土木工程专业英语带翻译Word格式文档下载.docx

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practice.Forexample,becausebridges,aswellasmostcivilengineering

structures,arelargeinsize,andhavequitelownaturalfrequenciesandvibration

levels,atlowamplitudes,thedynamicresponsesofbridgestructureare

substantiallyaffectedbythenonstructuralcomponents,unforeseen

environmentalconditions,andchangesinthesecomponentscaneasilytobe

confusedwithstructuraldamage.Allthesegivethedamageassessmentof

complexstructuressuchasbridgesastillchallengingtaskforbridgeengineers.

Thispaperfirstlypresentsthedefinitionofstructuralhealthmonitoringsystem

anditscomponents.Then,thefocusofthediscussionisplacedonthefollowing

sections:

①thelaboratoryandfieldtestingresearchonthedamage

assessment;

②analyticaldevelopmentsofdamagedetectionmethods,including

（a）signatureanalysisandpatternrecognitionapproaches,（b）modelupdating

andsystemidentificationapproaches,（c）neuralnetworksapproaches;

and③sensorsandtheiroptimumplacements.Thepredominanceand

shortcomingsofeachmethodarecomparedandanalyzed.Recentexamplesof

implementationofstructuralhealthmonitoringanddamageidentificationare

summarizedinthispaper.Thekeyproblemofbridgehealthmonitoringis

damageautomaticdetectionanddiagnosis,anditisthemostdifficultproblem.

Lastly,researchanddevelopmentneedsareaddressed.

1Introduction

Duetoawidevarietyofunforeseenconditionsandcircumstance,itwill

neverbepossibleorpracticaltodesignandbuildastructurethathasazero

percentprobabilityoffailure.Structuralaging,environmentalconditions,and

reuseareexamplesofcircumstancesthatcouldaffectthereliabilityandthelife

专业资料word

ofastructure.Thereareneedsofperiodicinspectionstodetectdeterioration

resultingfromnormaloperationandenvironmentalattackorinspections

followingextremeevents,suchasstrong-motionearthquakesorhurricanes.To

quantifythesesystemperformancemeasuresrequiressomemeanstomonitor

andevaluatetheintegrityofcivilstructureswhileinservice.SincetheAloha

Boeing737accidentthatoccurredonApril28,1988,suchinteresthasfostered

researchintheareasofstructuralhealthmonitoringandnon-destructive

damagedetectioninrecentyears.

AccordingtoHousner,etal.（1997）,structuralhealthmonitoringisdefined

as“theuseofin-situ,non-destructivesensingandanalysisofstructural

characteristics,includingthestructuralresponse,fordetectingchangesthat

mayindicatedamageordegradation”[1].Thisdefinitionalsoidentifiesthe

weakness.WhileresearchershaveattemptedtheintegrationofNDEwith

healthmonitoring,thefocushasbeenondatacollection,notevaluation.What

isneededisanefficientmethodtocollectdatafromastructurein-serviceand

processthedatatoevaluatekeyperformancemeasures,suchasserviceability,

reliability,anddurability.So,thedefinitionbyHousner,etal.（1997）shouldbe

modifiedandthestructuralhealthmonitoringmaybedefinedas“theuse

ofin-situ,nondestructivesensingandanalysisofstructuralcharacteristics,

includingthestructuralresponse,forthepurposeofidentifyingifdamagehas

occurred,determiningthelocationofdamage,estimatingtheseverityof

damageandevaluatingtheconsequencesofdamageonthestructures”（Fig.1）.

Ingeneral,astructuralhealthmonitoringsystemhasthepotentialtoprovide

bothdamagedetectionandconditionassessmentofastructure.

Assessingthestructuralconditionwithoutremovingtheindividualstructural

componentsisknownasnondestructiveevaluation（NDE）ornondestructive

inspection.NDEtechniquesincludethoseinvolvingacoustics,dye

penetrating,eddycurrent,emissionspectroscopy,fiber-opticsensors,

fiber-scope,hardnesstesting,isotope,leaktesting,optics,magneticparticles,

magneticperturbation,X-ray,noisemeasurements,patternrecognition,

pulse-echo,ra-diography,andvisualinspection,etc.Mostofthesetechniques

havebeenusedsuccessfullytodetectlocationofcertain

elements,cracksorwelddefects,corrosion/erosion,andsoon.The

FederalHighwayAdministration（FHWA,USA）wassponsoringalargeprogramof

researchanddevelopmentinnewtechnologiesforthenondestructive

evaluationofhighwaybridges.Oneofthetwomainobjectivesoftheprogram

istodevelopnewtoolsandtechniquestosolvespecificproblems.Theotheris

todeveloptechnologiesforthequantitativeassessmentoftheconditionof