 cm 0,66 kN/m2footfallsoundinsulation,woodfibre 0,028 kN/m2/cm 4 cm 0,10 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2 1,15 kN/m2floorjoists,glulamGL24h 3,7 kN/m3 14 cm 24 cm 65 cm 0,19 kN/m2

1,34 kN/m2

outerwall,facade characteristicweight dimensions spacing load h=3,195m γ b t a g innerplywoodsheathing,spruce 0,05 kN/m2/cm 1 cm 0,06 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2verticalcarriers,C24 4,2 kN/m3 6 cm 16 cm 60 cm 0,07 kN/m2outerplywoodsheathing,spruce 0,05 kN/m2/cm 1 cm 0,06 kN/m2airtightinsulation,wood‐fibre 0,0235 kN/m2/cm 2 cm 0,04 kN/m2ventilation+battens,C24 4,2 kN/m3 4 cm 3 cm 60 cm 0,01 kN/m2cladding,wood 5 kN/m3 3 cm 0,13 kN/m2

0,44 kN/m2

b)PanelConstruction

roof1,2 characteristicweight dimensions spacing load γ b h a g gravel,protectivelayer 0,2 kN/m2/cm 5 cm 1 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2ventilation+counterbattens,C24 4,2 kN/m3 4 cm 3 cm 30 cm 0,02 kN/m2airtightinsulation,wood‐fibre 0,026 kN/m2/cm 2 cm 0,0468 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2horizontalcarriers,C24 4,2 kN/m3 6 cm 16 cm 30 cm 0,13 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2roofjoists,glulamGL24h 3,7 kN/m3 16 cm 24 cm 60 cm 0,24 kN/m2

1,69 kN/m2

Self‐weight


roof3 characteristicweight dimensions spacing load γ b h a g gravel,protectivelayer 0,2 kN/m2/cm 5 cm 1 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2ventilation+counterbattens,C24 4,2 kN/m3 4 cm 3 cm 30 cm 0,02 kN/m2airtightinsulation,wood‐fibre 0,026 kN/m2/cm 2 cm 0,0468 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2horizontalcarriers,C24 4,2 kN/m3 6 cm 16 cm 30 cm 0,13 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2roofjoists,glulamGL24h 3,7 kN/m3 8 cm 24 cm 60 cm 0,12 kN/m2

1,58 kN/m2

floor1,2 characteristicweight dimensions spacing load γ b h a g floortilesincl.mortar 0,3 kN/m2/cm 1 cm 0,30 kN/m2cementscreed 0,22 kN/m2/cm 3 cm 0,66 kN/m2footfallsoundinsulation,woodfibre 0,028 kN/m2/cm 4 cm 0,10 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2floorjoists,glulamGL24h 3,7 kN/m3 16 cm 20 cm 60 cm 0,20 kN/m2

1,35 kN/m2

floor3 characteristicweight dimensions spacing load γ b h a g floortilesincl.mortar 0,3 kN/m2/cm 1 cm 0,30 kN/m2cementscreed 0,22 kN/m2/cm 3 cm 0,66 kN/m2footfallsoundinsulation,woodfibre 0,028 kN/m2/cm 4 cm 0,10 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2floorjoists,glulamGL24h 3,7 kN/m3 8 cm 20 cm 60 cm 0,10 kN/m2

1,25 kN/m2

outermodulewall28/28studs characteristicweight dimensions spacing load h=3,195m γ b t a g innerplywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2studs,glulamGL24h 3,7 kN/m3 28 cm 28 cm 60 cm 0,48 kN/m2bottomblocking,glulamGL24h 3,7 kN/m3 16 cm 28 cm 0,05 kN/m2bottomplate,glulamGL24h 3,7 kN/m3 10 cm 24 cm 0,03 kN/m2topblocking,glulamGL24h 3,7 kN/m3 16 cm 28 cm 0,05 kN/m2outerplywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2airtightinsulation,wood‐fibre 0,0235 kN/m2/cm 2 cm 0,04 kN/m2ventilation+battens,C24 4,2 kN/m3 4 cm 3 cm 60 cm 0,01 kN/m2cladding,wood 5 kN/m3 3 cm 0,13 kN/m2

1,04 kN/m2

Self‐weight



0,90 kN/m2


0,78 kN/m2


0,67 kN/m2

Self‐weight



0,59 kN/m2

innermodulewall28/28studs characteristicweight dimensions spacing load h=3,195m γ b t a g innerplywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2soundinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2studs,glulamGL24h 3,7 kN/m3 28 cm 28 cm 60 cm 0,48 kN/m2bottomblocking,glulamGL24h 3,7 kN/m3 16 cm 28 cm 0,05 kN/m2bottomplate,glulamGL24h 3,7 kN/m3 10 cm 24 cm 0,03 kN/m2topblocking,glulamGL24h 3,7 kN/m3 16 cm 28 cm 0,05 kN/m2outerplywoodsheathing,spruce 0,05 kN/m2/cm 2 cm 0,09 kN/m2

0,88 kN/m2


0,73 kN/m2


0,61 kN/m2

Self‐weight


c)CLTConstruction

roof1 characteristicweight dimensions spacing load γ b h a g gravel,protectivelayer 0,2 kN/m2/cm 5 cm 1 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 1,8 cm 0,09 kN/m2ventilation+counterbattens,C24 4,2 kN/m3 4 cm 3 cm 30 cm 0,02 kN/m2airtightinsulation,wood‐fibre 0,026 kN/m2/cm 1,8 cm 0,0468 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2horizontalcarriers,C24 4,2 kN/m3 6 cm 16 cm 30 cm 0,13 kN/m2CLT 4 kN/m3 14,5 cm 0,58 kN/m2

1,95 kN/m2

roof2,3 characteristicweight dimensions spacing load γ b h a g gravel,protectivelayer 0,2 kN/m2/cm 5 cm 1 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 1,8 cm 0,09 kN/m2ventilation+counterbattens,C24 4,2 kN/m3 4 cm 3 cm 30 cm 0,02 kN/m2airtightinsulation,wood‐fibre 0,026 kN/m2/cm 1,8 cm 0,0468 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2horizontalcarriers,C24 4,2 kN/m3 6 cm 16 cm 30 cm 0,13 kN/m2CLT 4 kN/m3 20,9 cm 0,84 kN/m2

2,20 kN/m2

roof4 characteristicweight dimensions spacing load γ b h a g gravel,protectivelayer 0,2 kN/m2/cm 5 cm 1 kN/m2plywoodsheathing,spruce 0,05 kN/m2/cm 1,8 cm 0,09 kN/m2ventilation+counterbattens,C24 4,2 kN/m3 4 cm 3 cm 30 cm 0,02 kN/m2airtightinsulation,wood‐fibre 0,026 kN/m2/cm 1,8 cm 0,0468 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2horizontalcarriers,C24 4,2 kN/m3 6 cm 16 cm 30 cm 0,13 kN/m2CLT 4 kN/m3 9,5 cm 0,38 kN/m2

1,75 kN/m2

floor1 characteristicweight dimensions spacing load γ b h a g floortilesincl.mortar 0,3 kN/m2/cm 1 cm 0,30 kN/m2cementscreed 0,22 kN/m2/cm 3 cm 0,66 kN/m2footfallsoundinsulation,woodfibre 0,028 kN/m2/cm 3,6 cm 0,10 kN/m2CLT 4 kN/m3 14,5 cm 0,58 kN/m2

1,64 kN/m2

floor2,3 characteristicweight dimensions spacing load γ b h a g floortilesincl.mortar 0,3 kN/m2/cm 1 cm 0,30 kN/m2cementscreed 0,22 kN/m2/cm 3 cm 0,66 kN/m2footfallsoundinsulation,woodfibre 0,028 kN/m2/cm 3,6 cm 0,10 kN/m2CLT 4 kN/m3 20,9 cm 0,84 kN/m2

1,90 kN/m2

Self‐weight


floor4 characteristicweight dimensions spacing load γ b h a g floortilesincl.mortar 0,3 kN/m2/cm 1 cm 0,30 kN/m2cementscreed 0,22 kN/m2/cm 3 cm 0,66 kN/m2footfallsoundinsulation,woodfibre 0,028 kN/m2/cm 3,6 cm 0,10 kN/m2CLT 4 kN/m3 9,5 cm 0,38 kN/m2

1,44 kN/m2

outerwallt=170mm characteristicweight dimensions spacing load h=3,195m γ b t a g CLT 4 kN/m3 17,0 cm 0,68 kN/m2heatinsulation,woodfibre 0,005 kN/m2/cm 16 cm 0,08 kN/m2verticalcarriers,C24 4,2 kN/m3 6 cm 16 cm 60 cm 0,07 kN/m2outerplywoodsheathing,spruce 0,05 kN/m2/cm 1,2 cm 0,06 kN/m2airtightinsulation,wood‐fibre 0,0235 kN/m2/cm 1,5 cm 0,04 kN/m2ventilation+counterbattens,C24 4,2 kN/m3 4 cm 3 cm 60 cm 0,01 kN/m2cladding,wood 5 kN/m3 2,5 cm 0,13 kN/m2

1,06 kN/m2


0,96 kN/m2


0,86 kN/m2


0,76 kN/m2

Self‐weight


halfinnerdividingwallt=170mm characteristicweight dimensions spacing load h=3,195m γ b t a g CLT 4 kN/m3 17 cm 0,68 kN/m2soundinsulation,woodfibre 0,005 kN/m2/cm 8 cm 0,04 kN/m2

0,72 kN/m2

halfinnerdividingwallt=145mm characteristicweight dimensions spacing load h=3,195m γ b t a g CLT 4 kN/m3 14,5 cm 0,58 kN/m2soundinsulation,woodfibre 0,005 kN/m2/cm 8 cm 0,04 kN/m2

0,62 kN/m2

halfinnerdividingwallt=120mm characteristicweight dimensions spacing load h=3,195m γ b t a g CLT 4 kN/m3 12 cm 0,48 kN/m2soundinsulation,woodfibre 0,005 kN/m2/cm 8 cm 0,04 kN/m2

0,52 kN/m2

halfinnerdividingwallt=95mm characteristicweight dimensions spacing load h=3,195m γ b t a g CLT 4 kN/m3 9,5 cm 0,38 kN/m2soundinsulation,woodfibre 0,005 kN/m2/cm 8 cm 0,04 kN/m2

0,42 kN/m2

innerwallt=246mm characteristicweight dimensions spacing load h=3,195m γ b t a g CLT 4 kN/m3 24,6 cm 0,98 kN/m2

0,98 kN/m2

innerwallt=170mm characteristicweight dimensions spacing load h=3,195m γ b t a g CLT 4 kN/m3 17 cm 0,68 kN/m2

0,68 kN/m2

innerwallt=95mm characteristicweight dimensions spacing load h=3,195m γ b t a g CLT 4 kN/m3 9,5 cm 0,38 kN/m2

0,38 kN/m2

Liveloads


LiveloadsVerticalLifeLoads

category description q kN/m Q kNA residential buildings, kitchen, bathroom, living and

sleepingrooms,e.g.inhospitals,hotels

floor 2,5* 2,0H roofs,notwalkable,onlymaintenance slopeα 0° 20° 0,75 1,5* including0,5kN/m additionalloadfornon‐loadbearingwalls

reductionfactorforverticaldistributedliveloadsq inmultiplestoreys

α2 n 2 ψ

n

α2 14 2 ⋅ 0,7

140,74

n 14

loadcategory A(ψ 0,7)

SnowloadssnowloadonthegroundforBergen,Hordaland,South‐Norway

s , 2,0kN/m

H 150m

H 2m. o. h.

s 2,0kN/m

snowloadontheroof

s μ ⋅ C ⋅ C ⋅ s exposurefactorC 1,0(normalexposure)

thermalfactorC 1,0

s μ ⋅ s

Snowloads


Figure1:Roofreference

Roof1

α 0° 15°

μ 0

b 2,10m

b 9,275m

h 52,92 49,92 3,0m

μb b2 ⋅ h

2,10 9,2752 ⋅ 3,0

1,90 2 ⋅ 3,67/2 3,67

s 1,90 ⋅ 2,0 3,80kN/m

Onthesafeside,thehighersnowloadisconsideredtobeconstantalongthelengthoftheroofofthelift,until4,08mbeforetheendoftheroof,andthendecreaselinearly.

l 2 ⋅ 3,0 6,0m 4,08m

μ 0,81,90 0,8

6,06,0 4,08 1,15

s 1,15 ⋅ 2,0 2,30kN/m

Roof2

α 0°

WindLoads


μ 0,8

s 0,8 ⋅ 2,0 1,6kN/m

Roof3

α 0° 15°

μ 0

b2,10 7,295

24,70m

b 9,275m

h 52,92 49,92 3,0m

μ4,70 9,275

2 ⋅ 3,02,33 2 ⋅ 3,00/2 3,00

s 2,33 ⋅ 2,0 4,66kN/m

l 2 ⋅ 3,0 6,0m b 9,275m

Figure2:Summaryofthesnowloadsontheroof

WindLoadsreferencewindspeedforterraincategoryII(openterrainwithindividualhousesortrees)

v , 26m/s v 30m/s

basicwindspeedwithdirectionfactorc 1,0,seasonfactorc 1,0andprobabilityfactorc 1,0.

H 2m. o. h.

H 900m

H 1500m

WindLoads


c 1,030 26 2 90026 1500 900

0,77 1,0

c 1,0

v 1,0 ⋅ 26 26m/s

10minutesaveragewindspeedovertheheightzforterraincategoryIV

roughnessfactor:k 0,24

roughnesslength:z 1,0m

z 16m

z 200m

c z 0,24 ⋅ lnz

1,0 m z z z

c z c z z

terrainformfactor: 1,0

0,24 ⋅1,0

⋅ 26 /

turbulenceintensity(ratiobetweenthestandardderivationfortheinstantaneouswindspeed(1second)andthe10minutesaveragewindspeed)

turbulencefactor: 1,0

1,0

1,0 ⋅ 1,0

10minutesaveragewindspeedpressure

airdensity 1,25 /

0,5 ⋅ 1,25 / ⋅

gustwindspeedpressure

peakfactor 3,5

1 2 ⋅ 3,5 ⋅ ⋅

generalgeometry

52,92 2,0 50,92

20,65

22,34

WindLoads


2

windfromthefront/back

20,65

0

20,65 16

50,92 20,65 30,27

50,92 200

i

3 50,92 24,52 0,254 375,8 1044,02 30,27 21,28 0,293 283,0 863,41 20,65 18,17 0,330 206,3 683,0

windfromthesides

22,34

0

22,34 16

50,92 22,34 28,58

50,92 200

i

3 50,92 24,52 0,254 375,8 1044,02 28,58 20,92 0,298 273,5 844,01 22,34 19,38 0,322 234,7 763,7

WindLoads


Figure3:Summaryofthegustwindspeedpressure

windpressure

⋅

windpressureonthewalls


22,34

20,65

22,3420,65

5 5 ⋅ 20,65 103,25

/ 50,92/20,65 2,47

WindLoads


A B D E

, ‐1,2 ‐0,8 0,8 ‐0,57

, ‐1,4 ‐1,1 1,0 ‐0,57

windfromthesides

20,65

22,34

20,65 22,34

/ 50,92/22,34 2,28

areaCisneglected

A B D E

, ‐1,2 ‐0,8 0,8 ‐0,56

c , ‐1,4 ‐1,1 1,0 ‐0,56

WindLoads


windpressureontheroof


F G Hc , ‐1,8 ‐1,2 ‐0,7

c , ‐2,5 ‐2,0 ‐1,2

windfromthesides

F G H Ic , ‐1,8 ‐1,2 ‐0,7 /‐0,2

c , ‐2,5 ‐2,0 ‐1,2 /‐0,2

Appendix


Appendix

a)FrameConstruction

Figure4:Verticalsectionthroughthewallandtheflooroftheframeconstruction

Appendix


Figure5:Verticalsectionthroughthewallandtheroofoftheframeconstruction

Appendix


b)PanelConstruction

Figure6:Verticalsectionthroughthewallandthefloorofthepanelconstruction

Appendix


Figure7:Verticalsectionthroughthewallandtheroofofthepanelconstruction

Appendix


c)CLTConstruction

Figure8:VerticalsectionthroughthewallandtheflooroftheCLTconstruction

Appendix


Figure9:VerticalsectionthroughthewallandtheroofoftheCLTconstruction

PreliminaryDesign

TableofContents

PreliminaryDesign‐LucasBienert 2


General...................................................................................................................................................................................4

Remarks............................................................................................................................................................................4

DescriptionoftheBuilding.......................................................................................................................................4

LoadbearingConcept...................................................................................................................................................4

Assumptions....................................................................................................................................................................6

Materials...........................................................................................................................................................................6

Software............................................................................................................................................................................7

Literature..........................................................................................................................................................................7

PreliminaryDesignFormulae..................................................................................................................................7

Loads..................................................................................................................................................................................8

a)FrameConstruction..................................................................................................................................................11

3.1Joists.........................................................................................................................................................................12

3.2Joists.........................................................................................................................................................................13

2.2Beam.........................................................................................................................................................................14

2.1Beam.........................................................................................................................................................................16

2.3Beam.........................................................................................................................................................................18

7Diaphragm.................................................................................................................................................................20

8Frame...........................................................................................................................................................................21

2.4Beam(Front)........................................................................................................................................................22

2.4Beam(Side)...........................................................................................................................................................24

1Columns......................................................................................................................................................................27

4Diagonal......................................................................................................................................................................31

5StructuralSheathingoftheFloors...................................................................................................................33

6VerticalFaçadeCarriers......................................................................................................................................35

ConnectionsOverview.............................................................................................................................................36

ConnectionBeam2.2toColumn1.1..................................................................................................................37

ConnectionOuterBeam2.4ontheSidetoColumn1.3..............................................................................38

ConnectionDiagonal4toColumn1.2................................................................................................................40

ConnectionSheathing5toJoists3......................................................................................................................42

ConnectionJoists3toBeams2............................................................................................................................43

b)PanelConstruction....................................................................................................................................................44

1.1FloorJoists.............................................................................................................................................................45

1.2FloorJoists.............................................................................................................................................................46

TableofContents


1.3FloorJoists.............................................................................................................................................................47

3Walls/Studs...............................................................................................................................................................48

3.y8StudsinWally3.................................................................................................................................................50

3.y1StudsinWally1.................................................................................................................................................54

4Sheathing...................................................................................................................................................................57

2FloorBeam................................................................................................................................................................59

6Beam............................................................................................................................................................................60

5Columns......................................................................................................................................................................62

ConnectionsOverview.............................................................................................................................................63

Anchoring......................................................................................................................................................................64

ConnectionFloorJoists1toFloorBeam2......................................................................................................66

ConnectionFloorBeam2toStuds3..................................................................................................................67

c)CLTConstruction.......................................................................................................................................................69

1FloorSlab...................................................................................................................................................................70

2,3FloorSlab..............................................................................................................................................................71

4FloorSlab...................................................................................................................................................................72

5Walls............................................................................................................................................................................73

5.y5OuterWall...........................................................................................................................................................75

Anchoring......................................................................................................................................................................78

Appendix.............................................................................................................................................................................79

Attachments.................................................................................................................................................................79

b)PanelConstruction...............................................................................................................................................80

c)CLTConstruction...................................................................................................................................................88

General


General

Remarks

This documentation summarises the results of the preliminary design. The relevant files areattachedforfurtherreference.Technicalreferenceplansarealsoattached(cf.appendix).

