土木外文翻译建筑造价.docx

土木外文翻译建筑造价.docx

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土木外文翻译建筑造价

TheCostofBuildingStructure

1.Introduction

Theartofarchitecturaldesignwascharacterizedasoneofdealingcomprehensivelywithacomplexsetofphysicalandnonphysicaldesigndeterminants.Structuralconsiderationswerecastasimportantphysicaldeterminantsthatshouldbedealtwithinahierarchicalfashioniftheyaretohaveasignificantimpactonspatialorganizationandenvironmentalcontroldesignthinking.

Theeconomicalaspectofbuildingrepresentsanonphysicalstructuralconsiderationthat,infinalanalysis,mustalsobeconsideredimportant.Costconsiderationsareincertainwaysaconstrainttocreativedesign.Butthisneednotbeso.Ifsomethingisknownoftherelationshipbetweenstructuralandconstructivedesignoptionsandtheircostofimplementation,itisreasonabletobelievethatcreativitycanbeenhanced.Thishasbeenconfirmedbytheauthors’observationthatmostenhanced.Thishasbeenconfirmedbytheauthors’observationthatmostcreativedesigninnovationssucceedundercompetitivebiddingandnotbecauseofunusualowneraffluenceasthefewpublicizedcasesofextravagancemightleadonetobelieve.Onecouldevensaythatadesignerwhoistrulycreativewillproducearchitecturalexcellencewithintheconstraintsofeconomy.Especiallytoday,wefindthatthereisaneedtorecognizethateleganceandeconomycanbecomesynonymousconcepts.

Therefore,inthischapterwewillsetforthabriefexplanationoftheparametersofcostanalysisandthemeansbywhichdesignersmayevaluatetheoveralleconomicimplicationsoftheirstructuralandarchitecturaldesignthinking.

Thecostofstructurealonecanbemeasuredrelativetothetotalcostofbuildingconstruction.Or,sincethetotalconstructioncostisbutapartofatotalprojectcost,onecouldincludeadditionalconsiderationforland（10～20percent）,financeandinterest（100～200percent）,taxesandmaintenancecosts（ontheorderof20percent）.Butadiscussionoftheseso-calledarchitecturalcostsisbeyondthescopeofthisbook,andwewillfocusonthecostofconstructiononly.

Ontheaverage,purelystructuralcostsaccountforabout25percentoftotalconstructioncosts,Thisissobecauseithasbeentraditionaltodiscriminatebetweenpurelystructuralandotherso-calledarchitecturalcostsofconstruction.Thus,intraditionwefindthatarchitecturalcostshavebeentakentobethosethatarenotnecessaryforthestructuralstrengthandphysicalintegrityofabuildingdesign.

“Essentialservices”formsathirdconstructioncostcategoryandreferstotheprovisionofmechanicalandelectricalequipmentandotherservicesystems.Ontheaverage,theseservicecostsaccountforsome15to30percentofthetotalconstructioncost,dependingonthetypeofbuilding.Mechanicalandelectricalreferstothecostofprovidingforair-conditioningequipmentandhemeansonairdistributionaswellasotherservices,suchasplumbing,communications,andelectricallightandpower.

Thesalientpointisthatthisbreakdownofcostssuggeststhat,uptonow,anaverageofabout45to60percentofthetotalcostofconstructingatypicaldesignsolutioncouldbeconsideredasarchitectural.Butthispictureisrapidlychanging.Withhighinterestcostsandascarcityofcapital,clientgroupsaredemandingleanerdesigns.Therefore,onemayconcludethattherearetwoapproachesthedesignermaytaketowardsinfluencingtheconstructioncostofbuilding.

Thefirstapproachtocostefficiencyistoconsiderthatwhereverarchitecturalandstructuralsolutionscanbeachievedsimultaneously,apotentialforeconomyisevident.Sincecurrenttrendsindicateareluctancetoallocatelargeportionsofaconstructionbudgettopurelyarchitecturalcosts,thisapproachseemsalogicalnecessity.But,evenwheremoneyisavailable,anyuseofstructuretoplayabasicarchitecturalrolewillallowthenonstructuralbudgettobeappliedtofulfillotherarchitecturalneedsthatmightnormallyhavetobeappliedtofulfillotherarchitecturalneedsthatmightnormallyhavetobecutback.Thesecondapproachachieveseconomythroughanintegrationofserviceandstructuralsubsystemstoroundoutone’sefforttoproduceatotalarchitecturalsolutiontoabuildingdesignproblem.

Thefinalpricingofaprojectbytheconstructororcontractorusuallytakesadifferentform.Thecostsarebrokendowninto

（1）costofmaterialsbroughttothesite,

（2）costoflaborinvolvedineveryphaseoftheconstructionprocess,（3）costofequipmentpurchasedorrentedfortheproject,（4）costofmanagementandoverhead,and（5）profit.Thearchitectorengineerseldomfollowssuchanaccuratepathbutshouldperhapskeepinmindhowtheactualcostofastructureisfinallypricedandmadeup.

