桥梁设计外文翻译

《桥梁设计外文翻译》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、附录2外文资料翻译原文11.7.4Deflection11.7.4.1DeadLoadandCreepDeflectionGlobalverticaldeflectionsofsegmentalbox-girderbridgesduetotheeffectsofdeadloadandpost-tensioningaswellasthelong-termeffectofcreeparenormallypredictedduringthedesignprocessbytheuseofacomputeranalysisprogram.Thedeflectionsaredependent,toalar

2、geextent,onthemethodofconstructionofthestructure,theageofthesegmentswhenpost-tensioned,andtheageofthestructurewhenotherloadsareapplied.Itcanbeexpected,therefore,thattheactualdeflectionsofthestructurewouldbedifferentfromthatpredictedduringdesignduetochangedassumptions.Thedeflectionsareusuallyrecalc

3、ulatedbythecontractor’sengineer,basedontheactualconstructionsequence.11.7.4.2CamberRequirementsThepermanentdeflectionofthestructureafterallcreepdeflectionshaveoccurred,normally10to15yearsafterconstruction,maybeobjectionablefromtheperspectiveofridingcomfortfortheusersorfortheconfidenceofthegeneralpu

4、blic.Evenifthereisnostructuralproblemwithaspanwithnoticeablesag,itwillnotinspirepublicconfidence.Forthesereasons,acamberwillnormallybecastintothestructuresothatthepermanentdeflectionofthebridgeisnearlyzero.Itmaybepreferabletoignorethecamber,ifitisotherwisenecessarytocastasaginthestructureduringons

5、truction.11.7.4.3GlobalDeflectionDuetoLiveLoadMostdesigncodeshavealimitontheallowableglobaldeflectionofabridgespanduetotheeffectsofliveload.ThepurposeofthislimitistoavoidthenoticeablevibrationfortheuserandminimizetheeffectsofmovingloadiMPact.Whenstructuresareusedbypedestriansaswellasmotorists,thel

6、imitsarefurthertightened.11.7.4.4LocalDeflectionDuetoLiveLoadSimilartothelimitsofglobaldeflectionofbridgespans,therearealsolimitationsonthedeflectionofthelocalelementsofthebox-girdercrosssection.Forexample,theAASHTOSpecificationslimitthedeflectionofcantileverarmsduetoserviceliveloadplusiMPactto¹₃ofth

7、ecantileverlength,exceptwherethereispedestrianuse[1].11.7.5Post-TensioningLayout11.7.5.1ExternalPost-TensioningWhilemostconcretebridgescastonfalseworkorprecastbeambridgeshaveutilizedpost-tensioninginductswhicharefullyencased