DescriptionoftheBuilding

ThesubjectofthisdesignisthebuildingTreet,locatedinBergen,Norway.Theexactaddressis:

Damsgårdsveien995058BergenHordaland,South‐Norway

Three different structures will be designed for this building, using three different timberconstructionmethods:

a) frameconstruction

b) panelconstruction

c) CLTconstruction

Thedimensionsofthebuildingarea/b/h 22,34/20,65/47,925m.Itconsistsofasinglelevelundergroundcarparkplus14normalstoreys,eachhavingaheightof3,195m.Theusageofthebuildingispurelyresidential.Eachstoreyconsistsof5units,4ofthemareapartmentsandoneiseitherastorageroomoranother,smallerapartment.

Eachstoreyhasacentralcorridorandallstoreysareconnectedviaalargestaircaseandaliftinthemiddleandsecondarystairwayononesideofthecorridor.

Thebuildinghasflatroofs,withtheareaofthecorridor,thestaircasesandtheliftsprotrudingonestorey higher than the apartments (which gives a height of 47,925 3,195 51,12m at thehighestpoint).Therefore,snowdriftsmustbeconsideredonthelowerroofs.

LoadbearingConcept

a)FrameConstruction

Theverticalloadsfromthefloorsarecarriedbythefloorjoists(elementreferencenumber3,cf.elementreferenceplanPa1.1)whichrunalongtheverticalaxes.Thejoistsaresingle‐spanbeamsandaresupportedbythebeams(2)whichrunperpendiculartothejoists,alongthehorizontalaxes.

Thebeamsarecompoundbeamsconsistingoftwoidenticalcross‐sectionsthatareattachedtothecolumns(1)onbothsides.TwoadditionalbeamsareattachedtotheoutsideofthecolumnsintheverticalaxesAandF.

Tostabilisethestructureagainstwind,diagonals(4)areaddedinbetweentheoutercolumns,formingtwoframesineachdirection.

Thewindpressureactsonthefaçade,inwhichverticalcarriers(6)carrythebendingmoment.Theverticalcarriersspanonestoreyandtransferthewindloadstotheouterbeams(2.4)andintothe floors.The floors act asdiaphragmswith the structural sheathing (5)providing the shearstiffnesstopasstheloadsontotheframesoneachside.

General


Thediaphragmsbehavelikesimplysupportedbeams.Theframesarethesupports,thebeams2.4theflanges,takingcompressionandtensionforces,andthesheathingthechord,takingtheshear.

Wind suctionon the roofwasnot considered, it canbe carriedby thebattens andhorizontalcarriersintheroofstructure,butisnotdecisiveincomparisontothesnowloadandself‐weight.

b)PanelConstruction

Thepanelconstructionfeaturestwelveprefabricatedmodulesperstoreythatconsistofwallsandthefloor(theuppersideisclosedwhenthenextmoduleisplacedontop).

Thevertical loadsarecarriedbythefloorjoists(1,cf.elementreferenceplanPb4.1).Theyaresupportedbythefloorbeams(2)whichareattachedtotheinsideofthewallsandtransfertheloadsintothewalls.Thewallsconsistofverticalstuds(3)whichcarrytheloads,thestructuralsheathing(4)whichprovidestheshearstiffnessandhorizontalblockinginbetweenthestuds.

Themodules1,2,6and7(cf.modulereferenceplanPb3)areopenononeofthefoursides.There,thefloorissupportedbyabeam(6)onfourcolumns(5).

Tocarrythehorizontalwindloads,thefloorsactasdiaphragmsandthewallsasshearwallswiththesheathingprovidingthenecessaryshearstiffness.Tocalculatetheloadsontheshearwallsfromthewind,astabilityanalysismustbeconducted.

Thenon‐loadbearingwallsinsidetheapartmentsarenotconsideredforstabilitytomakelaterchangestotheinteriorlayoutpossible.Thedoublewallswheretwomodulesmeetareconsideredastwoseparatewalls.

Forthestabilityanalysis,thebuildingisidealisedasaverticalcantileverbeamwiththemaximumverticalloads,horizontalshearandglobalbendingmomentatthesupportatthefoundation.Theshareofeverywallinshearandinbendingiscalculatedandtheverticalloadsfromtheself‐weightandthelifeloadareadded.Tocarrytheglobalbendingmoment,eachwallcarriesashareofthisbendingmomentdependingonitsstiffnessandanormalforcedependingonitsdistancetothecentreofgravity.

The studs carry the vertical forces in the walls. The studs in the outer walls also carry thehorizontalloadfromthewindandtransfertheseloadsintothediaphragms.

Onlyselectedstudsareconsideredtobeloadbearingandhaveanaccordinglylargercross‐sectioncomparedtothenon‐loadbearingstuds.Allstudsarearrangedonaregulargridwhichisfittedtothesizesoftheplywoodpanelsthatformthesheathingofthewalls.

Fortensilestresses,specialhold‐downdevicesfunctionasanchoring.Thelargesttensilestresseswill also occur at the support since the global bending moment, which causes the tension,increasesquadraticallywhiletheself‐weight,whichcancelsoutpartofthetension,onlyincreaseslinearlyovertheheight.

c)CLTConstruction

TheCLT‐constructionconsistssolelyofmasstimberpanelsmadefromCLT.Panelswithdifferentthicknessesareusedforthedifferentwalls(5,cf.elementreferenceplanPc3.1)andfloorslabs(1–4).Betweendifferentapartments,doublewallsareusedtoincreasethesoundprotection

Tocarrythehorizontalwindloads,thefloorsactasdiaphragmsandthewallsasshearwalls.Tocalculatetheloadsontheshearwallsfromthewind,astabilityanalysismustbeconducted.

Thenon‐loadbearingwallsinsidetheapartmentsarenotconsideredforstabilitytomakelaterchangestotheinteriorlayoutpossible.Thedoublewallsareconsideredastwoseparatewalls.

General


Toavoid large compression stressesperpendicular to thegrain, the floor slabs arenotput inbetweenthewallelements,butsetintoagroovecutintothelowerwall.

Toaccount for firesafety,onlyCLT‐panelswithat least5 layersareused. If theouter layer isdestroyedduringafire,thenextlayer,whichisorientedperpendiculartotheouterlayer,isalsorenderedineffectiveforthebearingoftheloadsandthreelayersremain,twoinloaddirectionandoneperpendiculartothat.Thus,theelementisstillabletocarryareducedamountofloads.

Assumptions

For the preliminary design, all checks are made with characteristic values and reducedpreliminarydesignstrengths.Theusedmaterialpropertiesaresummarisedintable…

material property preliminarydesignvaluesolid wood,glulam

strengthparalleltothegrain σ 5 N/mm

compressionstrengthperpendiculartothegrain σ , 1,5N/mm

Young’smodulus E 10000N/mm

plywood shearstrength σ , 1,5N/mm

out‐of‐planebendingstrength σ 8 N/mm

Young’smodulus E 4 000N/mm CLT strengthinthestrongdirection σ 5 N/mm

strengthintheweakdirection σ 4 N/mm

in‐planebendingaroundthestrongaxis σ , 4N/mm

compressionstrengthperpendiculartothegrain σ , 1,5N/mm

in‐planeshearstrength σ , 0,6N/mm

Young’smodulus E 4 000N/mm

steel strength σ 140N/mm

FortheCLT,thevaluesarederivedfromthetechnicalapproval[1].Thisdocumentalsoincludesrecommendationsconcerningthespanlengthofslabelements,whichareusedforthepreliminarydesign.

The loads in multi‐storey buildings change strongly over the height. In this design, only therequired cross‐sections in the lowest storey, where the loads are highest, are determined.Assumingtheforcesresultingfromtheverticalloadstochangelinearlyandtheforcesfromthebendingduetothewindloadstochangequadraticallyovertheheight,reducedcross‐sectionsortheupperstoreysareestimated.

Materials

Forthepreliminarydesign,noconcretestrengthclassesaredefinedyet,insteadthepreliminarydesignstrengthsareused(seetableabove).OnlyfortheCLTaspecificmaterialischosen,becausethepropertiesofthismaterialarenotdefinedinstandardsbutbythemanufacturerdirectly.

woodenmembers(beams,studs,floorjoists,…):glulam structuralsheathing:plywood CLTbyMartinsons(distributedinNorwaybySplitkonAS)

General


Software

Stab2d(simpleanalysisprogramfortwo‐dimensionalframeworks) MicrosoftEXCEL©

Extracts from the calculations with EXCEL can be found in the appendix. The EXCEL‐filesthemselvesarealsoattachedformoredetailedinformation.

Literature

[1] TekniskGodkjenningMartinsonsKL‐trä[2] BautabellenfürIngenieure,20thedition2012

Thetechnicalapproval[1]containstableswithrecommendedthicknessesforfloorslabsthathavebeenusedforthepreliminarydesign.

PreliminaryDesignFormulae

Thesimplifieddesignformulaeusedforthispreliminarydesignaretakenfrom[2].

element property formulafloorjoist height h l/20steelbolts,dowels capacity per fastener single

shearF 2,0 ⋅ d

capacityperfastener doubleshear

F 4,4 ⋅ d

requiredspaceperfastener req A 30 ⋅ d capacity at an angle to thegrain

F 1α360

⋅ F

capacitywithsteelplate F 1,25 ⋅ Ffullythreadedscrews capacity per screw axial

tensionF 5 ⋅ d

requiredspaceperscrew req A 60 ⋅ d nails capacitypernail shear F 3,5 ⋅ d din cm Ain cm Fin kN

Forcontinuousbeams,thereactionforcesarehigherthanforrowswithsimplysupportedbeams.Toaccountforthiscontinuityeffect,afactorof1,15isaddedincaseswhereit ispossiblethatbeamsactascontinuousbeams.

Toaccountforbuckling,generallyonly70%ofthestrengthareconsidered(factor0,7).Forthestudsinthepanelconstruction,afactorof0,8isused,becausethesheathingpreventsthestudsfrombucklingaroundintheirweakdirection.

General


Loads

Simplifiedloadsareusedforthepreliminarydesign.

verticalloads

liveload q 2,0 kN/mself‐weightfloors g 2,0 kN/mself‐weightwalls g 1,0 kN/msnowload s 2,0 kN/m

reductionfactorforlifeloadoverseveralstoreys

α 0,74

windloads

General


windfromthefront

c , A ‐1,2B ‐0,8D +0,8E ‐0,57

horizontalwindforce

q , 1,044 ⋅ 20,650,8634 0,6830

2⋅ 9,62 0,6830 ⋅ 20,65 43,1kN/m

Q , 43,1 ⋅ 22,34 962,9kN

c D E 0,8 0,57 1,37

W 1,37 ⋅ 962,9 1319kN

bendingmomentofthecantileverbeam

m , 1,044 ⋅ 20,65 ⋅ 50,9220,652

0,683 ⋅ 9,62 ⋅ 20,659,622

12⋅ 0,8643 0,683 ⋅ 9,62 ⋅ 20,65

23⋅ 9,62

0,683 ⋅ 20,65 ⋅20,652

1212kNm/m

M , 1212 ⋅ 22,34 27076kNm

c D E 0,8 0,57 1,37

M 1,37 ⋅ 27076 37094kNm

General


windfromthesides

c , A ‐1,2B ‐0,8D +0,8E ‐0,57

totalhorizontalwindforce

q , 1,044 ⋅ 22,340,844 0,7637

2⋅ 6,24 0,7637 ⋅ 22,34 45,4kN/m

Q , 45,4 ⋅ 20,65 937,5kN

c D E 0,8 0,56 1,36

W 1,36 ⋅ 937,5 1275kN


m , 1,044 ⋅ 22,34 ⋅ 50,9222,342

0,7637 ⋅ 6,24 ⋅ 22,346,242

12⋅ 0,844 0,7637 ⋅ 6,24 ⋅ 22,34

23⋅ 6,24

0,7637 ⋅ 22,34 ⋅22,342

1246kNm/m

M , 1246 ⋅ 20,65 25722kNm

c D E 0,8 0,56 1,36

M 1,36 ⋅ 25722 34982kNm

a)FrameConstruction


a)FrameConstructionElementReferenceOverview

referenceno element page

1 columns

1.1 innercolumns 27

1.2 cornercolumns 27

1.3 sidecolumns 27

1.4 sidecolumns 27

2 beams

2.1 beam 16

2.2 beam 14

2.3 beam 18

2.4 beam 22

3 joists

3.1 joists 12

3.2 joists 13

4 diagonal 31

5 structuralsheathingofthefloors 33

6 verticalfaçadecarriers 35

7 diaphragm 20

8 frame 21

connectionsoverview 36

a)FrameConstruction


3.1Joists

system

l9,2752

4,64m

hl20

46420

23,2cm

selectedspacing:e 65cm

loads

q 2,0kN/m

g 2,0kN/m

loadsononejoist

q 2,0 ⋅ 0,65 1,3kN/m

g 1,3kN/m

internalforces

maxM 2 ⋅ 0,125 ⋅ 1,3 ⋅ 4,64 7,0 kNm

reqW 700/0,5 1400cm

selecteddimensions

b/h 14/24e 65cm

I 16128 cm

W 1344 cm

deformation

maxδ2 ⋅ 1,3/100 ⋅ 46476,8 ⋅ 1000 ⋅ 16128

0,973cm

l/250 464/250 1,86cm

maxreactionforces

A 0,5 ⋅ 1,3 ⋅ 4,64 3,02kN

A 0,5 ⋅ 1,3 ⋅ 4,64 3,02kN

A 6,03kN

a)FrameConstruction


3.2Joists

system

l 2,10m

loads

q 2,0kN/m

g 2,0kN/m

loadsononejoist

q 2,0 ⋅ 0,65 1,3kN/m

g 1,3kN/m


selecteddimensions

b/h 14/24e 65cm

I 16128cm

W 1344cm

joist3.2isnotdecisive,thesamedimensionsareselectedasforjoist3.1

maxreactionforces

A 0,5 ⋅ 1,3 ⋅ 2,1 1,37kN

A 0,5 ⋅ 1,3 ⋅ 2,1 1,37kN

A 2,73kN

a)FrameConstruction


2.2Beam

system

l 4,47m forsimplicity,anaveragespaniscalculated

loads

g3,020,65

4,65kN/m

q 4,65kN/m

[email protected] 0,65misthespacingofthefloorjoists,

thereactionforcesareconvertedtodistributedloads

internalforces

maxmomentinthefirstfield

maxM 0,078 0,100 ⋅ 4,65 ⋅ 4,47 16,54kNm

reqW 1654/0,5 3308cm

correspondingmomentatthesupportB

M 0,105 0,053 ⋅ 4,65 ⋅ 4,47 14,7kNm

maxmomentatthesupport

maxM 0,105 0,12 ⋅ 4,65 ⋅ 4,47 20,9kNm

reqW 2090/0,5 4181cm

selecteddimensions

b/h 16/42I 98784 cm

W 4704 cm

a)FrameConstruction


deformation

maxδ2 ⋅ 4,65/100 ⋅ 44776,8 ⋅ 1000 ⋅ 98784

147016 ⋅ 1000 ⋅ 98784

⋅ 447

0,489 0,186 0,30cm

l/250 447/250 1,79cm

substitutesystem:

maxreactionforces

A 0,395 ⋅ 4,65 ⋅ 4,47 8,2kN

A 0,447 ⋅ 4,65 ⋅ 4,47 9,3kN

A 17,5kN

B 1,132 ⋅ 4,65 ⋅ 4,47 23,5kN

B 1,218 ⋅ 4,65 ⋅ 4,47 25,3kN

B 48,8kN

C 0,974 ⋅ 4,65 ⋅ 4,47 20,2kN

C 1,167 ⋅ 4,65 ⋅ 4,47 24,3kN

C 44,5kN

a)FrameConstruction


2.1Beam

system

l 4,47m averagespan

loads

g3,020,65

4,65kN/m

q 4,65kN/m

[email protected]

dimensions

b/h 16/42I 98784cm

W 4704cm

beam2.1isnotdecisive,thesamedimensionsareselectedasforbeam2.2

a)FrameConstruction


maxreactionforces

A 0,395 ⋅ 4,65 ⋅ 4,47 8,2kN

A 0,447 ⋅ 4,65 ⋅ 4,47 9,3kN

A 17,5kN

B 1,132 ⋅ 4,65 ⋅ 4,47 23,5kN

B 1,218 ⋅ 4,65 ⋅ 4,47 25,3kN

B 48,8kN

C 0,974 ⋅ 4,65 ⋅ 4,47 20,2kN

C 1,167 ⋅ 4,65 ⋅ 4,47 24,3kN

C 44,5kN

a)FrameConstruction


2.3Beam

system

l 4,47m averagespan

loads

g1,370,65

2,1kN/m

q 2,1kN/m

[email protected]

dimensions

b/h 16/42I 98784cm

W 4704cm

beam2.3isnotdecisive,thesamedimensionsareselectedasforbeam2.2

a)FrameConstruction


maxreactionforces

A 0,395 ⋅ 2,1 ⋅ 4,47 3,7kN

A 0,447 ⋅ 2,1 ⋅ 4,47 4,2kN

A 7,9kN

B 1,132 ⋅ 2,1 ⋅ 4,47 10,6kN

B 1,218 ⋅ 2,1 ⋅ 4,47 11,4kN

B 22,1kN

C 0,974 ⋅ 2,1 ⋅ 4,47 9,1kN

C 1,167 ⋅ 2,1 ⋅ 4,47 11,0kN

C 20,1kN

a)FrameConstruction


7Diaphragm

system

windload windfromthefrontbecomesdecisive

maxw D E 1,044 ⋅ 0,8 0,571,43kN/m

w 1,15 ⋅ 1,43 ⋅ 3,195 5,25kN/m

h 3,195 mistheheightofonestorey theverticalcarriersinthefaçade(6)in

betweenthebeams2.4aresingle‐spanbeams;toaccountforcontinuityeffects,afactorof1,15isadded

internalforces

|P | |P |5,25 ⋅ 22,34

8/20,65 15,9kN

V5,25 ⋅ 22,34

258,6 kN

a)FrameConstruction


8Frame

system


maxw D E 1,044 ⋅ 0,8 0,571,43kN/m

internalforces

normalforces[kN]

a)FrameConstruction


2.4Beam(Front)

Thebeam2.4onthefrontofthebuildingissubjectedmultipleloads:

horizontalbendingfromthewind verticalbendingfromtheself‐weightofthefaçade compressionortensionaspartofthediaphragm

Windfromthefrontbecomesdecisive.

