土木工程建筑外文翻譯外文文獻英文文獻歐洲橋梁研究

/BridgeresearchinEuropeAbriefoutlineisgivenofthedevelopmentoftheEuropeanUnion,togetherwiththeresearchplatforminEurope.Thespecialcaseofpost-tensionedbridgesintheUKisdiscussed.InordertoillustratethetypeofEuropeanresearchbeingundertaken,anexampleisgivenfromtheUniversityofEdinburghportfolio:relatingtotheidentificationofvoidsinpost-tensionedconcretebridgesusingdigitalimpulseradar.IntroductionThechallengeinanyresearcharenaistoharnessthefindingsofdifferentresearchgroupstoidentifyacoherentmassofdata,whichenablesresearchandpracticetobebetterfocused.AparticularchallengeexistswithrespecttoEuropewherelanguagebarriersareinevitablyverysignificant.TheEuropeanCommunitywasformedinthe1960sbaseduponapoliticalwillwithincontinentalEuropetoavoidtheEuropeancivilwars,whichdevelopedintoWorldWar2from1939to1945.ThestrongpoliticalmotivationformedtheoriginalcommunityofwhichBritainwasnotamember.ManyofthecontinentalcountriessawBritain’sinterestasbeingpurelyeconomic.The1970ssawBritainjoiningwhatwasthentheEuropeanEconomicCommunity(EEC)andthe1990shasseenthewideningofthecommunitytoaEuropeanUnion,EU,withcertainpoliticalgoalstogetherwiththeobjectiveofacommonEuropeancurrency.Notwithstandingthesefinancialandpoliticaldevelopments,civilengineeringandbridgeengineeringinparticularhavefoundgreatdifficultyinforminganykindofcommonthread.IndeedtheeducationalsystemsforUniversitytrainingarequitedifferentbetweenBritainandtheEuropeancontinentalcountries.TheformationoftheEUfundingschemes—e.g.Socrates,BriteEuramandotherprogramshavehelpedsignificantly.TheSocratesschemeisbasedupontheexchangeofstudentsbetweenUniversitiesindifferentmemberstates.TheBriteEuramschemehasinvolvedtechnicalresearchgrantsgiventoconsortiaofacademicsandindustrialpartnerswithinanumberofthestates—aBriteEurambidwouldnormallybeledbyanindustrialist.Intermsofdisseminationofknowledge,twoquitedifferentstrandsappeartohaveemerged.TheUKandtheUSAhaveconcentratedprimarilyupondisseminatingbasicresearchinrefereedjournalpublications:ASCE,ICEandotherjournals.WhereasthecontinentalEuropeanshavefrequentlydisseminatedbasicresearchatconferenceswherethecirculationoftheproceedingsisrestricted.Additionally,languagebarriershaveprovedtobeverydifficulttobreakdown.IncountrieswhereEnglishisastrongsecondlanguagetherehasbeenenthusiasticparticipationininternationalconferencesbasedwithincontinentalEurope—e.g.Germany,Italy,Belgium,TheNetherlandsandSwitzerland.However,countrieswhereEnglishisnotastrongsecondlanguagehavebeenhesitantparticipants}—e.g.France.EuropeanresearchExamplesofresearchrelatingtobridgesinEuropecanbedividedintothreetypesofstructure:MasonryarchbridgesBritainhasthelargeststockofmasonryarchbridges.IncertainregionsoftheUKupto60%oftheroadbridgesarehistoricstonemasonryarchbridgesoriginallyconstructedforhorsedrawntraffic.ThisislesscommoninotherpartsofEuropeasmanyofthesebridgesweredestroyedduringWorldWar2.ConcretebridgesAlargestockofconcretebridgeswasconstructedduringthe1950s,1960sand1970s.Atthetime,thesestructureswereseenasmaintenancefree.Europealsohasalargenumberofpost-tensionedconcretebridgeswithsteeltendonductspreventingradarinspection.ThisisaparticularprobleminFranceandtheUK.SteelbridgesSteelbridgeswentoutoffashionintheUKduetotheirneedformaintenanceasperceivedinthe1960sand1970s.However,theyhavebeenusedforlongspanandrailbridges,andtheyarenowreturningtofashionformotorwaywideningschemesintheUK.ResearchactivityinEuropeItgivesanindicationcertainareasofexpertiseandworkbeingundertakeninEurope,butisbynomeansexhaustive.InordertoillustratethetypeofEuropeanresearchbeingundertaken,anexampleisgivenfromtheUniversityofEdinburghportfolio.Theexamplerelatestotheidentificationofvoidsinpost-tensionedconcretebridges,usingdigitalimpulseradar.Post-tensionedconcreterailbridgeanalysisOveArupandPartnerscarriedoutaninspectionandassessmentofthesuperstructureofa160mlongpost-tensioned,segmentalrailwaybridgeinManchestertodetermineitsload-carryingcapacitypriortoatransferofownership,foruseintheMetrolinklightrailsystem..Particularattentionwaspaidtotheintegrityofitspost-tensionedsteelelements.Physicalinspection,non-destructiveradartestingandotherexploratorymethodswereusedtoinvestigateforpossibleweaknessesinthebridge.SincethesuddencollapseofYnys-y-GwasBridgeinWales,UKin1985,therehasbeenconcernaboutthelong-termintegrityofsegmental,post-tensionedconcretebridgeswhichmaybeproneto‘brittle’failurewithoutwarning.Thecorrosionprotectionofthepost-tensionedsteelcables,wheretheypassthroughjointsbetweenthesegments,hasbeenidentifiedasamajorfactoraffectingthelong-termdurabilityandconsequentstrengthofthistypeofbridge.Theidentificationofvoidsingroutedtendonductsatvulnerablepositionsisrecognizedasanimportantstepinthedetectionofsuchcorrosion.DescriptionofbridgeGeneralarrangementBesseso’th’BarnBridgeisa160mlong,threespan,segmental,post-tensionedconcreterailwaybridgebuiltin1969.Themainspanof90mcrossesoverboththeM62motorwayandA665BurytoPrestwickRoad.Minimumheadroomis5.18mfromtheA665andtheM62isclearedbyapprox12.5m.Thesuperstructureconsistsofacentralhollowtrapezoidalconcreteboxsection6.7mhighand4mwide.Themajorityofthesouthandcentralspansareconstructedusing1.27mlongpre-castconcretetrapezoidalboxunits,post-tensionedtogether.Thisboxsectionsupportstheinsiteconcretetransversecantileverslabsatbottomflangelevel,whichcarrytherailtracksandballast.Thecenterandsouthspansectionsareofpost-tensionedconstruction.Thesepost-tensionedsectionshavefivetypesofpre-stressing:1.Longitudinaltendonsingroutedductswithinthetopandbottomflanges.2.Longitudinalinternaldrapedtendonslocatedalongsidethewebs.Thesearedeflectedatinternaldiaphragmpositionsandareencasedininsiteconcrete.3.Longitudinalmacalloybarsinthetransversecantileverslabsinthecentralspan.4.Verticalmacalloybarsinthe229mmwidewebstoenhanceshearcapacity.5.Transversemacalloybarsthroughthebottomflangetosupportthetransversecantileverslabs.SegmentalconstructionThepre-castsegmentalsystemofconstructionusedforthesouthandcenterspansectionswasanalternativemethodproposedbythecontractor.Currentthinkingsuggeststhatsuchaformofconstructioncanleadto‘brittle’failureoftheentirestructurewithoutwarningduetocorrosionoftendonsacrossaconstructionjoint，Theoriginaldesignconcepthadbeenforinsiteconcreteconstruction.InspectionandassessmentInspectionInspectionworkwasundertakeninanumberofphasesandwaslinkedwiththetestingrequiredforthestructure.Theinitialinspectionsrecordedanumberofvisibleproblemsincluding:Defectivewaterproofingontheexposedsurfaceofthetopflange.Watertrappedintheinternalspaceofthehollowboxwithdepthsupto300mm.Variousdrainageproblemsatjointsandabutments.Longitudinalcrackingoftheexposedsoffitofthecentralspan.Longitudinalcrackingonsidesofthetopflangeofthepre-stressedsections.Widespreadsaplingonsomeinsiteconcretesurfaceswithexposedrustingreinforcement.AssessmentThesubjectofanearlierpaper,theobjectivesoftheassessmentwere:Estimatethepresentload-carryingcapacity.Identifyanystructuraldeficienciesintheoriginaldesign.Determinereasonsforexistingproblemsidentifiedbytheinspection.ConclusiontotheinspectionandassessmentFollowingtheinspectionandtheanalyticalassessmentonemajorelementofdoubtstillexisted.Thisconcernedtheconditionoftheembeddedpre-stressingwires,strands,cablesorbars.Forthepurposeofstructuralanalysistheseelements、hadbeenassumedtobesound.However,duetotheveryhighforcesinvolved,、arisktothestructure,causedbycorrosiontotheseprimaryelements,wasidentified.Theinitialrecommendationswhichcompletedthefirstphaseoftheassessmentwere:1.Carryoutdetailedmaterialtestingtodeterminetheconditionofhiddenstructuralelements,inparticularthegroutedpost-tensionedsteelcables.2.Conductconcretedurabilitytests.3.Undertakerepairstodefectivewaterproofingandsurfacedefectsinconcrete.TestingproceduresNon-destructiveradartestingDuringthefirstphaseinvestigationatajointbetweenpre-castdecksegmentstheobservationofavoidinapost-tensionedcableductgaverisetoseriousconcernaboutcorrosionandtheintegrityofthepre-stress.However,theextentofthisproblemwasextremelydifficulttodetermine.Thebridgecontains93jointswithanaverageof24cablespassingthrougheachjoint,i.e.therewereapprox.2200positionswhereinvestigationscouldbecarriedout.Atypicalsectionthroughsuchajointisthatthe24drapedtendonswithinthespinedidnotgiverisetoconcernbecausethesewereprotectedbyinsiteconcretepouredwithoutjointsafterthecableshadbeenstressed.Asitwasclearlyimpracticaltoconsiderphysicallyexposingalltendon/jointintersections,radarwasusedtoinvestigatealargenumbersoftendonsandhencelocateductvoidswithinamodesttimescale.Itwasfortunatethatthecorrugatedsteelductsaroundthetendonswerediscontinuousthroughthejointswhichallowedtheradartodetectthetendonsandvoids.Theproblem,however,wasstillhighlycomplexduetothehighdensityofothersteelelementswhichcouldinterferewiththeradarsignalsandthefactthattheareaofinterestwasatmost102mmwideandembeddedbetween150mmand800mmdeepinthickconcreteslabs.Trialradarinvestigations.Threecompanieswereinvitedtovisitthebridgeandconductatrialinvestigation.Onecompanydecidednottoproceed.Theremainingtwoweregiven2weekstomobilize,testandreport.Theirresultswerethencomparedwithphysicalexplorations.Tomakethecomparisons,observationholesweredrilledverticallydownwardsintotheductsataselectionof10locationswhichincludedseveralwherevoidswerepredictedandseveralwheretheductswerepredictedtobefullygrouted.A25-mmdiameterholewasrequiredinordertofacilitateuseofthechosenhoroscope.TheresultsfromtheUniversityofEdinburghyieldedanaccuracyofaround60%.Mainradarsurvey,horoscopeverificationofvoids.Havingcompletedaradarsurveyofthetotalstructure,abaroscopicwasthenusedtoinvestigateallpredictedvoidsandinmorethan60%ofcasesthisgaveaclearconfirmationoftheradarfindings.Inseveralothercasessomeevidenceofhoneycombingintheinsitestitchconcreteabovetheductwasfound.

Whenviewingvoidsthroughthebaroscopic,however,itprovedimpossibletodeterminetheiractualsizeorhowfartheyextendedalongthetendonductsalthoughtheyonlyappearedtooccupylessthanthetop25%oftheductdiameter.Mostofthesevoids,infact,weresmallerthanthediameteroftheflexiblebaroscopicbeingused(approximately9mm)andwereseenbetweenthehorizontaltopsurfaceofthegroutandthecurvedupperlimitoftheduct.Inaveryfewcasesthetopsofthepre-stressingstrandswerevisibleabovethegroutbutnosignofanytrappedwaterwasseen.Itwasnotpossible,usingthebaroscopic,toseewhetherthosecableswerecorroded.DigitalradartestingThetestmethodinvolvedexcitingthejointsusingradiofrequencyradarantenna:1GHz,900MHzand500MHz.Thehighestfrequencygivesthehighestresolutionbuthasshallowdepthpenetrationintheconcrete.Thelowestfrequencygivesthegreatestdepthpenetrationbutyieldslowerresolution.ThedatacollectedontheradarsweepswererecordedonaGSSISIRSystem10.Thissysteminvolvesradarpulsingandrecording.Thedatafromtheantennaistransformedfromananaloguesignaltoadigitalsignalusinga16-bitanaloguedigitalconvertergivingaveryhighresolutionforsubsequentdataprocessing.Thedataisdisplayedonsiteonahigh-resolutioncolormonitor.Followingvisualinspectionitisthenstoreddigitallyona2.3-gigabytetapeforsubsequentanalysisandsignalprocessing.Thetapefirstofallrecordsa‘header’notingthedigitalradarsettingstogetherwiththetracenumberpriortorecordingtheactualdata.Whenthedataisplayedback,oneisabletoclearlyidentifyalltherelevantsettings—makingforaccurateandreliabledatareproduction.Atparticularlocationsalongthetraces,thetracewasmarkedusingamarkerswitchontherecordingunitortheantenna.AllthedigitalrecordsweresubsequentlydownloadedattheUniversity’sNDTlaboratoryontoamicro-computer.（Therawdatapriortoprocessingconsumed35megabytesofdigitaldata.）Post-processingwasundertakenusingsophisticatedsignalprocessingsoftware.Techniquesavailablefortheanalysisincludechangingthecolortransformandchangingthescalesfromlineartoaskeweddistributioninordertohighlight、突出certainfeatures.Also,thecolortransformscouldbechangedtohighlightphasechanges.Inadditiontothesecolortransformfacilities,sophisticatedhorizontalandverticalfilteringproceduresareavailable.Usingalargescreenmonitoritispossibletodisplayinsplitscreenstherawdataandthetransformedprocesseddata.Thusoneisabletogetanaccurateindicationoftheprocessingwhichhastakenplace.Thecomputerscreendisplaysthetimedomaincalibrationsofthereflectedsignalsontheverticalaxis.Afurtherfacilityofthesoftwarewastheabilitytodisplaytheindividualradarpulsesastimedomainwiggleplots.Thiswasaparticularlyvaluablefeaturewhenlookingatindividualrecordsinthevicinityofthetendons.InterpretationoffindingsAfullanalysisoffindingsisgivenelsewhere,Essentiallythedigitizedradarplotsweretransformedtocolorlinescansandwheredoublephaseshiftswereidentifiedinthejoints,thenvoidingwasdiagnosed.Conclusions1.AnoutlineofthebridgeresearchplatforminEuropeisgiven.2.TheuseofimpulseradarhascontributedconsiderablytothelevelofconfidenceintheassessmentoftheBesseso’th’BarnRailBridge.3.Theradarinvestigationsrevealedextensivevoidingwithinthepost-tensionedcableducts.However,nosignofcorrosiononthestressingwireshadbeenfoundexceptfortheveryfirstinvestigation.

歐洲橋梁探討歐洲聯(lián)盟共同的探討平臺誕生于歐洲聯(lián)盟。為了說明歐洲的探討方法已經被這種方式所替代，一個典型的案例是后張橋在英國愛丁堡高校進行了探討，對數字脈沖雷達識別后張預應力混凝土橋梁孔隙互補的狀況。引言利用各探討小組的探討結果驗證了大量的相關參數是全部探討領域面臨的挑戰(zhàn)，這是使探討和實踐更有針對性的的結合。此外，在歐洲語言是不能忽視的是一個巨大的障礙，為了避開類低于1939到1945其次次世界大戰(zhàn)一樣的歐洲內戰(zhàn)，60年頭的其次十世紀的歐洲共同體的建立是基于歐盟各個國家這樣共同的目的。它是建立在一個強大的政治動機之上，但英國不是歐盟一員，因此許多歐洲國家視英國的為純粹的經濟利益，直到20世紀70年頭英國加入歐洲共同體進入歐洲經濟共同體。在90年頭，歐洲經濟共同體擴展為歐洲聯(lián)盟，在這個時候，歐洲聯(lián)盟既有共同的政治目標，也有建立一個共同的歐洲貨幣體系的經濟目標。隨著經濟和政治的發(fā)展，土木工程特殊是橋梁工程始終沒有能夠形成統(tǒng)一戰(zhàn)線。這是由于英國和其他歐洲國家不同的高校教化培訓體系，歐洲基金支配，如蘇格拉底支配，英國歐洲支配等。扮演一個獨特的角色來變更這種狀況，蘇格拉底方案是以國內交換生學習為主，而英國的歐洲支配則是給一些國家的學術機構和產業(yè)界的合作伙伴供應探討救濟；這通常是由一個工業(yè)國家領導的。傳播學問，現(xiàn)在似乎已經出現(xiàn)了兩個特殊不同的方式，英國和美國主要集中在將探討結果發(fā)表在相關的期刊，例如ASCE、LCE和其他期刊，和歐洲大陸國家主要集中于重要探討專題會議上展示探討成果，后者在探討成果上發(fā)布具有局限性。此外，語言是很難克服的障礙，在英語是一種強勢語言的國家里，在歐洲內陸國家主動參加各種國際會議，如德國，意大利，比利時，荷蘭和瑞士。然而，英語不是一種強大的語言國家里，在國際會議上不活躍，如法國。歐洲的探討在歐洲，橋梁的探討方向可分為三種類型：1圬工拱橋英國有最大的磚砌拱橋。在英國的某些地區(qū)，多達60%的道路橋梁是石砌石拱橋，這些最初為馬拉交通建立的。這在歐洲其他地方不太常見，因為它們在二戰(zhàn)期間，它們大多數已經破壞了。2混凝土橋在20世紀50年頭、到70年頭的時候，歐洲出現(xiàn)了大量的混凝土結構橋梁，在那時，這一結構被認為是免維護的。歐洲還運用了許多后張法建立的混凝土橋梁，但鐵制錨索套管會影響橋梁雷達監(jiān)測。這個問題只存在于英法兩國。3鋼結構橋在上世紀60年頭和70年頭被認為是對修理的需求，這種橋在英國被冷落了。但它照舊被用于大跨度橋梁和鐵路橋梁，現(xiàn)在，這種橋應用于英國正在進行的公路擴建工程行。歐洲的探討活動一個明確的信息表明，在這一領域的探討工作正在歐洲星期，但它并不意味著這中探討的方法沒有缺陷。為了說明歐洲探討正在進行的類型，愛丁堡高校給出了一個這種資源互補的案例：運用數字化脈沖雷達對后張法建立的混凝土橋梁的孔隙進行檢測。后張法混凝土鐵路橋探討OveArup和他的合作者對曼徹斯特的一座長160M的后張法分段預制施工建立的鐵路橋的上部結構的長期穩(wěn)定性進行了檢測和評估，這種技術已被運用于城市輕軌系統(tǒng)。特殊須要關注的是后張力法施工的橋梁的完整性。物理檢查、非損傷雷達檢測及其它的探討方法均已被用來去調查橋梁中潛在的缺陷。自從1985年2月1日英國威爾士地區(qū)的一座名叫Ynys-y-Gwas橋梁突然坍塌以來。接受后張力法分段預制施工的橋梁在長期穩(wěn)定性方面受到關注。因為這種橋梁可能會毫無預兆地出現(xiàn)脆性斷裂，后張法鋼絞線在預制段搭接部位的防腐工作是影響這種類型橋梁長期穩(wěn)定性的主要因素。對簡潔發(fā)生脆性破壞處錨索套管中的沙漿孔隙的鑒定被認為是防腐檢測中最為重要的步驟之一?？傮w布局Besseso’th’Barn大橋始建于1969年，是一座三跨總長160m的后張法分段預制施工的混凝土鐵路橋。它的主跨跨徑90米，橫跨M62公路和巴利A665公路和Prestwick公路連接，和A665公路最小橋下凈空高度為5.18米，和M62公路的橋下凈空則大約為12.5米。橋梁上部結構由空心梯形混凝土箱梁組成。箱體橫截面高6.7m，寬4m。橋梁南部分引橋和中心主跨徑均接受這種長為1.27M的梯形混凝土箱梁結構，后張法施工。這種箱形構件的作用是支撐用來承受鐵軌和行車荷載的現(xiàn)澆混凝土懸臂梁。大橋中跨和南部引橋跨徑均接受后張法裝配式預制結構，這些后張法預制構件構件包括五種類型的預應力張拉措施。1、緣內部的頂端和底部布置縱向錨索管道，管道內的鋼筋束用沙漿封?。?、分布在橫隔板部位的腹板兩側撓曲鋼筋束，鋼筋束被包袱在現(xiàn)澆混凝土內；3、橋梁跨中懸臂梁內布置縱向鋼絞束；

4、在229mm寬的腹板內側布置用以提高抗剪切實力的豎直鋼絞束；

5、布置穿過冀緣底部用以支撐懸臂梁的橫向鋼絞束。分段施工運用分段預制施工體系是包工單位針對大橋南部和中心跨徑建議的備選方案之一，Currentthinking認為這種施工體系在對穿越構件鉸接點處的鋼筋束沒有足夠的腐蝕措施時可能會導致整個結構的脆性斷裂，最初的設計構思是想接受現(xiàn)澆的混凝土結構。檢測和評估檢測各個階段的檢修工作貫穿在橋梁結構所需的試驗中，初期檢查主要記錄如下的一些明顯的缺陷：1、在翼緣上表面的不合格的防水材料。2、空心箱梁內部300mm深度內雨水的滲透狀況。3、鉸接縫和支座處有關排水裝置各種的問題。4、中心跨徑下端背面暴露出的縱向裂縫。5、翼緣頂部預應力構件旁邊的縱向裂縫。6、現(xiàn)澆混凝土表面大片的剝落部位和暴露在外的生銹的加強筋。評估參照最初的設計構想，評估以下目標項：1、估算現(xiàn)存的承載實力。2、挖掘原始設計資料中在結構上的缺陷部分。3、依據檢測出的問題作出推斷。檢測和評估的結論依據檢測和評估，照舊存