Unit 16TypesofCostEstimatesText Constructioncostestimatesmaybeviewedfromdifferentperspectivesbecauseofdifferentinstitutionalrequirements.Inspiteofmanytypesofcostestimatesusedatdifferentstagesofaproject，costestimatescanbebestclassifiedintothreemajorcategoriesaccordingtotheirfunctions.Aconstructioncostestimateservesoneofthethreebasicfunctions：design，bidandcontrol.Forestablishingthefinancingofaproject，eitheradesignestimateorabidestimateisused.Designestimates Intheplanninganddesignstagesofaproject，variousdesignestimatesreflecttheprogressofthedesign.Attheveryearlystage，inventmentseastimateisusuallymadebeforethefacilityisdesigned，andthereforemustrelyonthecostdataofsimilarfacilitiesbuiltinthepast.Apreliminaryestimateorconceptualestimateisbasedontheconceptualdesignofthefacilityatthestatewhenthebasictechnologiesforthedesignareknown.Thedetailedestimateordefinitiveestimateismadewhenthescopeofworkisclearlydefinedandthedetaileddesigninprogress，sothattheessentialfeaturesofthefacilityareidentifiable.Theengineer’sestimateisbasedonthecompletedplansandspecificationswhentheyarereadyfortheownertosolicitbidsfromconstructioncontractors.Inpreparingtheseestimates，thedesignprofessionalwillincludeexpectedamountsforcontractors’overheadsandprofits.Text Thecostsassociatedwithafacilitymaybedecomposedintoahierarchyoflevelsthatareappropriateforthepurposeofcostestimation.Thelevelofdetailindecomposingthefacilityintotasksdependsonthetypeofcostestimatetobeprepared.Forconceptualestimates，forexample，thelevelofdetailindefiningtasksisquitecoarse；fordetailedestimates，thelevelofdetailcanbequitefine. Fornewexample，considerthecostestimatesforaproposedbridgeacrossariver.Ascreeningestimateismadeforeachofthepotentialalternatives，suchasatiedarchbridgeoracantilevertrussbridge.Asthebridgetypeisselected，supposethate.g.thetechnologyischosentobeatiedarchbridgeinsteadofsomenewbridgeform，apreliminaryestimateismadeonthebasisofthelayoutoftheselectedbridgeformonthebasisofthepreliminaryorconceptualdesign①.Whenthedetaileddesignhasprogressedtoapointwhentheessentialdetailsareknown，adetailedestimateismadeonthebasisofthewelldefinedscopeoftheproject.Whenthedetailedplansandspecificationsarecompleted，anengineer’sestimatecanbemadeonthebasisofitemsandquantitiesofwork.TextBidestimates Thecontractor’sbidestimatesoftenreflectthedesireofthecontractortosecurethejobaswellastheestimatingtoolsatitsdisposal.Somecontractorshavewellestablishedcostestimatingprocedureswhileothersdonot.Sinceonlythelowestbidderwillbethewinnerofthecontractinmostbiddingcontests，anyeffortdevotedtocostestimatingisalosstothecontractorwhoisnotasuccessfulbidder.Consequently，thecontractormayputintheleastamountofpossibleeffortformakingacostestimateifitbelievesthatitschanceofsuccessisnothigh. Ifageneralcontractorintendstousesubcontractorsintheconstructionofafacility，itmaysolicitpricequotationsforvarioustaskstobesubcontractedtospecialtysubcontractors.Thus，thegeneralsubcontractorwillshifttheburdenofcostestimatingtosubcontractors.Ifallorpartoftheconstructionistobeundertakenbythegeneralcontractor，abidestimatemaybepreparedonthebasisofthequantitytakeoffsfromtheplansprovidedbytheowneroronthebasisoftheconstructionproceduresdevisedbythecontractorforimplementingtheproject②.TextForexample，thecostofafootingofacertaintypeandsizemaybefoundincommercialpublicationsoncostdatawhichcanbeusedtofacilitatecostestimatesfromquantitytakeoffs.However，thecontractormaywanttoassesstheactualcostofconstructionbyconsideringtheactualconstructionprocedurestobeusedandtheassociatedcostsiftheprojectisdeemedtobedifferentfromtypicaldesigns③.Hence，itemssuchaslabor，materialandequipmentneededtoperformvarioustasksmaybeusedasparametersforthecostestimates.Controlestimates