Constructionand Design of PrestressedConcreteSegmentalBridges WalterPodolny, Jr.,Ph.D.,P.E. BridgcDivision ()HiccorEllgineering h'dcr;tiII iglll\'dY :\dmillisl ratioll L' .S.Depart illenl01Tr;lIls[Jortalioll JeanM.Muller (:llaillll;11I(lilheBoard Figgalld),[uJkrEllgincers,[Ill. BR1T" LEM". -9 AUG 1982 82/19656 AWiley-IntersdencePublication JohnWiley&Sons NewYorkChichesterBrisbaneTorontoSingapore Copyright 1982by john Wiley&Sons,Inc. Allrightsreserved.PublishedsimuhaneollslyinCanada. Reproductionor translationof anypartof thisworkbeyond thatpermittedbySection107or108of the1976United StatesCopyrightActwithoutthepermissionof the copyright owner isunlawful.Requestsforpermissionorfurther informationshouldbe addressedtothePermissions Department. johnWilt)'&Sons,Inc Libraryof CongressCataloginginPublicationData: Podoln)',Walter. Constructionanddesignof prestressedconcrete segmentalbridges. (Wileyseries of practical constructionguides ISSN0271-6011) "AWiley-Intersciencepublication." Includesindex. I.Bridges, Concrete-Design and construction. 2.Prestressed concrete construction.I.Muller, jean M. II.Title.III.Series. TG355.P63624.281-13025 ISBN0471-05658-8AACR2 PrintedintheUnitedStatesof America 1098765432 -- ..-...---de.-------- .-------SeriesPreface The WileySeries of PracticalConstructionGuides providestheworking constructorwithup-to-date information that can help to increase the job profit margin.Theseguidebooks.whicharescaled mainlyforpractice,butincludethenecessary theoryanddesign.shouldaidaconstructioncontractorinapproachingI\orkproblemsI\'it hmore knowledgeableconfidence,Theguidesshouldbe usefulalsotoengineers.architects.planners. specificationwriters.projectmanagers,superintendents,materials andequipment manufacturers and, the source of allthese callings, instructors and their students. ConstructionintheUnitedStatesalonewill reach$250billionayear intheearlyI980s.In all nations,thebusinessof buildingwillcontinueto grow at aphenomenal rate, because the population proliferationdemands!1('I\living.I\'orking.and recreationalfacilities.Thisconstructionwillhave tobemoresubstantial.thusdemandingamore professional performance fromthe contractor. Before scienceandtechnologyhad seriously affected theideas,jobplans,financing,anderectionof structures,mostcontractorsdevelopedtheir know-howbyfieldtrial-and-error.Wheels,small andlarge,wereconstantlybeing reinventedinall St'C(ors.bccausethere,\asnointerchangeof knmdedge.Thecurrentcomplexityof cOlIStru{'tion. even in more rural areas, has revealeda dear needformoreproficient.professionalmethods andtoolsinbothpractice andlearning, Because construction ishighly competitive. sOllle practicaltechnologvisnecessarilyproprietary. BUI most practical day-to-day problems are common to thewholeconstructionindustry.Thesearethe subjectsfortheWileyPracticalConstruction Guides. M.D.MORRIS.P.E. v Preface Prestressedconcretesegmentalbridgeconstructionhasevolved,inthenaturalcourseof events, fromthecombiningof theconceptsof prestressing,boxgirder design,andthecantilevermethod ofbridgeconstruction.Itarosefromaneedto Qvercoml:construniondifficultiesinspalIning deepvalleysandriver crossmgs without theuse of conventionalfalsework,whichinsomeinstances maybeimpractical,economicallyprohibitive,or detrimentaltoenvironment andecology. Contemporaryprestressed,boxgirder,segmentalbridgesbeganinWesternEuropeinthe 1950s.UlrichFinsterwalderin1950,foracrossingof theLahnRiverinBalduinstein,Germany, wasthefirsttoapplycast-in-placesegmentalconstructiontoabridge.In1962inFrancethefirst applicationof precast.segmental,boxgirder COllstructionwasmadebyJeanMullertotheChoisyLe-RoiBridge crossing the SeineRiver.Sincethen theconceptof segmentalbridgeconstructionhas beenimprovedandrdinedandhasspreadfrom Europethroughoutmostof theworld. ThefirstapplicationofsegmentalbridgeconstructioninNorthAmericawasacast-in-place segmentalbridgeontheLaurentianAutoroute nearSte..\dele.Qllebec.in1964.Thiswasfollowedin1967byaprecastsegmentalbridge crossingtheLievreRivernear~ o t r eDameduLaus, Quebec.In1973thefirstU.S.precastsegmental bridgewasopeliedtotrafficinCorpusChristi. Texas,followedayearlaterbythecast-in-place segmentalPineValleyBridgenearSanDiego, California.Asofthisdate(1981)intheUnited Statesmorethaneightysegmentalbridgesare completed,inconstruction,indesign,orunder consideration. Prestressedconcretesegmentalbridgesmaybe identifiedasprecastorcastinplaceandcategorizedbymethodofconstructionasbalanced cantilever,span-by-span,progressiveplacement, or incrementallaunching.Thistype of bridgehas extendedthepracticalandcompetitiveeconomic spanrangeof concretebridges.Itisadaptableto almost any conceivable sitecondition. The objective of this book is to summarize inone volumethecurrentstateof theartof designand constrllctionmethodsforallI ypc,;ofsegmelHal bridgesasareadyreferencesourceforellgillcering faculties,practicing engineers, contractors, and local,state,andfederalbridgeengineers. ChapterIisaquick review of thehistorical evolutiontothecurrentstateof theart.ItbITersthe studentanappreciationofthewayinwhichsegmentalconstructionofbridgesdeveloped,thc factorsthatinfluenceditsdevelopment,andthe varioustechniquesusedinconstructing segmental bridges. Chapters 2and3presentcase,tudies of thepredominantmethodologyoi constructing segmental bridges bybalanced cantilever in both cast-in-place andprecastconcrete.Conceptionanddesignof the superstructure andpiers,respectively,arediscussedinChapters4and5.Theotherthreebasicmethodsofconstructingsegmentalbridgesprogressiveplacement,span-by-span,andincrementallaunching-arepresentedinChapters6 andi. Chapters 2through ideal essentially withgirder typebridges.However,segmentalconstruction mayalsobeappliedtobridgesofothertypes. Chaprer8discussesapplicationofthcsegmcntal concepttoarch,rigidframe,andtrussbridges. Chapter9dealswiththecable-stayedtypeof bridge andChapter10withrailroadbridges.The practicalaspectsoffabrication,handling,and erectionof segments arediscussedinChapterII. In selected a bridge type for aparticular site, one ofthemoreimportantparametersiseconomics. Economics,competitivebidding,andcontractual aspectsof segmental constructionare discussedin Chapter12. Most of the material presented in thisbook isnot -vii viiiPreface original.Althoughacknowledgmentofallthe manysourcesisnotpossible,fullcreditisgiven whereverthespecificsource canbeidentified. Everyeffort hasbeenmadetoeliminateerrors; theauthorswillappreciatenotificationfromthe reader of anythat remain. The authorsareindebtedtonumerouspublications,organizations,andindividualsfortheir assistanceandpermissiontoreproducephotographs,tables.andother data.Whereverpossible. credit isgiveninthetext. WALTERPODOLNY, JR. JEANM.MULLER Burkt,1Pans,France january 1982 .."iiliiI........... ________-----Contents 1Prestressed ConcreteBridgesand2.8GennevilliersBridge,France, 52 Segmental Construction12.9Grand';"'fereBridge,Canada, 55 2.10ArnhemBridge,Holland, 581.1Introduction,1 2.11:-';apaRiverBridge,C.S.A., 591.2Development of Cantilever 2.12Koror-Babelthuap,C.S.Pacific Construction,2 TrustTerriton', 61 1.3Evolution()fPrestressed 13Vejle\'jordBridge,Concrete, 4 Denmark, 631,4Evolution of Prestressed Concrete 2.14HoustonShip ChannelBridge,Bridges, 5 C.s.A.,681.5Long-SpanBridgeswith 2.15OtherStructures, 71ConventionalPrecast 2.lGConclusion, 81Girders. R References, 811.6SegmentalConstruction,10 1.7VariousTypesof Structures,12 3PrecastBaLanced Cantilever Girder 1.8Cast-in-Place andPrecast Bridges82Seg-mentalConstruction,17 1.9Various\Ici hodsof:UI III roclllU iOIl , 82 Construction,183,2ChoisyLeRoiBridge and Other 1.10Applicationsof SegmentalStructures inGreaterParis, ConstructionintheCnitedFrance, 83 States,26:5.3Pierre Benite Bridges near Lyons, 1.11ApplicabilityandAdvantages ofFrance, 89 SegmentalConstruction,283.