system

loads

self‐weightofthefaçade(vertical)

g 1kN/m

g 1,15 ⋅ 1 ⋅ 3,195 3,67kN/m

windload(windfromthefront,windareaD,horizontal)

w D 1,044 ⋅ 0,8 0,84kN/m

w 1,15 ⋅ 0,84 ⋅ 3,195 3,09kN/m

compressionfromthediaphragm

|P | 15,9kN

factor1,15toaccountforcontinuityeffects

dimensions

b/h 16/42A 672cm W 4704cm

W 1792cm

thesamedimensionsareselectedasforbeam2.2

a)FrameConstruction


internalforces

windload

maxM 4,41kNm

self‐weightofthefaçade

maxM 5,24kNm

σ4411792

5244704

15,9672

0,38kN/cm

0,5kN/cm

Forthewindload,thebeamisbentarounditsweakaxis(z)andfortheself‐weightofthefaçadearounditsstrongaxis(y).

maxreactionforces

windload

A 5,46kN

B 14,55kN

C 14,5kN


A 6,49kN

B 17,3kN

C 17,2kN

a)FrameConstruction


2.4Beam(Side)

Thebeam2.4onthesideofthebuildingissubjectedmultipleloads:

horizontalbendingfromthewind verticalbendingfromtheself‐weightofthefaçade compressionor tensionaspartof the frame(togetherwith theoutercolumnsand the

diagonals)

Windfromthefrontbecomesdecisive.

system

globalsystem(frame)

localsystem

loads


g 1kN/m

g 1,15 ⋅ 1 ⋅ 3,195 3,67kN/m


a)FrameConstruction


windload(windfromthefront,windareaAandB,horizontal)

w A 1,2 ⋅ 1,044 1,25kN/m

w 1,15 ⋅ 1,25 ⋅ 3,195 4,59kN/m

w B 0,8 ⋅ 1,044 0,84kN/m

w 1,15 ⋅ 0,84 ⋅ 3,195 3,09kN/m

dimensions

b/h 16/42A 672cm W 4704cm

W 1792cm

thesamedimensionsareselectedasforbeam2.2

internalforces

windload

maxM 7,94kNm


maxM 5,87kNm

normalcompressionforcefromtheframe

N 243kN

check

σ7941792

5874704

243672

0,93kNcm

0,5kN/cm

woodhasgoodstressredistributionproperties,whicharenotconsideredhere,theresultisthereforeacceptedforthepreliminarydesign

forthewindload,thebeamisbentarounditsweakaxis(z)andfortheself‐weightofthefaçadearounditsstrongaxis(y)

a)FrameConstruction


maxreactionforces

windload

A 8,55kN

B 21,5kN

C 9,94kN


A 6,59kN

B 20,1kN

C 11,3kN

a)FrameConstruction


1Columns

loads

self‐weightandliveload

reactionforcesofthebeams

windload(windfromthefront,windareaD+E)

horizontalwindforce

W 1319kN

W 1319/2 659,5kN oneframetakeshalfthetotalwindforce


M 1,37 ⋅ 27076 37094kNm

M 37094/2 18547kNm oneshearframetakeshalfthetotalmoment

internalforces

self‐weightandliveload theloadperstoreyN isaddedupfortheroofandthe14storeyswithareductionfactorα 0,74fortheliveload

a)FrameConstruction


column load 1.1 N , 2 ⋅ 23,5 47,0kN

N , 2 ⋅ 25,3 50,6kNN 47,0 ⋅ 15 50,6⋅ 1 14 ⋅ 0,74 1600 kN

[email protected](eachcolumncarriestheloadfromtwobeams)

1.2 N , 8,2 6,49 6,59 21,3 kNN , 9,3kNN 21,3 ⋅ 15 9,3⋅ 1 14 ⋅ 0,74 425,1 kN

[email protected] [email protected](front) [email protected](side)

1.3 N , 2 ⋅ 8,2 20,1 36,5 kNN , 2 ⋅ 9,3 18,6kNN 36,5 ⋅ 15 18,6⋅ 1 14 ⋅ 0,74 758,8 kN

[email protected] [email protected](side)

1.4 N , 8,2 3,7 11,3 23,2 kNN , 9,3 4,2 13,5kNN 23,2 ⋅ 15 13,5⋅ 1 14 ⋅ 0,74 501,4 kN

[email protected][email protected] [email protected](side)

windload

Theframesconsistoftwohalfframeswithdiagonalsthatareconnectedviathebeams2.4.

columns1.2,1.4

N18547/29,275

1000kN

column1.3

N 1000/2 500 kN

thenormalforcesinthecolumnsareestimated:themomentisdistributedoverthetwohalfframes,whereapairofforcescreatesthereactionmoment

a)FrameConstruction


This table sums up the results for all columns. The required cross‐sections are calculatedconsideringafactorof0,7forthecompressioncapacitytoaccountforbuckling.

column self‐weight andliveload[kN]

windload[kN] totalload[kN] A [cm

1.1 1600 0 1600 45711.2 425,1 1000 1425,1 40721.3 758,8 500 1258,8 35971.4 501,4 1000 1501,4 4290

selecteddimensions

b/h 40/120A 4800cm

inthefirststep,allcolumnshavethesamedimensions

Withthoseestimateddimensionsandtheestimateddimensionsofthediagonals(seebelow),asimpletwo‐dimensionalframeworkanalysisisconductedtoobtainmoreaccurateresultsfortheforces due to the wind. The results are shown in the following table. The dimensions of thecolumnsareadjusted.

1.step


windload[kN] totalload[kN] A [cm selecteddimensions

1.1 1600 0 1600 4571 40/1201.2 425,1 636,6 1062 3034 40/801.3 758,8 232,3 991 2831 40/801.4 501,4 815,1 1317 3763 40/120

2.step

Theanalysisisrepeatedwiththenewdimensionswhichleadstothefollowingfinalresults(cf.8Frame).


windload[kN] totalload[kN] A [cm selecteddimensions

1.1 1600 0 1600 4571 40/1201.2 425,1 613,7 1039 2968 40/801.3 758,8 185,5 944 2698 40/801.4 501,4 839,1 1341 3830 40/120

The cross‐section of the column can decrease over the height of the building because of thedecreasing loads. Assuming the loads due to the self‐weight and the life load (N) to decreaselinearlyandtheloadsduetothewind(M)todecreasequadratically,thefollowingcross‐sectionsarecalculated:

a)FrameConstruction


column1.1 column1.2 column1.3 column1.4storeyno M N b/h b/h b/h b/h‐ [%] [%] [cm/cm] [cm/cm] [cm/cm] [cm/cm]

0 100,00 100,00 40/120 40/80 40/80 40/1201 87,11 93,33 40/120 40/80 40/80 40/1202 75,11 86,67 40/120 40/80 40/80 40/1203 64,00 80,00 40/120 40/80 40/80 40/1204 53,78 73,33 40/100 40/60 40/60 40/805 44,44 66,67 40/100 40/60 40/60 40/806 36,00 60,00 40/100 40/60 40/60 40/807 28,44 53,33 40/100 40/60 40/60 40/808 21,78 46,67 40/60 40/40 40/40 40/609 16,00 40,00 40/60 40/40 40/40 40/6010 11,11 33,33 40/60 40/40 40/40 40/6011 7,11 26,67 40/60 40/40 40/40 40/6012 4,00 20,00 40/40 40/40 40/40 40/4013 1,78 13,33 40/40 40/40 40/40 40/4014 0,44 6,67 40/40 40/40 40/40 40/4015 0,00 0,00 40/40 40/40 40/40 40/40

Note that thecolumns1.2,1.3and1.4onthesidescannotbesmaller than40/60becausethebeamsareattachedtothem.

a)FrameConstruction


4Diagonal

Thediagonalsarepartoftheframesandthusresponsibleforthetransferofthewindloads.

system

angleofthediagonals

α arctan4 ⋅ 3,1959,275

54°

h 3,195 mistheheightofonestorey

loads

bendingmomentatthesupport

M 18547kNm

calculationofthewindloadsseeabove

simplifiedconstantwindpressure

w 2 ⋅ 18547/50,92 14,3kN/m

bendingmomentatthetopendofthediagonal

M12⋅ 14,3 ⋅

34⋅ 50,92 10428 kNm

forsimplicity,thewindpressureisconvertedintoanequivalentconstantload

internalforces

normalforceinthecolumnatthebottomendofthediagonal(seeabove)

N18547/29,275

1000kN

normalforceinthecolumnatthetopendofthediagonal

N10428/29,275

562 kN

tocalculatetheforceinthediagonal,thenormalforcesinthecolumnsatitsbottomend(atthesupport)andatitstopendareestimated

a)FrameConstruction


forceinthediagonal

F1000 562cos 54

745kN

A745

0,7 ⋅ 0,52129cm

factor0,7toaccountforbuckling

selecteddimensions

b/h 48/48

Thesimpletwo‐dimensionalframeworkanalysisleadstomoreaccurateresults(cf.above).

(…)

finalresults

F 512,2kN

A 1463cm

b/h 40/40

a)FrameConstruction


5StructuralSheathingoftheFloors

Thesheathingofthefloorshastwomainfunctions:

provide shear stiffness for the floor diaphragm (shear in the vertical sections, i.e.perpendiculartothesurfaceofthesheathing)

carrytheliveloadfromthefloor,spanningbetweenthefloorjoists

system

loads

windload(windfromthefront)

w 5,25kN/m

liveload

q 2,0kN/m

cf.diaphragm

internalforces

shear

V5,25 ⋅ 22,34

258,6kN

l 20,65 6 ⋅ 0,4 18,25m

v58,618,25

3,21kN/m

theshearforceVisdistributedoverthelengthofthefloor(columnsmustbesubtracted)

reqt3,21/1000,15

0,21cm preliminarydesignshearstrength

σ , 1,5 N/mm

a)FrameConstruction


bending

l 0,65m

M2 ⋅ 0,65

80,106kNm/m

thespanofthesheathingequalsthespacingofthesecondarybeams

reqW0,106 ⋅ 100

0,813,3cm /m

reqt13,3 ⋅ 6100

0,90cm

deformation

limitation:δ l/250

δ2/100 ⋅ 6576,8 ⋅ 400 ⋅ I

65/250

reqI 44,7cm /m

reqt44,7 ⋅ 12100

1,75cm

preliminarydesignbendingstrength

σ , 8

selecteddimension

t 18mm

indirectcomparison,thebendingisclearlydecisiveandtheshearalmostneglectable

a)FrameConstruction


6VerticalFaçadeCarriers

system

h 3,195m

carriersspacing

e 60cm

loads

q 1,044kN/m

c A 1,2

w 1,2 ⋅ 1,044 1,25kN/m

loadsononecarrier

w 0,6 ⋅ 1,25 2,0kN/m

internalforces

maxM2,0 ⋅ 3,195

82,55kNm

reqW 255/0,5 510cm

reqb510 ⋅ 616

12,0 cm

selecteddimensions

b/h 12/16e 60cm

W 512cm

theheightofthecarrierequalsthethicknessofthefaçade,whichagainequalsthebreadthoftheouterprimarybeams(cf.e.g.2.4),i.e.16cm

a)FrameConstruction


ConnectionsOverview

Thisisanoverviewofallconnections.Someconnectionsareshownindetailinthenextsections(markedinboldfont),theotherconnectionsfollowthesameprinciples.

connection b/hconnection loads typeoffastener

capacityperfastener *

numberoffasteners

beam/column2.2/1.1middle

120/42 2 ⋅ 48,897,6 kN

M20bolt 13,2kN 11M20

2.2/1.3side 40/42 2 ⋅ 17,535,0 kN

M20bolt 13,2kN 4M20

2.1 2.3/1.4side

80/42 17,5 7,925,4 kN

M20bolt 13,2kN 2M20

2.1 2.4/1.2front

40/42 18,5 6,4925 kN

M20bolt 13,2kN 2M20

2.1 2.4/1.4front

120/42 44,5 17,261,7 kN

M20bolt 13,2kN 5M20

2.1 2.4/1.3front

80/42 48,8 17,366,1 kN

M20bolt 13,2kN 5M20

2.4/1.2side 40/42 6,59 kN v8,55 kN h

Ø8screw 3,2kN 3up 2down

2.4/1.3side 40/42 20,1 kN v21,5 kN h


2.4/1.4side 40/42 11,3 kN v9,94 kN h


diagonal/column4/1.2 ‐ 530,9 kN M20dowel 17,6kN 2x10M20

3steelplates

4/1.4 ‐ 454,0 kN M20dowel 17,6kN 2x10M203steel

platessheathing/joists5/3 ‐ 0,19 kN/m Ø3nails 0,32kN 1nail/mjoists/beam3/2 ‐ 3,92 kN Ø3,4nails 0,4kN 2x5nails

steelangle

* per2shearplanesforboltsanddowels

a)FrameConstruction


ConnectionBeam2.2toColumn1.1

Fortheconnectionsbetweenthebeamsandthecolumns,M20boltsareused.

system

availablespace

A 120 ⋅ 42 5040cm

requiredspaceperboltM20

A 30 ⋅ d 30 ⋅ 2,0 120cm

maxn5040120

42

loads

F 2 ⋅ 48,8 97,6kN [email protected]

check

capacityperbolt(doubleshear)

F 4,4 ⋅ d 4,4 ⋅ 2,0 17,6kN

capacityat90°tothegrain

F 190360

⋅ 17,6 13,2kN

reqn97,613,2

7,4

selectedconnectors

11 M20

a)FrameConstruction


ConnectionOuterBeam2.4ontheSidetoColumn1.3

Fortheconnectionsoftheouterbeamsonthesidetothecolumns,fullythreadedscrewsØ8mmareused.Thescrewscarryloadsinaxialdirection.Boththeverticalloadsfromtheself‐weightofthefaçadeandthehorizontalloadsfromthewindsuctionmustbeconsidered.Thescrewsthatgoat45°upwardscarrytheverticalloads,whileanequalamountofupwardanddownwardscrewscarrythehorizontalloads.

system

availablespace

A 40 ⋅ 42 1680cm

requiredspaceperscrew

A 60 ⋅ d 60 ⋅ 0,8

38,4cm

maxn168038,4

43

principleoftheforcedistributionintheconnection

loads


F 20,1kN

inthedirectionofthescrew

F20,1sin 45

28,4kN

[email protected]‐weightofthefaçade

windloads(horizontal)

F 21,5kN

inthedirectionofthescrew

F21,5sin 45

30,4kN

[email protected]

check

a)FrameConstruction


capacityperscrew

F 5 ⋅ d 5 ⋅ 0,8 3,2kN

reqn28,43,2

9

reqn30,43,2

10 5 5

selectedconnectors

9up 5 down∅8

a)FrameConstruction


ConnectionDiagonal4toColumn1.2

Thediagonalsareinthesamelayerasthecolumnsandareconnectedtothemdirectlyviasteelplatesinsidethewood.Asfasteners,M20steeldowelsareused.

system

requiredspaceperdowel

A 30 ⋅ d 30 ⋅ 2,0 120cm

loads

maxtensionsforceinthediagonal

F 530,9kN

check

capacityperdowel(2shearplanes)

F 4,4 ⋅ 2 17,6kN

capacityfor6shearplanes

F 3 ⋅ 17,6 52,8 kN

3steelplatesareusedinsidethewood,giving6shearplanesintotal

thewidthofthesinglewoodlayersisb 40/4 10cmandshouldnotbesmallerthanmin b 5 ⋅ d 5 ⋅ 210 cm

capacityatanangle theangleofthediagonalsisα 54°(cf.4diagonal)

a)FrameConstruction


F 136360

⋅ 52,8 47,5kN

25%highercapacitywithsteelplates

F 1,25 ⋅ 47,5 59,4kN

reqn530,959,4

9 → 10

seln 10

reqA 10 ⋅ 30 ⋅ 2 1200cm

withsteelplatesthecapacityisapproximately25%higher

checkofthesteelplates:

F530,93

177kN

b 35,2 3 ⋅ 2 29cm

reqt 177/29/14 0,44cm

selectedthicknessofthesteelplate

t 6mm

preliminary design strength of steelσ 14 kN/cm

a)FrameConstruction


ConnectionSheathing5toJoists3

Thesheathingisconnectedtothejoistswithnails.

system

loads


w 5,25kN/m

cf.diaphragm7 windfromthesidesisnotdecisive

internalforces

forceinone“row”ofjoists

F 5,25 ⋅ 0,65 ⋅ 1,15 3,92kN

v3,9220,65

0,19kN/m

capacitypernailØ3,0mm

F 3,5 ⋅ 0,3 0,32kN

reqn0,190,32

1/m

spacingofthesecondarybeamse 65 cm


a)FrameConstruction


ConnectionJoists3toBeams2

Thejoistsareconnectedtothebeamswithsteelanglesandnails.

system

loads


w 5,25kN/m

cf.diaphragm7 windfromthesidesisnotdecisive

internalforces

forceinone“row”ofjoists

F 5,25 ⋅ 0,65 ⋅ 1,15 3,92kN

spacingofthesecondarybeamse65 cm

continuityfactor1,15

Thisforcemustbetransferredfromtheouterbeam2.1toeachjoist3.

capacitypernailØ3,4mm

F 3,5 ⋅ 0,34 0,4kN

reqn3,920,4

10 5 5

Thisappliestoallconnectionsofallsecondarybeams3withtheouterprimarybeam2.1.

Atallinnerconnection,withthebeams2.2and2.3,noloadtransferisnecessary,onlyareducedamountofnailsisselectedtoavoidlargedeformationdifferencesbetweenthedifferentbeams.

n 6 3 3

b)PanelConstruction


b)PanelConstructionElementReferenceOverview


1 floorjoists

1.1 floorjoistsmodules3,4 45

1.2 floorjoistsmodules1,2,6,7 46

1.3 floorjoistsmodules5 47

2 floorbeam 59

3 walls/studs 48

4 wallsheathing 57

5 columns 62

6 beam 60

connectionsoverview 63

b)PanelConstruction


1.1FloorJoists

system

l 5,15m

hl20

51520

25,8cm

loads

q 2,0kN/m

g 2,0kN/m

loadsononejoist

q 2,0 ⋅ 0,6 1,2kN/m

g 1,2kN/m


internalforces

maxM2 ⋅ 1,2 ⋅ 5,15

87,96kNm

reqW 796/0,5 1592cm

selecteddimensions

b/h 16/24e 60cm

I 18432 cm

W 1536 cm

deformation

maxδ2 ⋅ 1,2/100 ⋅ 51576,8 ⋅ 1000 ⋅ 18432

1,19cm

l/250 515/250 2,06cm

maxreactionforces

A 1,2 ⋅ 5,15/2 3,1 kN

A 1,2 ⋅ 5,15/2 3,1kN

A 6,2kN

b)PanelConstruction


1.2FloorJoists

system

l 4,215m

loads

q 2,0kN/m

g 2,0kN/m

loadsononebeam

q 2,0 ⋅ 0,6 1,2kN/m

g 1,2kN/m


selecteddimensions

b/h 16/24e 60cm

I 18432cm

W 1536cm

joists1.2arenotdecisive,thesamedimensionsareselectedasforjoist1.1

maxreactionforces

A 1,2 ⋅ 4,215/2 2,5kN

A 1,2 ⋅ 4,215/2 2,5kN

A 5,0kN

b)PanelConstruction


1.3FloorJoists

system

l 2,1m

loads

q 2,0kN/m

g 2,0kN/m

loadsononebeam

q 2,0 ⋅ 0,6 1,2kN/m

g 1,2kN/m


selecteddimensions

b/h 16/24e 60cm

I 18432cm

W 1536cm

joists1.3arenotdecisive,thesamedimensionsareselectedasforjoist1.1

maxreactionforces

A 1,2 ⋅ 2,1/2 1,3 kN

A 1,2 ⋅ 2,1/2 1,3kN

A 2,6kN

b)PanelConstruction


3Walls/Studs

ThefullstabilityanalysiswasperformedusingExcel(seeappendix).Here,onlythewallsWy1andWy8areshown.Wy8hasthehighestvertical load,whileWy1hasthehighesthorizontalwindload.