Boththeownerandthecontractormustadoptsomebaselineforcostcontrolduringtheconstruction.Fortheowner，abudgetestimatemustbeadoptedearlyenoughforplanninglongtermfinancingofthefacility.Consequently，thedetailedestimateisoftenusedasthebudgetestimatesinceitissufficientdefinitivetoreflecttheprojectscopeandisavailablelongbeforetheengineer’sestimate④.Astheworkprogresses，thebudgetedcostmustberevisedperiodicallytoreflecttheestimatedcosttocompletion.Arevisedestimatedcostisnecessaryeitherbecauseofchangeordersinitiatedbytheownerorduetounexpectedcostoverrunsorsavings.TextForthecontractor，thebidestimateisusuallyregardedasthebudgetestimate，whichwillbeUsedforcontrolpurposesaswellasforplanningconstructionfinancing⑤.Thebudgetedcostshouldalsobeupdatedperiodicallytoreflecttheestimatedcosttocompletionaswellastoinsureadequateliquidityforthecompletionoftheproject.quotationn.報(bào)價(jià)單，估價(jià)單takeofn.估計(jì)量budgetestimate概算budgetedcost預(yù)算成本conceptualadj.概念的identifiableadj.可以確定的solicitvt.懇求hierarchyn.層次，層級(jí)tiedarchbridge系桿拱橋cantilevertrussbridge懸臂桁架橋subcontractorn.轉(zhuǎn)包商，次承包商baseline底線budgetcontrol預(yù)算控制，預(yù)算管理revisevt.修訂，校訂，修正，修改initiatevi.開始，發(fā)動(dòng)，創(chuàng)始o(jì)verrunn.超支buildingproject建筑工程billofquantifies數(shù)量明細(xì)表，工程量清單allocationsofcost工程費(fèi)用分?jǐn)俥stimatedcost預(yù)算價(jià)值（費(fèi)用），估算成本cashflow（公司、政府等的）現(xiàn)金流轉(zhuǎn)breakdown毀掉，停頓，倒塌，中止，分解beappropriatefor對(duì)……適合atone’sdisposal隨某人自由處理，由某人隨意支配NewWordsandPhrasesNotes（1）Asthebridgetypeisselected，supposethate.g.thetechnologyischosentobeatiedarchBridgeinsteadofsomenewbridgeform，apreliminaryestimateismadeonthebasisofthelayoutoftheselectedbridgeformonthebasisofthepreliminaryorconceptualdesign. 一旦橋梁類型確定后，假定選定了系桿拱橋而不是其他新型橋梁，應(yīng)以所選定橋型的設(shè)計(jì)圖紙的初步設(shè)計(jì)或概念設(shè)計(jì)來進(jìn)行設(shè)計(jì)概算。（2）Ifallorpartoftheconstructionistobeundertakenbythegeneralcontractor，abidestimatemaybepreparedonthebasisofthequantitytakeoffsfromtheplansprovidedbytheowneroronthebasisoftheconstructionproceduresdevisedbythecontractorforimplementingtheproject. 如果總承包商承擔(dān)全部或部分建造工作，投標(biāo)報(bào)價(jià)將根據(jù)業(yè)主所提供的圖紙或根據(jù)執(zhí)行合同的承包商設(shè)計(jì)的施工程序來確定。（3）However，thecontractormaywanttoassesstheactualcostofconstructionbyconsideringtheactualconstructionprocedurestobeusedandtheassociatedcostsiftheprojectisdeemedtobedifferentfromtypicaldesigns. 但是，如果認(rèn)為項(xiàng)目不同于典型的設(shè)計(jì)，承包商的實(shí)際建筑成本應(yīng)結(jié)合實(shí)際的施工程序及其相關(guān)的費(fèi)用來評(píng)定。Notes（4）Consequently，thedetailedestimateisoftenusedasthebudgetestimatesinceitissufficientdefinitivetoreflecttheprojectscopeandisavailablelongbeforetheengineer’sestimate. 由于施工圖預(yù)算足以明確反映施工范圍，并且早在施工預(yù)算之前就可以采用，因而，施工圖預(yù)算經(jīng)常用做概算。（5）Forthecontractor，thebidestimateisusuallyregardedasthebudgetestimate，whichwillbeUsedforcontrolpurposesaswellasforplanningconstructionfinancing. 對(duì)于承包商，投標(biāo)報(bào)價(jià)通常被視為預(yù)算費(fèi)用，它將用做費(fèi)用控制基準(zhǔn)以及制訂工程籌資計(jì)劃的依據(jù)。1.對(duì)業(yè)主來說，一項(xiàng)建筑設(shè)施的成本包括初始投資和隨后的運(yùn)行與養(yǎng)護(hù)費(fèi)用。2.設(shè)計(jì)者和施工管理者應(yīng)當(dāng)非常明確的重要一點(diǎn)是，施工建設(shè)費(fèi)用是成本中最主要的一項(xiàng)費(fèi)用，但是其他費(fèi)用也不可忽視。3.在高密度建筑的市區(qū)建設(shè)一個(gè)項(xiàng)目，取得土地的費(fèi)用是一項(xiàng)主要的成本，而對(duì)核電站等這樣的大型項(xiàng)目建設(shè)，融資成本可能與項(xiàng)目的建造成本基本持平。4.站在業(yè)主方的角度看，為了分析項(xiàng)目全壽命周期的成本，對(duì)每個(gè)建設(shè)方案的運(yùn)行和維護(hù)成本進(jìn)行估計(jì)是同樣重要的。5.成本估算是項(xiàng)目管理中最重要的環(huán)節(jié)之一。它在項(xiàng)目建設(shè)的不同階段為項(xiàng)目的成本建立了一條基準(zhǔn)線。6.Acostestimateatagivenstageofprojectdevelopmentrepresentsapredictionprovidedbythecostengineerorestimatoronthebasisofavailabledata.7.costengineeringisdefinedasthatareaofengineeringpracticewhereengineeringjudgmentandexperienceareutilizedintheapplicationofscientificprinciplesandtechniquestotheproblemofco