-1:OtherPrecast SegmentalBridges References, 30inParis,91 OleronViaduct,France, 96 J.bChillonViaduct,Switzerland, 992Cast-In-Place Balanced Cantilever Girder HartelBridge,Holland,103Bridges31 :L8Bridge,Brazil,106 2.1Introduction,1 :t9BearRiverBridge,Canada,108 2,2Bendorf Bridge,German"353.1 ()J FK;"'lell1orialCause\\ay, 2.3Saint AdeleBridge,Canada, 37U.S.A.,109 2,4 BOllguenBridge inBrest and;) .11SaintAndre de CubzacBridges, LlcroixFalgardeBridge,France.113 France, 38 :U2Saint CloudBridge,France,114 2.5Saint JeanBridge overthe3.13SallingsundBridge, GaronneRiveratBordeaux,Denmark,122 France. 413.14B-3SouthViaducts,France,124 2.6SiegtalandKochertalBridges.3.15AlpineStructures, Germany, 43France,129 2.7PineValleyCreek Bridge,3.16Bridge over theEasternScheidt, U.S.A.,46Holland,134 IX xContents 3.17CaptainCookBridge,5.5PierswithDoubleElastomeric Australia,136Bearings, 241 3.18OtherNotableStructures,1395.6Piers with Twin Flexible Legs, 253 References,1475.7FlexiblePiersandTheir Stability During Construction, 263 4Designof Segmental Bridges148 5.8 5.9 Abutments. 271 Effect of DifferentialSettlements 4.1Introduction,148 onContinuousDecks,276 4.2LiveLoadRequirements,149 References, 280 4.3SpanArrangement andRelated 4.4 4.5 4.6 Principle of Construction,149 DeckExpansion,Hinges,and Continuity,151 Type,Shape andDimensions of theSuperstructure,159 TransverseDistributionof Loads 6Progressiveand Span-by-Span Constructionof Segmental Bridges 6.1Introduction, 281 6.2ProgressiveCast-i n- Place Bridges, 283 281 BetweenBox Girders in 6.3Progressive PrecastBridges,289 4.7 4.8 Girders,164 Effectof Temperature Gradients inBridge Superstructures,170 Designof LongitudinalMembers forFlexure andTendon 6.4 6.5 6.6 Span-by-SpanCast-in-Place Bridges, 293 Span-by-SpanPrecast Bridges, 308 DesignAspectsof Segmental 4.9 Profiles,173 UltimateBending Capacityof ProgressiveConst ruction,314 References,319 LongitudinalMembers,190 4.10Shear andDesignof Cross 7IncrementallyLaunched Bridges321 Section.193 7.1Illlrodunioll.321 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 JointsBetweenMatch-Cast Segments,199 Designof Superstructure Cross Section, 202 SpecialProblemsin SuperstructureDesign,203 DeAectionsof CantileverBridges andCamberDesign, 205 FatigueinSegmental Bridges, 210 ProvisionsforFuture Prestressing, 212 DesignExample, 212 Quantities of Materials, 219 PotentialProblemAreas, 220 7.2 7.3 7.4 7.5 7.G 7.7 7.8 7.9 7.10 RioCarolli,Venezuela, 323 ValResle!Viaduct,Italy,327 RavensboschValleyBridge. Holland, 329 Olifant'sRiverBridge,South Africa,331 VariousBridgesillFrance. 333 WabashRiver Bridge, U.S.A.,335 OtherBridges. 338 Designof Incrementall) Launched 34::1 Demolitionof aStructureby Incremental 352 References, 352 References, 224 8ConcreteSegmental Arches,Rigid Frames,andTrussBridges354 5Foundations,Piers,and Abutments225 8.1Introduction, 354 5.1Introduction, 2258.2SegmentalPrecastBridges over 5.2LoadsAppliedto the Piers, 230theMarneRiver,France, 357 5.3Suggestions on Aesthetics of Piers8.3CaracasViaducts,Venezuela, 363 andAbutments, 2328.4GladesvilleBridge,Australia,371 5.4Moment-Resisting Piersand8.5ArchesBuiltinCantilever, 374 TheirFoundations,2348.6RigidFrame Bridges, 382 ........_ .. _._. ______------- iI' .... Contentsxi 8.7TrussBridges,39211Technologyand Constructionof References.399Segmental Bridges465 9 ConcreteSegmental Cable-StayedBridges400 Il.l 11.2 ScopeandIntroduction. 465 Concrete andFormworkfor 9.1Introuuction,400SegmentalConstruction. 466 9.2LakeMaracaiboBridge,11.3Post-tensioningMaterialsand Venezuela. 405Operations, 470 9.3WadiKuf Bridge,Libya. 40711.1SegmentFabricationfor 9.1Chaco/CorrientesBridge,Cast-In-PlaceCantilever Argentina, 408Construction, 475 9.5\lainbrticke,GermallV, 41011.5Characteristicsof Precast 9.6TielBridge. 412Segmellts and\Iatch-Cast 9.7Pasco-KennewickBridge.Epoxy Joints. 485 C.S.A., 41811.6\1anufactureof Precast 9.8BrolOnneBridge,France. 41!:lSegments, 493 9,9DalluheCanalBridge,11.7Handling andTemporan :\ssclllhhof Preca,1 9.10 ExamplesofSegments, 507 Concepls, 4:W11.8PlacingPrecastSegments, 50!} Referellces, 439References. 517 10Segmental Railway Bridges441 12Economicsand Contractual Aspectsof IO.lIlltl'OdllUioll10PanicubrSegmental Construction518 IO,':! 10.:l IO,,! :\spects ofBridges and Fieldof Applicatioll, 441 LaVOlllteBridgeoverthe RholleRi\'('l'.Frallct'.412 \Ior:llldBridgeIIIL\om, Frallce,442 Cerg\POlltoiseBridgeIleal'

12.2 BiddingProcedures, 518 Exampiesof SomeInterest illg BiddillgsalldCosts, 523 j lit ICI,CillEITlticll(\ill Concrete 528 References, 535 ":Iris,Frallce, 'H 10,5:-'!allleLaValleeandTorn13FutureTrendsandDevelopments536 !(Ui 10.7 1O.H 10.9 Bridgesforthe Express LillelIeal'Paris,Fl'allce,444 ClichyBridgeIleal'Paris, Frallce, l!q Oidaill'sBridge, SOllth :\frica, '1:)2 [ncremental"Lallllched R;lil\\';!\Bri(forthe High-SpeedLine,Paristo Lmlls,France, Segll1entalRaih,'avill 1:3.1 1:),2 1 1:3.4 LL") 13,6 Introductiol1,536 536 SegmentalApplicationto Bridg;eDecks,542 BridgePiersand Substructures,543 ApplicationtoExistingor:\ew BridgeI)ijH Summary,548 References,;")49 Japall,457 to, 1()SpecialOe'iignpeetsofIndexof Bridges551 SegmenralRailwavBridges, 458Index of Personal Names555 10.11ProposedConceptsforFutureIndex of FirmsandOrganizations557 SegmentalRailwav Bridges,404Indexof Subjects559 1 Prestressed Concrete Bridges and Segmental Construction 1.1INTRODUCTION 1.2DEVELOP!'v1ENTOF CANTILEVER CONSTRUCTION 1.3EVOLUTION OFPRESTRESSED CONCRETE 1.4EVOLUTION OF PRESTRESSED CONCRETEBRIDGES 1.5LONG-SPANBRIDGESWITHCONVENTIONALPRECASTGIRDERS 1.6SEGMENTAL CONSTRUCTION 1.7VARIOUS TYPES OF STRUCTURES 1.7.1GirderBridges 1.7.2TnJsses 1.7.3Frarn(>,withSlant1.7.4ConcreteArchBridges 1.7.5Concrete Cable-StayedBridges 1.8CAST-IN-PLACEANDPRECASTSEGMENTALCONSTRUCTION 1.1Introduction The conception,development,andworldwideacceptanceof seglllentalintill'fieldor prestressedconcrelebridgesrepresents one 01the mostandilllport;lIltachievelllentsin civilengineering durillg thepastthirtv\ears.Recognizedto\ -spancOllstructioll.(:I)progressiveplacclIlelltCOllst ruet iOIl.alld(4)111 ('r('lIlcl)tallaunchillgorpush-oUlconstruction. 1,9,1c.'ISr/.\'j'j.,l(J,li.1LJ.\'CUl C/.\T/UJUI Theh;li;lllccdorfrcecalli iI('\('1COllst run ionCO)l(ejlt\\'asorigillalhdcn'lopedtoelilllilJate Lllsework,TClIJporansllOrillgIlotollhis('XPCIlsi\'('hUIcallhe;1hazardilltileLiseofsuddcll floods,as cOlJfirllJed1)\lll;tmf;tilllles.(her Ila\'igablewaterwaysorIranledhighwa\'sorrailways, lals('\\orkiseithernotallowedor;,('\eIT"restrictcd.Cantiien:rcOllstructiol],\\hetliercastill placeorprecast,clilliinatesslIchdifficulties:C()IJstructiolJilia\,pro(cedfromIhepermallelltpiers, andtheSlrllctureissell-supportillgatallsLtges, Thehasicprillcipleof thelIIethod\\asoutlincdill Section1.J(FigmeIncast-ill-placeCOllst ructiollthejonn\\'orkis sllpportedfroma1ll00ahieformcarrier,Figure 1.1.Detaibof thelorlllIranlers arcshowllillFiglire1.43. The forllltra\'eier 1IJ00es forward 011rails attachedtothedeckofthecompletedstructure andisanchoredtothedeckattherear.Withthe formt r;J\e!erillplace,ancwsegmelltisformed, cast,andstrcssedtotheIHe\'iolishconstructed segment.I nsome instances a covering m' (,. i ':0 I ! ., i t'3ali 29'(>' I 1's'I , FIGURE2.26.Saint JeanBridge atBordeaux,typicalsectionatriverpiers. :: 42 43Siegtal and KochertalBridges,Germany FIGURE2.27.SaintJeanBridgeatBordeaux,work progressonpiersanddeck. 