Basedontheloadsonthewalls,theloadsontheindividualstudswerecalculatedasthereactionforcesofacontinuousbeam(seesystemsketchbelow).

system

h 3,195m

loads

windloads(windfromthefront)

W 1319

M 37094kNm

windloads(windfromtheside,windareaD+E)

totalhorizontalwindforce

W 1275kN


M 34982kNm

internalforces

wallWy8forwindfromthefront

shearforce

v 20,39kN/m

normalforce(compression)

n 394,3kN/m

horizontalwindload

w 0

fordetailedcalculations,seeExcelanalysis

b)PanelConstruction


wallWy1forwindfromtheback

shearforce

v 6,22kN/m

normalforce(compression)

n 237,5kN/m

horizontalwindload

w 0,98kN/m

In the endof thepreliminarydesign, twodifferent thicknessesof thewallsweredetermined:20cm(withtheloadbearingstudsbeingb/h 20/20cm)and28cm(withtheloadbearingstudsbeingb/h 28/28cm).Becauseofthedecreasingloadswiththeheightofthebuilding,thecross‐sectionsofthestudscouldbeadaptedinthehigherstoreys.Assumingtheloadsduetotheself‐weightandthelifeload(N)todecreaselinearlyandtheloadsduetothewind(M)todecreasequadratically,thefollowingcross‐sectionsarecalculated:

storeyno M N b/h b/h

‐ [%] [%] [cm/cm] [cm/cm]

0 100,00 100,00 20/20 28/281 87,11 93,33 20/20 28/282 75,11 86,67 20/20 28/283 64,00 80,00 20/20 28/284 53,78 73,33 20/20 28/285 44,44 66,67 16/16 24/246 36,00 60,00 16/16 24/247 28,44 53,33 16/16 24/248 21,78 46,67 16/16 24/249 16,00 40,00 16/16 24/2410 11,11 33,33 16/8 20/2011 7,11 26,67 16/8 20/2012 4,00 20,00 16/8 20/2013 1,78 13,33 16/8 20/2014 0,44 6,67 16/8 20/2015 0,00 0,00 16/8 20/20

b)PanelConstruction


3.y8StudsinWally3

system

loads

self‐weightofthewall

g 1,0kN/m

over14storeys

g 1 ⋅ 14 ⋅ 3,195 44,7kN/m

floorload

p3,20,6

⋅ 153,20,6

⋅ 1 14 ⋅ 0,74

136kN/m

totalverticalload(constant)

n 44,7 136 181kN/m

[email protected] theloadperstoreyisaddedupforthe

roofandthe14storeyswithareductionfactorα 0,74fortheliveload

b)PanelConstruction


windloads(linear)

windfromthefront

maxn 178kN/m

minn 213kN/m

windfromtheback

maxn 213kN/m

minn 178kN/m

windfromtheleftside

maxn minn 9,2kN/m

windfromtherightside

maxn minn 9,2kN/m

cf.Excelanalysis

b)PanelConstruction


internalforces

windfromthefront

windfromtheback

windfromtheleftside


For each loadbearing studs (each support), the required cross‐section is calculated using thepreliminarydesignstrengthoftimberof5 N/mm witha factorof0,8toaccountforbuckling.Sincethesheathingpreventsthestudsfrombucklinginonedirectionandalsomakesbucklingintheotherdirectionmoredifficultbyeffectivelyconnectingtheindividualstuds,ahigherbucklingfactorischosen.

selecteddimensions

b/t 28/28A 784 cm

b)PanelConstruction


studno 1 2 3 4 5 6 7 8 9 10 11 12maxforce[kN]

116 295 111 275 281 230 311 292 150 222 232 78

reqb[cm] 10 26 10 25 25 21 28 26 13 20 21 7selectedb[cm]

28 28 28 28 28 28 28 28 28 28 28 28

b)PanelConstruction


3.y1StudsinWally1

system

loads


g 1,0kN/m

over14storeys

g 1 ⋅ 14 ⋅ 3,195 44,7kN/m

floorload

p2,50,6

⋅ 152,50,6

⋅ 1 14 ⋅ 0,74

109,8kN/m


n 44,7 109,8 154,5kN/m

[email protected] theloadperstoreyisaddedupforthe


windloads(linear)

windfromthefront

maxn 83kN/m

minn 133kN/m

windfromtheback

maxn 133kN/m

minn 83kN/m

cf.Excelanalysis

b)PanelConstruction


windfromtheleftside

maxn minn 40kN/m


maxn minn 40kN/m

horizontalwindpressure(windfromtheback)

c B 1,2

q 1,044kN/m

|w| 1,2 ⋅ 1,044 1,25kN/m

windpressureperstud

|w| 1,15 ⋅ 1,25 ⋅ 0,61 0,88kN/m

spacingofthestudse 0,61cm continuityfactor1,15

internalforces

windfromthefront

windfromtheback

windfromtheleftside

windformtherightside

b)PanelConstruction


bendingmomentfromwindpressure

M 0,88 ⋅ 3,195 /8 1,12kNm

selecteddimensions

b/t 28/28A 784cm W 3659 cm

studno 1 2 3 4 5 6maxforce[kN]

139 295 145 182 258 129

reqb[cm] 12 26 13 16 23 12selectedb[cm]

28 28 28 28 28 28

stresscheck

σ295784

1123659

0,38 0,03 0,41kN/cm

0,8 ⋅ 0,5 0,40kN/cm

thewindpressurehasalmostnoeffectcomparedtothehighnormalforces

b)PanelConstruction


4Sheathing

Thesheathingisconnectedtothestudsandtheblockingvianails.

WallWx15becomesdecisiveforthesheathingforwindfromtheleftside.

system

loads

v 21,4kN/m

cf.Excelanalysis

nails

selected:Ø5mm

shearcapacitypernail

F 3,5 ⋅ d 3,5 ⋅ 0,5 0,88kN

reqn 20,4/0,88 23,3/m

selectednails

Ø5mml 100 mme 8 cm in2rows

minimumdistances(α 0°)

betweennailsin1row a 12 ⋅ 0,5 6 cm 8 cm

betweentherows a 5 ⋅ 0,5 2,5cm

tothesideedges a 5 ⋅ 0,5 2,5cm

requiredbreadthofthewoodenmembers(studsandblocking)

reqb 3 ⋅ 2,5 7,5 cm

selectedblocking

b 16cmhacc.tothewidthofthewall

attheseamsofthesheathingpanels,theblockingmustbeb 2 ⋅ 7,5 15cm

b)PanelConstruction


selectedsheathing

reqt21,4/1000,15

1,43cm

t 18mm

preliminarydesignshearstrengthσ , 1,5 N/mm

b)PanelConstruction


2FloorBeam

The floor beams are only connected to the load‐bearing studs. The floor beam in axis 1–3/Abecomesdecisive.

system

loads

g2,50,6

4,2kN/m

q 4,2kN/m

thesingleforcesfromthefloorjoistsareconvertedtoaconstantcontinuousload

[email protected]

internalforces

maxmomentatsupportD

maxM 2,38kNm

reqW2380,5

476 cm

selecteddimensions

b/h 10/24I 11520cm

W 960 cm

A 240 cm

b)PanelConstruction


6Beam

system

l 9,275/4 2,32m

loads

g2,50,6

4,17kN/m

q2,50,6

4,17kN/m

[email protected] spacingofthefloorjoists=0,6m

internalforces

maxmomentinthefirstfield

maxM 0,08 0,101 ⋅ 4,17 ⋅ 2,32 4,06kNm

reqW4060,5

812cm

correspondingmomentatthesupport:

M 0,1 0,05 ⋅ 4,17 ⋅ 2,32 3,37kNm

maxmomentatthesupportB

maxM 0,10 0,117 ⋅ 4,17 ⋅ 2,32 4,87kNm

reqW4870,5

974 cm

b)PanelConstruction


selecteddimensions

b/h 10/24W 960 cm

I 11520 cm

deformation

maxδ2 ⋅ 4,17/100 ⋅ 23276,8 ⋅ 1000 ⋅ 11520

33716 ⋅ 1000 ⋅ 11520

⋅ 232

0,273 0,098 0,18cm

l/250 232/250 0,93cm

substitutesystem:

b)PanelConstruction


5Columns

system

loads

g2,50,6

⋅ 15 62,5kN/m

q2,50,6

⋅ 1 14 ⋅ 0,74 47,3kN/m

[email protected] spacingofthefloorjoists=0,6m theloadsareaddedupoverall15

storeys

internalforces

columnsA,D

N 0,400 ⋅ 62,5 ⋅ 2,32 0,45 ⋅ 47,3 ⋅ 2,32 107,4kN

reqA107,40,7 ⋅ 0,5

306,9cm

columnsB,C

N 1,100 ⋅ 62,5 ⋅ 2,32 1,2 ⋅ 47,3 ⋅ 2,32 291,2kN

reqA291,20,7 ⋅ 0,5

832 cm

selecteddimensions

columnsA,D

2 b/h 16/28A 2 ⋅ 448cm

columnsB,C

2 b/h 28/28A 2 ⋅ 784 cm

b)PanelConstruction


ConnectionsOverview

connection b/hoverlap loads typeoffastener

capacityperfastener

numberoffasteners

anchoring3/3 ‐ 134,7kN M20

dowels22,0kN * 2 7M20

steelplatefloorjoists/floorbeam1/2 16/24 6,2kN v screwsØ8 3,2kN 3Ø8floorbeam/studs2/3 24/28 26,6kN M20

dowels8,0kN ** 5M20

* doubleshear** singleshear

b)PanelConstruction


Anchoring

Fortension,wallWx7becomesdecisiveforwindfromtheleftside.

Thehold‐downdeviceconsistsofasteelplateinsideeachload‐bearingstudandsteeldowels.

system

globalsystem

localsystem

b)PanelConstruction


loads


g 1,0kN/m

over14storeys

g 1 ⋅ 14 ⋅ 3,195 44,7kN/m

liveload

p 0


n 0,5 ⋅ 44,7 22,4kN/m tobeonthesafeside,only50%oftheself‐weightandliveloadsareconsidered

windloads(linear)

windfromtheleftside

maxn 140,1kN/m

minn 78,3kN/m

cf.Excelanalysis

internalforces

windfromtheleftside

maxF 134,7kN

steeldowels

capacityperdowelM20(doubleshearwithinnersteelplate)

F 4,4 ⋅ 2 17,6kN

25%highercapacitywithsteelplates

F 1,25 ⋅ 17,6 22,0kN

req n134,722

7

b)PanelConstruction


ConnectionFloorJoists1toFloorBeam2

ThisconnectionusesscrewsØ8mmthataresubjectedtotension.

system

loads

F 6,2kN [email protected]

internalforces

forceinthescrewsatanangleof45°

S6,2sin 45

8,77kN

check

capacityperscrew

F 5 ⋅ d 5 ⋅ 0,8 3,2kN

reqn8,773,2

3

requiredspace

reqA 3 ⋅ 60 ⋅ 0,8 115,2cm

availablespace

A 16 ⋅ 24 384cm

theavailablespaceequalsthecross‐sectionofthefloorjoist16/24

b)PanelConstruction


ConnectionFloorBeam2toStuds3

Forthisconnection,steeldowelsM20areused,thatdon’tinterferewiththehold‐downdevice(cf.anchoring).Thefloorbeaminaxis1–3/Aisdecisive.

system

loads

F 15,5kN

check

capacityperdowel(singleshear)

F 2 ⋅ d 2 ⋅ 2 8kN

at90°tothegrainforthefloorbeam

F 190360

⋅ 8 6kN

req n15,56

3

requiredspace

reqA 3 ⋅ 30 ⋅ 2 360cm

b)PanelConstruction


availablespace

A 24 ⋅ 20 480cm

floorbeam:14/24 stud: 20/20 (in the upper storeys, the

cross‐section28/28isreducedto20/20)

c)CLTConstruction


c)CLTConstructionElementReferenceOverview


1 floorslab 70

2,3 floorslab 71

4 floorslab 72

5 Walls 73

anchoring 78

Remarks

Thefloorslabsaredesignedassumingtheyonlyspaninonedirection.Thisisonthesafeside,astheyactuallyspaninbothdirectionssothatamulti‐axialstateofstresscanbedevelopedandloadscanbebetterdistributed.

The load transfer from the floor slabs to the walls is calculated in a simplified manner bydeterminingalengthofinfluenceforeverywallandtransferringtheloadsfromtheslabwithintheresultingareaofinfluencetothewall.

Tocalculatetheshearforcesandbendingmomentsinthewallsfromthewindloads,astabilityanalysiswasperformedusingExcel.Onlyselectedwallsarepresentedinthisreport.

c)CLTConstruction


1FloorSlab

Itcouldbeseenfromthesheathingofthediaphragmintheframeconstructionthatshearfromhorizontalwindforcescanbeneglectedforthepreliminarydesign.

system

l8,5952

4,30m

themiddlesupportisthebeam6

loads

g 2,0kN/m

q 2,0kN/m

selecteddimensions

t 145mm19 44 19 44 19

maxreactionforces

A 0,375 ⋅ 2,0 ⋅ 4,30 3,2kN/m

A 0,438 ⋅ 2,0 ⋅ 4,30 3,8kN/m

A 7,0kN/m

B 1,25 ⋅ 2,0 ⋅ 4,3 10,75kN/m

B 1,25 ⋅ 2,0 ⋅ 4,3 10,75kN/m

B 21,5kN/m

pressureperpendiculartothegrain

endwallsupports

reqt6,99/1000,15

0,47cm

middlewallsupport

reqt21,5/1000,15

1,43cm

preliminarydesigncompressionstrengthperpendiculartothegrainσ , 1,5N/mm

c)CLTConstruction


2,3FloorSlab

system

l 5,15m

loads

g 2,0kN/m

q 2,0kN/m

selecteddimensions

t 170 mm19 31,5 19 31,5 19 31,5 19

maxreactionforces

A 2,0 ⋅ 4,30/2 4,3 kN/m

A 2,0 ⋅ 4,30/2 4,3kN/m

A 8,6kN/m


wallsupports

reqt8,6/1000,15

0,57cm


c)CLTConstruction


4FloorSlab

system

l 2,10m

loads

g 2,0kN/m

q 2,0kN/m

selecteddimensions

t 95mm19 19 19 19 19

forfiresafetyreasons,aslabwithatleast5layersisselected

maxreactionforces

A 2,0 ⋅ 2,1/2 2,1kN/m

A 2,0 ⋅ 2,1/2 2,1kN/m

A 4,2kN/m


wallsupports

reqt4,2/1000,15

0,28cm


c)CLTConstruction


5Walls

The full stabilityanalysiswasperformedusingExcel (seeappendix).Here,only thewally5 isshown.

system

globalloads

windloads(windfromthefront)

W 1319

M 37094kNm

windloads(windfromtheside)

W 1275kN

M 34982kNm

Intheendofthepreliminarydesign,wallswiththreedifferentthicknesseswereused:95mm,120mmand259mm.Toachieveamoreeconomicdesign,thethicknessesweredecreasedinthehigherfloors,makinguseofthedecreasingloads.Assumingtheloadsduetotheself‐weightandthelifeload(N)todecreaselinearlyandtheloadsduetothewind(M)todecreasequadratically,thefollowingthicknessesarecalculated:

c)CLTConstruction


storeyno M N t t t‐ [%] [%] [mm] [mm] [mm]

0 100,00 100,00 95 120 2591 87,11 93,33 95 120 2592 75,11 86,67 95 120 2593 64,00 80,00 95 120 2594 53,78 73,33 95 120 2595 44,44 66,67 95 95 1706 36,00 60,00 95 95 1707 28,44 53,33 95 95 1708 21,78 46,67 95 95 1709 16,00 40,00 95 95 17010 11,11 33,33 95 95 9511 7,11 26,67 95 95 9512 4,00 20,00 95 95 9513 1,78 13,33 95 95 9514 0,44 6,67 95 95 9515 0,00 0,00 95 95 95

c)CLTConstruction


5.y5OuterWall

system

loads


g 1,0kN/m

over15storeys

g 1 ⋅ 15 ⋅ 3,195 47,9kN/m

floorload

g 2,0kN/m

q 2,0kN/m

c)CLTConstruction


loadfactortoaccountfortheopenings

k20,65

5,125 1,1 2,6 1,1 5,1251,37

lengthofinfluence

l4,382

2,19m

g 1,37 ⋅ 2 ⋅ 2,19 6,01kN/m

q 1,37 ⋅ 2 ⋅ 2,19 6,01kN/m

over15storeys

g 15 ⋅ 6,01 90,15kN/m

q 15 ⋅ 0,74 ⋅ 6,01 66,71kN/m


n 47,9 90,15 66,71 204,8 kN/m

fromfloorslab1 theloadperstoreyisaddedupforthe


windload(linear)

windfromtheback

maxn 76,5kN/m

minn 133,4kN/m

v 9,2kN/m

cf.Excelanalysis

windpressure

c 0,8

q 1,044kN/m

w 0,8 ⋅ 1,044 0,835kN/m

internalforces

totalnormalforce

n 204,8 133,4 338,2kN/m

reqt338,2/1000,7 ⋅ 0,5

9,66cm factor0,7toaccountforbuckling

bendingmomentduetowind

M 0,835 ⋅ 3,195 /8 1,07kNm/m

selecteddimensions

t 95mmA 100 ⋅ 9,5 950cm /m

W 100 ⋅ 9,5 /6 1504cm /m

c)CLTConstruction


check

normalforce

σ338,2950

1071504

0,36 0,07

0,43kN/cm

0,8 ⋅ 0,5 0,40kN/m

thewindpressurehasalmostnoinfluencecomparedwiththehighverticalloads

0,8isusedasafactortoaccountforbucklingbecauseitisassumedthatmassiveelementsarelesspronetobuckling

shearforces

τ9,2

100 ⋅ 9,50,01kN/cm

0,06kN/cm

c)CLTConstruction


Anchoring

Fortensilestresses,wally7becomesdecisiveforwindfromthefront.Toconnecttwowallsontopofeachother,aninternalsteelplate isput intoagroovecut intothewallsoverthewholelengthusingsteeldowelsM20.

system

loads

n 132,4kN/m

tobeonthesafeside,only50%oftheself‐weightandliveloadsareconsidered

steeldowels

capacity per dowel M20 (double shear withsteelplate)

F 1,25 ⋅ 4,4 ⋅ 2 22kN

reqn 132,4/22 7/m

7M20/m

Appendix


Appendix

Attachments

stabilityanalysisforthepanelconstruction(XLSX) calculationofthepanelstuds(XLSX) stabilityanalysisfortheCLTconstruction(XLSX) technicalplansfortheframeconstructionPa1.1,Pa2(PDF) technicalplansforthepanelconstructionPb1–Pb3,Pa4.1(PDF) technicalplansfortheCLTconstructionPc1–Pc2,Pc3.1(PDF)

Appendix


b)PanelConstruction

SummaryoftheStabilityAnalysis

Appendix


Appendix


LoadsandSelectedCross‐SectionsoftheStuds

Utilisingthesymmetryofthebuilding,onlyonehalfofthewallsisconsidered.

