Design and Analysis of Connections in Steel Structures: Fundamentals and Examples

375 Pages·1980·12.27 MB·English

by  Alfredo Boracchini

DesignandAnalysisofConnectionsinSteelStructures
Design and Analysis
of Connections
in Steel Structures
FundamentalsandExamples
AlfredoBoracchini
Author AllbookspublishedbyErnst&Sohnare
carefullyproduced.Nevertheless,authors,
AlfredoBoracchini,P.E. editors,andpublisherdonotwarrantthe
[e-mail] informationcontainedinthesebooks,
includingthisbook,tobefreeoferrors.
Readersareadvisedtokeepinmindthat
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statements,data,illustrations,procedural
DetailofaMomentConnection
detailsorotheritemsmayinadvertently
inaCompositeBuildingStructure
beinaccurate.
(“InterPulsspa”Building,ReggioEmilia,
Italy) LibraryofCongressCardNo.:
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vii
Preface
StructuralSteelConnectionDesignisanengineeringmanualdirectedtowardthe
engineeringaudience.Thefirstsectionprovidesanintroductiontokeyconcepts,
thenprogressestoprovideamorein-depthdescriptionforthedesignofstruc-
turalsteelconnections.
Acorrectapproachtoconnectiondesignisfundamentalinordertohaveasafe
and economically sound building. Therefore, this book will attempt to explain
howtosetupconnectionswithinthemaincalculationmodel,choosethetypes
ofconnections,checkthem(limitstatestobeconsidered),andutilizeeverything
inpractice.
The focal point of the book is not to closely follow and explain one specific
standard;rathertheaimistotreatconnectionsgenerallyspeakingandtounder-
standthemainconceptsandhowtoapplythem.Thismeansthat,eventhough
Eurocode(EC)andtheAmericanInstituteofSteelConstruction(AISC)arethe
mostreferencedstandards,otherinternationalnormswillbementionedanddis-
cussed.Thishelpstounderstandthatconnectiondesignisnotanexactscience
andthatnumerousapproachescanbeviable.
Typebytype,connectionbyconnection,detailedexampleswillbeprovidedto
helpperformafullanalysisforeachlimitstate.
Anexcellentsoftwaretool(SCS–SteelConnectionStudio)willbeillustrated
and used as an aid to assist in the comprehension of connection design. The
software can be downloaded for free at www.steelconnectionstudio.com or at
www.scs.pe and can be installed as a demo (trial) version (limitations about
printing,saving,membersizes,andreporting),see“SoftwareDownloadsandits
Limitations”(pagexxiv).Aprofessionalfullversioncanalsobepurchasedonline
butthedemoversionisenoughtoreproducetheexamplesinthebook.
The book will also try to deliver some practical suggestions for the profes-
sional engineer: how to talk about bracings to the architect, how to interact
with fabricators showing an understanding of erection and fabrication, and
muchmore.
Many countries have a deeper engineeringculture about concrete structures
thansteelstructures.Thismanualthereforeaimstoillustratetoengineersthat
donotdesignsteelstructuresdaily,someconceptsthatwillfacilitateandmake
theirdesignofconnectionsforsteelstructuresmoreefficient.Thiswillbedone
usingapractical,ratherthanatheoretical,approach.
viii Preface
Designofsteelstructurescanbecometrickywhenitisaboutstability(buckling)
andjoints:thissecondfundamentalaspectofsteelconstructions,whichiscrucial
foreconomicperformance,willbeexaminedindetail.
The text, figures, charts, formulas, and examples have been prepared and
reported with maximum care in order to help the engineer better understand
andsetuphisorherowncalculationsforstructuralsteelconnections.However,
itispossiblethatthebookcontainserrorsandomissions,andthereforereaders
are encouraged to have standards at hand as their primary reference. No
responsibility is accepted and taken for the application of concepts explained
inthemanual:theengineermustprepareandperformanyanalysisanddesign
underhisorhercompletecompetence,responsibility,andliability.
Foralistoferrorsandomissionsfoundinthebookandtheircorrections,please
checkwww.steeldesign.info.
Finally, please use www.steeldesign.info to send comments, suggestions,
criticisms,andopinions.Theauthorthanksyouinadvance.
April2018 AlfredoBoracchini
ReggioEmilia
ix
AbouttheAuthor
Alfredo Boracchini is a Professional Engineer in Italy,
Canada, and some states of the United States. His
professional experience is mainly in steel structures that
hehasdesignedandcalculatedformanyapplicationsand
in various parts of the world. He is an active member