18.5ft(5.601l1)indiameter and10ft(3m)high, tloatedandsunktotheriverbedandthenopendredgedtothegravelbed.Precast circularmatchcastsegmentsprestressedverticallymakeupthe permanentwallsof caissons,whileadditionalsegmentsareusedtemporarilyascofferdamsand supportforthedeckduringcantileverconstructioll.Alowerrrel11iesealallowsalld placi llg of plain concretefillinside the caisson .. n.e reinforcedconcretefOOlingandpiershaftare finallycastillone([;\\'. Thesuperstructureboxgirderswerecastin placein10ftC3.05Ill)longsegmentsusingtwelve formtravelers,allowingsimultaneousworkonthe threeparallclcantileversat.twodifferentpiers. The 20 fl(0.1111)long pier segment was castonthe temporary supportsprovidedbvthepier caissons. allowing the formtravelerstobe installed and cantileverconstructiontoproceed.Sixworkingdays werenecessarvforacompletecycleof operations Oileachtraveler.Workprog-ressisshownillFiglues 2.27 and 2.28. Total constructiontillleforthe entire130,000 sqIt (12,000m2)was approximatelv FIGURE2.28.SaintJeanBridgeatBordeaux.cantileverconstructionontvpicalpier. oneyear, asshownonthe actualprogram of work summarizedingraphicforminFigure2.29.To meettheverystrictconstructiondeadlineor the contract, it wasnecessary to bring to the project site anotherset of threetravelerstocastthelastcantilever onthe left bank andachieve continuity with thesouthernriverpiercantilever.Altogether. meetingthetwo-yearconstructionschedulewas recognizedasanengineering achievement. Exactlyonehundredyearsearlier,GustaveEiffelhadbuilttheneighboringrailwaybridgein exactlytwoyears-foodforthoughtandasomewhathumblingreHectionforthepresentgeneration. 2.6Siegtal and Kochertal Bridges,Germany The SiegtalBridgenearthetownof Sieger,north of Frankfort,Germany,representsthefirstindustrialapplicationofcast-in-placecantileverconstructionwithanauxiliaryoverheadtruss.This methodwasinitiallydevelopedbyHansWittfoht andthefirmofPolensky-und-ZollneramIsubsequentlyusedforseverallargestructuresinGermany and other countries.One of the1110Strecent andrcmarkablcexamplesof thistechniqueisthe KochenalBridgebetweenNurembergandHeilbron,Germany.Bothstructureswillbebrieflydescribed inthis section, while asimilar application ill Denmarkiscoveredinanothersectionofthis chapter. SiegtalBridgeisatwelve-spanstrllctUl'e3450rt (1050m)long resting on piers up to 330 it (lOOIll) high,withmaximumspanlengthsof 344ft(105 m).Figure2.30.Twoseparateboxgirderscarr" thethreelrafliclanesineachdirectionforatotal widthof100ft m).Figure2.:31.Structural height of the constant-depth box girder is19 ft(5,8 Ill),correspondingtoaspan-to-depthratioof18. Thedeckiscontinuousthroughoutitsentire length,withfixedbearingsprovidedatthethree highestcenterpiersandroilerbearingsofhighgradesteelforallotherpiersandendabutments. Piershave slip-formedreinforcedconcretehollow boxshaftswithaconstanttransversewidthof 68 ft(20.7m)andavariablewidthinelevationwith aslopeof 40to1 onbothfaces. The superstructure wascast inplace inbalanced cantileverfromallpiersin33ft(10m)longsegmentswith an auxiliary overheadtruss supporting thetwosymmetricaltravelers,andacycleof one weekwasobtainedwithoutdifficultyfortheconstruction of twosymmetrical33ft(10m)long seg,IPONTOESCHAMPS .L 1 w fl'!'tTl' g ;t

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I' ,I U" FIGURE2.37.KochenalBridge.e\nation.planand ero,ssect iOIl. commutlit\ofPineValle\andwithintheCle\eland:'\ation,IlForest.Interstate1-8crossesover a sell1i,lridl-cgionthatishighlyerodiblewhenthe groundc()\'Crisdisturbed;consequenth'strillgent controlswereimposedonaccessroadsand ground-c()\'crdisturbances.Structuretypewas influenced1)\thefollowingfactors:siterestrictions.ecollomics.ecologicalconsiderations.and Forest Sel'\ice limitatiolls.After com paring \arious possibleschemessllchassteelarch,decktruss,or steel.boxgirder.theCaliforniaDepartmentof Transport,ltionselectedaconcreteboxgirder bridgepredicatedontheuseofcantileverseg(1/) JO,7&58J13.10 8.83 (b) FIGURE2.38.KochertalBridge.typicalcrossseclions.(Il)Firststagecasting.(b)Finalstage. 48Cast-in-Place Balanced Cantilever Girder Bridges ... FIGURE2.39.KocherralBridge,cantileverconstruclion. mentalconstruction,particularly wellsuitedtothe site because the depth and steep slopes of the "allev madetheuseof falseworkimpractical.Also,the cantilevermethodminimizedscarringofthe natural em'ironment, whichwasamajor consideration[or aprC!iectlocatedina:\:ationalForest. The bridge has an average length of 1716 ft(523 m)ane!consistsoftwintwo-lanesingle-cell, trapezoidalboxgirders each42ft(12.8m) out-toout.Thedeckis450it(137m)abovethecreek bed.Thesuperstructurec o n s i s ~ soffivespansof prestressedboxgirders19ft(5.8m)deep.The center spanis450ft(137Ill)inlength,Rankedby side spans of340 fl (103.6 lll) and 380 ft(115.8111), with end spans averaging 270 ft(82.3Ill) and 276 ft (84.111l).Thebridgewasconstructedwithfour cantilevers.Pier 2 has cantilevers115ft(35.1m) in length.piers3and4have225ft(69.6m)cantilevers,andpier5has155ft(47.2m)cantilevers,6.7.RFigure2.40.Provisionsweremadeinthe design10permittheportions of spansIand5 adjacenttothe abutmentstobeconstructedsegmentallyor un falsework atthe contractors' option. The lateroptionwasexercisedbythe contractor. !I. 10 CANTu.evtR ABUT.6 ,.,. PIERZ PitR~ PltR3 PIER" ELEVATION I TYPICALSECTION FIGURE2.40.PineValleyCreekBridge, ele\'ationandtypicalsenion,fromref.8. 49PineValleyCreekBridge,V.SA. Hingeswereproddedinspans2and4atthe end of the main cantilevers.Inthepreliminarv design,considerationwasgiven10theconceptof a continuousstructureforabutmenttoabutment withoutanyintermediatejoints.Continuityhas mallVadvantagesinsohlrast hisparticularstructureisconcerned.Howner,ithasthesignificant dis::: o;;::.. ;:; o I-:..; 1".N " ;:l ::2 .... CL 65 tn ANIl UNSti PPORTU)_ TO ALTERNATE CASTTNG Of t)ORK lNG cYeLl]S PER TENDONS. REHOVAL BOX-TYPE GIRDER C'> C'> LONGITUDINAL SECTION POSI TlON Of PRESTRESSING TE N DON S C[NTR[ lIN( or SPAN ,,-CHHRE UNE Of SPAN SUPERSTRUCTURE, PRINCIPLE OF EXECUTION

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..(FIGURE2.76.\'ejlcFjordBridge.tranS\'erseribs. Constructionprogressillthespringof1978isillustrated inFigures 2.75through2.78.Figure 2.79 isanaerialviewshowingthestructurenearing completion.Tokeepwithintheconstruction schedule,itwashnalhnecessan'tousetwocompletesetsoflaunchinggirdersandtwilltravelers workingsimultaneousl \frol11bothendsofthe bridge. FIGURE2.77.VejlcFjordBridge.piersegment\\itll diaphragm. FIGURE2.78.\'ejlcFjordBridge.)Il\truction\ic\\. spring197H(courtes\of H.A,Lindberg). FIGURE2.79.VejleFjordBridge.aerialvIewfrom thenorth\\est. 68 "LE 1 o.-, . J

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FIGURE 3.19. Paris Belr (Dowllstrealll), cross sect iOIl. 1..0 1.10 Precast Balanced Cantilever Girder Bridges 94 FIGURE3.20.ParisBelt(Downstream),segment placing. endspan,whichcouldnotbe changedbecauseof stringentpier locationrequirements. 3.4.2P,4RISBELT (UPSTREAM) OntheothersideofParisanothersegmental structure, also carrying the Beit Motor-way over the Seine,wasdesignedforfivetrafficlanesineither 56,6265.m FIGURE3.21.ParisBelt(Upstream),vIewofthe finishedbridge. direction,Figure3.21.Thetwinbridgeshavedimensionssimilartothoseofthedownstream bridge,andeachstructurehastwoparallelbo;-: girders connectedbytransverseprestress.Dimensions areshowninFigures 3.22 and 3.23.Acircular intradosprofilewasusedinlieuof the straight haunches.Allsegmentswereprecastontheriver bank inthe immediate vicinity of the bridge, using d~ u t , . u i l FIGURE3.22.ParisBelt(L'pstrcam),longitudinalsection. E o o N... 3.50 m3.50m3.50 m3.50m 3.50 m3.50m 3.5Om 3.50 m3.50m 3.50m FIGURE3.23.ParisBelt (Upstream),typicalcrosssection. ._--_._--_. 95 Other PrecastSegmental Bridgesin Paris PHASESD'EXECUTIONDUT AllllERSEQtll!NCESOFnu:Dl!'.CKCOIISTRUCTlctI RightBank QuayofBercy FIGURE3.24.P;ll'isBell(l'pstream),typicalsegmentplacingscheme. the sallietwocastingmachineslIsedpreviouslyfor thedowns! reambridge. PlacingsegmentsinthestruClureposedsome interestingproblems,asshowninthesequence diagramsofFigure3.2-!