Appendix


Appendix


c)CLTConstruction

SummaryoftheStabilityAnalysis

Appendix


EurocodeDesign

TableofContents

EurocodeDesign‐LucasBienert 2


General...................................................................................................................................................................................4

Remarks............................................................................................................................................................................4

Materials...........................................................................................................................................................................4

Software............................................................................................................................................................................4

Literature..........................................................................................................................................................................4

Loadcasesandcombinations...................................................................................................................................4

DesignFactors................................................................................................................................................................5

a)FrameConstruction.....................................................................................................................................................6

3.1RoofJoists.................................................................................................................................................................7

3.1FloorJoists................................................................................................................................................................9

3.2Joists.........................................................................................................................................................................11

2.2RoofBeam..............................................................................................................................................................12

2.2FloorBeam............................................................................................................................................................17

2.1RoofBeam..............................................................................................................................................................20

2.1FloorBeam............................................................................................................................................................21

2.3Beams......................................................................................................................................................................22

7Diaphragm.................................................................................................................................................................23

8Frame...........................................................................................................................................................................24

2.4Beam(front).........................................................................................................................................................25

2.4Beam(side)...........................................................................................................................................................29

1.1Column....................................................................................................................................................................36

1.4Column....................................................................................................................................................................38

4Diagonal......................................................................................................................................................................40

5StructuralSheathingoftheFloors...................................................................................................................42

6VerticalFaçadeCarriers......................................................................................................................................45

ConnectionBeam2.2toColumn1.1..................................................................................................................47

ConnectionOuterBeam2.4ontheSidetoColumn1.3..............................................................................50

ConnectionDiagonal4toColumn1.2or1.4...................................................................................................53

b)PanelConstruction....................................................................................................................................................56

1.1RoofJoists..............................................................................................................................................................57

1.1FloorJoists.............................................................................................................................................................59

1.2RoofJoists..............................................................................................................................................................61

1.2FloorJoists.............................................................................................................................................................62

TableofContents


1.3RoofJoists..............................................................................................................................................................63

1.3FloorJoists.............................................................................................................................................................64

2RoofBeam..................................................................................................................................................................65

2FloorBeam................................................................................................................................................................70

3Studs............................................................................................................................................................................75

6Beam(Roof)..............................................................................................................................................................77

6Beam(Floor)............................................................................................................................................................82

5Columns......................................................................................................................................................................87

Anchoring......................................................................................................................................................................90

ConnectionRoofJoists1toRoofBeam2.........................................................................................................92

ConnectionFloorJoists1toFloorBeam2......................................................................................................94

ConnectionFloorBeam2toStuds3..................................................................................................................95

ConnectionRoofBeam2toStuds3....................................................................................................................98

c)CLTConstruction.......................................................................................................................................................99

1RoofSlab..................................................................................................................................................................100

1FloorSlab................................................................................................................................................................104

5.x9OuterWall.........................................................................................................................................................106

AnchoringWall5.y3...............................................................................................................................................108

Appendix..........................................................................................................................................................................110

Attachments..............................................................................................................................................................110

a)FrameConstruction..........................................................................................................................................110

b)PanelConstruction............................................................................................................................................116

c)CLTConstruction................................................................................................................................................121

General


General

Remarks

TheintentionoftheECdesignistoprovethefeasibilityofthestructures.Adescriptionofthebuildingandtheloadbearingconceptofthethreestructuresisincludedinthedocumentationofthepreliminarydesign.

Onlythedecisiveloadcombinationsareshowninthisdocument,acompletesummaryofallthecheckswasdoneinExcel.AnextractoftheExceldocumentcanbefoundintheappendix,thefilesthemselvesareattachedelectronically.Technicalreferenceplansarealsoattached(cf.appendix).

Materials

woodenmembers(beams,studs,floorjoists,…):glulamGL24ho propertiesaccordingtoEN14080

structuralsheathing:plywoodFinnforestSprucekonstruksjonskryssfiner(distributedunderthename“GranIII/III”byFritzøeEngrosAS)

o typeEN636‐1(plywoodforuseindryclimate)o propertiesaccordingtothetechnicalapproval[3]

masstimber:CLTKL‐träbyMartinsons(distributedbySplitkonAS)o propertiesaccordingtothetechnicalapproval[1]

Software

Stab2d(simpleanalysisprogramfortwo‐dimensionalframeworks) MicrosoftEXCEL© DlubalRFEM©

Extracts from the calculationswith EXCEL andRFEM can be found in the appendix. The filesthemselvesareattachedelectronically.

Literature

[1] TekniskGodkjenningMartinsonsKL‐trä[2] BautabellenfürIngenieure,20thedition2012[3] TekniskGodkjenningFinnforestSprucekonstruksjonskryssfiner[4] EN1990[5] EN1991‐1‐1[6] EN1995‐1‐1[7] TechnicalDataSheetSimpsonStrongtieBT4Bjelkebærere

Loadcasesandcombinations

ForconsistentnumberingbetweenthisdesignandtheRFEM‐models,alwaystwonumbersarereservedforloadcasesandcombinationsthatincludewindloads,oneforwindfromthefront(orback)andoneforwindfromtheside.IntheFEM‐analysiswithRFEM,onlywindfromthefrontandfromtheleftsidewasexamined,makinguseofthesymmetryofthebuilding.

General


loadcase description symbol durationLC1 self‐weight G permanentLC2 snow S short‐termLC3/4 wind W instantaneousLC5 liveload Q medium‐term

loadcom‐binationno

combinationrule duration

CO1 E 1,2 ⋅ G permanentCO2 E 1,2 ⋅ G 1,5 ⋅ Q medium‐termCO3 E 1,2 ⋅ G 1,5 ⋅ S 1,5 ⋅ 0,7 ⋅ Q short‐termCO4 E 1,2 ⋅ G 1,5 ⋅ Q 1,5 ⋅ 0,7 ⋅ S short‐termCO5/6 E 1,2 ⋅ G 1,5 ⋅ W 1,5 ⋅ 0,7 ⋅ S 1,5 ⋅ 0,7 ⋅ Q instantaneousCO7/8 E 1,2 ⋅ G 1,5 ⋅ Q 1,5 ⋅ 0,7 ⋅ S 1,5 ⋅ 0,6 ⋅ W instantaneousCO9/10 E 1,2 ⋅ G 1,5 ⋅ S 1,5 ⋅ 0,6 ⋅ W 1,5 ⋅ 0,7 ⋅ Q instantaneousCO11/12 E 1,0 ⋅ G 1,5 ⋅ W instantaneous

DesignFactors

SinceCLTisnotconsideredintheEC,thesamedesignfactorsareappliedasforglulam.

materialsafetyfactors

material γglulam 1,25CLT 1,25plywood 1,2connections 1,3

modificationfactors

material loadduration climateclass1 2 3

glulam,CLT,plywood permanent 0,6 0,6 0,5medium‐term 0,8 0,8 0,65short‐term 0,9 0,9 0,7instantaneous 1,1 1,1 0,9

deformationfactors

material climateclass1 2 3

glulam,CLT 0,6 0,8 2,0plywood 0,8 ‐ ‐

a)FrameConstruction


a)FrameConstructionElementReferenceOverview


1 columns

1.1 innercolumns 36

1.2 cornercolumns ‐

1.3 sidecolumns ‐

1.4 sidecolumns 38

2 beams

2.1 beam 20

2.2 beam 12

2.3 beam 22

2.4 beam 25

3 joists

3.1 joists 7

3.2 joists 11

4 diagonal 40

5 structuralsheathingofthefloors 42

6 verticalfaçadecarriers 45

7 diaphragm 23

8 frame 24

connections 47

Remarks

In comparison to the preliminarydesign, the cross‐sections of the columnswere reduced.Allcolumnsarenowb/h 40/40cm,exceptforthoseatthesides.Becausethebeamsareattachedtothem,theyneedalargercross‐section:b/h 40/60cm.Becausetheconnectionstothebeamsrequirethisspace,thecross‐sectionsarenotdecreasedovertheheightofthebuilding.

a)FrameConstruction


3.1RoofJoists

system

l9,2752

4,64m

cross‐section

b/h 14/24

e 65cm

A 336cm

I 16128cm

W 1344cm

material

glulamGL24h

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

k 0,6

loads

g 1,65kN/m

s 3,8kN/m

q 1044N/m

c I 0,2

g 1,65 ⋅ 0,65 1,07 kN/m

s 3,8 ⋅ 0,65 2,47 kN/m

w 0,2 ⋅ 1,044 0,21 kN/m

q H 0,75kN/m

w 0,21 ⋅ 0,65 0,14 kN/m

q 0,75 ⋅ 0,65 0,49 kN/m

Q 1,5 kN

ULSCO3

k 0,9

p 1,20 ⋅ 1,07 1,50 ⋅ 2,47 4,99kN/m

Q 1,50 ⋅ 0,70 ⋅ 1,5 1,58kN

M 0,125 ⋅ 4,99 ⋅ 4,64 0,250 ⋅ 1,58 ⋅ 4,6415,26kNm

σ15261344

1,14kN/cm

f 0,9 ⋅2,41,15

1,88 kN/cm

thesingleloadQbecomesdecisive

a)FrameConstruction


η1,141,88

0,60 1,0

V 0,500 ⋅ 4,99 ⋅ 4,64 1,58 13,16 kN

nolateraltorsionalbuckling,becausethesheathingsecuresthecompressionflangeofthejoists

τ 1,5 ⋅13,16

0,67 ⋅ 3360,088kN/cm

f 0,9 ⋅0,351,15

0,27kN/cm

η0,0880,27

0,32 1,0

τ 1,5 ⋅V

k ⋅ A

(forrectangularcross‐sections)

SLSCO9/10

w ,

1,07100 ⋅ 464

76,8 ⋅ 1150 ⋅ 161280,349 cm

w , 0,804cm

w , 0,044cm

w ,1,5 ⋅ 464

48 ⋅ 1150 ⋅ 161280,168cm

wp ⋅ l

76,8 ⋅ EI

(forsinglespanbeams)

instantaneousdeformation

w0,349 0,804 0,6 ⋅ 0,044 0,7 ⋅ 0,1681,30cm

maxw464300

1,55cm

η1,301,55

0,84 1,0

characteristiccombinationacc.toEC5‐1‐12.2.3(2):

w w w , ψ , w ,

finaldeformation

w0,349 ⋅ 1 0,6 0,804 ⋅ 1 0,2 ⋅ 0,60,044 ⋅ 0,6 0 ⋅ 0,6 0,168

⋅ 0,7 0,3 ⋅ 0,6 1,63cm

maxw464150

3,09cm

η1,633,09

0,53 1,0

simplifiedapproachacc.toEC5‐1‐12.2.3(5):

w w , w , , w , ,

w , w , 1 k

w , , w , , 1 ψ , k

w , , w , , ψ , ψ , k

maxreactionforces

A 0,500 ⋅ 1,07 ⋅ 4,64 2,49kN

A 0,500 ⋅ 2,47 ⋅ 4,64 5,73kN

A 0,500 ⋅ 0,14 ⋅ 4,64 0,31kN

A 0,500 ⋅ 0,49 ⋅ 4,64 1,13kN

a)FrameConstruction


3.1FloorJoists

system

l9,2752

4,64m

cross‐section

b/h 14/24

e 65cm

A 336cm

I 16128cm

W 1344cm

material

glulamGL24h

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

k 0,6

loads

g 1,34kN/m

s 0

q 0

g 1,34 ⋅ 0,65 0,87 kN/m

q A 2,5kN/m

q 2,5 ⋅ 0,65 1,63 kN/m

Q 2 kN

ULSCO2

k 0,8

p 1,20 ⋅ 0,87 1,05kN/m

q 1,5 ⋅ 1,63 2,44kN/m

M 0,125 ⋅ 1,05 2,44 ⋅ 4,64 9,37kNm

σ9371344

0,70kN/cm

f 0,8 ⋅2,41,15

1,67 kN/cm

η0,701,67

0,42 1,0

V 0,500 ⋅ 1,05 2,44 ⋅ 4,64 8,08 kN


a)FrameConstruction


τ 1,5 ⋅8,08

0,67 ⋅ 3360,054kN/cm

f 0,8 ⋅0,351,15

0,24kN/cm

η0,0540,24

0,22 1,0

SLSCO7/8

w ,

0,87100 ⋅ 464

76,8 ⋅ 1150 ⋅ 161280,283cm

w , 0

w , 0

w , 0,529cm


w 0,283 0,529 0 0 0,81cm

maxw464300

1,55cm

η0,811,55

0,53 1,0

finaldeformation

w 0,283 ⋅ 1 0,6 0,529 ⋅ 1 0,3 ⋅ 0,6 0 0 1,08cm

maxw464150

3,09cm

η1,083,09

0,35 1,0

maxreactionforces

A 0,500 ⋅ 0,87 ⋅ 4,64 2,02kN

A 0

A 0

A 0,500 ⋅ 1,63 ⋅ 4,64 3,77kN

a)FrameConstruction


3.2Joists

Thejoists3.2havethesamedimensionsandloadsasthecorrespondingjoists3.1,buttheirspanisonly2,10m.Acheckisthereforenotnecessary.

a)FrameConstruction


2.2RoofBeam

system

maxl 5,15m

cross‐section

b/h 16/42

A 672cm

I 98784cm

W 4704cm

material

glulamGL24h

γ 3,7kN/m

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

k 0,6

loads

g2,490,65

3,7 ⋅ 0,16 ⋅ 0,42 4,08kN/m

s5,730,65

8,82kN/m

w0,310,65

0,48kN/m

q1,130,65

1,74kN/m

[email protected] thesingleforcesfromthejoistsare

convertedintoaconstantdistributedload

reactionforces,internalforcesanddeformations

thereactionforces,internalforcesanddeformationsarecalculatedbymeansofdimensionless“1”‐loads

theactualinternalforcesarethencalculatedbymultiplyingtherealloadwiththecorrespondingresultfromthe“1”‐loads

a)FrameConstruction


constantload

loadingandreactionforces

bendingmoment

shearforce

deformations

a)FrameConstruction


unfavourableloads


bendingmoment

shearforce


a)FrameConstruction



deformations

ULSCO3

k 0,9

p 1,20 ⋅ 4,08 1,50 ⋅ 8,82 18,12kN/m

q 1,5 ⋅ 0,7 ⋅ 1,74 1,83kN/m

M 1,884 ⋅ 18,12 2,457 ⋅ 1,83 38,66 kNm

σ38664704

0,82kN/cm

f 0,9 ⋅2,41,15

1,88 kN/cm

η0,821,88

0,44 1,0

V 2,572 ⋅ 18,12 2,871 ⋅ 1,83 51,86kN

τ 1,5 ⋅51,86

0,67 ⋅ 6720,17kN/cm

f 0,9 ⋅0,351,15

0,27kN/cm

η0,170,27

0,64 1,0

nolateraltorsionalbucklingbecausethejoistssecurethecompressionflangeofthebeam

SLSCO9/10

w , 4,08 ⋅ 0,0254 0,104cm

w , 8,82 ⋅ 0,0254 0,224cm

w , 0,48 ⋅ 0,0254 0,012cm

a)FrameConstruction


w , 1,74 ⋅ 0,0435 0,076cm


w0,104 0,224 0,6 ⋅ 0,012 0,7 ⋅ 0,0760,39cm

maxw515300

1,72cm

η0,391,72

0,23 1,0

finaldeformation

w0,104 ⋅ 1 0,6 0,224 ⋅ 1 0,2 ⋅ 0,60,012 ⋅ 0,6 0 ⋅ 0,6 0,076 ⋅ 0,7 0,3

⋅ 0,6 0,49cm

maxw515150

3,43cm

η0,493,43

0,14 1,0

maxreactionforces

A 4,08 ⋅ 1,768 7,21kN

A 8,82 ⋅ 1,768 15,59kN

A 0,48 ⋅ 1,768 0,86kN

A 1,74 ⋅ 1,892 3,29kN

B 4,08 ⋅ 4,714 19,22kN

B 8,82 ⋅ 4,714 41,56kN

B 0,48 ⋅ 4,714 2,28kN

B 1,74 ⋅ 5,268 9,17kN

C 4,08 ⋅ 4,691 19,12kN

C 8,82 ⋅ 4,691 41,36kN

C 0,48 ⋅ 4,691 2,27kN

C 1,74 ⋅ 5,446 9,48kN

maxinternalforces

V , 2,612 ⋅ 4,08 10,65kN

V , 2,612 ⋅ 8,82 23,03kN

V , 2,612 ⋅ 0,48 1,27kN

V , 2,701 ⋅ 1,74 4,70kN

a)FrameConstruction


2.2FloorBeam

system

maxl 5,15m

cross‐section

b/h 16/42

A 672cm

I 98784cm

W 4704cm

material

glulamGL24h

γ 3,7kN/m

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

k 0,6

loads

g2,020,65

3,7 ⋅ 0,16 ⋅ 0,42 3,36kN/m

s 0

w 0

q3,770,65

5,8kN/m

[email protected]

internalforces

cf.2.2RoofBeam

ULSCO2

k 0,8

p 1,20 ⋅ 3,36 4,03 kN/m

a)FrameConstruction


q 1,5 ⋅ 5,8 8,7kN/m

M 1,884 ⋅ 4,03 2,457 ⋅ 8,7 29,0 kNm

σ29004704

0,62kN/cm

f 0,8 ⋅2,41,15

1,67 kN/cm

η0,621,67

0,37 1,0

V 2,572 ⋅ 4,03 2,871 ⋅ 8,7 35,34kN

τ 1,5 ⋅35,34

0,67 ⋅ 6720,12kN/cm

f 0,8 ⋅0,351,15

0,24kN/cm

η0,120,24

0,49 1,0


SLSCO7/8

w , 3,36 ⋅ 0,0254 0,085cm

w , 0

w , 0

w , 5,8 ⋅ 0,0435 0,252cm


w 0,085 0,252 0 0 0,34cm

maxw515300

1,72cm

η0,341,72

0,20 1,0

finaldeformation

w0,085 ⋅ 1 0,6 0,252 ⋅ 1 0,3 ⋅ 0,60 0 0,434cm

maxw515150

3,43cm

η0,433,43

0,13 1,0

maxreactionforces

A 3,36 ⋅ 1,768 5,94kN

A 0

A 0

a)FrameConstruction


A 5,8 ⋅ 1,892 10,97kN

B 3,36 ⋅ 4,714 15,83kN

B 0

B 0

B 5,8 ⋅ 5,268 30,55kN

C 3,36 ⋅ 4,691 15,75kN

C 0

C 0

C 5,8 ⋅ 5,446 31,59kN

a)FrameConstruction


2.1RoofBeam

cf.2.2RoofBeam

a)FrameConstruction


2.1FloorBeam

cf.2.2FloorBeam

a)FrameConstruction


2.3Beams

Thebeams2.3havethesamedimensionsandspansasthecorrespondingbeams2.2,buttheirloadissmallerbecausetheygettheloadsfromthejoists3.2whichhaveasmallerspan.Acheckisthereforenotnecessary.

