SeismicProvisionsforStructural

SteelBuildings(1997)

SupplementNo.2

November10,2000

SupersedesSupplementNo.1totheAISCSeismicProvisionsforStructuralSteelBuildings,datedFebruary15,1999

PreparedbytheAmericanInstituteofSteelConstruction,Inc.underthedirectionoftheAISCCommitteeonSpecificationsand

approvedbytheAISCBoardofDirectors

AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC.

OneEastWackerDrive,Suite3100,Chicago,Illinois60601-2001

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10

AISCSeismicProvisions(1997)SupplementNo.2(11/00)

AISCSeismicProvisions(1997)SupplementNo.2(11/00)

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AMERICANINSTITUTEOFSTEELCONSTRUCTION

AMERICANINSTITUTEOFSTEELCONSTRUCTION

SeismicProvisionsforStructural

SteelBuildings(1997)

SupplementNo.2

November10,2000

PartI,Glossary

DeletethedefinitionofInelasticRotationofBeam-to-ColumnConnection.

Addthefollowingdefinitions:

“InterstoryDriftAngle.Interstorydisplacementdividedbystoryheight,radians.

ZipperColumn.Avertical(ornearlyvertical)strutconnectingthebrace-to-beamintersectionofaninverted-V-bracedframeatoneleveltothebrace-to-beamintersectionatanotherlevel.SeeFigureC-13.4(b).”

ChangedefinitionofReducedBeamSectionasfollows:

“Aductilereductionincross-section...<remainderunchanged>”

PartI,Section2

Changethissectionasfollows:

...

AmericanSocietyofCivilEngineersASCE7-9598

AmericanSocietyforTestingandMaterials

ASTMA6-96b98

ASTMA500-9399

ASTMA673-95

ASTMA36-9697a

ASTMA501-9399

ASTMA913-95a97

ASTMA53-9699b

ASTMA572-94c99

ASTMA992-98

ASTMA283-93a

ASTMA588-9497a

AmericanWeldingSocietyAWSD1.1-96D1.1:2000

….

PartI,Section6.1

AddASTMA992tothelistofmaterialspecificationsthatareapprovedforuseintheSeismicForceResistingSystem.

PartI,Section6.2

Changethissectionasfollows:

“WhenrequiredintheseProvisions,therequiredstrengthofaconnectionorrelatedmembershallbedeterminedfromtheExpectedYieldStrengthFyeoftheconnectedmember,where

Fye=RyFy (6-1)

Fyisthespecifiedminimumyieldstrengthofthegradeofsteeltobeused.Forrolledshapesandbars,RyshallbeasshowninTableI-6-1takenas1.5forASTMA36and1.3forA572Grade42.Forrolledshapesandbarsofothergradesofsteelandforplates,Ryshallbetakenas1.1.OthervaluesofRyarepermittedtobeusedifthevalueofFyeisdeterminedbytestingthatisconductedinaccordancewiththerequirementsforthespecifiedgradeofsteel.

TABLEI-6-1

RyValuesforDifferentMemberTypes

Application

Ry

Platesandallotherproducts

Hot-rolledstructuralshapesandbarsASTMA36

A572Grade42Allothergrades

HollowStructuralSections

ASTMA500,A501,A618andA847

SteelPipe

ASTMA53

1.1

1.5

1.3

1.1

1.3

1.4

Whenboththerequiredstrengthandthedesignstrengthcalculationsaremadeforthesamememberorconnectingelement,itispermittedtoapplyRytoFyinthedeterminationofthedesignstrength.”

PartI,Section6.3

Changethissectionasfollows:

“WhentheyareusedasmembersintheSeismicForceResistingSystem,ASTMA6Groups3,4,and5shapeswithflanges1?in.thickandthicker,ASTMA6Groups4and5shapes,andplatesthatare21?in.thickorthickerinbuilt-upcross-sectionsshallhaveaminimumCharpyV-Notch(CVN)toughnessof20ft-lbsat

70degreesF,determinedasspecifiedinLRFDSpecificationSectionA3.1c.”

