P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 ANSI/AISC 360-05 An American National Standard Specification for Structural Steel Buildings March 9, 2005 Supersedes the Load and Resistance Factor Design Specification for Structural Steel Buildings dated December 27, 1999, the Specification for Structural Steel Buldings— Allowable Stress Design and Plastic Design dated June 1, 1989, including Supplement No. 1, the Specification for Allowable Stress Design of Single-Angle Members dated June 1, 1989, the Load and Resistance Factor Design Specification for Single- Angle Members dated November 10, 2000, and the Load and Resistance Factor Design Specification for the Design of Steel Hollow Structural Sections dated November 10, 2000, and all previous versions of these specifications. Approved by the AISC Committee on Specifications and issued by the AISC Board of Directors AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC. One East Wacker Drive, Suite 700 Chicago, Illinois 60601-1802 P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 Copyright(cid:1)c 2005 by AmericanInstituteofSteelConstruction,Inc. Allrightsreserved.Thisbookoranypartthereof mustnotbereproducedinanyformwithoutthe writtenpermissionofthepublisher. Theinformationpresentedinthispublicationhasbeenpreparedinaccordancewith recognized engineering principles and is for general information only. While it is believedtobeaccurate,thisinformationshouldnotbeusedorrelieduponforany specific application without competent professional examination and verification ofitsaccuracy,suitability,andapplicabilitybyalicensedprofessionalengineer,de- signer,orarchitect.Thepublicationofthematerialcontainedhereinisnotintended asarepresentationorwarrantyonthepartoftheAmericanInstituteofSteelCon- structionorofanyotherpersonnamedherein,thatthisinformationissuitablefor any general or particular use or of freedom from infringement of any patent or patents.Anyonemakinguseofthisinformationassumesallliabilityarisingfrom suchuse. Caution must be exercised when relying upon other specifications and codes de- velopedbyotherbodiesandincorporatedbyreferencehereinsincesuchmaterial maybemodifiedoramendedfromtimetotimesubsequenttotheprintingofthis edition.TheInstitutebearsnoresponsibilityforsuchmaterialotherthantorefer to it and incorporate it by reference at the time of the initial publication of this edition. PrintedintheUnitedStatesofAmerica SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC. P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 DEDICATION ProfessorLynnS.Beedle ThiseditionoftheAISCSpecificationisdedicatedtothememoryofDr.LynnS.Beedle, UniversityDistinguishedProfessoratLehighUniversity.Dr.Beedleservedasafaculty memberatLehighUniversityfor41yearsandwonaverylargenumberofprofessional andeducationalawards,includingthe1973T.R.HigginsAwardandthe2003Geerhard HaaijerAwardfromAISC.HewasamajorcontributortoseveraleditionsoftheAISC Specificationandalong-timememberoftheAISCCommitteeonSpecifications.Hewas instrumentalinthedevelopmentofplasticdesignmethodologiesanditsimplementation intotheAISCSpecification.HewasDirectoroftheStructuralStabilityResearchCouncil for 25 years, and in that role fostered understanding of various stability problems and helped develop rational design provisions, many of which were adopted in the AISC Specifications. In 1969, he founded the Council on Tall Buildings and Urban Habitat andsucceededinbringingtogetherthedisciplinesofarchitecture,structuralengineer- ing,construction,environment,sociologyandpolitics,whichunderlieeverymajortall buildingproject.Hewasactivelyinvolvedinthiseffortuntilhisdeathinlate2003atthe ageof85.Hiscontributionstothedesignandconstructionofsteelbuildingswilllong be remembered by AISC, the steel industry and the structural engineering profession worldwide. ForamorecompletediscussionofDr.Beedle’slifeandaccomplishments,seeCatalystfor SkyscraperRevolution:LynnS.Beedle—ALegendinhisLifetimebyMirAli,published bytheCouncilonTallBuildingsandUrbanHabitat(2004). SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC. iii P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 iv SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC. P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 v PREFACE (ThisPrefaceisnotpartofANSI/AISC360-05,SpecificationforStructuralSteelBuild- ings,butisincludedforinformationalpurposesonly.) This Specification has been based upon past successful usage, advances in the state of knowledge, and changes in design practice. The 2005 American Institute of Steel Construction’sSpecificationforStructuralSteelBuildingsforthefirsttimeprovidesan integratedtreatmentofAllowableStressDesign(ASD)andLoadandResistanceFactor