工程成本预算毕业论文外文文献翻译.docx
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工程成本预算毕业论文外文文献翻译.docx
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工程成本预算毕业论文外文文献翻译
外文翻译
Constructionprojects,privateandpublicalike,havealonghistoryofcostescalation.Transportationprojects,whichtypicallyhavelongleadtimesbetweenplanningandconstruction,arehistoricallyunderestimated,asshownthroughareviewofthecostgrowthexperiencedwiththeHollandTunnel.Approximately50%oftheactivelargetransportationprojectsintheUnitedStateshaveoverruntheirinitialbudgets.Alargenumberofstudiesandresearchprojectshaveidentifiedindividualfactorsthatleadtoincreasedprojectcost.Althoughthefactorsidentifiedcaninfluenceprivatelyfundedprojectstheeffectsareparticularlydetrimentaltopubliclyfundedprojects.Thepublicfundsavailableforapoolofprojectsarelimitedandthereisabacklogofcriticalinfrastructureneeds.Therefore,ifanyprojectexceedsitsbudgetotherprojectsaredroppedfromtheprogramorthescopeisreducedtoprovidethefundsnecessarytocoverthecostgrowth.Suchactionsexacerbatethedeteriorationofastate’stransportationinfrastructure.Thisstudyisananthologyandcategorizationofindividualcostincreasefactorsthatwereidentifiedthroughanin-depthliteraturereview.Thiscategorizationof18primaryfactorswhichimpactthecostofalltypesofconstructionprojectswasverifiedbyinterviewswithover20statehighwayagencies.Thesefactorsrepresentdocumentedcausesbehindcostescalationproblems.Engineerswhoaddresstheseescalationfactorswhenassessingfutureprojectcostandwhoseektomitigatetheinfluenceofthesefactorscanimprovetheaccuracyoftheircostestimatesandprogrambudgets
HistoricallylargeconstructionprojectshavebeenplaguedbycostandscheduleoverrunsFlyvbjergetal.2002.Intoomanycases,thefinalprojectcosthasbeenhigherthanthecostestimatespreparedandreleasedduringinitialplanning,preliminaryengineering,finaldesign,orevenatthestartofconstruction“Megaprojectsneedmorestudyupfronttoavoidcostoverruns.”Theramificationsofdifferencesbetweenearlyprojectcostestimatesandbidpricesorthefinalcostofaprojectcanbesignificant.Overthetimespanbetweenprojectinitiationconceptdevelopmentandthecompletionofconstructionmanyfactorsmayinfluencethefinalprojectcosts.Thistimespanisnormallyseveralyearsindurationbutforthehighlycomplexandtechnologicallychallengingprojectsitcaneasilyexceed10years.Organizationsfaceamajorchallengeincontrollingprojectbudgetsoverthetimespanbetweenprojectinitiationandthecompletionofconstruction.Thedevelopmentofcostestimatesthataccuratelyreflectprojectscope,economicconditions,andareattunedtocommunityinterestandthemacroeconomicconditionsprovideabaselinecostthatmanagementcanusetoimpartdisciplineintothedesignprocess.Projectscanbedeliveredonbudgetbutthatrequiresagoodstartingestimate,anawarenessoffactorsthatcancausecostescalation,andprojectmanagementdiscipline.Whendisciplineislacking,significantcostgrowthononeprojectcanrazethelargerprogramofprojectsbecausefundswillnotbeavailableforfutureprojectsthatareprogrammedforconstruction
Ahistoryofpastprojectexperiencescanserveonewellinunderstandingthechallengesofdeliveringaqualityprojectonbudget.Repeatedly,thesameproblemscauseprojectcostescalationandmuchwisdomcanbegainedbystudyingthepast.TheHollandTunnelwas,whenitopenedin1927,thelongestunderwatertunneleverconstructedanditwasalsothefirstmechanicallyventilatedunderwatertunnel.ItsinitialcostestimatewasmadebytherenownedcivilengineerGeorgeWashingtonGoethals.AreviewoftheHollandTunnelprojectservestohighlightthecriticalissuesassociatedwithestimatingthecostsoflargecomplexprojectsandthefactthateventhemostdistinguishedengineershavetroubleassessingcostdriversbeyondthephysicalcharacteristicsofaproject.Manytimesthereisnorecognitionofthecostdriversoperatingoutsidetheproject’sphysicalconfiguration.AjointNewYorkandNewJerseycommissionin1918recommendedatransportationtunnelundertheriver“UrgesnewtunnelundertheHudson.”1918;“AsknationtoshareintunneltoJersey.”1918.Theautomobilewasemergingasthepredominatemeansoftransportationanditwasdecidedthatthistunnelshouldbeforvehiculartraffic.Asaresultthetunnelwouldemploynewventilationtechnologiestopurgetheexhaustgasesproducedbytheinternalcombustionengine.Elevendesignswereconsideredforthetunnel,mostnotably,onebytheengineerrecentlyresponsibleforfinishingthePanamaCanal,GeorgeWashingtonGoethals.Heenvisionedasingle,bileveltunnelwithopposingtrafficoneachlevel.Goethalsmadeaplanningprojectcostestimateof$12millionand3yearsforconstruction.WorldWarIhadconsumedmuchofthenation’ssteelandironproduction,sohisdesignmadeuseofcementblocksasthetunnel’sstructuralshell.Hisdesignwasthefrontrunningplan“Hudsonvehicletube.”buthehadresponsibilitieselsewhereandwasnotnamedchiefengineerfortheproject.CliffordM.Hollandwasnamedtoheadtheprojectalongwithaboardoffiveconsultingengineers“Nameinterstatetunnelengineers.”1919.HollandcametotheprojectwithvastexperienceinconstructingsubwaysandtunnelsinNewYork.Thecostoftheprojectwastakentobe$12million,Goethals’planningestimate.HollandproducedareportinFebruaryof1920basedonhisanalysisoftheGoethals’designoftheproject.Hisfindingswerenotwhathadbeenexpected.Hollandfound
•Goethals’widthof7.47mwouldnotaccommodatethevolumeoftraffic.
