桥梁工程毕业设计外文翻译及原文

KSCEJournalofCivilEngineeringVol.9,No.3/May2005pp.219~224StructuralEngineeringVol.9,No.3/May2005219WindCharacteristicsofExistingLongSpanBridgeBasedonMeasuredDataByByungWanJo*,JongChilPark**,andChangHyunKim***···································································································································································································································AbstractThispaperpresentsthewindcharacteristicsofanexistinglongspanbridgebasedonthemeasuredwinddata.ThewinddataobtainedfromthetwomeasuringstationsontheSeohaebridgeareprocessedandstatisticallyanalyzed.TheWeibulldistributionisusedtomodelthewindspeedonthebridge.TheparametersoftheWeibulldistribution,kandcareestimatedusingtwomethods,theregressionmethodandtheChi-Squaremethod.Toexaminethefitsoftwomethods,theKolmogorov-Smirnovtestisused.Itisfoundthatthetwomethodsgiveagoodfittothedistributionofthemeasuredwindspeeddataonthebridge.ThedominantwinddirectionsontheFCMbridgearenorthwestandeast.Thewindrosediagramshowsthatstrongwindsusuallycomefromthenorthwest.FromtheWeibulldistributionforeachdirection,itcanbeknownthattheparametersofkandcarequitedifferentaccordingtothewinddirection.Keywords:longspanbridge,Weibulldistribution,windcharacteristics,windrosediagram···································································································································································································································1.IntroductionRecently,manylongspancable-supportedbridges,suchastheSeohaebridge(2000),theYoungjongbridge(2000)andtheKwanganbridge(2003),havebeenconstructedinKorea.Theseareequippedindividuallywithintegratedmonitoringsystems.FortheSeohaebridge,manyinstrumentswereplacedintheoptimalsectionsandthebridgeisbeingcontinuouslymonitored.Inthispaper,thewinddatameasuredfromanemometersinstalledontheSeohaebridgeareprocessedandanalyzedstatistically.Extremewindsareoneofthemostimportantfactorsinbridgeengineering.Thus,windcharacteristicscanprovidethedesignerandthebridgemanagerwithinformationontheextremewindsthatmightaffectastructureduringitslifetime.OneoftheprobabilitydistributionsusedbroadlyforwindengineeringistheWeibulldistribution(SimiuandScanlan,1996).Tofindthewindcharacteristicsofthebridge,theWeibulldistributionisapplied.Twomathematicalmodelshavebeenusedtoestimatetheparametersk(shapeparameter)andc(scaleparameter)oftheWeibulldistribution.Thisstudypresentstheapplicabilityoftheassumedmodels,anddiscussesthevariationsofkandcaccordingtoseasonsandwinddirections.2.MethodsforEstimatingParametersofWeibullDistributionImportanteffortshavebeenmadesincethe1970’stoconstructanadequatestatisticalmodelfordescribingthewindspeedfrequencydistribution(Rehmanetal.,1994;Rohatgietal.,1989;StevensandSmulders,1979).TheWeibulldistributionprovidesacloseapproximationtotheprobabilitylawsofmanynaturalphenomena.Ithasbeenusedtorepresentwindspeeddistributionsforapplicationinwindloadstudiessometimes.Inrecentyears,alotofattentionhasbeenfocusedonthismethodforwindenergyapplications,notonlyduetoitsgreaterflexibilityandsimplicity,butalsobecauseitcangiveagoodfittotheexperimentaldata.Thismodeliscommonlyusedforwindengineering.TheWeibullprobabilitydensityfunctionisgivenby(1)wherevisthewindspeed,kisashapeparameter,andcisascaleparameter.Thecorrespondingcumulativedistributionfunctionis(2)whereFrepresentstheprobabilityforthewindspeedvlowerthanacertainwindspeedv0.Hennessey(1977)andJustusetal.(1978)discussedseveralmethodsforestimatingtheparametersoftheWeibulldistribution,suchasthemomentsmethod,theregressionmethod,andtheChi-Squaremethod.Dorvlo(2002)estimatedthewinddistributionsbyapplyingtheabovethreemethodstotheactuallyobtainedwindspeeddata.Inthispaper,twomodelsbyusingtheregressionmethodandtheChi-Squaremethodareadoptedtostudythepossiblestatisticaldistributionsofthewindspeedontheexistingbridge.2.1.RegressionMethodThecumulativedistributionfunction,Eq.(2),canbewrittenasfvkc--©¹§·vc--©¹§·k1–expvc--©¹§·k–=Fvv01v0c----©¹§·k–exp–=*Member,Professor,DepartmentofCivilEngineering,HanyangUniversity,Korea(E-mail:[e-mail])**Member,Ph.D.Candidate,DepartmentofCivilEngineering,HanyangUniversity,andHighway&TransportationTechnologyInstitute,Korea(CorrespondingAuthor,E-mail:[e-mail])***Member,Ph.D.Candidate,DepartmentofCivilEngineering,HanyangUniversity,Korea(E-mail:[e-mail])ByungWanJo,JongChilPark,andChangHyunKim220KSCEJournalofCivilEngineeringfollows:(3)Theparametersintheresultingequationcanbeobtainedusingtheleastsquaresmethod.Ifaandbaretheestimatorsoftheinterceptandslopefromthelinearregressionequation,then,thescaleandshapeparameterestimatorsareb=kandc=exp(a/k).2.2.Chi-SquareMethodWewillletFm(vi)andF(vi)denotetheobserveddistributionobtainedfromthewindspeeddataandtheassumedtheoreticaldistributioninjintervalsrespectively.Then,theparameterskandcareestimatedsuchthatEq.(4)isminimized(Dorvlo,2002).(4)=(minimized)3.MeasurementsandStatisticalAnalysis3.1.Descriptionsof