道桥专业外文文献翻译.docx

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1、DesignofreinforcedconcretebridgesP.JacksonGiordandPartnersTheshortestspanreinforcedconcretedecksarebuiltassolidslabs.Thesemaybesupportedonbearingsalthough,duetodurabilityissueswithexpansionjointsandbearings,itisusuallypreferabletocastthemintegralwithin-situabutmentsorplacethemaspartofprec

2、astboxculverts.Asthespanincreases,theoptimumformofconstructionchangestovoidedslaborbeamandslabthenboxgirderbridges.Openspandrelarchesenablerelativelylongspans,morecommonlybuiltinsteelorprestressedconcrete,tobebuiltefficientlyinreinforcedconcrete.Reinforcedconcreteisalsousedfordeckslabsand

3、substructuresforbridgeswithmainelementsofsteelorprestressedconcrete.Thekeydesigncriteriaandchecksrequiredbycodesarethesameregardlessoftheformofconstruction.Theseareforultimatestrengthinflexure,shearandtorsionandforserviceabilityissuesincludingcrackwidthsandservicestresses.Forelementswiths

4、ignificantliveloadratios,reinforcementfatiguemaysometimesalsohavetobechecked.IntroductionMostmodernsmallbridgesareofreinforcedconcreteconstructionandnearlyallmodernbridgescontainsomeelementsofreinforcedconcrete(RC).Inthischapter,thedesignofreinforcedconcretebridgesuperstructuresisconsider

5、edandsomeaspectsofthedesigncriteriaforreinforcedconcrete,whicharealsorelevanttootherreinforcedconcretesubstructuresandreinforcedconcretepartsofbridgeswithsteelorprestressedmainelements,arereviewed.Somespecificaspectswhicharemostoftenrelevanttodeckslabsinbridgeswithprestressedorsteelbeamsw

6、illbeconsideredinthesectiononbeamandslabbridges.Insitureinforcedconcreteconstructionhasthegreatadvantageofsimplicity;formworkisplaced,reinforcementfixedandconcretepouredandthestructureisthencom-plete.Inmodernpractice,precastbridgeelementsareusuallyprestressed.Forsmallerelements,thisisbeca

7、usepretensioningonlonglinebedsisaconvenientmethodofprovidingthesteel.Forlargerstructures,post-tensioningprovidesthemostconvenientwayoffixingmanageablesizedelementstogether.Theresultisthat,withsomeexceptionswhichwillbediscussed,purelyreinforcedconcretebridgesareusual