a)FrameConstruction


7Diaphragm

system


maxw D E 1,044 ⋅ 0,8 0,571,43kN/m

w 1,15 ⋅ 1,43 ⋅ 3,195 5,25kN/m

h 3,195 mistheheightofonestorey theverticalcarriersinthefaçade(6)in

betweenthebeams2.4aresingle‐spanbeams;toaccountforcontinuityeffects,afactorof1,15isadded

internalforces

|P | |P |5,25 ⋅ 22,34

8/20,65 15,9kN

V5,25 ⋅ 22,34

258,6 kN

a)FrameConstruction


8Frame

system


maxw D E 1,044 ⋅ 0,8 0,571,43kN/m

internalforces

normalforcesN[kN]

a)FrameConstruction


2.4Beam(front)

system

maxl 5,15m

cross‐section

b/h 16/42

A 672cm

I 98784cm

W 4704cm

i42

√1212,1cm

I 14336cm

W 1792cm

i16

√124,6cm

ih

√12

I 0,140 ⋅ 42 ⋅ 16 24084cm

material

glulamGL24h

γ 3,7kN/m

f 24N/mm

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

E , 9600N/mm

G , 540N/mm

k 0,6

I 0,140 ⋅ h ⋅ b

(forrectangularcross‐sections)

a)FrameConstruction


loads

g 0,5kN/m g 1,15 ⋅ 3,195 ⋅ 0,5 3,7 ⋅ 0,16 ⋅ 0,422,09 kN/m

s 0

q 1044N/m

c D 0,8

windfromthefront

w 0,8 ⋅ 1,044 0,84 kN/m

N , 15,9kN

q 0

w 1,15 ⋅ 3,195 ⋅ 0,84 3,07kN/m


cf.2.2RoofBeamforverticalloads becauseofthesmallermomentofinertiaforhorizontalloads(I ),thedeformationsdue

tohorizontalloadsmustbecalculatedseparately

constantload


deformation

ULSCO5/6

k 1,1

p 1,20 ⋅ 2,09 0 2,50kN/m

w 1,50 ⋅ 3,07 4,60kN/m

N 1,50 ⋅ 15,9 23,85kN

q 0

M 1,884 ⋅ 2,50 0 4,72kNm

a)FrameConstruction


σ472474

0,10kN/cm

M 1,884 ⋅ 4,60 8,68kNm

σ8681792

0,48kN/cm

σ23,85672

0,035kN/cm

f 1,1 ⋅2,41,15

2,30kN/cm

f 1,1 ⋅2,41,15

2,30kN/cm

lateraltorsionalbuckling

l 5,15m

σ ,π ⋅ √960 ⋅ 14336 ⋅ 54 ⋅ 24084

515 ⋅ 47045,49kN/cm

λ ,2,45,49

0,66 0,75

k 1,0

flexuralbuckling

λ51512,1

42,6

λ ,42,6π

⋅249600

0,677

k 0,5 ⋅ 1 0,1 ⋅ 0,677 0,3 0,677

0,748

k ,1

0,748 0,748 0,6770,938

λ5154,6

112,0

λ ,112π

⋅249600

1,78

k 0,5 ⋅ 1 0,1 ⋅ 1,78 0,3 1,782,16

k ,1

2,16 2,16 1,780,296

a)FrameConstruction


η0,035

0,938 ⋅ 2,300,10

1,0 ⋅ 2,300,482,30

0,10

1,0

η0,035

0,296 ⋅ 2,300,10

1,0 ⋅ 2,300,482,30

0,27

1,0

V 2,572 ⋅ 2,50 0 6,54kN

τ 1,5 ⋅6,54

0,67 ⋅ 6720,022kN/cm

V 2,572 ⋅ 4,60 12,02kN

τ 1,5 ⋅12,02

0,67 ⋅ 6720,040kN/cm

f 1,1 ⋅0,351,15

0,33kN/cm

η0,022 0,040

0,330,14 1,0

σk , ⋅ f

σ

k ⋅ fσf

1

and

σk , ⋅ f

σ

k ⋅ fσf

1

cf.[2,9.33]

SLSCO9/10

w , , 2,09 ⋅ 0,0254 0,053cm

w , , 0

w , , 3,07 ⋅ 0,1751 0,537cm

w , , 0


w , 0,053 0 0 0,053cm

w . 0,537cm

w 0,053 0,537 0,54cm

maxw515300

1,72cm

η0,541,72

0,31 1,0

finaldeformation

w , 0,053 ⋅ 1 0,6 0 0 0,085cm

w , 0,537 ⋅ 1 0 0,537cm

w 0,085 0,537 0,54cm

maxw515150

3,43cm

η0,543,43

0,16 1,0

a)FrameConstruction


2.4Beam(side)

system

maxl 5,15m

cross‐section

b/h 16/42

A 672cm

I 98784cm

W 4704cm

i42

√1212,1cm

I 14336cm

W 1792cm

i16

√124,6cm

I 0,140 ⋅ 42 ⋅ 16 24084cm

material

glulamGL24h

γ 3,7kN/m

f 24N/mm

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

E , 9600N/mm

G , 540N/mm

k 0,6

a)FrameConstruction


loads

g 0,5kN/m g 1,15 ⋅ 3,195 ⋅ 0,5 3,7 ⋅ 0,16 ⋅ 0,422,09 kN/m

s 0

q 1044N/m

c A 1,2

c B 0,8

windfromthefront

w A 1,2 ⋅ 1,044 1,25kN/m

w B 0,8 ⋅ 1,044 0,84kN/m

N , 243,2kN

q 0

w A 1,15 ⋅ 3,195 ⋅ 1,25 4,60kN/m

w B 1,15 ⋅ 3,195 ⋅ 0,84 3,07kN/m


verticalconstantload


bendingmoment

a)FrameConstruction


shearforce

deformations

horizontalwindload becausethewindloadisnotconstant,itmustbecalculatedseparately

loading

bendingmoment

a)FrameConstruction


shearforce

deformation

ULSCO5/6

k 1,1

p 1,20 ⋅ 2,09 0 2,50kN/m

w A 1,50 ⋅ 4,60 6,90kN/m

w B 1,50 ⋅ 3,07 4,60kN/m

N 1,50 ⋅ 243,2 364,8kN

q 0

M 2,442 ⋅ 2,50 0 6,11kNm

σ611474

0,13kN/cm

M 14,59kNm

σ14591792

0,81kN/cm

σ364,8672

0,54kN/cm

f 1,1 ⋅2,41,15

2,30kN/cm

f 1,1 ⋅2,41,15

2,30kN/cm

lateraltorsionalbuckling

l 4,64m

a)FrameConstruction


σ ,π ⋅ √960 ⋅ 14336 ⋅ 54 ⋅ 24084

464 ⋅ 47046,09kN/cm

λ ,2,46,09

0,63 0,75

k 1,0

flexuralbuckling

λ46412,1

38,3

λ ,38,3π

⋅249600

0,61

k 0,5 ⋅ 1 0,1 ⋅ 0,61 0,3 0,61

0,702

k ,1

0,702 0,702 0,610,953

λ4644,6

100,9

λ ,100,9π

⋅249600

1,61

k 0,5 ⋅ 1 0,1 ⋅ 1,61 0,3 1,611,86

k ,1

1,86 1,86 1,610,358

η0,54

0,953 ⋅ 2,300,13

1,0 ⋅ 2,300,812,30

0,43

1,0

η0,54

0,358 ⋅ 2,300,13

1,0 ⋅ 2,300,812,30

1,01

1,0

V 2,727 ⋅ 2,50 0 6,82kN

τ 1,5 ⋅6,82

0,67 ⋅ 6720,024kN/cm

V 19,16kN

τ 1,5 ⋅19,16

0,67 ⋅ 6720,065kN/cm

f 1,1 ⋅0,351,15

0,33 kN/cm

a)FrameConstruction


η0,024 0,065

0,330,21 1,0

SLSCO5/6

w , , 2,09 ⋅ 0,02488 0,053cm

w , , 0

w , , 1,353cm

w , , 0


w , 0,053 0 0 0,053cm

w . 1,353cm

w 0,053 1,353 1,35cm

maxw464300

1,55cm

η1,351,55

0,88 1,0

finaldeformation

w , 0,053 ⋅ 1 0,6 0 0 0,085cm

w , 1,353 ⋅ 1 0 0,537cm

w 0,085 1,353 1,36cm

maxw464150

3,09cm

η1,363,09

0,44 1,0

maxreactionforces

vertical

B 2,09 ⋅ 5,48 11,43kN

B 0

B 0

B 0

C 2,09 ⋅ 3,442 7,18kN

C 0

C 0

C 0

horizontal

a)FrameConstruction


B 20,88kN

a)FrameConstruction


1.1Column

Thecolumn1.1carriesonlytheverticalself‐weightandlifeload,butdoesnottakepartincarryingtheglobalbendingmomentfromthewindloads.ThecolumninaxisBbecomesdecisive.

system

cross‐section

b/h 40/40

A 1600cm

I I 213333cm

i i40

√1211,5cm

material

glulamGL24h

γ 3,7kN/m

f 24N/mm

loads

g 3,7 ⋅ 0,4 ⋅ 0,4 0,592kN/m self‐weightofthecolumn

N 2 ⋅ 19,22 14 ⋅ 2 ⋅ 15,83 481,6 kN

s 0

N 2 ⋅ 41,56 83,12kN

w 0

N 2 ⋅ 2,28 4,57kN

q 0

N 2 ⋅ 9,17 14 ⋅ 0,74 ⋅ 2 ⋅ 30,55 651,4 kN

[email protected] 2beamsareattachedto1column theloadsareaddedupfortheroofand

14floors

ULSCO2

k 0,8

g 1,2 ⋅ 0,592 0,71 kN/m

N1,2 ⋅ 481,6 0,71 ⋅ 16 ⋅ 3,195 1,5 ⋅ 651,41591,4kN

σ1591,41600

0,99kN/cm

f 0,8 ⋅2,41,15

1,67kN/cm

flexuralbuckling

λ319,511,5

27,8

onthesafeside,theself‐weightofthecolumnisaddedupover16storeys

a)FrameConstruction


λ27,8π

⋅249600

0,44

k 0,5 ⋅ 1 0,1 ⋅ 0,44 0,3 0,440,604

k1

0,604 0,604 0,440,983

η0,99

0,983 ⋅ 1,670,61 1,0

a)FrameConstruction


1.4Column

Thecolumn1.4ispartoftheframethatcarriestheglobalbendingmomentfromthewindloads.

system

cross‐section

b/h 40/40

A 1600cm

I I 213333cm

i i40

√1211,5cm

material

glulamGL24h

γ 3,7kN/m

f 24N/mm

loads

g 3,7 ⋅ 0,4 ⋅ 0,4 0,592kN/m

N 19,12 7,18 14 ⋅ 15,75 7,18

347,3kN

s 0

N 41,36kN

w 0

N 839,1kN

q 0

N 9,48 14 ⋅ 0,74 ⋅ 31,59 336,7 kN

[email protected](side) 1beam2.1and1beam2.4areattached

tothecolumn

ULSCO5/6

k 1,1

g 1,2 ⋅ 0,592 0,71kN/m

N1,2 ⋅ 347,3 0,71 ⋅ 16 ⋅ 3,195 1,5 ⋅ 839,11,5 ⋅ 0,7 ⋅ 41,36 1,5 ⋅ 0,7 ⋅ 336,72108,7kN

σ2108,71600

1,32kN/cm

f 1,1 ⋅2,41,15

2,30 kN/cm

a)FrameConstruction


flexuralbuckling

λ319,511,5

27,8

λ27,8π

⋅249600

0,44

k 0,5 ⋅ 1 0,1 ⋅ 0,44 0,3 0,440,604

k1

0,604 0,604 0,440,983

η1,32

0,983 ⋅ 2,300,58 1,0

a)FrameConstruction


4Diagonal

Thediagonalispartoftheframethatcarriestheglobalbendingmomentfromthewindloads.Although the tensile forces in thediagonalsareslightlyhigher, compressionbecomesdecisivebecauseoftheflexuralbuckling.

system

maxl15,792

7,90m

cross‐section

b/h 40/40

A 1600cm

I I 213333cm

i i40

√1211,5cm

material

glulamGL24h

γ 3,7kN/m

f 24N/mm eachdiagonalconsistsoftwoindividualmemberswhichspantwostoreys

loads

g 0

s 0

w 0

N 512,2kN

q 0

see8Frame

ULSCO5/6

k 1,1

N 1,5 ⋅ 512,2 768,3kN

σ768,31600

0,48kN/cm

f 1,1 ⋅2,41,15

2,30kN/cm

flexuralbuckling

λ79011,5

68,7

λ68,7π

⋅249600

1,09

a)FrameConstruction


k 0,5 ⋅ 1 0,1 ⋅ 1,09 0,3 1,091,14

k1

1,14 1,14 1,090,678

η0,48

0,678 ⋅ 2,300,31 1,0

a)FrameConstruction


5StructuralSheathingoftheFloors

Intheroof,theverticalloadsarecarriesbythehorizontalcarriersandthejoists,thesheathingdoesnotcarryanyloads.Thehorizontalcarriersrunperpendiculartotheroofjoists,sothattheloadsfromtheroofdonotlieonthesheathing.Onlyinthefloorsthesheathingmustcarrytheverticalloads,self‐weightandlifeload,betweenthejoists.Additionally,italsoisresponsiblefortheshearstiffnessofthediaphragm.

system

globalsystem(diaphragm)

localsystem

l 0,65m

t 18mm

A 180cm/m

I 48,6cm /m

W 54cm /m

a)FrameConstruction


material

plywood

m 1200Nmm/mm

k 1,0

EI 4320kNmm /mm

k 0,8

the material properties are taken fromthetechnicalapproval[3]

loads

g 1,34kN/m

s 0

w 0

shearfromthediaphragm

l 20,65 6 ⋅ 0,4 18,25m

v58,618,25

3,21kN/m

q A 2,5kN/m

the shear force is distributed over thewholelengthofthebuilding,thecolumnsmust be subtracted because they gothroughthesheathing

ULSCO2

k 0,8

g 1,20 ⋅ 1,34 1,61kN/m

q 1,5 ⋅ 2,5 3,75kN/m

M 0,125 ⋅ 1,61 3,75 ⋅ 0,650,28kNm/m

M 0,8 ⋅1200/1000

1,150,83kNm/m

η0,280,83

0,34 1,0

Theshearloadsfromthediaphragmarenotdecisive,cf.preliminarydesign.

SLSCO7/8

w ,

1,34100 ⋅ 65

76,8 ⋅ 4320/100,072cm

w , 0

w , 0

w ,

2,5100 ⋅ 65

76,8 ⋅ 4320/100,135cm


w 0,072 0,135 0 0 0,21cm

a)FrameConstruction


maxw65300

0,22 cm

η0,210,22

0,95 1,0

finaldeformation

w0,072 ⋅ 1 0,8 0,135 ⋅ 1 0,3 ⋅ 0,80 0 0,30cm

maxw65150

0,43cm

η0,300,43

0,68 1,0

a)FrameConstruction


6VerticalFaçadeCarriers

system

h 3,195m

cross‐section

b/h 6/16

e 60cm

A 96cm

I 2048cm

W 256cm

material

glulamGL24h

f 24N/mm

k 0,67

f 3,5N/mm E , 11500N/mm k 0,6

loads

g 0

q 1044N/m

c A 1,2

w 1,2 ⋅ 1,044 1,25 kN/m w 1,25 ⋅ 0,6 0,75 kN/m

ULSCO5/6

k 1,1

w 1,50 ⋅ 0,75 1,13kN/m

M 0,125 ⋅ 1,13 ⋅ 3,195 1,44kNm

σ144256

0,56kN/cm

f 1,1 ⋅2,41,15

2,30 kN/cm

η0,562,30

0,24 1,0

V 0,500 ⋅ 1,13 ⋅ 3,195 1,80kN

τ 1,5 ⋅1,80

0,67 ⋅ 960,042kN/cm

f 1,1 ⋅0,351,15

0,33 kN/cm

nolateraltorsionalbuckling,becausethesheathingofthewallssecuresthecarriersfrombothsides

a)FrameConstruction


η0,420,33

0,13 1,0

SLSCO5/6

w , 0

w , 0

w ,

0,75100 ⋅ 319,5

76,8 ⋅ 1150 ⋅ 20480,433cm

w , 0


w 0,433cm

maxw319,5300

1,07cm

η0,4331,07

0,41 1,0

finaldeformation

w 0,433 ⋅ 1 0 ⋅ 0,6 0,433cm

maxw319,5150

2,13cm

η0,4332,13

0,20 1,0

a)FrameConstruction


ConnectionBeam2.2toColumn1.1

Theconnectionundertheroofbecomesdecisive.

system

angleoftheforcetothegrain

beam:α 90°

column:α 0°

fasteners

11M20bolts

f 240N/mm

f 400N/mm

material

glulamGL24h

ρ 385kg/m

strengthclass4.6

minimumdistances

beam

a 4 cos 90 ⋅ 2,0 8cm

a 4 ⋅ 2,0 8cm

a max 2 2 sin 90 ⋅ 2,0 8; 3 ⋅ 2,0 68cm

a 3 ⋅ 2,0 6cm

column

a 4 cos 0 ⋅ 2,0 10cm

a 4 ⋅ 2,0 8cm

a 3 ⋅ 2,0 6cm

capacityperfastenerpershearplane

a)FrameConstruction


M , 0,3 ⋅ 400 ⋅ 20 , /1000 289,6 Nm

beam(member1)

f , , 0,082 ⋅ 1 0,01 ⋅ 20 ⋅ 38525,26N/mm

k 1,35 0,015 ⋅ 20 1,65

f , ,25,26

1,65 ⋅ sin 90 cos 9015,3N/mm

column(member2)

f , , 0,082 ⋅ 1 0,01 ⋅ 20 ⋅ 38525,26N/mm

β25,2615,3

1,65

F ,

1,15 ⋅2 ⋅ 1,651 1,65

⋅ 2 ⋅ 289,6 ⋅ 1000 ⋅ 15,3 ⋅ 20/100017,1kN

failuremodekbecomesdecisive the axial capacity of the fasteners is

neglected

loads

F 2 ⋅ 19,22 38,4 kN

F 2 ⋅ 41,56 83,1kN

F 2 ⋅ 2,28 4,6kN

F 2 ⋅ 9,17 18,3kN

shearforcesinthebeamattheconnection

V 2 ⋅ 10,65 21,3kN

V 2 ⋅ 23,03 46,1kN

V 2 ⋅ 1,27 2,53kN

V 2 ⋅ 4,70 9,4kN

[email protected]