PartI,Section7.3b

Changelanguageasfollows:

“Allcomplete-joint-penetrationgrooveweldsusedinprimarymembersandconnectionsintheSeismicForceResistingSystemshallbemadewithafillermetalthathasaminimumCVNCharpyV-notchtoughnessof20ft-lbsatminus20degreesF,asdeterminedbyAWSclassificationormanufacturercertification.Thisrequirement...<remainderunchanged>”

PartI,Section7.3c

Changethissectionasfollows:

“FormembersandconnectionsthatarepartoftheSeismicForceResistingSystem,discontinuitieslocatedwithinaplastichingingzoneasdefinedinSection7.4a,createdbyerrorsorbyfabricationorerectionoperations,suchastackwelds,erectionaids,air-arcgouging,andthermalflamecutting,shallberepairedasrequiredbytheEngineerofRecord.”

PartI,Section7.4

Addthefollowingnewsection:

“7.4.OtherConnections

7.4a.Weldedshearstudsshallnotbeplacedonbeamflangeswithinthezonesofexpectedplastichinging.Thelengthofaplastichingingzoneshallbedefinedasone-halfofthedepthofthebeamoneithersideofthetheoreticalhingepoint.Deckingarc-spotweldsasrequiredtosecuredeckingshallbepermitted.Deckingattachmentsthatpenetratethebeamflangesshallnotbeusedinthehingingzone.

7.4b.Welded,bolted,screwed,orshot-inattachmentsforperimeteredgeangles,exteriorfacades,partitions,ductwork,piping,orotherconstructionshallnotbeplacedwithintheexpectedzoneofplastichinging,asdefinedinSection7.4a,orofothermembersoftheSeismicForceResistingSystemwhichareexpectedtoundergoplastichinging.Outsidethedefinedhingearea,calculations,basedontheexpectedmomentattheplastichinge,shallbemadetodemonstratetheadequacyofthemembernetsectionwhenconnectorswhichpenetratethememberareused.

Exception:Weldedshearstudsandotherconnectionsarepermittedwheretheyhavebeenincludedintheconnectiontestsusedtoqualifytheconnection.”

PartI,Section8.3

Addthefollowingnewsection:

“8.3c.ColumnsplicesinSpecialMomentFramesshallbelocatedasdescribedinSection8.3a,andshallhaveanominalflexuralstrengththatisatleastequaltothenominalflexuralstrengthofthesmallercolumn.Wheregrooveweldsareusedtomakethesplice,theyshallbecomplete-joint-penetrationgroovewelds.WeldbackingneednotberemovedunlessrequiredbytheEngineerofRecord.Thedesignshearstrengthoftheconnectionshallbeequaltoorgreaterthantherequiredshearstrengthcalculatedusingtheexpectedyieldmomentsthatcanbedevelopedateachendofthecolumn.

Exception:Thedesignstrengthofthecolumnspliceneednotexceedtherequiredstrengthasdeterminedbyinelasticanalysesinwhichappropriatestressconcentrationfactorshavebeenconsideredforthetypeofconnectionbeingused.”

PartI,Section9.2a

Changethefirstsentenceasfollows:

“Thedesignofallbeam-to-columnjointsandconnectionsusedintheSeismicForceResistingSystemshallbebaseduponqualifying

cyclictestresultsinaccordancewithAppendixSthatdemonstrateaninterstorydriftangleofatleast0.04radiansinelasticrotationofatleast0.03radians.”

Addthefollowingsentenceattheendofthelastparagraph:“Columnsandconnectionelementswithatestedyieldstrengththatismorethan15percentaboveorbelowFyeshallnotbeusedinqualificationtesting.”

PartI,Section9.3a

Changethissectionasfollows:

“ShearStrength:TherequiredthicknessshearstrengthRuofthepanelzoneshallbedeterminedinaccordancewiththemethodusedinproportioningthepanelzoneofthetestedconnectionbyapplyingLoadCombinations4-1and4-2totheconnectedbeamorbeamsintheplaneoftheframeatthecolumn.Runeednotexceedtheshearforcedeterminedfrom0.8timesRyMpofthebeamsframingtothecolumnflangesattheconnection.Asaminimum,therequiredshearstrengthRuofthepanelzoneshallbedeterminedfromthesummationofthemomentsatthecolumnfacesasdeterminedbyprojectingtheexpectedmomentsattheplastichingepointstothecolumnfaces.Thedesignshearstrength

vRvofthepanelzoneshallbedeterminedusingv=0.751.0.WhenPu0.75Py,….”[Remainderunchanged].