-.Piersegmentsweretoo heavvtobehandledasoneunitandweresubdividedintotwosegments,assembleduponthe piershaftbeforecantilnerplacingcouldstart.A FIGURE3.25.JuvisvBridge.completedstructur:. crane,eitheroncrawlersoronabarge,together withthebeam-and-winchequipmenthandledall segmentplacing, 3.4.3JUVISY BRIDGE Thisbridge,Figure3.25,isalsoontheSeine just somhof Choisy-Ie-Roi;seethelocationmap.Figure3,1.DimensionsareshowninFigure3.26. Segmentswere castbytheshort-linemethodnear thesiteandplacedwithafloatingcrane,Anauxiliaryfalseworkonbothbanksallowedsegment placingandassemblvbeyondthereachofthe floatingcrane, 3.4.4nnv BRIDGESAT CONFL4NS These twinbridges,Figure 3.27,placed about 320 ft(100m)apart to allowfor interchange ramps on both banks, areupstreamof Pariswhere the Seine andMarneRiversmerge;seethelocationmap,. Figure3.1.Dimensionsandconstructionmethods were similar tothose of theCourbevoieBridge alreadydescribed. 96 : V EL133 I /1\ I I I I I I .,.. I =t== I 1 f--.I iI I EL.122 7 / EL.69 I l !: I.j Precast Balanced Cantilever Girder Bridges' ,., I"t24-3 24-3 10' EL133i FIGURE3.26.Ju\'isyBridge, crossseclion. FIGURE3.27.TwinBridgesatConflans,finished hridge. 3.5OieronViaduct,France TheOleronViaductprovidesalinkbetweenthe mainland of France and the resort island of Oleron off the Atlantic West Coast 80 miles (128km)north of Bordeaux, This structurehasatotallengthbetweenabutments of 9390 ft(2862m).In thenavigable centralpart of thestructureare 26 spans of 260 ft (79m),Figure 3.28.Approach spans consist of twoat194ft(59m),sixteenat130 ft(39.5m), andtwo at 94ft(29 m). The superstructure issupportedby45piersandwasassembledbyprestressingmatch-castsegments,usingepoxy joints. Balancedcantileverconstructionwasaccomplishedutilizingalaunchinggantryforerection. Intheapproachspansthesuperstructurehasa constantdepthof8.2ft(2.5m).Depthofthe center spans varies from14.9 ft(4.5m)at thepiers to 8.2ft(2.5m)at midspan,Figure3.29.The rectangularboxsegmenthasabottomflangewidth of18ft(5.5m)andatopflangewidthof 34.8ft (10.6m).Websha,'eaconstant thicknessof 12in. (0.3m),whilethetop andbottomflangesare 8in. (0.2m)and7in.(0.18m)thick,respectively,Figure 3.30. Typical segment length is10.8 ft (3.3m). Expansionofthedeckisprovidedinevery fourthspanbyaspecialstepped(ship-lap)joint withhorizontalelastomericbearingpads,Figure FIGURE3.28.OJeronViaduct, cQmpletedstructure. 97OleronViaduct,France 1 '1I I iI " ~ ~ . \r/_. 18' FIGURE3.29.OlcronViaduct.typicalcrosssection.fromref.:>(courtesyof I heAmericanConcretel!lStitute). 3,30.Throughoutthetotallengthofstructure therearetenexpansionjoints:oneateachabutmentandeightintermediateones.Thelatterare locatedatpointsorcOlltraftexureinatvpical interiorspansubjectedtoacontinuousuniform l o a d . ~The segmentswiththe expansion joint have the same lengthastypical segments and are infact twohair-segmentsthataretemporarilypreassembledwithbolts.withaspeciallavoutof temporary andpermanentprestressingtendons.Itisthen possibletomaintainthebalancedcantilevererectionprocedurebeyondtheexpansionjointto midspan.Lateron,whencontinuityhasbeen achievedintheadjacentspans,theexpansionjointsegmentis"unlocked"toperforminthein.tendedmanner. Theprecastingplantwaslocatedinthevicinity of the mainland abutment. Production inthisplant wasscheduled so that the 24 segments required for atypical260ft(79m)central span couldbefabricatedinnineworkingdays.Segmentswereproducedbythelong-linemethod,describedin Chapter11.Four setsof steelformsrodea bench thatwascarefullyalignedtothelongitudinal profile of the roadway and the variable-depth soffit withdueprovisionforcamber.Segmentswere match-cast inthe same relative order in whichthey were subsequentlv assembled at the site.;;An aerial viewof thecastingyardisshowninFigure3.31. Handling of segments inthe casting and storage yardwasaccomplishedbyaspecialrailwavmounted gantry capable of handling loadsvarying r: I I ! 1I-;:V'" "I II!Il.JI!L '2FIGt:RE3.30.OleronViaduct,typicalcenter span elevation,fromref.5(courtesyof theAmericanConcreteInstitute). 98Precast Balanced CantileverGirder Bridges' FIGURE3.31.OlemnViaduct.aerial"iewof casting \ard. from45tons(42I11t)forthe center-spansegment toHOtons(i3111t)forthepiersegment.Alowboy dollyridingonrailsorthefinishedbridgeand pmhed by a farmtractor transported the segments fromstor:tgetotheir10catiol1forassembly. Cantilevererectionatthesitewasaccomplished byalaunchinggantry,Figure3.32.Thisgantry wasthe keyto the successful operation of thisproject.Althoughthestructureiserectedoyerwater, theuseoffloatingequipmentwouldhavebeen difficult,expensive,andsubjecttouncertaintybecauseof thegreattidalrangeandtheshallowness ofwaterinmostoftheareatraversedbythe structure.Floatingequipmentwouldhavebeen abletoreachthe approachpiers only at hightide. During lowtidethemarsharea,whichisthe locati011ofFrance'sfamedMarennesoysterbeds, couldnotacceptanytire-mountedorcrawlermounted equipment. Consequently, it wasdecided toworkentirelyfromabovewithalaunching gantry.Thisnewtechniquewasdevelopedforthe firsttimeforthisstructureandwaslaterrefined forotherstructures.Forthetypicalcentralspans theerectioncyclerequiredbetweeneightandten workingdays.f' ConstructionbeganinMay1964,threemonths afterdesignworkhadstarted.Thefirstsegment wascastin JulyandplacedinAugust1964.Side spans laid on acu I'vewere completedinDecember andthelaunchinggantrywasthenmodifiedfor constructionof thecenterspans.Thelastof the 8iOprecast segmentswasinplace inMarch1966, alldthebridgeopenedtotrafficinMay,afteran overallconstructiontimeoftwoy e a r s ~ ;seethe summaryof theworkprograminFigure3.33.A FIGURE3.32.OleHln\'iarluct.cOllStruCliollyic\\ showingcamilcHTspan.fromref.:>(counes\,orlhe AmericanCOf1cr('lCInslillHc). viewof thefinalstructure isshowninFigurcs3.28 and3.34. The OlcronViaductwasthcfirstapplicJtiolJof the launching-gantry conceptforplacing segments incantilever.Se\'craJstructureswerelaterdesiglledandhuilt\\'iththesameconstruction method.\ientionshouldbelIladehereofthree specialbridges: I.BloisBridp,fmin tlt(,Loir('Hit'('rTheprincipaldimensiollsaregiveninFigure3.35.The superstructureboxgirdersrestonthepier shafts throughtwinelastomericbearings,whichallow thermalexpansionwhileprm'idingpartialrestraintforbcnding-momenttransfer between deck and piers. Consequently, sa\'illgs are ohtained both inthedeckandinthefoundations.Allsegments wereplacedinthebridgewit hanimprovedversionof thelaunching gantryfirstdesignedforthe OleronViad uct.High-strengthsteelandstays wereusedtoprovideminimumweightwithasatisfactorystillnessduringoperations,Figure 3.36.High-strengthboltconnectionswereused throughout tomake the gantTv completely capable ofdismantlingandeasilytransportabletoother constructionsites. 2.Aramon Bridge over theRhone RiverThis was thenext structure where the samegantry couldbe used,Figure3.37. 3.SeudreViaductLocatedjustafewmiles south of Oleron over the Seudre River, this 3300 ft (1000m)long viaductwasalsoof precast segmentalconstructionandusedthe same launching gan99ChillonViaduct,Switzerland CONTiNENTOLERON PIERSONFOOTINGSPIERSONFOOTINGS FIGURE3.33.Olcl'OlIViaduct,programof work, tn. The linished structure isshowninFigure 3.:HL FoundationsfoJ'the cellter spallswerebuiltIllside sheetpilecofferdamsinspiteofvervswifttidal currents. 3.6ChillonViaduct,Switzerland The7251ft(2210111)longdualstructuresof the Chillon Viaduct are part of EuropeanHighwav E-2 andarelocatedatthe eastern end of LakeGeneva passing throughanenvironmentallvsensitivearea andveryclosetothefamedCastleof Chillon,Figure3.39.Inaddition,thestructureshaveverv difficultgeometricalconstraintsconsistingof3% grades, 6%superelevation, and tight-radius curves aslowas2500ft(760m).Eachstructurehas23 spans of 302 ft(92m),322 ft(98m),or 341ft(104 m).Thevariablespansallowedtheviaducttobe fittedtothegeologyandtopography,providing minimum impact on the scenic forest. The viaducts are divided bvexpansion joints into five sections of anapproximatelengthof 1500ft(457m), Twinrectangularslip-formedshaftswereused forthepiers.varying inheight from10to150 ft(3 to45m).Stabilityduringconstructionwasexcel lentandrequiredlittletemporarybracingexcept betweentheslenderwallstopreventelasticinsta bility.!Withtheexceptionof threepiersineach FIGURE3.34.Oleron Viaduct, aerial view of finished bridge. 