土木工程中基础系统的知识:三个案例研究
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Knowledge-basedsystemsincivilengineering:Threecasestudies
Fa´timaFarinhaa,*,ElianePortelab,CristinaDominguesc,Luı´sSousab
aICIST—InstituteforStructuralEngineering,TerritoryandConstruction,Av.RoviscoPais,1049-001Lisboa,PortugalbLNEC—NationalLaboratoryofCivilEngineering,Av.doBrasil101,1700-066Lisboa,PortugalcIPP—PolytechnicSchoolofPorto,RuaDrA.BernardinodeAlmeida431,4200-072Porto,PortugalReceived26November2003;accepted17March2005Availableonline8September2005
AbstractAlthoughsubstantialadvanceshavebeenachievedinlasttwentyyears,inpracticewearestillfarfromtakingfulladvantageofthepotentialofknowledge-basedsystems(KBS).VeryfewKBShavesurvivedtheirevaluationperiodandonlyonethirdofthosethatwereinitiallyreportedassuccessfularestillinuse.TheprimarypurposeofthepaperistoreportonthreeKBSapplicationsthathavebeendevelopedforresearchpurposesinthefieldofcivilengineering.Themainchallengeunderlyingallthreeprojectshasbeentodevelopcomputersupportsystemsthatwouldinducechangesandimprovementstothewaythatengineerssolvetheireverydayproblems.Agreatdealofefforthasbeenputintoelicitingknowledgeandreasoningstrategiesfromengineeringexpertswiththeaimofbuildingupacomputermodeloftheirexpertiseinordertoassistengineersintheirdecision-makingprocesses.ThepaperclosesbyhighlightingtheprincipalachievementsandthemainissuesconcerningthefuturedevelopmentofKBSforsolvingreallifeproblems.q2005Civil-CompLtdandElsevierLtd.Allrightsreserved.Keywords:Knowledge-basedsystems;Damengineering;Tunnelling;Reinforcedconcretedesign;Safetyassessment;Decision-makingprocess
1.Introduction
Theongoingadvancesininformationandcommunicationtechnologies(ICT)arechangingmanyaspectsofengineeringproblem-solvingaswellasthedecision-makingprocessesofexperts.BothICTitselfandtheexpectationsofendusersareimposingnewapproachestocivilengineeringproblemsthroughtheuseofavarietyofinnovativetools,whicharenowbecomingmorewidelyavailable.Towardstheendofthe1980s,intenseactivityinKBStechnologyledtothedevelopmentofavarietyofsystemsinanumberofengineeringfields.ThispaperreviewsthreeKBSapplicationsthathavebeendevelopedtosolvequitedifferentcivilengineeringproblems.Themainchallengeoftheseapplicationswastoelicitknowledgeandreasoningstrategiesfromengineeringexperts,sothatacomputermodelofsuchexpertisecouldbedevelopedtoassistingengineersinavarietyoftasks.Thefirstapplicationisinthefieldofdamengineering,itsmainpurposebeingtoassistdammanagersinarangeofsafetyassessmenttasks.Thesecondapplicationfocusesonthemainissuesrelatedtosafetycontrolofoldrailwaytunnels,withspecialemphasisonthemaintenanceoftheseundergroundstructures.Thethirdapplicationistosupportstructuraldesignprocesses,namelytheanalysisanddetailingofreinforcedconcrete.TheKBSapplicationsdiscussedhereintegrateawiderangeofknowledgethathasbeenobtainedfromexpertsintheirfieldsandthathasbeendesignedtosupportthedecision-makingprocessesinvolvedinthesafetycontrolofdamsandtunnelsandthedesignofreinforcedconcretestructures.
2.Casestudies
2.1.Damengineeringapplication
2.1.1.IntroductionThebeginningofthelastcenturysawtheemergenceofdamengineeringthroughouttheworld.Manyoftheresultingstructuresarenowover50yearsold,and
specialAdvancesinEngineeringSoftware36(2005)729–739www.elsevier.com/locate/advengsoft
0965-9978/$-seefrontmatterq2005Civil-CompLtdandElsevierLtd.Allrightsreserved.
doi:10.1016/j.advengsoft.2005.03.019*Correspondingauthor.Tel.:C351289800154;fax:C351289823539.E-mailaddress:mfarinha@ualg.pt(F.Farinha).attentionhasbeenpaidtoissuesrelatedtotheageingofsuchstructures.Asoldstructuresrequiresuchattentionfrommanagersandasmorestructuresarebuilteveryday,engineersarefacedwithahugeamountofinformationthatneedstobeprocessedinordertohighlightanyanomaloussituationthatmayendangerthesafetyandserviceabilityofthestructure.Themanagementoflargedamsrequirescomplexcomputingandtheinvolvementofmulti-disciplinaryteamswithspecialisedknowledge.Thisknowledgeisaccumulatedthroughaprocessoflearningtounderstandhowthestructurerespondsbothtothecurrentandexceptionaloccurrences.Materialpropertiesmaychangeduringthecourseofthedam’slife,whichmeansthattheresponsesofthestructuretocertainactionsmaychangefromtimetotime.ThissectionpresentsadiscussiononhowaKBScanhelpengineersintheeverydaytasksofcontrollingdamsafety.
2.1.2.DamsafetyapproachTheuseofstructuralsafetyproceduresareawell-establishedanditisgenerallyacceptedthatsafetynotonlydependsonproperdesignandconstruction,butalsoonmonitoringtheactualbehaviourofthedamduringitsfirstfewyearsofoperationaswellasoverthewholeservicelifeofthestructure.Furthermore,propermonitoringofferstheprospectofobtaininginformationtoenhanceone’sknowl-edgeabouttheactualbehaviourinvolved.It,therefore,alsoofferstheengineertheopportunitytomakerefinementsinanalyticalandexperimentaltechniquesforbetterandsaferdesignsinthefuture.Thecatastrophicfailureofadamduetocausesotherthananextremeeventisinvariablyprecededbyaperiodofprogressivedistresswithinthedamand/oritsfoundations.Damsurveillanceschemaandinstrumentationareinstalledtodetect,andpossiblytoidentify,symptomsofdistressattheearliestpossiblestage.Theautomationofmonitoringsystemsisafairlynewsubjectinthecontextofdamengineeringanditprovidesapossibilityforincreasingdamsafety.Intheprocessofautomation,themostimportantissueisthechoiceofthebestvariableorparametersthatwillactassafetyindicators.Thisincludeschoosingtheideallocationoftheinstrumentsandadequatecontrolintervals,bearinginmindthatthehighcostofautomationveryoftenlimitsthenumberofinstrumentsthatcanbeautomated.Thefirstattempttoimplementanautomaticmonitoringsystem(AMS)onadamdatesbacktothe1970s.Inthoseearlydays,automationwasrestrictedtotheacquisition,transmissionanddisplayofdatainapermanentlymannedoperationroom.ThelaststageofanAMS,knownasthedataprocessingandmanagementsystem(DPS),takesfulladvantageofthecontinuousadvancesinelectronics,communicationandinformationtechnologies.Thispro-videsmanagerswithsupportfortheautomaticidentificationofanomaloussituations(thosethatmayendangerthesafetyofadam)andtoproposecorrectiveactionstoavoidmajorincidentsoraccidents.