PartI,Section9.4b

Changethissectionasfollows:

“Width-ThicknessRatios:BeamsshallcomplywithpinTableI-9-1.WhentheratioinEquation9-3islessthanorequalto2.01.25,columnsshallcomplywithpinTableI-9-1.Otherwise,columnsshallcomplywithpinLRFDSpecificationTableB5.1.”

PartI,Section9.6

ChangedefinitionofM*pbasfollows:

“Thesumofthemoment(s)inthebeam(s)attheintersectionofthebeamandcolumncenterlines.M*pbisdeterminedbysummingtheprojectionsoftheexpectedbeamflexuralstrength(s)...”

PartI,Section9.7a.1

ChangeSection9.7a.1.asfollows:

Columnflangesatbeam-to-columnconnectionsrequirelateralsupportonlyatthelevelofthetopflangesofthebeamswhenacolumnisshowntoremainelasticoutsideofthepanel-zone.undereitherofthefollowingconditions:ItshallbepermittedtoassumethatthecolumnremainselasticwhentheratiocalculatedusingEquation9-3isgreaterthan2.

a.TheratiocalculatedusingEquation9-3isgreaterthan1.25.b.ThecolumnremainselasticunderLoadCombination4-1.

PartI,Sections10&11

ReplaceSections10and11withthefollowing:

INTERMEDIATEMOMENTFRAMES(IMF)

Scope

IntermediateMomentFrames(IMF)areexpectedtowithstandlimitedinelasticdeformationsintheirmembersandconnectionswhensubjectedtotheforcesresultingfromthemotionsoftheDesignEarthquake.IMFshallmeettherequirementsinthisSection.

Beam-to-ColumnJointsandConnections

10.2a.Thedesignofallbeam-to-columnjointsandconnectionsusedintheSeismicForceResistingSystemshallbebaseduponqualifyingcyclictestresultsinaccordancewithAppendixSthatdemonstrateaninterstorydriftangleofatleast0.02radians.QualifyingcyclictestresultsshallconsistofatleasttwocyclictestsandshallmeettherequirementsinSection9.2a.

b.Beam-to-columnconnectiontestingshalldemonstrateaflexuralstrength,determinedatthecolumnface,thatisatleastequaltothenominalplasticmomentofthebeamMpattherequiredinelasticrotation(seeAppendixS),exceptasfollows:

Whenbeamlocalbucklingratherthanbeamyieldinglimitstheflexuralstrengthofthebeam,orwhenconnectionsincorporatingaReducedBeamSectionareused,theflexuralstrengthshallbetakenas0.8Mpofthetestedbeam.

Connectionsthataccommodatetherequiredrotationswithintheconnectionelementsand

maintainthedesignstrengthasspecifiedarepermitted,provideditcanbedemonstratedbyrationalanalysisthatanyadditionaldriftduetoconnectiondeformationcanbeaccommodatedbythebuilding.Suchrationalanalysisshallincludetheeffectsofoverallframestabilityincludingsecondordereffects.

TherequiredshearstrengthVuofabeam-to-columnconnectionshallbedeterminedusingtheloadcombination1.2D+0.5L+0.2Splustheshearresultingfromtheapplicationofamomentofmagnitudeequalto1.1RyFyZintheoppositesenseoneachendofthebeam.Alternatively,alesservalueofVuispermittedifjustifiedbyrationalanalysis.TherequiredshearstrengthneednotexceedtheshearresultingfromLoadCombination4-1.

ContinuityPlates

Continuityplatesshallbeprovidedtobeconsistentwiththetestedconnection.

ORDINARYMOMENTFRAMES(OMF)

Scope

OrdinaryMomentFrames(OMF)areexpectedtowithstandminimalinelasticdeformationsintheirmembersandconnectionswhensubjectedtotheforcesresultingfromthemotionsoftheDesignEarthquake.OMFshallmeettherequirementsinthisSection.