100Precast Balanced Cantilever Girder Bridges CDELEVATIOn- ELEVATION 9.1009\0091,0061,50 PIP?P3 p, CI)(DUPETfiAnSVERSALr CROSSSECTION to4 ~79matmidspan FIGURE3.35.BloisBridge.elevationandt\'picalcrosssection, \'iaduct,allpiersarehingedatthetop.Thepiersmentof thesuperstructure. thatarelessthan72ft(22m)higharehingedatThesuperstructureconsistsof asingle-cellrecthebase;tallerpiersarefixedattheirbase,beingtangularboxwithacellularcantilevertopflange, sufficientlyflexibletoabsorblongitudinalmove- Figure 3.40, andwithadepth varying from18.5 ft FIGURE3.36.BloisBridge,launchinggantry operating onthesuperstructure. FIGURE3.37.AramonBridge,launchinggantry. ChillonViaduct,Switzerland101 FIGURE3.38.SeudreBridge,finishedstructure. (5.64m) at the longer-span piers to 7.2ft(2.2m)at midspan.Widths of topandbottomflangearerespectively42.7ft(13m)and16.4ft(5m).Dimensionsofthetwotypicalcantileversarenotedin Figure g.41.:\laximum segmem weight was88 tons (80mIl.:\cellularcantilevertopBangewasused becausetheoverallwidthofthetopflangeex-FIGURE3.39.ChillonViaduct,aerialvie\\'. ceeded40ft(approx.12m)andthecantilever lengthwas13.15ft(4Ill).Analtemativewould havebeentoprovidestiffeningribsasusedinthe Saint Andre de Cubzac Viaducts (Section 3.11) and theSallingsundBridge(Section3.13). Segmentswereprecastinayardatoneendof thestructurewithfivecastingmachines,allowing Over supports (a) 13001300 5.00 Atmid-span (b) FIGURE3.40.ChilionViaduct,crosssections.(a)Over supports.(b)Atmidspan, III91= 102 103Hartel Bridge,Holland FIGURE3.42.ChillonViaduct,precastingyard. anaverageproductionof22to24segmentsper week(seeaerialview,Figure3.42). Erectionwasbytheconventionalbalancedcantilever method witha launching gantry designed to accommodatethebridge-deckgeometryinterms of curveandvariablesuperelevation.Theoverall lengthofthegantrywas400ft(122m)andthe totalweight2,50tons(230mt).Specialfeaturesof thisgantrywillbediscussedinChapter11.Cantilever placing of precast segments isshown inFigure3.43. Thisstructureistrulyanachievementofmoderntechnologywithemphasisupontheaesthetic andecologicalaspectsof design. 3.7Hartel Bridge,Holland The1917ft(584.5m)long HartelBridge crosses a .canalinRotterdam,Figllre3.44,andconsistsof thefollowingelements: FIGURE3.43.ChillonViaduct,cantileverconstructionwithlaunchinggantry. SectionsI,II,andV,conventionalcast-in-place prestressedconcreteboxgirders SectionsIIIandIV,precastprestressedconcrete segmentalboxgirders Twosteelbasculebridges. Theoriginaldesigncontemplatedthatthetotal structurewouldbeconstructedasconventional cast-in-place box girders on falsework. Substitution atthecontractor'srequestofcast-in-placesegmentalconstructionbyprecastsegmentalconstructionforsectionsIIIandIVsavedtheextensivetemporary pile foundationsystemnecessary to avoidunevensettlementoffalse workbecauseof initialsoilconditions.Theredesignproposedtwo single-cellrectangularboxgirdersasopposedto one three-cell box girder,Figure 3.44, omitting the center portion of the bottomflangeand providing thinnerwebsandathickerbottomflange. Inthesegmentalboxgirderdesigntheclimensionsof thedeckslabareconstant overtheentire length,girder depth variesfrom4.92ft(1.5m)to 17ft(5.18m),thewebshaveaconstantthickness of 13.8 in. (0.35 m), and the bottom flange thickness varies from10 in.(0.26m)to 33 in. (0.85m).Up to adepthof9.35ft(2.85m)thesegmentshavea lengthof15.8ft(4.8m);over9.3ft(2.85m)the lengthdecreasesto12.3ft(3.75m). Theverticalcurvatureofthebridgewasmade constantforthefulllengthof sectionsIIIandIV byincreasing theradius from9842.,5ft(3000 111)to J9,029ft(,5800m),whichresultedinarepetition of eight timeshalf the center span. This repetition justifiedprecastsegments. A long-line casting bed (see Chapter 11)was constructed on the centerline of the bridge box girders atgroundlevel,Figure3.45.Thus,aportalcrane wasabletotransport the cast segments tothe storage area and also erect them inthe superstructure, Figure3.46.The endspanshavethreemoresegmentsthanhalfthecenterspan;theseweresupportedontemporaryfalseworkuntilalltheprestressing tendons wereplacedand stressed,Figure 3.46. Thefirstsegmentcastwasthepiersegment; eachof theremainingsegmentswasthenmatchcastagainsttheprecedi.ngsegment.Thepier segment waspositioned on bearings on top of the pier, Figure3.47,andthetwoadjoiningsegmentswere positioned(oneaftertheother)andthejoints gluedwithepoxyresin.Temporaryhigh-tensile barslocatedonthetop of the deck slab andinthe bottomflangewere stressedtoprestressthethree 104PrecastBalanced Cantilever Girder Bridges ._v~ 84.1117.4 Elevation I III r ~ I l....-I '" 0"no '" ~ , -~ ~ - - -.---. Cross sectionofthe original design F HALFCROSSSECTION A HALFCROSSSleTtON _B Crosssectionsof the redesign FIGURE3.44.Hartd Bridge.typicaldimensions:c!('yatioll,crosssections ofthe originaldesign.noss sectionsof theredesign(coune,\"orBriceBender,BV:\ISTS). segments together.After the epoxy had hardened, thepermanenttendonswereplacedandstressed. The two segments adjoining the pier segment were supported during erectiononHat jacksonthetop of the outside struts of asteel scaffolding bearing on thepier foundation.Thus,the flat jacks were used foradjustmentof thesegmentstoachieveproper geometrycontrol.Theremainingsegmentswere FIGURE3.45.HanelBridge.methodof castingsegments (courtesyof Brice Bender,BVN/STS. 105Hartel Bridge,Holland FIGURE3.48.HartelBridge,completedstructure. FIGURE3.46.HartelBridge,portalcraneforhandlingsegments. ercctedinthccOT1\'enlionalbalancedGlnlilever met hod.Thc cOl11pletedstruclurcisshowninFigure3.4H. Othcrslructuresusingprccastscgmentalconstrllctionwcresuhscquentl\'designcdandbuiltin the\iclhcrlands.ShowninFigurc3.49isthe Ilridgco\'cr theljsselatDeventcr,where segments inthc2nIt(74111)SP;Il1Swereplacedwitha launching gallln. The overallIcngthof thegantry wasS2()ft(i:')ti111),allowing the legs tobear onthe permanentconcretepiersandimposenoloading onthedeckduring construction.Figure3.50. ... ....--f--..--._- .. ---f .___._____ ._%_n__n_______: ~ ~ [FIGURE3.49.DnenlerBridge,placingsegments \\'iththelaunching gantry. FIGURE3.47.HartelBridge,erectionsequenceanddetailof temporan- pierbracing(courtesyof BriceBender,BVN/STS). 106Precast Balanced Cantilever Girder Bridges 156 m(520 It) 74 mttl Maxbridge span74m(247 ttl FIGURE3.50.DeventerBridge.elevationof gantry. 3.8RioNiteroi Bridge,Brazil The Rio-NiteroiBridge crosses the Guanabara Bay connecting the cities of Rio de Janeiro andNiteroi, thereby avoiding a detour of 37 miles (60 km). This structure alsoclosesthegapinthenew2485mile (4()OOkm)highwaythatinterconnectsnorthand southBrazilandlinksthetownsandcitiesonthe eastern seaboard,Figure3.51.Althoughtheroute taken bythe bridge across the Bay seems somewhat indirect, itwas selected because itavoids very deep waterandisclearoftheflightpathfromSantos DumontAirport. Totalprojectlengthisapproximately10.5miles (17km).of whichabout 5.65miles(9. Ikm)is{)\"er water.The alignment begins at theRio sidewitha 3940ft(1200m)radiuscurve, thenastraightsec: tioll.\\itl1inwhicharelocatedsteelboxgirder na\'igation spans totaling 2872 ft(848m)in length. Thisisfollowedbyanisland,wheretheviaductis interrupted by aroad section of604 ft(184ml. and finally f4C "I' I I It

