气候变化和结构工程外文翻译.docx
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气候变化和结构工程外文翻译
毕业设计外文资料翻译
题目气候变化和结构工程
Climatechangeandstructuralengineering
51/2（2007）47–50
PéterLenkei
DepartmentofStructuralEngineering,UniversityofPécs,H-7625Boszorkányu.2,Pécs,Hungary
Abstract
Basedonlastyearsexperiencesitisobviousforthemajorityofprofessionalsandforthegeneralpublictoo,thatclimatechangeisarealisticpresentandfuture.
Inthebeginningthispaperdealswiththesignsandperspectivesofclimatechange.Inthesecondparttheconsequencesofclimatechangeonbuildingandcivilengineeringstructuresaretreated.Theemphasisislaidontheeffectoftemperature,windendwatercirculationoftheglobe.Theresearchisdirectedmainlytowardsgettingreliablefuturedataanditsevaluationforpracticaluse.Finallysomeaspectsofstandardizationprocedureandtheproblemofold/existingandnewstructuresaretreated.
Keywords
climatechange·effectsonstructures·meteorologicalactions
Acknowledgement
TheauthorwouldliketoexpresshissinceregratitudetoProfessorJuditBartholyoftheMeteorologicalChairofL.EötvösUniversityforherhelpandunderstanding.AcknowledgementsareduetotheNationalOfficeforResearchandTechnologyDevelopment（NKTH）andtotheHungarianScientificResearchFund（OTKA）foracceptingthistopicforcommonfuturenancing.
1Introduction
Theclimatechange,theglobalwarmingandtheirconsequencesarewellrepresentedinthemedia.Inadditionpeopleexperienceineverydaylifesmallerorbiggersignsofthisprocess.Neverthelessonecanmeetskepticopinions,butthenumberofsuchopinionsaredecreasingduetotheobviousevidences.Theproblemofclimatechangeisverywideandextremelycomplex,involvingeveryfieldsofscience,andeveneverysideofthelifeontheglobe.Itshouldbepointedout,thatthisproblemsinstructuralengineeringareimportant,butinvolvingonlyasmallpartofthegeneralproblem.Accordingtotheopinionoftheauthortheadaptationandmitigationproceduresoftheclimatechangeshouldbeappliedtotheactivityofeachprofession.Todrawtheconsequences,andproposethenecessarystepsinourprofession,instructuralengineeringisthegoalofthispaper.
2Theclimatechange
Theglobalwarmingduetotheincreasedemissionofgreenhousegasesisinvestigatedbymanyofthemeteorologicalinstitutions,offices,bureausandstations.Greatmanyofreportshavebeenpublishedallaroundtheworld.OneofthemostimportantdocumentsistheseriesofAssessmentReportsoftheIntergovernmentalPanelonClimateChange（establishedbytheUN）.Thelastonetitled„ClimateChange2007–ClimateChangeImpacts,AdaptationandVulnerability”（IPCC2007）.ThisReportdeclares„Muchmoreevidencehasaccumulatedoverthelastfiveyearstoindicatethechangesinmanyphysicalandbiologicalsystemslinkedtoanthropogenicwarming.”
TheReportstatesforthefutureMagnitudeofimpactcannowbeestimatedmoresystematicallyforarangeofpossibleincreasesinglobalaveragetemperature.”Aboutthefutureimpactduetothealteredfrequencies,andintensitiesofextremeweather,climateandseelevelevents...”theReportpointedout„Disruptionbyfloodsandhighwind,withdrawalofriskcoverageinvulnerableareasbyprivateinsurers...”wouldbeofgreatimportance.RespondingtotheclimatechangetheReportstressedthenecessityofadaptationandmitigationmeasures.
Theabovedescribedgeneralsituationmakesnecessarytheadaptationandmitigationmeasuresinstructuralengineeringtoo.ForspecifyingourtaskweshouldknowtheperspectivesonhelongtermaboutglobalwarmingintheCarpathianRegion.Inthefollowingsomeregionalaspects,e.g.averagetemperatureincrease（Fig.1）andaverageprecipitationchanges（Fig.2）arehownintheCarpathianRegionelaboratedbytheMeteorologyChairoftheEötvösUniversity,Budapest（Bartholyetal[2]）.Inthesediagramsareshowntheexpectedchangeintheperiodof2071-2100relativeto1961-1990incaseofanadversescenario.Thedatawasdrawnfromresearchresultsof18meteorologicalinstitutionusingregionalclimatechangemodels.
NextyearssomesimilardiagramswillbeelaboratedforaveragewindspeedoftheaboveperiodbytheMeteorologyChairoftheL.EötvösUniversityintheframeofaresearchprojectsponsoredbytheNationalOfficeforResearchandTechnologyDevelopment（NKTH）andtheHungarianScientificResearchFund（OTKA）.