Design(LRFD),andthuscombinesandreplacesearlierSpecificationsthattreatedthe twodesignmethodsseparately.AsindicatedinChapterBoftheSpecification,designs canbemadeaccordingtoeitherASDorLRFDprovisions. This Specification has been developed as a consensus document to provide a uniform practiceinthedesignofsteel-framedbuildingsandotherstructures.Theintentionisto providedesigncriteriaforroutineuseandnottoprovidespecificcriteriaforinfrequently encounteredproblems,whichoccurinthefullrangeofstructuraldesign. ThisSpecificationistheresultoftheconsensusdeliberationsofacommitteeofstruc- tural engineers with wide experience and high professional standing, representing a wide geographical distribution throughout the United States. The committee includes approximatelyequalnumbersofengineersinprivatepracticeandcodeagencies,engi- neers involved in research and teaching, and engineers employed by steel fabricating andproducingcompanies.Thecontributionsandassistanceofmorethan50additional professionalvolunteersworkingintentaskcommitteesarealsoherebyacknowledged. TheSymbols,GlossaryandAppendicestothisSpecificationareanintegralpartofthe Specification.Anon-mandatoryCommentaryhasbeenpreparedtoprovidebackground fortheSpecificationprovisionsandtheuserisencouragedtoconsultit.Additionally,non- mandatoryUserNotesareinterspersedthroughouttheSpecificationtoprovideconcise andpracticalguidanceintheapplicationoftheprovisions. Thereaderiscautionedthatprofessionaljudgmentmustbeexercisedwhendataorrec- ommendationsintheSpecificationareapplied,asdescribedmorefullyinthedisclaimer noticeprecedingthisPreface. SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC. P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 vi PREFACE ThisSpecificationwasapprovedbytheCommitteeonSpecifications, JamesM.Fisher,Chairman TonyC.Hazel RogerE.Ferch,ViceChairman MarkV.Holland HansrajG.Ashar LawrenceA.Kloiber WilliamF.Baker RobertoT.Leon JohnM.Barsom StanleyD.Lindsey WilliamD.Bast JamesO.Malley ReidarBjorhovde RichardW.Marshall(deceased) RogerL.Brockenbrough HarryW.Martin GregoryG.Deierlein DavidL.McKenzie DuaneS.Ellifritt DuaneK.Miller BruceR.Ellingwood ThomasM.Murray MichaelEngelhardt R.ShankarNair Shu-JinFang JackE.Petersen StevenJ.Fenves DouglasA.Rees-Evans JohnW.Fisher RobertE.Shaw,Jr. TimothyP.Fraser DonaldR.Sherman TheodoreV.Galambos W.LeeShoemaker LouisF.Geschwindner WilliamA.Thornton LawrenceG.Griffis RaymondH.R.Tide JohnL.Gross CynthiaJ.Duncan,Secretary TheCommitteegratefullyacknowledgesthefollowingtaskcommitteemembersfortheir contributiontothisdocument. FaridAlfawakhiri ChristopherHewitt GeorgesAxmann RonaldHiatt JosephBohinsky KeithHjelmstad BruceButler SocratesIoannides CharlesCarter NestorIwankiw RobertDexter(deceased) RichardKaehler CarolDrucker DeanKrouse W.SamuelEasterling BarbaraLane MichaelEngestrom JayLarson M.ThomasFerrell MichaelLederle ChristopherFoley KevinLeSmith ArvindGoverdhan J.WalterLewis JeromeHajjar DanielLinzell TomHarrington LeRoyLutz JamesHarris PeterMarshall StevenHerth BrianMeacham ToddHelwig SaulMednick RichardHenige JamesMilke SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC. P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 PREFACE vii HeathMitchell JamesSwanson JeffreyPacker EmileTroup FrederickPalmer Chia-MingUang DhirenPanda SriramuluVinnakota TeomanPekoz RobertWeber CarolPivonka DonaldWhite ClintonRex RobertWills JohnRuddy RonaldZiemian DavidSamuelson SergioZoruba ThomasSchlafly SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC. P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 viii SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC. P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 ix TABLE OF CONTENTS .SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxix .GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xliii SPECIFICATION A. GENERALPROVISIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 A1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. Low-SeismicApplications.................................. 2 2. High-SeismicApplications.................................. 2 3. NuclearApplications....................................... 2 A2. ReferencedSpecifications,CodesandStandards. . . . . . . . . . . . . . . . 2 A3. Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. StructuralSteelMaterials................................... 5 1a. ASTMDesignations ....................................... 6 1b. UnidentifiedSteel ......................................... 7 1c. RolledHeavyShapes....................................... 7 1d. Built-UpHeavyShapes..................................... 7 2. SteelCastingsandForgings................................. 