Ill) Icllglh. - -~ 7.1:,g ' ~ - ...,.. ~ ~- y:;... u:!.I; _ ~ : ~i & : ~-;'" " ~ ...:::,:;:\:;~ ,.,:,....: ;:: 1~scr-...:;;; :... :::; r;"r; .", :::cC,;:!-::-::: :::r.,",::5.,:":_ ::~~ .:...r; 379 380 ConcreteSegmental Arches, Rigid Frames,and TrussBridges '" .. FIGURE8.41. Bridge,temporal):Dywidagbarstayssupportingcantileveredarchrib(courtesYof WillhelmZellner). FIGURE8.43.Neckarburg Bridge. launching of deck girder. FIGURE8.42.:":eckarburgBridge,temporaryDywidagbarstayssupportingcantileveredarchrib(courtes\'of'WillhelmZellner). ThetrapezoidalboxgirdersofthesuperstructuredeckwereconstructedbehindtheSingen abunnentandincrementallylaunched"downhill" towardtheStuttgartabutment,Figure8.43.A close-upof thelaunchingnoseisshowninFigure 8.44.Overall girder width is48.8 ft (14.9 m) witha constantdepthof 7.5it (2.3m).Girdersegments were castinlengths of 65.6 fl(20m).The lift and pushcombinationof hydraulic jacks(seeChapter 7)launchedthegirderinlOin.(0.25m)increments.To maintaindeformationsof thearchand FIGURE8.44.:":eckarburgBridge,dose-up01 launchingnose. piers.resultingfromthehorizontalforcesof the incremental launching operations. within allowable limits,thetopsofthepiersweretiedbacktothe abutmentsandthearchwastiedbackbvthetemporary staysused during the arch construction. An inno\'ationintroducedbvZublinonthisproject wastheuseofbearingsfortheincremental launchingthatremainedaspermanentbearings. Priorprocedure had employed asystem of' temporarybearingsfortheincrementallaunchingand thenatransfertopermanent bearings.s 8.5.3NIESENBACKBRIDGE,AUSTRIA Thisisatwo-ribarchstructureutilizingthefree cantilever constructionmethod for each half-arch, Figure 8.45.The archhas aspan of 394ft(120 m) withariseof123ft(37.5m).Eacharchribisa two-cellboxwithexterior dimensionsof 16.4ft(5 m)wideby8.2ft(2.5m)deep.Theroadway consistsof aconcreteslabandgirdersystemwithan overall width of 57.7ft(17.6 m). Although the longitudinalaxisof thearchisinastraight line,the 381 Arches Built in Cantilet'er Structure during constructionFinalstructure Hllfspylon 17.60 9.90 lSJO FIGURE8.45.:-;iesenback Bridge. ele\3.tion. plan. and cross section. fromreference 7. roadwayitsupportshasacenterlineradius.in plan.ofl092it (332.8m). The curvedroadway structure hasspans of 65.6 ft(20m)over the arch and issupported bytwo 3.3 ft(1.0m)squarepiers,oneoneacharchrib.At the archfoundations,roadway support isby awall pierwithdimensionsof 4.6ft(l.4m)by33.8ft (10.3m).' Eachtwo-cellboxarchribisconstructedr.vthe cantilevermethod.usinga41ft(l2.5m.long traveling form.The formclamps totheprec--::ding constructionsuchthata19,7ft(6.0m)s e ~ ~ . m e n t can be cast.Acrew of sevenmen wasableto':ast a segment onaweeklycycle. Tokeepmomentsinthe cantilevering arcC1toa minimumduringconstruction,thecantik-,ered 382ConcreteSegmental Arches,Rigid Frames,andTrussBridges portionof thearchwassupportedbyaS\'stemof Dvwidagbarstays,Figure8.45.Staystressesare monitoredateachstageof constructiontomaintainanearlymoment-freeconditioninthearch. Dywidagbal'susedinthestayswere1in.(26.5 111m)diameterandwereusedbecausetheywere easilycoupled andcouldbereused.7 8.5.4KIRKBRIDGES,rUGOSLAVIA Thesestructuresconnectthemainlandwiththe Islandof KirkintheAdriaticSea.Inbetweenisa smallrockyolllcroppingknownasSt.Mark,such thatfromthemainland10SI.i\1arkistheworld's longestconcretearchwithaspanof1280ft(390 m) and from SI.Mark to Kirk isthe seventh longest concrete arch with aspan of 800 ft(244 Ill), Figures lAOamIH.4G. Becausethedistallcebetweentheshoresof the mainland andSt.Mark is1509 ft (460 m), the arch support ispartially foundedinthe sea, Figure 8.17. Thearchreactionof approximately15,400LOllS (14,000mt)isaccoIllmodatedbytheinclinedpier inthesea,whichtakes9900tons(9000mt)tothe rock,whilethenearlyhorizontalboxstructure :.--+ I.co +--1 ILW above sealeveltakes the other reaction component of 6600tons(6000mt). Asystemof temporarystays was usedto s.upport thearchasitwasprogressivelycantileveredout from the springings, Figure 8.48. These temporary stays were used as the top chord and diagonals of a temporaryvariable-depthPratttrussduringconstruction,Figures 8.48 and8.49.The archrib consistsof athree-cellrectangularprecast box,which wascastinsegmentlengthsof16.4ft(5m)and assembledwith,Sl'ptember26 to28,1966,London. 3.W.Podolny,jr.,andJ.F.Fleming,"HistoricalDevelopmentof Cable-StavedBridges," journaluj the StructuralDivisiun,ASCE,Vol.98,No.ST9,September197::. '4:,W.Podolny,jr., and]. B.Scalzi,"Constructionand DesignofCable-StayedBridges,"johnWiley& Sons,Inc.,:--JewYork,1976. 5. S.Troitsky, "Cable-Staved Bridges-Theory and Design,"CrosbyLockwoodStaples,London,1977. 6.F.Leonhardt,"LatestDevelopmentsofCableStayedBridgesforLongSpans,"Saetrykaf Bygoningsstatiskeivfeddelelser,Vol.45,No.4,1974 Denmark). 7.'E. Torroja,Philosophyof Structures,Englishversion byJ.].Polivkaand!filosPolivka,V niversityof CaliforniaPress,Berkelev andLosAngeles,1958. 8.H.M.Hadley,"Tied-CantileverBridge-Pioneer Structure in V.S.," CivilEngineering,ASCE, january 1958. 9.F.Leonhardt andW,Zellner, "Vergleiche zwischen HzmgbruckenundSchragkabelbruckenfurSpannweitentiber600Ill."Intemationnldssociationj(n Bridge and StructuralEngineering,Vol.32,1972. 10.R.Morandi,"SomeTypesof TiedBridgesillPrestressedConcrete,"FirstInternationalSymposium, ConcreteBridgeDesign,ACIPublicationSP::3, Paper23-25,AmericanConcreteInstitute,Detroit, 1969. II. Anon.,TIll"Brid!il'S/JIlnnmgI.rlkp.H{/mmilJl)1/1Vrnezw11l.Wiesbaden,Berlin,Bauverlag(;m1)I-L,

I::.Anon.,"LongestConcrete SpanCantileveredoverToughTerrain,"EnginfenngNPll',\Record,julv15,1971. 13.::\. Gray,"Chaco/CorrientesBridgeinArgentina," JJ unicipal EngillCPrs journal,Pa per:\1).380,Vol.59. Fourth Quarter,1973. 14.H.B.Rothman, andFK.Chang, "Ll)ngest PrecastConcreteBox-GirderBridgeinWesternHemisphere," Civil Engineering,ASCE,March1974. 15.W.Podoiny,jr.."ConcreteCable-StayedBridges," TransportationResearchRecord665,BridgeEngineering,Vol.2, Proceedings,TranspurtatiunResearch BoardConference,September25-27,1978,St.Louis, Mo.,NationalAcademyofSciences,Washington, D.C. 16.H.Schambeck,"TheConstructionoftheMain Bridge-HoechsttotheDesignofthe365mSpan RheinBridgeDusseldorf-Flehe,"Cable-Staved Bridges,StructuralEngineering SeriesNo.4, june 1978,BridgeDivision,FederalHighwayAdministration,Washington,D.C. 17.Anon.,"TielBridge,"Frey'>sinetInternational,STUP Bulletin,March-April1973. IR.A.l'vidGrant,"Pasco-KennewickBridge-The 440ConcreteSegmental Cable-Stayed Bridges LongestCable-StayedBridgein!'\orthAmerica." ~Frl'"),ssinetinternational,STUPBullrtill,May-June, Ch'l}Ellginrrring,ASCE,\'o!.47,:\'0.8,August1975. 1977. 23.Anon., "Morandi-Stde DesignAllowsConstantSus19.ArvidGrant,"IntercityBridge:AConcreteRibbonpendedSpans,"COl/.witingEligilll'l')(l,ondon), on']'theColu!I1biaRiver,Washingtoll,"Cablc ~ 1 a r c h1967. StavedBridges,StructuralEngineeringSeriesNo. 24.H.J.Graham,"DamePointBridge,"Cable-Stayed 4,June1978,BridgeDi\'ision,FederalHighway Bridges,StructuralEngineeringSeriesNo.4, June Administration.\\'ashington.D.C. 1978,BridgeDivision,FederalHighwayAdminis20.C.Lenglet,"BrotonneBridge:LongestPrestressedtration,Washington,D.C. ConcreteCableStayedBridge,"Cable-Stayed 25.Anon., "DamePointBridge,"DesignReport,HowBridges,StructuralEngineeringSeries!'\o.4, June ard:\'eedlesTammen&Bergendoff,;'\ovember 1978,BridgeDivision,FederalHighwa\'Adminis1976. tration,\\'ashington,D.C. 26.T.Y.Lin, Y.C.Yang,H.K.Lu, and C.M.Redfield, 21.Anon., "Cable-StavedBridge Goesto aRecordwith "DesignofRuck-A-ChuckyBridge,"Cable-Stayed IhbridCirclelDesign."Lligill(,l'Iill{!,.\'('il',I-R('rou/, Bridges,StructuralEngineeringSeriesNo.4. June October28.1976. 1978,BridgeDivision,FecleralHighw;1\AdminisqqAIIOIl.,"TheDanubeCallalBridge(Austria),"tration,Washington,D.C. 10 Segmental Railway Bridges 10.1INTRODUCTION TO PARTICULARASPECTSOF RAILWAY BRIDGES ANDFIELD OF APPLICA TlON 10.2LAVOULTEBRIDGE OVER THE RHONE RIVER, FRANCE 10.3MORAND BRIDGEIN LYONS, FRANCE lOACERGY PONTOISEBRIDGENEAR PARIS, FRANCE 10.5MARNE LAVALLEEAND TORCYBRIDGES FOR THE NEW EXPRESS LINt NEAR PARIS, FRANCE 10.6CLICHYR.