3PossiblefutureimpactsofclimatechangeonstructuresThereareseveralpossibledisadvantageousimpacts（thefollowinglistisnotcomplete）.Impactsoftemperaturechanges
•Droughtareas（longseasonswithoutprecipitation）
•Morefrequentfreezing-thawingcycles（concretetechnology）
•Warmingofoceansurfaces（resultinginhurricanesortyphoons）
•Thawingoficereserves（resultinginrisingofseelevel）Impactsofprecipitationchanges
•Biggerandabruptfloods（higherwaterlevelsinlakesandrivers）
•Changingofgroundwaterlevel（foundationproblems）
•Heavyabruptsnowfalls
•Heavyhails（precipitationintheformoficelumps）Impactsofhigherwindspeed
•Higherwindimpulses
•Windintensityincreaseistimedepended
•DifferentwindprofilesImpactsofdrivingrain（combinationofheavyrainandlargewindspeed）
•Deteriorationofstructuralsurfaces
•DamagetothewatertightnessofdifferentelementsImpactsofsignificantlymorefrequentextremes
•Lowcyclefatigueofstructuralelements
•Accumulationofdamagesinstructures
Thesedrawbacksmakeabsolutelynecessarytheengineeringresponse.Butadaptationandmitigationmeasuresaremadedifficultbythetimedependent（mainlyincreasing）characteroftheseimpacts.Theotherproblemisthelackofreliablefuturedatabaseduetouncertainnatureoftheseimpacts.
4Futureresearchtasks
Oneshouldunderstandthatallthenecessaryresearchtaskscannotbesolvedintheframeofouractuallyfinancedfouryearsresearchandthefactthatanyresearchinthisfieldcannotmadewithoutclosecooperationofmeteorologists.
4.1Thisresearchcannotdisregardthetemperatureandprecipitationchangesintime
•Firstofallthetemperaturechangesintimeareoneofthemainbasesforeveryfurtherstepsininvestigatingtheeffectsofclimatechange
•Theyearlyfrequencyofextremes（minandmax）anddistributionofextremesareincloseconnectionwithtemperaturechanges
•Thenumberoffreezingandmeltingcyclesaredependedontemperatureandpreviousprecipitation.
4.2Themainconcernsofthisresearcharetheproblemsconnectedwithfuturewindactionsandthefuturechangeofthetemperatureandchangeofprecipitation.Problemstobesolvedinthefieldofwindactions
•Thefirstproblemisthetraditionalwindmeasuringmethod.Thisconsistsofmeasuringineachhouroroneandhalfhourtheaveragewindspeedinthelasttenminutes.Naturallythiswouldnotthelargestwindspeedforthemeasuringperiod.
•Inadditionweneednottheaveragewindspeed,butthewindimpulseof3secduration.Thereshouldbecleareduptherelationbetweenthewindspeedandwindimpulse.
•Anotheropenquestionisthefrequencyanddistributionofmaximalwindspeeds.
•Themethodofinterpolationbetween1961-1990and2071-2100averagewindspeedsshouldbeinvestigatedtoo.
•Veryimportantquestionistodeterminetherelationbetweenthewindprofile（thewindspeedchangesinelevation）andthechangingvalueofthewindspeed.
Fig.1.Seasonaltemperaturechange（˚C）intheCarpathianbasinfor2071-
2100basedonEuropeanregionalmodelsimulation（Bartholyetal.）
Dispersionσ=0,3-1,1oC
Fig.2.Seasonalprecipitationchange（%）intheCarpathianbasinfor2071-2100basedonEuropeanregionalmodelsimulation（Bartholyetal.）
Dispersionσ=12-20%
5Standardizationofmeteorologicalactions
Theoccurrenceprobabilityofmeteorologicalactionsindifferentstructuraldesigncodesgenerallyequalto0.02,i.e.50yearsoccurrenceprobabilityofhighest,mostdangerousvalue.Itisobvious,thatinchangingcircumstancesthe50yearsoccurrenceprobabilitywouldbedifferentineachconsecutiveyear.Theotherproblemisthatuptonowthesevalueshavebeendeterminedfromrelevantpastdata.Inthefuturethesevaluesshouldbedeterminedfromuncertainfuturedata（Lenkei2006）.Inadditiontheseuncertaindatashouldbeconnectedfunction-
allywiththemeasuredpastdataandpreviousuncertainvalues.Todealwithlongtermforecasttheintervalsofrevisionshouldbedesignated.Anothersolutioncouldbetheuseoftimedependentformulae.
6Differentdesignprocedureforold/existingandfornewstructures
Atfirstsightitappearsthattheproblemofnewstructuresiseasy:
onejustshouldtakeintoaccountthenewdesigncodessuitabletothechallengesoftheclimatechange.Theywillbealittlemoreexpensive,thatisall.Butdonotforget,thetodaynewstructuresin10-20yearswillbeold,thechangekeepon.Whattodowithold/existingstructures?
Mostprobablethereshouldbemademoreorlesssignificantandconsequentlymoreorlessexpensiveinterventions.Theseinterventionscouldbedifferent,e.g.changeofsomestructuralelement（s）,strengtheningofsomepart（s）ofthestructures,changeofstructuralbehaviorofthewholestructurebyincreasingstaticindeterminacyormakethestructuremorerobust.Itshouldbementioned,thatthebuildings,thecivilengineeringandinfrastructuralobjectsamountsoneofthebiggestpartofnationalwealth.Consequentlyanynecessaryinterventionwouldbeconnectedwithgreatexpenses.
7Conclusions
Thestructuralengineersshouldtakeintoaccountamongotherstheobviousclimatechangeanditsimpactsonstructures.Thetaskisnoteasy:
toworkouttheanswerstot
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