7 3. Bolts,WashersandNuts.................................... 8 4. AnchorRodsandThreadedRods............................. 8 5. FillerMetalandFluxforWelding............................ 9 6. StudShearConnectors ..................................... 9 A4. StructuralDesignDrawingsandSpecifications . . . . . . . . . . . . . . . . . 9 B. DESIGNREQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 B1. GeneralProvisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 B2. LoadsandLoadCombinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 B3. DesignBasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1. RequiredStrength ......................................... 10 2. LimitStates............................................... 11 3. DesignforStrengthUsingLoadandResistanceFactorDesign (LRFD).................................................. 11 4. DesignforStrengthUsingAllowableStrengthDesign(ASD)..... 11 5. DesignforStability........................................ 12 6. DesignofConnections ..................................... 12 6a. SimpleConnections........................................ 12 6b. MomentConnections....................................... 12 7. DesignforServiceability.................................... 12 8. DesignforPonding ........................................ 13 9. DesignforFatigue......................................... 13 10. DesignforFireConditions.................................. 13 11. DesignforCorrosionEffects ................................ 13 SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC. P1:GIG GRBT055-FM AISC-Sample(LRFD) June20,2005 12:16 CharCount=0 x TABLEOFCONTENTS 12. DesignWallThicknessforHSS.............................. 13 13. GrossandNetAreaDetermination ........................... 14 B4. ClassificationofSectionsforLocalBuckling . . . . . . . . . . . . . . . . . . 14 1. UnstiffenedElements ...................................... 15 2. StiffenedElements......................................... 15 B5. Fabrication,ErectionandQualityControl . . . . . . . . . . . . . . . . . . . . 18 B6. EvaluationofExistingStructures . . . . . . . . . . . . . . . . . . . . . . . . . . 18 C. STABILITYANALYSISANDDESIGN . . . . . . . . . . . . . . . . . . . . . . . . 19 C1. StabilityDesignRequirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1. GeneralRequirements...................................... 19 2. MemberStabilityDesignRequirements....................... 19 3. SystemStabilityDesignRequirements........................ 20 3a. Braced-FrameandShear-WallSystems ....................... 20 3b. Moment-FrameSystems.................................... 20 3c. GravityFramingSystems................................... 20 3d. CombinedSystems ........................................ 20 C2. CalculationofRequiredStrengths. . . . . . . . . . . . . . . . . . . . . . . . . . 20 1. MethodsofSecond-OrderAnalysis........................... 21 1a. GeneralSecond-OrderElasticAnalysis ....................... 21 1b. Second-OrderAnalysisbyAmplifiedFirst-OrderElastic Analysis.................................................. 21 2. DesignRequirements....................................... 23 2a. DesignbySecond-OrderAnalysis............................ 23 2b. DesignbyFirst-OrderAnalysis.............................. 24 D. DESIGNOFMEMBERSFORTENSION . . . . . . . . . . . . . . . . . . . . . . 26 D1. SlendernessLimitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 D2. TensileStrength. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 D3. AreaDetermination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1. GrossArea ............................................... 27 2. NetArea ................................................. 27 3. EffectiveNetArea ........................................ 28 D4. Built-UpMembers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 D5. Pin-ConnectedMembers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1. TensileStrength........................................... 28 2. DimensionalRequirements.................................. 30 D6. Eyebars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1. TensileStrength........................................... 30 2. DimensionalRequirements.................................. 30 E. DESIGNOFMEMBERSFORCOMPRESSION . . . . . . . . . . . . . . . . . 32 E1. GeneralProvisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 E2. SlendernessLimitationsandEffectiveLength . . . . . . . . . . . . . . . . . 32 E3. CompressiveStrengthforFlexuralBucklingofMemberswithout SlenderElements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 SpecificationforStructuralSteelBuildings,March9,2005 AMERICANINSTITUTEOFSTEELCONSTRUCTION,INC.