-\ILWAYBRIDGEl'iEARPARIS, FRANCE 10.iOLIFANTS RIVER BRIDGE, SOUTH AFRICA 10.1Introduction toParticular Aspects of Railway Bridgesand Field of Application Constructionof segmentalpost-tensionedbridges forrailwaystructllresstartedinFrancein1952 . withabridge!J)(Plrp(?lP FIGURE10.24.Clichy RailwayBridge,maindimensions of segmentalstructure. portionofthedeck,Figure10.27.Maximum weightofprecastwebswas19tons(17mt), whereas segments that included the fullthree-web box(orevenamoreconventionalsingleboxfor the equivalent span length) wouldhave weighed in excess of 66 tons (60 mt),After assembly of precast webswithlongitudinalpost-tensioning,thetwo twin slab sections were poured in place between the websinbalanced cantileveronverysimpletravelers, Web segments were 7.3 ft (2.22 m) long for the constant-depth part of the deck and 4.8 ft (l.48 m) forthe variable-depthpart.In fact,theslabswere cast in place between the three webs in two or three increments of that lengthrespectively(alengthof 451Clichy Railway Bridgenear Paris,France ___.--'"--_____. .2110)------"l!G!:NDE _Ouvroge\bcon\frulre. (a) i, Sl.b.s J . '>-, FIGURE10.26.ClichvRailwavBridge,pierseglllCIIt andca ntilever ducedthroughbrakingorstartingofthetrains overthebridge),tothepiersandfoundations.A single fixedbearing wasprovided over pier P6,the foundationof whichwasdesignedtotransferto FIGURE10.25,ClidnIbih,PADSFORPUSHt (bottomslabduringthefirststage,websandtop slabduringthesecondstage).Thetypicalconstructioncycleallowedcastingahalf-spanevery week-that is,constructingtwospansper month. Thelaunchingoperationpropercalledfora veryefficientsystem,developedandperfected previouslyinGermany,including under eachweb of thebox section: One vertical jack withsliding plate Two coupled horizontal jacks for actual launching, allowingmovementsin3ftincrements Typically,launching of an80 ftsectiontookthree tothree and ahalf hours,despitethe large weight of the concrete superstructure, reaching 9000 tons (8000mt)at the end of construction. Figure10.37showsacompletedstructure,and Figure10.38showsanotheraspectoftheconstructionof thesesevenviaducts. 10.9Segmental Railway BridgesinJapan ManyrailroadbridgeshavebeenbuiltinJapan usingthesegmentalconstructiontechnique.The sketches shown in Figures10.39 through10.42 depicttheelevationandthecrosssectionof thefollowing cast-in-placesegmentalbridges: KyobashigawaBridge NatorigawaBridge APPROACH SPt.NPRECASTYt.RO- (WITHJACK),50DOm50.00430023!10 ....-SITUATIONDURINGFABRICATIONOFSEGMENT7 2(\.5010252070.250025.00 - ....................... SrTUATIONAFTERPUSHINGOFSEGMENT7 GENERALPRINCIPLEOFTHECONSTRUCTIONMETHODBYPUSHING FIGURE10.36.SaoneRiverBridge.typicalconstructionstagesof incrementallaunching. 458Segmental Railway Bridges FIGURE10.37.SaoneRiverBridge,viewof the completedstructure. FIGURE10.38.DigoineBridge,incrementallaunching over highpiers. KisogawaBridge AshidagawaBridge Figure 10.43 shows the Kakogawa Bridge during construction.Thesuperstructureismadeof twin constant-depthboxgirders,one boxgirder carryingonerailwaytrack.Thetotallengthofthe bridge is1640 ft(500m),withtypicalspan length of 180ft(55m).Eachboxis13ft(4m)wide and 11.5ft(.3.50 m)deep.The precast segments were handledbyalaunchinggantryandassembledby longitudinal post-tensioning tendons. The erection usedthebalanced cantilever system. Themost outstandingprestressedconcreterailwaystructure,however,istheAkayagawaarch bridgeshowninFigure10.44.Totallengthis980 ft(298m)andthecenter archspan is410ft (126 m).The13ft(4.00m)deepboxgirdercarrying tworailwaytracksiscontinuedthroughoutbetweenabutmentsandrestsoverthecentergorge onaveryflatarchribthroughtenspandrelcolumns. The respective proportions are such that the deck carries allbending moments andthe arch rib carriesthenormalloadinducedbyitscurvature. Theerectionschemewasuniqueandcalledfor cantilever constructionstarting fromboth sides. Avery strong back stay made up of aprestressed concretememberwithaprestressforceof5300 tons (4800 mt) was installed diagonally between the topof themaintransitionpiersbetweenthearch structure and the approaches on one hand, and the foundationof theadjacentpiersintheapproach structures ontheother hand. Whileerectionprogressed,high-strengthsteel barswereplaceddiagonallybetweenthevertical members,formingatemporarytrussstructure untilthe crown wasreachedfromboth ends.Controlof tensioning of those steelbars wasvery criticalandcomplicated.Finally,allsteelbars andthe twotemporaryback stayswereremovedafter closure of thearchatmidspan. 10.10Special DesignAspectsof Segmental Railway Bridges 10.10.1M.AGNITUDEOFVERTICALLOADS Mostbridgescarrytrackslaidonballastwitha minimum thickness of 10 to14in.(0.25 to 0.35 m). 459Special DesignAspectsof Segmental Railway Bridges HAKATA ELEVATION CROSSSECTION FIGURE10.39.HvobashigawaBridge, Japan. Liveloadingusedindesignofrailwaybridges variesbetweencountries-Cooperloadingfor Anglo-Saxon countries,newUICloading formost European countries-and alsoaccording tothenature of the structure:mass-transitlines are usually designedformuch lighter loadsthannormaltrain lines.Theheaviestloadingsareforarefreight trains. Toexemplifythebasicdiff.erencebetweena highwayandarailwaybridge,Figure10.45comparesatypical150ftspananda36ftwidedeck normallydesignedforthreehighwaylanesof trafficortworailwaytracks.Thetotalsuperimposeddeadandliveloadis3.6timesgreaterfor therailwaybridge.hiaddition,theweightof ballast(representing40%of thetotalload)mustbe consideredasaliveloadtocoverthecaseswhere the ballast isremoved from the deck or hasnot yet beenplaced on anewbridge. /0./0.2HORIZONTAL FORCES Railway bridges have to carry very important horizontalforces,betweenfiveandtentimesthe horizontal forces carried bya highway bridge of similar size.Thestandardcurrentpracticeforlongviaducts istohave afixedbearing on one abutment if the bridge length islessthan1500 ft(450m),and onbothabutmentsandonintermediatespecial bentsif itisgreater.Theorder ofmagnitude of this horizontal force on the abutments carrying the fixedbearingsisoften1000tonsforatwo-track viaduct. The various forces involved are described below: Long-itudinal Forces Braking andaccelerationforces ---460Segmental Railway Bridges TOKYOMORIOKA r------------ -- 524.90m-- Ir 51.9552.0052.00I52.00- 54.50.54.50- 52.00,52.0052.00_5195 T"---r-O..----..-'---....--- 10,.'0 0.' !Jl:Ur[2 I-1- HF9rELEVATION L...2:=====i'.. - - .. iI I]-: J -----j -----1 _-=-5::-9--t--t-....:2:::,:.2::..::5......,.1_-=-2.:.:.,75::...--liI 2. ,56.00I2.45

CROSSSECTION FIGURE10.40.NatorigawaBridge, Japan. Forcesduetoboxgirderdeformations:creep, shrinkage,andtemperaturevariations Loadsinducedbythelengthvariationsoflong weldedrailsunder temperaturevariations Longitudinalcomponent of windforces Brakingandaccelerationforcesareoneseventhofthetotalweightofliveloads,witha ceiling of 285tonsforbraking and53.tonsfor acceleration(Frenchregulations). Forcesduetolongitudinaldeformationsof the boxgirdervarybecauseof creep,shrinkage,and temperaturevariations.Thebearingdisplacementsinducehorizontalloadsbydistortionor friction. Length variations of the long welded rails due to temperaturevariationscreateahorizontalforce paralleltotherail.Thisforcecanbeestimatedat 50tonsper rail(length of railmore than100 meters).For atwo-track bridge it is2x2x50= 200 tons. Longitudinalcomponent of windforcesaredescribedinthe AASHTO specificationsforbridges. Transverse Horizontal ForcesCentrifugal horizontal forcecanbeveryimportantforhigh-speedtrains. Forthe200mphtrainfromParistoLyonsthis force ismore than 400 tonsforsome viaducts1200 ft(380m)longwithtwotracksandradius of curvature of 10,500 ft(3200m),Thelateral accelerationismorethan20%of thatof gravity. Transversewindforceisdescribedinthe AASHTO standards(50Ib/ft2 ). 10.10.3BEARINGS Inordertogaincompletecontrolofthesevery largehorizontalforces,thebearingsarespecially designedtotake care of theverticalloads androtation of the box girder and simultaneously to provideallpossiblehorizontalrestraints(fixedbearing,bearing free lengthwise or crosswise,or both), 461Special DesignAspects of Segmental Railway Bridges m ----1 ---I HAGOn, -=>ELEVATION 76