Beam-to-ColumnJointsandConnections

a.Beam-to-columnconnectionsshallbemadewithweldsand/orhigh-strengthbolts.ConnectionsarepermittedtobeFRorPRmomentconnectionsasfollows:

FRmomentconnectionsthatarepartoftheSeismicForceResistingSystemshallbedesignedforarequiredflexuralstrengthMuthatisatleastequalto1.1RyMpofthebeamorgirderorthemaximummomentthatcanbedeliveredbythesystem,whicheverisless.Forconnectionswithweldedflangejoints,weldbackingandweldtabsshallberemovedexceptthatthetop-flangebackingispermittedto

remaininplaceprovidedthatitisattachedtothecolumnflangebyacontinuousfilletweldontheedgebelowthecomplete-joint-penetrationgrooveweld.Afterremovalofweldbacking,thesurfaceshallberepairedandacontouringfilletweldadded.Weldtabsshallberemovedandthesurfacefinishedflushandsmooth.Single-sidedpartial-joint-penetrationgrooveweldsandsingle-sidedfilletweldsshallnotbeusedtoresisttensileforcesintheconnections.Double-sidedpartial-joint-penetrationgrooveweldsanddouble-sidedfilletweldsthatresisttensileforcesintheconnectionsshallbedesignedtoresistarequiredforceof1.1RyFyAgoftheconnectedelementorpart.

PRmomentconnectionsarepermittedwhenthefollowingrequirementsaremet:

SuchconnectionsshallprovideforthedesignstrengthasspecifiedinSection11.2a.1.

Thenominalflexuralstrengthoftheconnectionshallbenolessthan50percentofMpoftheconnectedbeamorcolumn,whicheverisless.

ThestiffnessandstrengthofthePRmomentconnectionsshallbeconsideredinthedesign,includingtheeffectonoverallframestability.

11.2b.ForFRmomentconnections,therequiredshearstrengthVuofabeam-to-columnconnectionshallbedeterminedusingtheloadcombination1.2D+0.5L+0.2Splustheshearresultingfromtheapplicationof1.1RyFyZintheoppositesenseoneachendofthebeam.Alternatively,alesservalueofVuispermittedifjustifiedbyrationalanalysis.ForPRmomentconnections,VushallbedeterminedfromtheloadcombinationaboveplustheshearresultingfromthemaximumendmomentthatthePRmomentconnectionsarecapableofresisting.

ContinuityPlates

WhenFRmomentconnectionsaremadebymeansofweldsofbeamflangesorbeam-flangeconnectionplatesdirectlytocolumnflanges,continuityplatesshallbeprovidedtotransmitbeamflangeforcestothecolumnweborwebs.Suchplatesshallhaveaminimumthicknessequaltothatofthebeamflangeorbeam-flangeconnectionplate.Theweldedjointsofthecontinuityplatestothecolumnflangesshallbemadewitheithercomplete-joint-penetrationgroovewelds,two-sidedpartial-joint-penetrationgrooveweldscombinedwithreinforcingfilletwelds,ortwo-sidedfilletweldsandshallprovideadesignstrengththatisatleastequaltothedesignstrengthofthecontactareaoftheplatewiththecolumnflange.Theweldedjointsofthecontinuityplatestothecolumnwebshallhaveadesignshearstrengththatisatleastequaltothelesserofthefollowing:

Thesumofthedesignstrengthsattheconnectionsofthecontinuityplatetothecolumnflanges.

Thedesignshearstrengthofthecontactareaoftheplatewiththecolumnweb.

Thewelddesignstrengththatdevelopsthedesignshearstrengthofthecolumnpanel-zone.

Theactualforcetransmittedbythestiffener.

Continuityplatesarenotrequirediftestedconnectionsdemonstratethattheintendedinelasticrotationcanbeachievedwithouttheiruse.

PartI,Section13.2d

Changelanguageasfollows:

“Width-thicknessRatios:Width-thicknessratiosofstiffenedandunstiffenedcompressionelementsofbracesshallmeetthecompactnessrequirementsinLRFDSpecificationTableB5.1(i.e.,

<p)andthefollowingrequirements:

Bracedshallbecompact(i.e.,<p).Thewidth-thickness

Fy

ratioofanglesshallnotexceed52/ .

I-shapedmembersandchannelsusedasbracesshallcomplywithpinTableI-9-1.

