ACI 423.3R-96 Recommendations for Concrete Members

423.3R-1Thisreportisresentedasaguideforthedesignofflexuralstructuralmem-bersinbuildingswithunbondedtendons.SuggestionsarepresentedforneededrevisionsandadditionstotheACI318BuildingCoderegardhissubject.Considerationisgiventodeterminationoffireendurancedesignforseismicforces,andcatastrophicloadings,inadditiontodesignforrav-ityandlateralloads.Recommendationsarepresentedconcerningdetailsandpropertiesoftendons,protectionagainstcrosion,andconstuctionprocedures.Keywords:anchorage(structural);beams(supports);bond(concretetoreinforcement);concreteconstruction;concreteslabs;cover;cracking(fracturing);earthquake-resistantstructures;fireresistance;atconcreteplates;atconcreteslabs;joints(junctions);loads(forces);post-tensioning;prestressedconcrete;prestressing;prestressingsteels;shearproperties;stresses;structuralanalysis;structuraldesign;unbondedpre-stressingCONTENTSChapter1—Introduction,p.423.3R-21.1—General1.2—Objective1.3—Scope1.4—NotationsanddefinitionsChapter2—Designconsideration,,p.423.3R-22.1—General2.2—Continuousmembers2.3—Corrosionprotection2.4—Fireresistance2.5—EarthquakeloadingChapter3—Design,,p.423.3R-63.1—GeneralACI423.3R-96RecommendationsforConcreteMembersPrestressedwithUnbondedTendonsReportedbyACICommittee423ACICommitteeReports,Guides,StandardPractices,DesignHandbooks,andCommentariesareintendedforguidanceinplanning,designing,executing,andinspectingconstruction.Thisdocumentisintendedfortheuseofindividualswhoarecompetenttoevaluatethesignificanceandlimitationsofitscon-tentandrecommendationsandwhowillacceptresponsibilityfortheapplicationofthematerialitcontains.TheAmericanCon-creteInstitutedisclaimsanyandallresponsibilityfortheappli-cationofthestatedprinciples.TheInstituteshallnotbeliableforanylossordamagearisingtherefrom.Referencetothisdocumentshallnotbemadeincontractdocu-ments.IfitemsfoundinthisdocumentaredesiredbytheArchi-tect/Engineertobeapartofthecontractdocuments,theyshallberestatedinmandatorylanguageforincorporationbytheAr-chitect/Engineer.ACI4823.3R-96supersedesACI423.3R-89andbecameeffectiveFebruary1,1996.Copyright©1996,AmericanConcreteInstitute.Allrightsreservedincludingrightsofreproductionanduseinanyformorbyanymeans,includingthemakingofcopiesbyanyphotoprocess,orbyelectronicormechanicaldevice,printed,written,ororal,orrecordingforsoundorvisualreproductionorforuseinanyknowledgeorretrievalsystemordevice,unlesspermissioninwritingisobtainedfromthecopyrightproprietors.CharlesW.DolanChairmanHenryCronin,Jr.SecretaryKennethB.BondySubcommitteeChairmanRobertN.BruceMohammadIqbaDenisC.PuC.DaleBucknerFrancisJ.JacquesJulioRamirezNedH.BurnsDanielP.JennyKenB.RearGregoryP.ChacosPaulJohalBruceRussellJackChristiansenSusanLaneDavidSandersToddChristophersonWardN.MarianosThomasC.SchacfferStevenCloseLeslieMartinMorrisSchupackThomasE.CousinsAlanH.MattockKennethShushkewichApostolosFifitisGerrardMcGuirePatrickJ.SullivanMarkW.FantozziMarkMooreLucR.TaerweMartinJ.FraduaAntoineNaamanCarlH.WalkerCatherineW.FrenchKennethNapiorJimZhaoCliffordFreyermuthThomasE.NehilPaulZiaWilliamL.GamblePaniMrutyunjayaHansGanzH.KentPreston423.3R-2ACICOMMITTEEREPORT3.2—One-waysystems3.3—Two-waysystems3.4—Tendonstressatfactoredload3.5—Prestresslosses3.6—Averageprestress3.7—Supportingwallsandcolumns3.8—Serviceabilityrequirements3.9—Designstrength3.10—AnchoragezonereinforcementChapter4—Materials,p.423.3R-144.1—Tendons4.2—Protectionmaterials4.3—Protectionofanchoragezones4.4—ConcretecoverChapter5—Construction,p.423.3R-155.1—Constructionjoints5.2—Closurestrips5.3—Placementoftendons5.4—Concreteplacementandcuring5.5—Stressingoperations5.6—Formremovalandreshoring5.7—WeldingandburningChapter6—References,p.423.3R-176.1—Specifiedandrecommendedreferences6.2—CitedreferencesCHAPTER1—INTRODUCTION1.1—GeneralThisreportisintendedtoupdatethepreviousACI-ASCECommittee423reportentitled“RecommendationsforCon-creteMembersPrestressedwithUnbondedTendons,”(ACI423.3R-89)publishedin1989.Intheintervalsincethepub-licationofthatreportandthethreepreviousreportsthatitre-placed,manyofitsrecommendationshavebeenincor-poratedintotheACIBuildingCode(ACI-318).Asaresult,designwithunbondedtendonsiscoveredinACI318-95innearlythesamedegreeofcompletenessasisdesignwithbondedtendons.Nonetheless,theserecommendationshavebeenpreparedtoprovideanup-to-dateandcomprehensiveguideforde-sign,materials,andconstructionforconcretememberspre-stressedwithunbondedtendons.SuggestedrevisionsandadditionstotheACIBuildingCodearealsoincludedinthisreport.1.2—Objective1.2.1Theobjectiveofthisreportistopresentrecommen-dationsformaterials,design,andconstructionforconcretestructuresprestressedwithunbondedtendonsthatarecom-mensuratewiththesafetyandserviceabilityrequirementsoftheACIBuildingCode(ACI-318).1.2.2Thisreportisaguide,notabuildingcodeorspecifi-cation.Therecommendationsarepresentedfortheguidanceandinformationofprofessionalengineerswhomustaddtheirengineeringjudgmenttoapplicationsoftherecommen-dations.1.3—Scope1.3.1Therecommendationsareintendedtocoverspecialconsiderationspertinenttodesignwithunbondedtendons.Consideredinthisre