ULSCO3

k 0,9

F 1,2 ⋅ 38,4 1,5 ⋅ 83,1 1,5 ⋅ 0,7 ⋅ 18,3190,0kN

F . 17,1 ⋅ 11 ⋅ 2 376,0

F , 0,9 ⋅376,01,3

260,3kN

η190,0260,3

0,73 1,0

11boltsand2shearplanes

a)FrameConstruction


checkfortensionperpendiculartothegraininthebeam

V 1,2 ⋅ 21,3 1,5 ⋅ 46,1 1,5 ⋅ 0,7 ⋅ 9,4104,5kN

F 14 ⋅ 2 ⋅ 160 ⋅ 1 ⋅330

13346

/1000

153,1kN

F 0,9 ⋅153,11,3

106,0kN

η104,5106,0

0,99 1,0

a)FrameConstruction


ConnectionOuterBeam2.4ontheSidetoColumn1.3

system

angleofthescrews

α 45°

principleoftheforcedistributionintheconnection


beam:α 90°

column:α 0°

fasteners

forverticalloads

9screwsØ8mm

n 9 , 7,22

forhorizontalloads

10screwsØ8mm

n 10 , 7,94

the9screwsatthebottomthatgoupwardscarrytheverticalloads,the5upperscrewstogetherwith5ofthelowerscrewscarrythehorizontalloads

f 240N/mm

f 400N/mm

material

glulamGL24h

strengthclass4.6

a)FrameConstruction


ρ 385kg/m

minimumdistances

a 7 ⋅ 0,8 5,6cm

a 5 ⋅ 0,8 4cm

a 4 ⋅ 0,8 3,2cm

capacityofthescrews

pull‐outoftheshaft

(notdecisive)

tensilecapacityofthescrews

f , f 240N/mm

forverticalloads

F , 7,22 ⋅ 240 ⋅ π ⋅82

/1000 87,2kN

forhorizontalloads

F , 7,94 ⋅ 240 ⋅ π ⋅82

/1000 95,8 kN

fullythreadedscrewsareused,thereforepull‐throughoftheheaddoesnotneedtobeconsidered

loads

vertical

F 11,43kN

horizontal

F 20,88kN

beam2.4ontheside

internalforces

vertical

V 5,94kN

horizontal

V 12,15kN

ULSCO5/6

k 1,1

vertical

F 1,2 ⋅11,43sin 45

19,4kN

F , 1,1 ⋅87,21,3

73,7kN

η19,473,7

0,26

a)FrameConstruction


horizontal

F 1,5 ⋅20,88sin 45

44,3kN

F , 1,1 ⋅95,81,3

81,1kN

η44,381,1

0,55

η 0,26 0,55 0,81 1,0checkfortensionperpendiculartothegraininthebeam

vertical

V 1,2 ⋅ 5,94 7,13kN

F 14 ⋅ 160 ⋅ 1 ⋅340

13446

/1000 80,9kN

F 1,1 ⋅80,91,3

68,4kN

η7,1368,4

0,10 1,0

horizontal

V 1,5 ⋅ 12,15 18,23kN

F 14 ⋅ 460 ⋅ 1 ⋅80

1816

/1000 81,5kN

F 1,1 ⋅81,51,3

68,9kN

η18,2368,9

0,26 1,0

η 0,10 0,26 0,37 1,0

a)FrameConstruction


ConnectionDiagonal4toColumn1.2or1.4

Theprinciplethatisshownherecanbeappliedtoallconnectionsofthediagonalwithacolumn.

system

fasteners

10M20dowels

inthediagonal

α 0°

n 5 ⋅ 2 , ⋅136

13 ⋅ 207,93

inthecolumn

α 54°

n 5 ⋅ 2 , ⋅102

13 ⋅ 206,74

f 240N/mm

f 400N/mm

material

glulamGL24h

ρ 385kg/m

strengthclass4.6

minimumdistances

diagonal

a)FrameConstruction


a 3 2 ⋅ cos 0 ⋅ 2,0 10cm

a 3 ⋅ 2,0 6cm

a max 7 ⋅ 2,0 14; 8 14cm

a 3 ⋅ 2,0 6cm

column

a 3 2 ⋅ cos 54 ⋅ 2,0 9,24cm

a 3 ⋅ 2,0 6cm

amax 2 2 ⋅ sin 54 ⋅ 2,0 6,51; 3 ⋅ 2,0

6 6,51cm


M , 0,3 ⋅ 400 ⋅ 20 , /1000 289,6 Nm

f , , 0,082 ⋅ 1 0,01 ⋅ 20 ⋅ 38525,26N/mm

k 1,35 0,015 ⋅ 20 1,65

f , ,25,26

1,65 ⋅ sin 54 cos 5420,62N/mm

diagonal

F ,

25,26 ⋅ 100 ⋅ 20

⋅ 24 ⋅ 289,6 ⋅ 100025,26 ⋅ 20 ⋅ 100

1 /1000

24,9kN

column

F , 21,0kN

failuremodegbecomesdecisive

dowelshavenoaxialcapacity

loads

F , 530,9kN

V 20,2kN

see8Frame

ULSCO5/6

k 1,1

F 1,5 ⋅ 530,9 796,4kN

diagonal

F . 7,93 ⋅ 6 ⋅ 24,9 1185,8kN

F , 1,1 ⋅1185,81,3

1003,4kN


a)FrameConstruction


η796,41003,4

0,79 1,0

column

F . 6,74 ⋅ 6 ⋅ 21,0 850,9kN

F , 1,1 ⋅850,91,3

720,0kN

η796,4720,0

1,11 1,0 additionalstrengtheningisrequired,e.g.byfullythreadedscrewsperpendiculartothegraintoincreasethecapacityoftheconnection

checkfortensionperpendiculartothegraininthecolumn

V 1,5 ⋅ 20,2 30,3kN

F 14 ⋅ 400 ⋅ 1 ⋅160

11660

/1000

82,7kN

F 1,1 ⋅82,71,3

70,0kN

η30,370,0

0,43 1,0

b)PanelConstruction


b)PanelConstructionElementReferenceOverview


1 floorjoists

1.1 floorjoistsmodules3,4 57

1.2 floorjoistsmodules1,2,6,7 61

1.3 floorjoistsmodules5 63

2 floorbeam 65

3 walls/studs 75

5 columns 87

6 beam 77

connections 90

Remarks

Forthecalculationoftheinternalforcesinthestuds,theFEsoftwareRFEMwasused.

Comparedtothepreliminarydesign,thecross‐sectionsofthejoists,thebeamsandthecolumnswereadapted.Undertheroof,largercross‐sectionswererequired,whilethecross‐sectionsinthefloorscouldbedecreased.Thestudswerenotchanged.

b)PanelConstruction


1.1RoofJoists

system

l 5,15m

cross‐section

b/h 16/24

e 60cm

A 384cm

I 18432cm

W 1536cm

material

glulamGL24h

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

k 0,6

loads

g 1,69kN/m

s 4,66kN/m

q 1044N/m

c I 0,2

g 1,69 ⋅ 0,6 1,01 kN/m

s 4,66 ⋅ 0,6 2,80 kN/m

w 0,2 ⋅ 1,044 0,21 kN/m

q H 0,75kN/m

w 0,21 ⋅ 0,6 0,13 kN/m

q 0,75 ⋅ 0,6 0,45 kN/m

Q 1,5 kN

ULSCO3

k 0,9

p 1,20 ⋅ 1,01 1,50 ⋅ 2,80 5,41kN/m

Q 1,50 ⋅ 0,70 ⋅ 1,5 1,58kN

M 0,125 ⋅ 5,41 ⋅ 5,15 0,250 ⋅ 1,58 ⋅ 5,1519,97kNm

σ19971536

1,30kN/cm

f 0,9 ⋅2,41,15

1,88 kN/cm

b)PanelConstruction


η1,301,88

0,69 1,0

V 0,500 ⋅ 5,41 ⋅ 4,64 1,58 15,51kN

τ 1,5 ⋅15,51

0,67 ⋅ 3840,09kN/cm

f 0,9 ⋅0,351,15

0,27kN/cm

η0,090,27

0,33 1,0


SLSCO9/10

w ,

1,04100 ⋅ 515

76,8 ⋅ 1150 ⋅ 184320,438cm

w , 1,208cm

w , 0,054cm

w ,1,5 ⋅ 515

48 ⋅ 1150 ⋅ 184320,201cm


w0,438 1,208 0,6 ⋅ 0,054 0,7 ⋅ 0,2011,82cm

maxw515300

1,72cm

η1,821,72

1,06 1,0

finaldeformation

w0,438 ⋅ 1 0,6 1,208 ⋅ 1 0,2 ⋅ 0,60,054 ⋅ 0,6 0 0,201 ⋅ 0,7 0,3 ⋅ 0,62,26cm

maxw515150

3,43cm

η2,263,43

0,66 1,0

maxreactionforces

A 0,5 ⋅ 1,01 ⋅ 5,15 2,61kN

A 0,5 ⋅ 2,80 ⋅ 5,15 7,20kN

A 0,5 ⋅ 0,13 ⋅ 5,15 0,32kN

A 0,5 ⋅ 0,45 ⋅ 5,15 1,16kN

b)PanelConstruction


1.1FloorJoists

system

l 5,15m

cross‐section

b/h 16/20

e 60cm

A 320cm

I 10667cm

W 1067cm

material

glulamGL24h

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

k 0,6

loads

g 1,39kN/m

s 0

w 0

g 1,39 ⋅ 0,6 0,83 kN/m

q A 2,5kN/m

q 2,5 ⋅ 0,6 1,5 kN/m

Q 1,5 kN

ULSCO2

k 0,8

p 1,20 ⋅ 0,83 1,50 ⋅ 1,5 3,25kN/m

M 0,125 ⋅ 3,25 ⋅ 5,15 10,78kNm

σ10781067

1,01kN/cm

f 0,8 ⋅2,41,15

1,67 kN/cm

η1,011,67

0,61 1,0

V 0,500 ⋅ 3,25 ⋅ 4,64 8,37kN

τ 1,5 ⋅8,37

0,67 ⋅ 3200,06kN/cm


b)PanelConstruction


f 0,8 ⋅0,351,15

0,24 kN/cm

η0,060,24

0,24 1,0

SLSCO7/8

w ,

0,83100 ⋅ 515

76,8 ⋅ 1150 ⋅ 106670,623cm

w , 0

w , 0

w , 1,120cm


w 0,623 1,120 0 0 1,74cm

maxw515300

1,72 cm

η1,741,72

1,02 1,0

finaldeformation

w0,623 ⋅ 1 0,6 1,120 ⋅ 1 0,3 ⋅ 0,60 0 2,32cm

maxw515150

3,43cm

η2,323,43

0,68 1,0

thisisstillOK,becauseamongstothersthebeneficialeffectofthesheathingwasnotconsideredyet

maxreactionforces

A 0,5 ⋅ 0,83 ⋅ 5,15 2,15kN

A 0

A 0

A 0,5 ⋅ 1,5 ⋅ 5,15 3,86kN

b)PanelConstruction


1.2RoofJoists

Theroofjoists1.2havethesameloadsanddimensionsastheroofjoists1.1butasmallerspan,theyarethereforenotdecisive,andacheckisnotnecessary.

maxreactionforces

A 0,5 ⋅ 1,01 ⋅ 4,38 2,22kN

A 0,5 ⋅ 2,80 ⋅ 4,38 6,12kN

A 0,5 ⋅ 0,13 ⋅ 4,38 0,27kN

A 0,5 ⋅ 0,45 ⋅ 4,38 0,99kN

b)PanelConstruction


1.2FloorJoists

Thefloorjoists1.2havethesameloadsanddimensionsasthefloorjoists1.1butasmallerspan,theyarethereforenotdecisive,andacheckisnotnecessary.

maxreactionforces

A 0,5 ⋅ 0,83 ⋅ 4,38 1,83kN

A 0

A 0

A 0,5 ⋅ 1,5 ⋅ 4,38 3,29kN

b)PanelConstruction


1.3RoofJoists

Thedimensionsfortheroofjoists1.3couldbedecreasedtob/h 8/24.

b)PanelConstruction


1.3FloorJoists

Thedimensionsforthefloorjoists1.3couldbedecreasedtob/h 8/20.

b)PanelConstruction


2RoofBeam

Thebeamundertheroofinaxis3–5/Cbecomesdecisive.

system

maxl 2,10m

cross‐section

b/h 12/24A 288cm I 13824cm

W 1152cm

material

glulamGL24hf 24N/mm k 0,67f 3,5N/mm E , 11500N/mm k 0,6

loads

g2,610,6

4,35kN/m

s7,200,6

12,0kN/m

w0,320,6

0,54kN/m

q1,160,6

1,93kN/m

[email protected]

b)PanelConstruction



constantload


bendingmoment

shearforce

deformations

b)PanelConstruction


unfavourableloads


bendingmoment

shearforce


b)PanelConstruction


deformations

ULSCO3

k 0,9

p 1,20 ⋅ 4,35 1,50 ⋅ 12,0 23,2kN/m

q 1,5 ⋅ 0,7 ⋅ 1,93 2,03kN/m

M 23,2 ⋅ 0,4243 2,03 ⋅ 0,436710,74kNm

σ10741152

0,93kN/cm

f 0,9 ⋅2,41,15

1,88 kN/cm

η0,931,88

0,50 1,0

V 23,2 ⋅ 1,252 2,03 ⋅ 1,258 31,6kN

τ 1,5 ⋅31,6

0,67 ⋅ 2880,25kN/cm

f 0,9 ⋅0,351,15

0,27kN/cm

η0,250,27

0,90 1,0


SLSCO9/10

w , 4,35 ⋅ 0,0087 0,038cm

w , 12,0 ⋅ 0,0087 0,104cm

w , 0,54 ⋅ 0,0087 0,005cm

w , 1,93 ⋅ 0,0089 0,017cm


w0,038 0,104 0,6 ⋅ 0,005 0,7 ⋅ 0,0170,157

maxw210300

0,70cm

η0,1570,70

0,22 1,0

b)PanelConstruction


finaldeformation

w0,038 ⋅ 1 0,6 0,104 ⋅ 1 0,2 ⋅ 0,60,005 ⋅ 0,6 0 0,017 ⋅ 0,7 0,3 ⋅ 0,60,195cm

maxw210150

1,40cm

η0,1951,40

0,14 1,0

b)PanelConstruction


2FloorBeam

Thebeaminaxis3–5/Cbecomesdecisive.

system

maxl 2,10m

cross‐section

b/h 8/24A 192cm I 9216cm

W 768cm

material

glulamGL24hf 24N/mm k 0,67f 3,5N/mm E , 11500N/mm k 0,6

loads

g2,150,6

4,35kN/m

s 0

w 0

q3,860,6

6,44kN/m

[email protected]


constantload


b)PanelConstruction


bendingmoment

shearforce

deformations

unfavourableloads


b)PanelConstruction


bendingmoment

shearforce


deformations

ULSCO2

k 0,8

g 1,20 ⋅ 3,58 4,30kN/m

q 1,5 ⋅ 6,44 9,66kN/m

M 4,30 ⋅ 0,4243 9,66 ⋅ 0,4367 6,04 kNm

b)PanelConstruction


σ604768

0,79kN/cm

f 0,8 ⋅2,41,15

1,67 kN/cm

η0,791,67

0,47 1,0

V 4,30 ⋅ 1,252 9,66 ⋅ 1,258 17,53kN

τ 1,5 ⋅17,53

0,67 ⋅ 1920,20kN/cm

f 0,8 ⋅0,351,15

0,24kN/cm

η0,200,24

0,84 1,0


SLSCO7/8

w , 3,58 ⋅ 0,01935 0,069cm

w , 0

w , 0

w , 6,44 ⋅ 0,01987 0,128cm


w 0,069 0,128 0 0 0,20cm

maxw210300

0,70cm

η0,200,70

0,28 1,0

finaldeformation

w0,069 ⋅ 1 0,6 0,128 ⋅ 1 0,3 ⋅ 0,60 0 0,26cm

maxw210150

1,40cm

η0,261,40

0,19 1,0

Thefloorbeaminaxis1–3/Abecomesdecisivefortheconnectiontothestuds(cf.ConnectionFloorBeam2toStuds3).

maxreactionforces

A 3,04 ⋅ 1,817 5,53kN

A 0

b)PanelConstruction


A 0

A 5,475 ⋅ 1,88 10,29kN

maxinternalforces

V , 0,9393 ⋅ 3,04 2,86kN

V , 0

V , 0

V . 0,9785 ⋅ 5,475 5,36kN

b)PanelConstruction


3Studs

Becausethecross‐sectionofthestudsdecreasesinthehigherstoreys,checksmustbeperformedateverytransition,i.e.inthe11.,the6.andthe1.floor.Still,the1.floorbecomesdecisive.TheinternalforcesweredeterminedusingtheFEMsoftwareRFEM.