RoundHSSshallhave…<remainderunchanged>”

PartI,Sections14.2through14.5

DeleteSections14.2through14.5andreplacewiththefollowing:

“14.2Strength

Fy

Therequiredstrengthofthemembersandconnections,otherthanbraceconnections,inOCBFsshallbebaseduponLoadCombinations4-1and4-2.Thedesignstrengthofbraceconnectionsshallequalorexceedtheexpectedtensilestrengthofthebrace,determinedasRyFyAg.Braces

withKl/rgreaterthan720/

inverted-Vconfigurations.”

shallnotbeusedinVor

PartI,Section16

AddthefollowingsentenceattheendoftheSection:

“Whenweldsfromwebdoublerplatesorcontinuityplatesoccurinthe‘k-area’ofrolledsteelcolumns,the‘k-area’adjacenttotheweldsshallbeinspectedafterfabrication,asrequiredbytheEngineerofRecord,usingapprovednondestructivemethodsconformingtoAWSD1.1.”

AppendixS,SectionS2

Replacethissectionwiththefollowing:

“S2.SYMBOLS

ThenumberinparenthesisafterthedefinitionofasymbolreferstotheSectionnumberinwhichthesymbolisfirstused.

Interstorydriftangle(S6)

Linkrotationangle(S6)”

AppendixS,SectionS3

Addthefollowingdefinitions:

“CompleteLoadingCycle.Acycleofrotationtakenfromzeroforcetozeroforce,includingonepositiveandonenegativepeak.”

“InterstoryDriftAngle.Interstorydisplacementdividedbystoryheight,radians.”

ReplacethedefinitionofInelasticRotationwiththefollowing:“InelasticRotation.ThepermanentorplasticportionoftherotationanglebetweenabeamandthecolumnorbetweenaLinkandthecolumnoftheTestSpecimen,measuredinradians.The

InelasticRotationshallbecomputedbasedonananalysisofTestSpecimendeformations.Sourcesofinelasticrotationincludeyieldingofmembers,yieldingofconnectionelementsandconnectors,andslipbetweenmembersandconnectionelements.Forbeam-to-columnmomentconnectionsinMomentFrames,inelasticrotationshallbecomputedbasedupontheassumptionthatinelasticactionisconcentratedatasinglepointlocatedattheintersectionofthecenterlineofthebeamwiththecenterlineofthecolumn.Forlink-to-columnconnectionsinEccentricallyBracedFrames,inelasticrotationshallbecomputedbasedupontheassumptionthatinelasticactionisconcentratedatasinglepointlocatedattheintersectionofthecenterlineofthelinkwiththefaceofthecolumn.”

AppendixS,SectionS5.5

Change#2asfollows:

“2.Theyieldstressofthebeamshallnotbemorethan15percentbelowFyeforthegradeofsteeltobeusedforthecorrespondingelementsofthePrototype.Columnsandconnectionelementswithatestedyieldstressshallnotbemorethan15percentaboveorbelowFyeforthegradeofsteeltobeusedforthecorrespondingelementsofthePrototype.FyeshallbedeterminedinaccordancewithSection6.2.”

AppendixS,SectionS6.1

Replacethissectionwiththefollowing:

“S6.1.GeneralRequirements

TheTestSpecimenshallbesubjectedtocyclicloadsaccordingtotherequirementsprescribedinSectionS6.2forbeam-to-columnmomentconnectionsinMomentFrames,andaccordingtotherequirementsprescribedinSectionS6.3forlink-to-columnconnectionsinEccentricallyBracedFrames.

LoadingsequencesotherthanthosespecifiedinSectionsS6.2andS6.3maybeusedwhentheyaredemonstratedtobeofequivalentorgreaterseverity.”

AppendixS,SectionS6.2

Replacethissectionwiththefollowing:

“S6.2LoadingSequenceforBeam-to-ColumnMomentConnections

Qualifyingcyclictestsofbeam-to-columnmomentconnectionsinMomentFramesshallbeconductedbycontrollingtheinterstorydriftangle,,imposedontheTestSpecimen,asfollows:

6cyclesat=0.00375rad.

6cyclesat=0.005rad.

6cyclesat=0.0075rad.

4cyclesat=0.01rad.

2cyclesat=0.015rad.

