ACI 423.5R-99 State-of-the-Art Report on Partiall

ACI423.5R-99becameeffectiveDecember3,1999.Copyright2000,AmericanConcreteInstitute.Allrightsreservedincludingrightsofreproductionanduseinanyformorbyanymeans,includingthemakingofcopiesbyanyphotoprocess,orbyelectronicormechanicaldevice,printed,written,ororal,orrecordingforsoundorvisualreproduc-tionorforuseinanyknowledgeorretrievalsystemordevice,unlesspermissioninwritingisobtainedfromthecopyrightproprietors.ACICommitteeReports,Guides,StandardPractices,andCommentariesareintendedforguidanceinplanning,designing,executing,andinspectingconstruction.Thisdocumentisintendedfortheuseofindividualswhoarecompetenttoevaluatethesignificanceandlimitationsofitscontentandrecommendationsandwhowillacceptresponsibilityfortheapplicationofthematerialitcontains.TheAmericanConcreteInstitutedisclaimsanyandallresponsibilityforthestatedprinciples.TheInstituteshallnotbeliableforanylossordamagearisingtherefrom.Referencetothisdocumentshallnotbemadeincontractdocuments.IfitemsfoundinthisdocumentaredesiredbytheArchitect/Engineertobeapartofthecontractdocuments,theyshallberestatedinmandatorylanguageforincorporationbytheArchitect/Engineer.423.5R-1Partiallyprestressedconcreteconstructionusesprestressed,oracombina-tionofprestressedandnonprestressed,reinforcement.Partiallyprestressedconcretefallsbetweenthelimitingcasesofconventionallyreinforcedcon-creteandfullyprestressedconcrete,whichallowsnoflexuraltensionunderserviceloads.Whenflexuraltensilestressesandcrackingareallowedunderserviceloads,theprestressedmembershavehistoricallybeencalledpartiallyprestressed.Thisreportispresentedasanoverviewofthecurrentstateoftheartforpartialprestressingofconcretestructures.Researchfindingsanddesignapplicationsarepresented.Specifictopicsdiscussedincludethehistoryofpartialprestressing,behaviorofpartiallyprestressedconcretemembersunderstaticloads,time-dependenteffects,fatigue,andtheeffectsofcyclicloadings.Keywords:bridges;buildings;concreteconstruction;corrosion;cracking;crackwidths;cyclicloading;deflections;earthquake-resistantstructures;fatigue;partiallyprestressedconcrete;post-tensioning;prestressing;pre-stresslosses;shear;stresses;structuralanalysis;structuraldesign;time-dependenteffects;torsion.CONTENTSChapter1—Introduction,p.423.5R-21.1—Historicalperspective1.2—Definition1.3—DesignphilosophyofpartialprestressingState-of-the-ArtReportonPartiallyPrestressedConcreteReportedbyJointACI-ASCECommittee423ACI423.5R-99WardN.Marianos,Jr.*ChairmanHenryCronin,Jr.SecretarySarahL.BillingtonWilliamL.GambleH.KentPrestonKennethB.BondyHansR.GanzDenisC.PuRobertN.Bruce,Jr.*J.WestonHallJulioA.Ramirez*DaleBucknerMohammadIqbalKenB.RearNedH.Burns*FrancisJ.JacquesDaveRogowskyGregoryP.Chacos*DanielP.JennyBruceW.RussellJackChristiansenPaulJohalDavidH.SandersToddChristophersonSusanN.LaneThomasSchaeffer*StevenR.CloseLesMartin*MorrisSchupackThomasE.CousinsAlanH.Mattock*KennethW.ShushkewichCharlesW.Dolan*GerardJ.McGuireKhaledS.SoubraApostolosFafitisMarkMoore*RichardW.StoneMarkW.FantozziAntoineE.Naaman*PatrickSullivanMartinJ.FraduaKennethNapiorLucR.TaerweCatherineW.French*ThomasE.NehilH.CarlWalkerCliffordFreyermuthMrutyunjayaPaniJimJ.ZhaoPaulZia**Subcommitteepreparingreport(MichaelBarkercontributedtowritingChapters4and5ofthisreport).423.5R-2ACICOMMITTEEREPORT1.4—Advantagesanddisadvantagesofpartialprestressing1.5—Partialprestressingandreinforcementindexes1.6—ReportobjectiveChapter2—Partiallyprestressedmembersunderstaticloading,p.423.5R-52.1—Behavior2.2—Methodsofanalysis2.3—Cracking2.4—Deflections2.5—ShearandtorsionChapter3—Time-dependentbehavior,p.423.5R-123.1—Prestresslosses3.2—Cracking3.3—Deflections3.4—CorrosionChapter4—Effectsofrepeatedloading(fatigue),p.423.5R-154.1—Background4.2—Materialfatiguestrength4.3—Fatigueinpartiallyprestressedbeams4.4—Predictionoffatiguestrength4.5—Serviceabilityaspects4.6—SummaryofserviceabilityChapter5—Effectsofloadreversals,p.423.5R-205.1—Introduction5.2—Designphilosophyforseismicloadings5.3—Ductility5.4—Energydissipation5.5—Dynamicanalyses5.6—Connections5.7—SummaryChapter6—Applications,p.423.5R-286.1—Earlyapplications6.2—Pretensionedconcretecomponents6.3—Post-tensionedbuildingconstruction6.4—Bridges6.5—OtherapplicationsChapter7—References,p.423.5R-307.1—Referencedstandardsandreports7.2—CitedreferencesAppendix—Notations,p.423.5R-36CHAPTER1—INTRODUCTION1.1—HistoricalperspectiveApplicationofprestressingtoconcretemembersimpartsacompressiveforceofanappropriatemagnitudeatasuitablelocationtocounteracttheservice-loadeffectsandmodifiesthestructuralbehaviorofthemembers.Althoughthecon-ceptofprestressedconcretewasintroducedalmostconcur-rentlyintheU.S.andinGermanybeforetheturnofthe20thcentury(LinandBurns1981),itsprinciplewasnotfullyestablisheduntilFreyssinetpublishedhisclassicalstudy(Freyssinet1933).Freyssinetrecognizedthatastheloadonaprestressedmemberisincreased,flexuralcrackswouldappearinthetensilezonesatacertainloadlevel,whichhereferredtoasthetransformationload.Eventhoughthecrackswouldcloseastheloadwasreducedandthestructurewouldrecoveritsoriginalappearance,Freyssinetadvoc