system

decisivestud

generalglobalsystem(wall)

cross‐section

b/h 20/20

b)PanelConstruction


A 400cm

I I 13333cm

i i16

√125,77cm

material

glulamGL24h

f 24N/mm

ULSCO6

k 1,1

N 460,8kN

σ460,8400

1,27kN/cm

f 1,1 ⋅2,41,15

2,30kN/cm

flexuralbuckling

λ319,55,77

55,3

λ55,3π

⋅249600

0,88

k 0,5 ⋅ 1 0,1 ⋅ 0,88 0,3 0,880,92

k1

0,92 0,92 0,880,853

η1,27

0,853 ⋅ 2,300,67 1,0

b)PanelConstruction


6Beam(Roof)

system

maxl 2,32m

cross‐section

b/h 12/24

A 288cm

I 13824cm

W 1152cm

material

glulamGL24h

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

k 0,6

loads

g2,220,6

3,70kN/m

s6,120,6

10,21kN/m

w0,270,6

0,46kN/m

q0,990,6

1,64kN/m

[email protected]


b)PanelConstruction


constantload


bendingmoment

shearforce

deformations

b)PanelConstruction


unfavourableloads


bendingmoment

shearforce


b)PanelConstruction


deformations

ULSCO3

k 0,9

p 1,20 ⋅ 3,70 1,50 ⋅ 10,21 19,75kN/m

q 1,5 ⋅ 0,7 ⋅ 1,64 1,72kN/m

M 19,75 ⋅ 0,5382 1,72 ⋅ 0,629711,72kNm

σ11721152

1,02kN/cm

f 0,9 ⋅2,41,15

1,88 kN/cm

η1,021,88

0,54 1,0

V 19,75 ⋅ 1,392 1,72 ⋅ 1,431 29,96kN

τ 1,5 ⋅29,96

0,67 ⋅ 2880,23kN/cm

f 0,9 ⋅0,351,15

0,27kN/cm

η0,230,27

0,85 1,0


SLSCO9/10

w , 3,70 ⋅ 0,01254 0,046cm

w , 0,128cm

w , 0,006cm

w , 1,64 ⋅ 0,01801 0,030cm


w 0,046 0,128 0,6 ⋅ 0,006 0,7 ⋅ 0,300,199cm

maxw232300

0,77 cm

b)PanelConstruction


η0,1990,77

0,26 1,0

finaldeformation

w0,046 ⋅ 1 0,6 0,128 ⋅ 1 0,2 ⋅ 0,60,006 ⋅ 0,6 0 0,030 ⋅ 0,7 0,3 ⋅ 0,60,247cm

maxw232150

1,55cm

η0,2471,55

0,16 1,0

maxreactionforces

A 3,70 ⋅ 0,928 3,43kN

A 9,47kN

A 0,42kN

A 1,64 ⋅ 1,044 1,71kN

B 3,70 ⋅ 2,552 9,45kN

B 26,04kN

B 1,17kN

B 1,64 ⋅ 2,784 4,57kN

b)PanelConstruction


6Beam(Floor)

system

maxl 2,32m

cross‐section

b/h 8/24

A 192cm

I 9216cm

W 768cm

material

glulamGL24h

f 24N/mm

k 0,67

f 3,5N/mm

E , 11500N/mm

k 0,6

loads

g1,830,6

3,04kN/m

s 0

w 0

q3,290,6

5,48kN/m

[email protected]

b)PanelConstruction



constantload


bendingmoment

shearforce

deformations

b)PanelConstruction


unfavourableloads


bendingmoment

shearforce


b)PanelConstruction


deformations

ULSCO2

k 0,8

g 1,20 ⋅ 3,04 3,65kN/m

q 1,5 ⋅ 5,48 8,21kN/m

M 3,65 ⋅ 0,5382 8,21 ⋅ 0,6297 7,14kNm

σ714768

0,93kN/cm

f 0,8 ⋅2,41,15

1,67 kN/cm

η0,931,67

0,56 1,0

V 3,65 ⋅ 1,392 8,21 ⋅ 1,431 16,84kN

τ 1,5 ⋅16,84

0,67 ⋅ 1920,20kN/cm

f 0,8 ⋅0,351,15

0,24kN/cm

η0,200,24

0,81 1,0


b)PanelConstruction


SLSCO7/8

w , 3,04 ⋅ 0,0188 0,057cm

w , 0

w , 0

w , 5,48 ⋅ 0,02701 0,148cm


w 0,057 0,148 0 0 0,205cm

maxw232300

0,77cm

η0,2050,77

0,26 1,0

finaldeformation

w0,057 ⋅ 1 0,6 0,148 ⋅ 1 0,3 ⋅ 0,60 0 0,266cm

maxw232150

1,55cm

η0,2661,55

0,17 1,0

maxreactionforces

A 3,04 ⋅ 0,928 2,82kN

A 0

A 0

A 5,48 ⋅ 1,044 5,72kN

B 3,04 ⋅ 2,552 7,77kN

B 0

B 0

B 5,48 ⋅ 2,784 15,24kN

b)PanelConstruction


5Columns

system

cross‐sectionscolumnA,D

b/h 16/20

A 320cm

I I 10667cm

i i16

√124,62cm

columnB,C

b/h 20/20

A 400cm

I I 13333cm

i i20

√125,77cm

materialglulamGL24hγ 3,7kN/m f 24N/mm

globalsystem(beam6)

localsystem

loads

columnA,D


N 3,43 14 ⋅ 2,82 43,0kN

s 0

N 9,47kN

w 0

N 0,42kN

q 0

N 1,71 14 ⋅ 0,74 ⋅ 5,72 60,9kN

columnB,C

reactionforceA@6 theloadisaddedupfortheroofand14

storeys


N 9,45 14 ⋅ 7,77 118,2kN

s 0

N 26,04kN

w 0

reactionforceB@6 theloadisaddedupfortheroofand14

storeys

b)PanelConstruction


N 1,17kN

q 0

N 4,57 14 ⋅ 0,74 ⋅ 15,24 162,5 kN

ULSCO2

k 0,8

columnA,D

g 1,2 ⋅ 0,037 0,044kN/m

N1,2 ⋅ 43,0 0,044 ⋅ 16 ⋅ 3,195 1,5

⋅ 60,9 145,2kN

σ145,2320

0,45kN/cm

f 0,8 ⋅2,41,15

1,67kN/cm

flexuralbuckling

λ319,54,62

69,2

λ69,2π

⋅249600

1,10

k 0,5 ⋅ 1 0,1 ⋅ 1,10 0,3 1,101,15

k1

1,15 1,15 1,100,683

η0,45

0,683 ⋅ 1,670,40 1,0

columnB,C

g 1,2 ⋅ 0,046 0,055kN/m

N1,2 ⋅ 118,2 0,055 ⋅ 16 ⋅ 3,195 1,5

⋅ 162,5 388,4kN

σ388,4400

0,97kN/cm

f 0,8 ⋅2,41,15

1,67kN/cm

flexuralbuckling

λ319,55,77

55,3

b)PanelConstruction


λ55,3π

⋅249600

0,88

k 0,5 ⋅ 1 0,1 ⋅ 0,88 0,3 0,880,92

k1

0,92 0,92 0,880,853

η0,97

0,853 ⋅ 1,670,68 1,0

b)PanelConstruction


Anchoring

Thehold‐downdeviceconsistsoftwointernalsteelplatesanddowelsinsidethecorrespondingstuds.Atstudswithsmallertensileforces,theconnectioncanbeadapted,e.g.byusingonlyoneinternalsteelplateand/orlessdowels.

system


α 0°

fasteners

8M20dowels

n 2 ⋅ 4 , ⋅200

13 ⋅ 206,52

strengthclass4.6

f 240N/mm

f 400N/mm

material

glulamGL24h

ρ 385kg/m

minimumdistances

a 3 2 ⋅ cos 0 ⋅ 2,0 10cm

a 3 ⋅ 2,0 6cm

a max 7 ⋅ 2,0 14; 8 14cm

a 3 ⋅ 2,0 6cm


M , 0,3 ⋅ 400 ⋅ 20 , /1000 289,6 Nm

f , , 0,082 ⋅ 1 0,01 ⋅ 20 ⋅ 38525,26N/mm

F ,

25,26 ⋅ 67 ⋅ 20

⋅ 24 ⋅ 289,6 ⋅ 100025,26 ⋅ 20 ⋅ 67

1 /1000

19,8kN



b)PanelConstruction


ULSCO11/12

k 1,1

F 448,6kN cf.RFEManalysis

F . 19,8 ⋅ 6,52 ⋅ 4 516,2kN

F , 1,1 ⋅516,21,3

436,8kN

η448,6436,8

1,03 1,0

6,52boltsand4shearplanes

b)PanelConstruction


ConnectionRoofJoists1toRoofBeam2

Thisconnectionhadtobechangedincomparisontothepreliminarydesign.Insteadofdiagonalfullythreadedscrews,joisthangersareused.

system


α 90°

fasteners

JoistHangerSimpsonStrongtieBT4‐120orsimilar

material

glulamGL24h

ρ 385kg/m

capacity

F , 23,9kN

cf.technicaldatasheet[7]

loads

F 2,61kN

F 7,20kN

F 0,32kN

F 1,16kN

[email protected] theshearforcesinthejoistareequalto

thesupportforces

ULSCO3

b)PanelConstruction


k 0,9

F 1,2 ⋅ 2,61 1,5 ⋅ 7,20 1,5 ⋅ 0,7 ⋅ 1,1615,1kN

F . 23,9kN

F , 0,9 ⋅23,91,3

16,5kN

η15,116,5

0,92 1,0



V F 15,1kN

F 14 ⋅ 160 ⋅ 1 ⋅165

116,524

/1000

51,5kN

F 0,9 ⋅51,51,3

35,6kN

η15,135,6

0,43 1,0

b)PanelConstruction


ConnectionFloorJoists1toFloorBeam2

Forthisconnection,thesamesystemisused,buttheloadsarelowerfromthefloorthanfromtheroof,sothatthisconnectionisnotdecisive.

b)PanelConstruction


ConnectionFloorBeam2toStuds3

Thefloorbeaminaxis1–3/AbecomesdecisiveatsupportC.

system


floorbeam

α 90°

stud

α 0°

fasteners

4M20dowels

n 2 ⋅ 2 , ⋅100

13 ⋅ 202,94

f 240N/mm

f 400N/mm

material

glulamGL24h

ρ 385kg/m

strengthclass4.6

minimumdistances

floorbeam

a 3 2 ⋅ cos 90 ⋅ 2,0 6cm

b)PanelConstruction


a 3 ⋅ 2,0 6cm

amax 2 2 ⋅ sin 90 ⋅ 2,0 8; 3 ⋅ 2,0 68cm

a 3 ⋅ 2,0 6cm

stud

a 3 2 ⋅ cos 0 ⋅ 2,0 10cm

a 3 ⋅ 2,0 6cm

a 3 ⋅ 2,0 6cm


M , 0,3 ⋅ 400 ⋅ 20 , /1000 289,6 Nm

floorbeam(member1)

f , , 0,082 ⋅ 1 0,01 ⋅ 20 ⋅ 38525,26N/mm

k 1,35 0,015 ⋅ 20 1,65

f , ,25,26

1,65 ⋅ sin 90 cos 9015,3N/mm

stud(member2)

f , , 0,082 ⋅ 1 0,01 ⋅ 20 ⋅ 38525,26N/mm

β25,2615,3

1,65

failuremodedbecomesdecisive


F ,

1,05 ⋅15,3 ⋅ 80 ⋅ 202 1,65

⋅ 2 ⋅ 1,65 ⋅ 1 1,654 ⋅ 1,65 ⋅ 2 1,65 ⋅ 289,64 ⋅ 1000

15,3 ⋅ 20 ⋅ 801,65

13,1kN

loads

F 5,53kN

F 10,29kN

shearforcesinthebeamattheconnection

V 2,86kN

V 5,36kN

reactionforceC@2

ULSCO2

b)PanelConstruction


k 0,8

F 1,2 ⋅ 5,53 1,5 ⋅ 10,29 22,08kN

F . 2,93 ⋅ 1 ⋅ 13,09 38,5kN

F , 0,8 ⋅38,51,3

23,7kN

η22,0823,7

0,93 1,0

2,94boltsand1shearplane

tensionperpendiculartothegrain

V 1,2 ⋅ 2,86 1,5 ⋅ 5,36 11,5kN

F 14 ⋅ 80 ⋅ 1 ⋅180

11824

/1000 30,1kN

F 0,8 ⋅30,11,3

18,5kN

η11,518,5

0,62 1,0

b)PanelConstruction


ConnectionRoofBeam2toStuds3

This connection follows the same principle as the connection of the floor beam to the studs.Becauseofthehigherloadsfromtheroofthanfromthefloors,6dowelsarerequiredinsteadof4.Therefore,thestudsinthehigheststoreymustbe28/28(likethestudsinstorey1to5)toallowforenoughspaceforthe6dowels.

c)CLTConstruction


c)CLTConstructionElementReferenceOverview


1 floorslab 100

2,3 floorslab ‐

4 floorslab ‐

5 Walls 106

Anchoring 108

Remarks

Becauseofgoodlateraldistributionoftheloadsintheslabs,thesingleconcentratedforceQwillnotbecomedecisive.

Forthecalculationoftheinternalforcesofthewalls,theFEsoftwareRFEMwasused.

BecauseofmissingrulesforCLTintheEC,thesamedesignfactorsasforglulamareapplied.

Comparedtothepreliminarydesign,thethicknessesofthewallshadtobeincreased.Nowwallswiththethicknesses145mm,170mmand246mmareused.Thereductionofthethicknessovertheheightofthebuildingwasadapted.

storeyno M N t t t‐ % % mm mm mm 0 100,00 100,00 145 170 2461 87,11 93,33 145 170 2462 75,11 86,67 145 170 2463 64,00 80,00 145 170 2464 53,78 73,33 145 170 246

5 44,44 66,67 120 120 1706 36,00 60,00 120 120 1707 28,44 53,33 120 120 1708 21,78 46,67 120 120 1709 16,00 40,00 120 120 170

10 11,11 33,33 95 95 9511 7,11 26,67 95 95 9512 4,00 20,00 95 95 9513 1,78 13,33 95 95 9514 0,44 6,67 95 95 9515 0,00 0,00 95 95 95

c)CLTConstruction


1RoofSlab

system

maxl 4,38m

cross‐section

t 145mm

A 1450cm /m

I 25405cm /m

W 3504cm /m

material

CLTKL‐trä145

f 10,1N/mm

k 0,67

f 0,7N/mm

E , 5290N/mm

k 0,6

seetechnicalapproval[1]

loads

g 1,97kN/m

s 4,41kN/m

q 1044N/m

c I 0,2

w 0,2 ⋅ 1,044 0,21 kN/m

q H 0,75kN/m


constantload


c)CLTConstruction


bendingmoment

shearforce

deformations

unfavourableloads


c)CLTConstruction


bendingmoment

shearforce

deformations

ULSCO3

k 0,9

p 1,20 ⋅ 1,97 1,50 ⋅ 4,41 8,97kN/m

q 1,50 ⋅ 0,7 ⋅ 0,75 0,79kN/m

M 8,97 ⋅ 2,311 0,79 ⋅ 2,31122,55kNm/m

σ22553504

0,64kN/cm

f 0,9 ⋅1,011,15

0,79 kN/cm

η0,640,79

0,81 1,0

V 8,97 ⋅ 2,718 0,79 ⋅ 2,718 26,52kN

τ 1,5 ⋅26,52

0,67 ⋅ 14500,041kN/cm

c)CLTConstruction


f 0,9 ⋅0,071,15

0,055 kN/cm

η0,0410,055

0,75 1,0

SLSCO9/10

w , 1,97 ⋅ 0,1546 0,305cm

w , 0,681cm

w , 0,032cm

w , 0,75 ⋅ 0,2483 0,186cm


w0,305 0,681 0,6 ⋅ 0,032 0,7 ⋅ 0,1861,14cm

maxw438300

1,46cm

η1,141,46

0,78 1,0

finaldeformation

w0,305 ⋅ 1 0,6 0,681 ⋅ 1 0,2 ⋅ 0,60,032 ⋅ 0,6 0 0,186 ⋅ 0,7 0,3 ⋅ 0,61,43cm

maxw438150

2,92cm

η1,432,92

0,49 1,0

c)CLTConstruction


1FloorSlab

system

maxl 4,38m

cross‐section

t 145mm

A 1450cm /m

I 25405cm /m

W 3504cm /m

material

CLTKL‐trä145

f 10,1N/mm

k 0,67

f 0,7N/mm

E , 5290N/mm

k 0,6


loads

g 1,64kN/m

s 0

w 0

q A 2,5kN/m


cf.1.1RoofSlab

ULSCO2

k 0,8

g 1,20 ⋅ 1,64 2,0kN/m

q 1,50 ⋅ 2,5 3,75kN/m

M 2,0 ⋅ 2,311 3,75 ⋅ 2,311 13,21kNm/m

σ13213504

0,38kN/cm

f 0,8 ⋅1,011,15

0,70 kN/cm

η0,380,70

0,54 1,0

V 2,0 ⋅ 2,718 3,75 ⋅ 2,718 15,54 kN

c)CLTConstruction


τ 1,5 ⋅15,54

0,67 ⋅ 14500,024kN/cm

f 0,8 ⋅0,071,15

0,049kN/cm

η0,0240,049

0,50 1,0

SLSCO7/8

w , 1,64 ⋅ 0,1546 0,253cm

w , 0

w , 0

w , 2,5 ⋅ 0,2483 0,621cm


w 0,253 0 0 0,7 ⋅ 0,621 0,69cm

maxw438300

1,46cm

η0,691,46

0,47 1,0

finaldeformation

w0,253 ⋅ 1 0,6 0 0 0,621

⋅ 0,7 0,3 ⋅ 0,6 0,95cm

maxw438150

2,92cm

η0,952,92

0,33 1,0

c)CLTConstruction


5.x9OuterWall

system

cross‐section

t 145mm

A 1450cm /m

I 25405cm /m

W 3504cm /m

i14,5

√124,19cm

material

CLTKL‐trä145

f 8,3N/mm

f 10,1N/mm

k 0,67

E , 5290N/mm

E , 2300N/mm

k 0,6


internalforces

n 68,6kN/m

n 4,9kN/m

c)CLTConstruction


n 222,1kN/m

n 50,7kN/m

windfromthesidebecomesdecisive

ULSCO6

k 1,1

n1,2 ⋅ 68,6 1,5 ⋅ 222,1 1,5 ⋅ 0,7 ⋅ 4,91,5 ⋅ 0,7 ⋅ 50,7 473,7kN/m

σ473,7

100 ⋅ 14,50,33kN/cm

f 1,1 ⋅0,831,15

0,79 kN/cm

flexuralbuckling

λ319,54,19

76,3

λ76,3π

⋅8,32300

1,46

k 0,5 ⋅ 1 0,1 ⋅ 1,46 0,3 1,461,62

k1

1,62 1,62 1,460,429

η0,33

0,429 ⋅ 0,790,96 1,0

c)CLTConstruction


AnchoringWall5.y3

system


α 90°

fasteners

7M20dowels/m

f 240N/mm

f 400N/mm

material

CLTKL‐trä170

ρ 385kg/m

strengthclass4.6

minimumdistances

a 4 ⋅ 2,0 8cm

a max 7 ⋅ 2,0 14 ; 8 14cm


M , 0,3 ⋅ 400 ⋅ 20 , /1000 289,6 Nm

f , , 0,082 ⋅ 1 0,01 ⋅ 20 ⋅ 38525,26N/mm

k 1,35 0,015 ⋅ 20 1,65

f , ,25,26

1,65 ⋅ sin 90 cos 9015,3N/mm

c)CLTConstruction


F ,

15,3 ⋅ 170/2 ⋅ 20

⋅ 24 ⋅ 289,6 ⋅ 1000

15,3 ⋅ 20 ⋅ 170/21 /1000

15,3kN


theaxialcapacityofthefastenersisneglected

ULSCO11/12

k 1,1

F 138,4kN/m cf.RFEManalysis

F . 15,3 ⋅ 7 ⋅ 2 214,4kN/m

F , 1,1 ⋅214,41,3

181,5kN

η138,4181,5

0,76 1,0

7boltsand2shearplanesperm


V 0,61 ⋅ 138,4 ⋅ 0,143 12,1kN

F 14 ⋅ 95 ⋅ 1 ⋅150

1150319,5

/1000

16,7kN

F 1,1 ⋅16,71,3

14,1kN

η12,114,1

0,85 1,0

theshearforceisestimatedassumingthewalltobeabeamsupportedbythedowelswiththeuniformloadF

Appendix


Appendix

Attachments

Eurocodedesign(XLSX) RFEMresultsforthepanelconstruction(XLSX) RFEMresultsfortheCLTconstruction(XLSX) RFEMmodelsfortheframe,panelandCLTconstruction(RF5) technicalplansfortheframeconstructionPa1.2,Pa2(PDF) technicalplansforthepanelconstructionPb1–Pb3,Pa4.2(PDF) technicalplansfortheCLTconstructionPc1–Pc2,Pc3.2(PDF)

a)FrameConstruction

Elements

Appendix


Appendix


Connections

Appendix


Appendix


b)PanelConstruction

Elements

Appendix


Appendix


Connections

Appendix


Appendix


c)CLTConstruction

Elements

Appendix


Connections

different construction for storey timber

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