I-Iii Ico:1, 1'9240I'I 0.u!.''1Ii' 2.00,I 5:30,.2.00 9.30mI CROSSSECTION FIGURE10.11.KisogawaBridge. Japan. These bearings are speciallymanufactured forthis typeofstructure.Figures10.46and10.47.The slidingparts consist of ateflon-coatedplateresting on astainless steel plate, and the restraints are providedbysteelkeys. 10.10.4STRAY CURREVTS For structures carrying electrifiedrailwaysthere is someuncertaintyaboutthelong-termeffectof straycurrentsgeneratednearthepowerlines.In ordertoprecludeelectrolyticcorrosionofreinforcingsteelandprestressingsteel,thefollowing precautions arenowtakeninprestressedconcrete structures: Thedeckiselectricallyisolatedfromtheground, piers,andabutmentsbye1astomericplates. Thereinforcingandprestressingsteelsvstemsof theentiredeckareinterconnectedbymildsteel barstoequalizetheelectricpotential.Thedifferenceof potential withthegroundmaybemeasuredatregularintervals,andapermanentconnectionwiththegroundmaybedecidedonasa result. 10.10.5DURABILITY OFTHESTRUCTURE Becauseverydifficultproblemsoftraintraffic wouldariseduringrepairstothesebridges,their durabilityneedsspecialattention.Thefollowing provisionswereestablishedforthehigh-speed bridgesbetweenParisandLyons: Undertheworstserviceloadstheconcretemust remainunder a140psiminimum compression. Forcontinuousbridges,thedesignshallbe checkedbyweighingthedead-loadverticalforce onthe bearings. The stressing force of thepost-tensioning tendons shallbelessthan80%of theultimatestrengthof thetendons. 462Segmental RailwayBridges ELEVATION HAKAlA ----::.. CROSSSECTION FIGURE10.42.AshidagawaBridge, Japan. FIGURE10.43.KakogawaRailwayBridge,placing precastsegmentswithlaunching gantry. Theultimatestrengthof thestructureshouldbe capableof supportingtheserviceloadsincreased by30%,if30%of thepost-tensioningsteelwere missing. Provisionsshallbemadeforinstallingadditional tendonswhilethestructureisundertraffic.The additionalpost-tensioningforceshallbe15%of thedesignedforceminimum. 10.10.6CONCLL'SlON This reviewof specificdesignproblems of railway bridgesshouldraisenodoubtswhatsoeverabout theadvantagesofprestressedconcreteandsegmentalconstructioninthisfield.Prestressedconcreteisthesafestmaterialknowntodaytoresist indefinitelythelargevariationsofloadssuchas thoseappliedtoarailwaybridge. The problem of fatigue has been covered briefly inChapter4,andtheresultsmentionedthere applyparticularlywelltorailwaybridges.The mainobjectiveinthedesignandconstructionof prestressed concrete bridges should be to minimize andeveneliminate concrete cracking,whichisalwaysasource of weaknessinastructure subject to cyclicloading.. Theuseof theprovisionslaiddowninSection 10.10.5shouldresultinpracticallycrack-free structureswithanexpectedlifefreeofmajor It shallbepossibletoreplace allthebearings.maintenance. (a) Archrib (b) FIGCRE10.44..\k;n;lg;maI{'ast plo:.>ll1 P !lts1'2 l'!'p>iII'PSS tf'IUI-H! mll!lU'13. f2cturp cps.11 I c)

Iii.

Toll .;atp PUSIU\JII (t'utucp

\'7 al \ .'111\1('1\ I FIGURE 11.54. Sl. C10tld Viaducl, precislillg rani IalOtll. (I) I ami

Access ramp. (3) Loadillg pOilll for segmellts. (-1) assembly wile. (5) Segmellt storage. (6) Tral'dillg crane track. (7) :\(old bottom. Presll'essillg Sled stor;lge, (9) rower (Jalle Irack. (10) Reiul()lu'1I1elll asselllbly. (II) COliCrete plallt.

Precast ('1('IIll'llIS.

Prestress (elldon mallufaCiure. (H) Of'fices. (15) (;clleral ,ell ices. (Ifi) '1011 g:lIe pmilioll. (t7). hUlIll' clrri'14 F-II-AL4 F-IIAK3 F-12-AT4 F12-AS4 TOlal LengthLengthLowSteelCost IF!".LowConnete (It )(it )HidSteelBid 7'27 880 6YO 6682965S5,992.155$48.12 220 240 350 368 6001778$3,777,549$50.59$4.111,170 310 222$994.347$44.50$1,053,364 740 744 514 4502448$4,257,771$41.41$4,108,057 726 7261452$2,29S,409$37.69$2,598,938 9175$17,320,231$44.95$17,39S,84 7 Cost/Ft2 , COllcrele $44.39 $55.05 $47.14 $39.96 $42.62 $45.15 Examplesof SomeInteresting Biddings and Costs525 TABLE12.3.LongKeyBridge, Alternatives Substructure Supers t rucw rePrecastPilesDrilledShalts PrecastI!;irders,.\,\SHTO Segllle n tal: Spanbvspan,Vpiers Spanbyspan,verticalpiers Cantilever,\'erticalpiers Firstoption. slabreinforcing Secondoption, barrier curbs AB CD EF GH RIC epoxy coated Pretensioning Cast.-in-placeconventional Precast (never integral) methodwasdiscardedbecauseitwasfelttobe(at the lime)too newfor acceptance inL' .S.practice. It waslaterintroducedontheLinnCoveBridgein :--JorthCarolina.Thebasicdifferenceinthetwo span-by-span alternativesfor theLongKeyBridge isinthepierconfiguration:Vpiersorvertical piers, Asidefromtheconst ructiollalternativesand piert.-pes,thecontractorwasofferedtheoption Oilallsegmemalalternativesoftransverselyreinforcingthetopflange' withepoxy-coated conventionalreinforcingsteelorbytransversely pretensioningwithill.mm)diameter strand.Further, he had the option on all segmental alternatives of either precasting or casting inplace thetrafficbarriers. The contractor alsohad the option of casting the segmentsrightside lipor upside down. Casting the segmentsupsidedownwasintendedtofacilitate transverselypretensiol1ingthetopBange.However,sincenowaterproofmembraneorwearing surfacewasspecified,the top flangesurface of the deckwasrequiredtohaveagroovedor tinedsurfaceforsUdresistance.If thesegmentv.rerecast upside down,then,theformwouldberequiredto producethedesiredtexture.Specificationswere leftopensuchthatstrand orbarprestressingtendonscouldbebid.Allconventionalsteelrell1forcementwasrequiredtobeepoxycoatedinall alternatives. The eightbasicalternativesforthisprojectproducedbidsfromeightcontractors,asindicatedin Table12.4.:--Jotethatthereweresixbidsforthe span-by-spanmethod,oneforthebalancedcantilevermethod,andonefortheprecastpretensionedAASHTOIgirders. Thelowbidinprecastsegmentalwas$2.6millionlessthantheAASHTOI-girderbid.Lowbid wasfor the span-by-span alternativewithprecast V TABLE12.4.LongKeyBridge, Bid Tabulation BidRankA!ternati\'e ChosenRelativeBid D1.0000 2F1.0225 :)F1.0539 -tFI .0911:) :iB1.I 7:11 ()F1.1HH 7F1.2557 HH1.306:) piers and drilled shaft foundations. The contractor elected to precast the segments near the project site andcastthesegmentsrightsideup,usingtransverseprestressinginthetopflange.Heslipformedthecast-in-placebarriersaftersegment erection.Further,he electedtomovethe scaffoldingtrussworkfromspantospanbyusinga barge-mountedcraneasopposedtohavingthe falseworktrussesmOllntedonbarges. Table12.5presents acost analvsis of the lowbid ascomparedwiththeAASHTOpretensionecl1girder alternative." TABLE12.5.Long KeyBridge. Cost Analysis of the LowBid and theAASHTO I-Girder Bid Sp1.0884Steel alternative asper plan 61.1128Steel alternative asper plan 71.1508Redesignconcrete alternative 81.4099Redesignconcrete alternative TABLE12.15.Summary of California's SegmentalPrestressedBridge Experience DateLength!:'I!ax.Cost-HndgeDesignAlterllatiH:' BidBridgeSpall (ft)Work Olll)"ProvidedRemarks 21i2Pine\. alleyI iOO/-I:JOSH.2\\ =S69/1t2A.Camilel'er prestressedCR I PhycontractorreCreekconcrete scgrnenlalI'isedsuperstnldllre denox girderwithsignand cOllstruct;ollSeeither:quence. Savingstoslale, I,PrestressedrockSl9I,OOO, anchorI()()tings" 2.:'v!inedrockshaft foundatioll '1172StanislausS]2,0:'IISI271111(ind,A.Cantilever prestressedSeven contractors bidsteel Riveratprol'.lor future widelling)t:oncrelCsegrnenlalandt\\'ohid concrele\.1>'..1 '(clonesboxgirderseparatedlo\\'sleeland B.Sth'Clllralsteelboxlowconcrete. g-inlcr(J Bothwitheither: I,Prestressedrock anchorfootiugs 2,:'v(illedshaft f'H1mlatiolls