in some international steel associations and the owner
of an engineering firm with offices in Europe, Asia, and
America. This allowed him to collect extensive interna-
tional experience in the field of steel connection design that he shares in this
manuscriptwithotherengineersinterestedinthisfield.
xi
Contents
Acknowledgments xxi
ListofAbbreviations xxiii
1 FundamentalConceptsofJointsinDesignofSteel
Structures 1
1.1 PinConnectionsandMomentResistingConnections 1
1.1.1 Safety,Performance,andCosts 1
1.1.2 LateralLoadResistingSystem 2
1.1.3 PinsandFullyRestrainedJointsintheAnalysisModel 7
1.2 PlasticHinge 8
1.2.1 BasePlates 9
1.2.2 Trusses 11
References 12
2 FundamentalConceptsoftheBehaviorofSteel
Connections 13
2.1 JointClassifications 13
2.2 ForcesintheCalculationModelandfortheConnection 14
2.3 ActionsProportionaltoStiffness 17
2.4 Ductility 18
2.5 LoadPath 19
2.6 IgnoranceoftheLoadPath 20
2.7 AdditionalRestraints 21
2.8 MethodstoDefineUltimateLimitStatesinJoints 21
2.9 BoltResistance 22
2.10 YieldLine 22
2.11 EccentricJoints 22
2.12 Economy,Repetitiveness,andSimplicity 22
2.13 Man-hoursandMaterialWeight 23
2.14 DiffusionAngles 23
2.15 BoltPretensioningandEffectsonResistance 24
2.15.1 IsResistanceAffectedbyPretensioning? 24
2.15.2 IsPretensioningNecessary? 24
2.15.3 WhichPretensioningMethodShouldBeUsed? 25
xii Contents
2.16 TransferForces 25
2.17 BehaviorofaBoltedShearConnection 25
2.18 BehaviorofBoltedJointsUnderTension 27
References 29
3 LimitStatesforConnectionComponents 31
3.1 DeformationCapacity(Rotation)andStiffness 31
3.1.1 RotationalStiffness 32
3.2 InelasticDeformationduetoBoltHoleClearance 33
3.3 BoltShearFailure 34
3.3.1 ThreadsInsidetheShearPlane 35
3.3.2 NumberofShearPlanes 37
3.3.3 PackingPlates 37
3.3.4 LongJoints 38
3.3.5 AnchorBolts 39
3.3.6 StiffnessCoefficient 39
3.4 BoltTensionFailure 40
3.4.1 CountersunkBolts 41
3.4.2 StiffnessCoefficient 41
3.5 BoltFailureinCombinedShearandTension 42
3.6 Slip-ResistantBoltedConnections 42
3.6.1 CombinedShearandTension 44
3.7 BoltBearingandBoltTearing 44
3.7.1 CountersunkBolts 49
3.7.2 StiffnessCoefficients 49
3.8 BlockShear(orBlockTearing) 49
3.9 FailureofWelds 52
3.9.1 WeldCalculationProcedures 54
3.9.1.1 DirectionalMethod 54
3.9.1.2 SimplifiedMethod 57
3.9.2 TackWelding(IntermittentFilletWelds) 58
3.9.3 Eccentricity 58
3.9.4 FilletWeldGroups 58
3.9.5 WeldingMethods 60
3.9.6 Inspections 60
3.9.6.1 VisualTesting 60
3.9.6.2 PenetrantTesting 60
3.9.6.3 MagneticParticleTesting 60
3.9.6.4 RadiographicTesting 60
3.9.6.5 UltrasonicTesting 61
3.10 T-stub,PryingAction 61
3.10.1 T-stubwithPryingAction 62
3.10.2 PossibleSimplifiedApproachAccordingtoAISC 64
3.10.3 BackingPlates 65
3.10.4 LengthLimitforPryingForcesandT-stubwithoutPrying 66
3.10.5 T-stubDesignProcedureforVarious“Components”
AccordingtoEurocode 67
Contents xiii
3.10.5.1 ColumnFlange 67
3.10.5.2 EndPlate 71
3.10.5.3 AngleFlangeCleat 71
3.10.6 T-stubDesignProcedureforVarious“Components”
Accordingtothe“GreenBook” 71
3.10.6.1 𝓁 forEquivalentT-stubsforBoltRowActingAlone 74
eff
3.10.6.2 𝓁 toConsiderforaBoltRowActingAlone 77
eff
3.10.6.3 𝓁 toConsiderforBoltRowsActinginGroup 79
eff
3.10.6.4 Examplesof𝓁 forBoltsinaGroup 80
eff
3.10.7 T-stubforBoltsOutsidetheBeamFlanges 81
3.10.8 StiffnessCoefficient 81
3.11 Punching 82
3.12 EquivalentSystems 82
3.13 WebPanelShear 82
3.13.1 StiffnessCoefficient 84
3.14 WebinTransverseCompression 84
3.14.1 TransformationParameter𝛽 86
3.14.2 FormulasforOtherLocalBucklingLimitStates 87
3.14.3 StiffnessCoefficient 88
3.14.4 T-stubinCompression 88
3.15 WebinTransverseTension 88
3.15.1 StiffnessCoefficient 89
3.16 FlangeandWebinCompression 89
3.17 BeamWebinTension 89
3.18 PlateResistance 90
3.18.1 MaterialProperties 90
3.18.2 Tension 90
3.18.2.1 StaggeredBolts 92
3.18.3 Compression 92
3.18.4 Shear 92
3.18.5 Bending 93
3.18.6 DesignforCombinedForces 93
3.18.7 WhitmoreSection 93
3.19 ReducedSectionofConnectedProfiles 93
3.19.1 ShearLag 95
3.20 LocalCapacity 99
3.21 BucklingofConnectingPlates 100
3.21.1 GussetPlateBuckling 100
3.21.2 FinPlate(ShearTab)Buckling 101
3.22 StructuralIntegrity(andTieForce) 103
3.23 Ductility 105
3.24 PlateLamellarTearing 106
3.25 OtherLimitStatesinConnectionswithSheetsandCold-formed
SteelSections 108
3.26 Fatigue 108
3.27 LimitStatesofOtherMaterialsintheConnection 109
References 109