2cyclesat=0.02rad.

2cyclesat=0.03rad.

Continueloadingatincrementsof=0.01rad.,withtwocyclesofloadingateachstep.”

AppendixS,SectionS6.3

Replacethissectionwiththefollowing:

“S6.3LoadingSequenceforLink-to-ColumnConnectionsQualifying cyclic tests of link-to-column momentconnectionsinEccentricallyBracedFramesshallbeconductedbycontrollingthelinkrotationangle,,imposedontheTestSpecimen,asfollows:

3cyclesat=0.0025rad.

3cyclesat=0.005rad.

3cyclesat=0.01rad.

2cyclesat=0.02rad.

2cyclesat=0.03rad.

Continueloadingatincrementsof=0.01rad.,withtwocyclesofloadingateachstep.”

AppendixS,SectionS9

ChangeItemNo.6.asfollows:

“6.AplotofbeammomentversustotalInelasticRotationinterstorydriftangleforbeam-to-columnmomentconnections;oraplotoflinkshearforceversuslinkrotation

angleforlink-to-columnconnections.Forbeam-to-columnconnections,thebeammomentandthetotalInelasticRotationinterstorydriftangleshallbecomputedwithrespecttothefacecenterlineofthecolumn.”

ChangeItemNo.7asfollows:

“7.TheinterstorydriftangleandthetotalInelasticRotationdevelopedbytheTestSpecimen.<Remainderunchanged>”

AppendixS,SectionS10

Changethissectionasfollows:

“Foreachconnectionusedintheactualframe,atleasttwotestsarerequiredforeachconnectioninwhichtheEssentialVariables,aslistedinSectionS4,remainwithintherequiredlimits.BothtestsshallsatisfythecriteriastipulatedinSections8.5,9.2,10.2,or15.4,asapplicable.InordertosatisfyInelasticRotationinterstorydriftanglerequirements,eachTestSpecimenshallsustaintherequiredrotationinterstorydriftangleforatleastonecompleteloadingcycle.”

PartII,Section6.5c

ChangeEquation6-3asfollows:

1.40bFy/Es

Fy/(2Es)

b (6-3)

PartII,Section13.4

ChangePartII,Section13.4asfollows:

“13.4.Braces

StructuralsteelbracesshallmeettherequirementsforOCBFSCBFinPartISection1413.CompositebracesshallmeettherequirementsforcompositecolumnsinSection13.2.”

PartII,Section13.5

ChangePartII,Section13.5asfollows:

“BracingconnectionsshallmeettherequirementsinSection7andPartISection1413.”

CommentaryPartI,SectionC1

Addthefollowingparagraph:

“Itshouldbenotedthattheseprovisionsweredevelopedspecificallyforbuildings.Theprovisions,therefore,maynotbeapplicable,inwholeorinpart,tonon-buildingstructures.Extrapolationoftheirusetonon-buildingstructuresshouldbedonewithdueconsiderationoftheinherentdifferencesbetweentheresponsecharacteristicsofbuildingsandnon-buildingstructures.”

CommentaryPartI,SectionC4

Replaceallreferencesto“1997NEHRPProvisions(FEMA,1997A)”with“2000NEHRPProvisions(FEMA,2000e)”.

InTableI-C4-1replacethevaluesgivenforIntermediateMomentFrames(IMF)andOrdinaryMomentFrames(OMF)withthefollowing:

BASICSTRUCTURALSYSTEMANDSEISMICFORCERESISTINGSYSTEM

R

Cd

IntermediateMomentFrames(IMF)

4.5

4

OrdinaryMomentFrames(OMF)

3.5

3

CommentaryPartI,SectionC6.2

Addthefollowingtotheendofthissection:

“WhileASTMA709isprimarilyusedinthedesignandconstructionofbridges,itcouldalsobeusedinbuildingconstruction.Writtenasanumbrellaspecification,itsgradesareessentiallytheequivalentofotherapprovedASTMspecifications.Forexample,ASTMA709grade50isessentiallyASTMA572grade50andASTMA709grade50WisessentiallyASTMA588grade50.Thus,ifused,ASTMA709materialshouldbetreatedaswouldthecorrespondingapprovedASTMmaterialgrade.”