•Concreteblockswouldnotwithstandthestructuralloadsexertedonthetunnel.
•TheconstructionmethodsrequiredbyGoethals’designwerecompletelyuntried.
•Theestimatedcostofconstructionwasgrosslylow.
•Theworkcouldnotbecompletedin3years.
TheboardofconsultingengineersgaveunanimoussupportforHolland’sanalysis.Hollandthenpresentedadesignofhisownwhichwassupportedunanimouslybytheconsultingengineers.Holland’sdesign,whichwasamajorscopechange,calledfortwincast-irontubes.OneadvantagewasthatconstructionwouldfollowestablishedmethodsoftunnelconstructionthathadbeenimplementedforrailtunnelsundertheEastRiverandfurtheruptheHudson.Hollandestimatedthecostat$28,669,000“Asks$28,669,000forJerseytube.”1920andconstructiontimeat31/2years.
DebateaboutthetunneldesigncontinuedformorethanayearcreatingdisagreementsbetweentheNewYorkandNewJerseyCommissionsanddelayingthework—aschedulechange.AdisagreementaboutawardingacontractontheNewJerseysidefurtherdelayedthestartofconstructionandaddedoverhalfofamilliondollarsincost.ConstructionstartedontheNewYorksideinOctoberof1920andinlateDecember1921theNewJerseyportionofthetunnelwasbid“WayallclearedforJerseytunnel.”ThemandatedcompletiondatewasDecember31,1926.Theconstructionschedulehadnowgrownto5years.Estimatedprojectcostincreasedmultipletimesthroughouttheearlyyearsofconstructionasaresultofscopecreep,scheduledelays,andinflation.Increasedtrafficforecastnecessitatelargerentrance/exitplazasandacquisitionofmorerightofway“Vehiculartubeisgrowing.”1923.Thenincreasesinmaterialandlaborcostshadaddedanother$6milliontotheprojectinflation.Bythebeginningof1924,reestimatedcostshadbeenincreasedby$14,000,000“Vehiculartunnelcostup$14,000,000.”1924duetofunctionalandaestheticfactorsscopecreep.Moreintricateroadwaydesignsforapproaches,wideningoftheapproachroadways,andarchitecturaltreatmentsincreasedthecostsmorescopecreep.Redesignoftheventilationsystemadded15.24cmtothetunneldiameterand$4,422,000.Hollandalsodecidedtosubstitutecast-steelforcastirontoincreasethestrengthandsafetyfactorsofthetunnelmorescopecreep.Last,theNewJerseyventilationshaftshadtoberedesignedalongwiththeircorrespondingfoundationsatacostof$700,000duetounexpectedsoilconditionsunforeseenconditions.Allofthesechangesincreasedtheestimatetoover$42.5million.Newfundswereappropriatedanditwasbelievedthattheseweresufficienttocompletetheproject,butbyFebruaryof1926,therewasanotherincreaseof$3,200,000“$3,200,000moreaskedfortunnel.”Thecommissionexplainedthatthenewcostswereduetoincreasesinlaborandmaterialcostschallengeincontrollingcost.AtthistimeHollanddiedofheartfailureandhisassistant,MiltonH.Freeman,tookoveraschiefengineeronlytodieofpneumonia4monthslater.OleSingstad,thedesigneroftheventilationsystemthenbecamechiefengineerandbroughttheprojecttocompletion.Havingthreedifferentchiefengineerswithin5monthscreatedconfusionunforeseenevents.InAprilof1924waterrushedintooneofthetunnelsfromaleakforcingworkerstomakeahastyescapemoreunforeseenconditions.Afinalappropriationwasrequestedinearly1927broughtthetotalprojectcostto$48,400,000.OnNovember13of1927thetunnelofficiallyopened“Workontunnelbegan7yearsago.”Methodology
Thecostescalationfactorsthatleadtoprojectcostgrowthhavebeendocumentedthroughalargenumberofstudies.Studieshaveidentifiedfactorsindividuallyorbygroups.Eachfactorpresentsachallengetoanagencyseekingtoproduceaccurateprojectcostestimates.Aspartofalargerstudyseekingtoimprovecostestimatesandmanagementofcostsfromprojectconceptiontobidday,athoroughliteraturereviewwasconductedtoidentifyfactorsthatinfluencecostestimatesAndersonetal.2006.Theliter
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