CommentaryPartI,SectionC6.3

ChangeItem(3)inthefirstparagraphasfollows:

“…(3)plateelementswiththicknessgreaterthanorequalto21?in.thatarepartoftheSeismicForceResistingSystem,suchastheflangesofbuilt-upgirders.”

CommentaryPartI,SectionC7.3

Changethefirstsentenceofthesecondparagraphofthissectionasfollows:

“ForallweldsusedinprimarymembersandconnectionsintheSeismicForceResistingSystem,weldmetalnotchtoughnessisrequiredintheseProvisions.”

Addthefollowingsentencetotheendofthesecondparagraph:“TheseweldtoughnessrequirementsarenotintendedtoapplytoERWandSAWweldingprocessesusedintheproductionofHSS(ASTMA500)andpipesections(ASTMA53).”

Addthefollowingsentencetotheendofthelastparagraphofthissection:

“TheEngineerofRecordshouldrefertoAWSD1.1forguidanceinestablishingtheacceptancecriteriaforrepairofdiscontinuities.Outsidetheplastichingeregions,AWSD1.1requirementsforrepairofdiscontinuitiesshouldbeapplied.”

CommentaryPartI,SectionC7.4

AddthefollowingnewcommentarySectionC7.4:“C7.4OtherConnections

TheFEMA/SACtestinghasdemonstratedthesensitivityofregionsundergoinglargeinelasticstrainstodiscontinuitiescausedbywelding,rapidchangeofsection,penetrations,orconstructioncausedflaws.Forthisreason,operationsthatcausediscontinuitiesareprohibitedinthecriticalhingingregion.Areaswherecriticalhingingisexpectedincludemomentframehingingzonesasdefined,linkbeamsofEBFs,theendsandthecenterofSCBFbraces,etc.Itshouldbenotedthatyieldlevelstrainsarenotstrictlylimitedtotheplastichingezones(beam-columnjointregionforcoverplateorRBSconnections,e.g.).Cautionshouldalsobeexercisedincreatingdiscontinuitiesintheseregionsaswell.”

CommentaryPartI,SectionC8.3

ReplaceCommentarySectionC8.3withthefollowing:“C8.3ColumnSplices

InelasticanalysesconductedaspartoftheFEMA/SACprogramhavedemonstratedthatthecommonassumptionthatcolumnflexuralstressesinthemid-heightofmoment

framecolumnsarelowisnotnecessarilytrue.Bendingmomentsequaling,orexceeding,theyieldmomentofthecolumnarepossibleatcolumnsplices,evenwhenthesplicesarelocatedasrequiredbySection8.3a.Accordingly,therequirementisgiventhatthenominalflexuralstrengthofthespliceshouldequalorexceedthenominalflexuralstrengthofthesmallercolumn.Itisnotnecessarytoapplyover-strengthfactorsandfactorstotherequirement,sinceitisacomparisonofrelativemembernominalstrengths.

TheexceptionisprovidedtoallowforcaseswheretheEngineerofRecordcandemonstratethatthelargestdemandsthatcanoccuratcolumnsplicesarebelowtheyieldlevel.Inelasticdynamicanalysesarerequiredtojustifyusingthisexception.Inthesecases,theuseofweldedjointsotherthancomplete-joint-penetrationgrooveweldsmaybeused,providedthatstressconcentrationfactors(e.g.estimatedusingafracturemechanicsapproach)generatedbytheproposedjointconfigurationaretakenintoaccount.”

CommentaryPartI,SectionC9.2a

Addthefollowing:

“LimitationsareplacedonpermissibledifferencesbetweenthetestedyieldstrengthandFyeforbeams,columnsandconnectionelements.Itisnotintendedthattheselimitationsbeappliedretroactivelytotheexistingdatabaseofqualificationtests.Rather,theserequirementsareintendedtoapplyforuseinnewqualificationtesting.”

FEMA350,RecommendedSeismicDesignCriteriaforNewSteelMoment-FrameBuildingsincludesrecommendationsfordesignandfabricationofseveraltypesofconnectionswhicharedeemedtobeprequalifiedforuseinSpecialMomentFramesofsteel.TheseconnectiondesignsarebasedonextensivetestingandanalysisperformedbytheSACJointVentureunderaprogra