Thus,thepercentaveragesstatedaboveareobviouslycrude,buttheycansufficetointroducethenatureofthecostpicture.Thefollowingsectionswilldiscusstherangeoftheseaveragesandthenproceedtoadiscussionofsquarefootagecostsandvolume-basedestimatesforuseinroughapproximationofthecostofbuildingastructuralsystem.

2.PercentageEstimates

Thetypeofbuildingprojectmayindicatetherangeofpercentagesthatcanbeallocatedtostructuralandothercosts.Asmightbeexpected,highlydecorativeorsymbolicbuildingswouldnormallydemandthelowestpercentageofstructuralcostsascomparedtototalconstructioncost.Inthiscasethestructuralcostsmightdropto10～15percentofthetotalbuildingcostbecausemoremoneyisallocatedtotheso-calledarchitecturalcosts.Onceagainthisimpliesthatthesymboliccomponentsareconceivedindependentofbasicstructuralrequirements.However,wherestructureandsymbolismaremore-or-lesssynthesized,aswithachurchorCathedral,thestructuralsystemcostcanbeexpectedtobesomewhathigher,say,15and20percent（ormore）.

Attheotherendofthecostscalearetheverysimpleandnonsymbolicindustrialbuildings,suchaswarehousesandgarages.Inthesecases,thenonstructuralsystems,suchasinteriorpartitionwallsandceilings,aswillasmechanicalsystems,arenormallyminimal,asisdecoration,andthereforethestructuralcostscanaccountfor60to70percent,even80percentofthetotalcostofconstruction.

Buildingssuchasmedium-riseofficeandapartmentbuildings（5～10stories）occupythemedianpositiononacostscaleatabout25percentforstructure.Lowandshort-spanbuildingsforcommerceandhousing,say,ofthreeorfourstoriesandwithspansofsome20or30ftandsimpleerectionrequirements,willyieldstructuralcostsof15～20percentoftotalbuildingcost.

Special-performancebuildings,suchaslaboratoriesandhospitals,representanothercategory.Theycanrequirelongspansandamorethanaverageportionofthetotalcostswillbeallocatedtoservices（i.e.,30～50percent）,withabout20percentgoingforthepurelystructuralcosts.Tallofficebuilding（15storiesormore）and/orlong-spanbuildings（say,50to60ft）canrequireahigherpercentageforstructuralcosts（about30to35percentofthetotalconstructioncosts）,withabout30to40percentallocatedtoservices.

Inmycase,thesepercentagesaretypicalandcanbeconsideredasameasureofaverageefficiencyindesignofbuildings.Forexample,ifalow,short-spanandnonmonumentalbuildingweretobebidat30percentforthestructurealone,onecouldassumethatthestructuraldesignmaybecomparativelyuneconomical.Ontheotherhand,thearchitectshouldbeawareoftheconfusingfactthateconomicalbidsdependonthepracticalabilityofboththedesignerandthecontractortointerpretthedesignandconstructionrequirementssothatalowbidwillensue.Progressinstructuraldesignisoftenlimitedmorebythedesigner’sorcontractor’slackofexperience,imagination,andabsenceofcommunicationthanbytheideaofthedesign.Ifacontractorisuncertain,hewilladdcoststohedgetheriskhewillbetaking.Itisforthisreasonthatboththearchitectandtheengineershouldbewell-versedintheareaofconstructionpotentialsifinnovativedesignsatetobecompetitivelybid.Attheleastthearchitectmustbecapableofworkingcloselywithimaginativestructuralengineers,contractorsandevenfabricatorswhereverpossibleevenifthearchitectureisveryordinary.Efficiencyalwaysrequiresknowledgeandaboveallimagination,andtheseareessentialwhendesignsareunfamiliar.

Theforegoingpercentagescanbehelpfulinapproximatingtotalconstructioncostsiftheassumptionismadethatstructuraldesignisatleastofaverage（oftypical）efficiency.Forexample,ifatotalofficebuildingconstructioncostbudgetis﹩5,000,000,and25percentisthe“standard”tobeusedforstructure,aprojectedstructuralsystemshouldcostnomorethan﹩1,250,000.Ifaveryefficientdesignwererealized,say,at80percentofwhatwouldbegivenbythe“average”efficientdesignestimatestatedabovethesavings,（20percent）,wouldthenbe﹩250,000or5percentoftotalconstructioncosts﹩5,000,000.Ifthe﹩5,000,000figureiscommitted,thenthesavingsof﹩250,000couldbeappliedtoexpandthebudgetfor“other”costs.

Allthissuggeststhatcreativeintegrationofstructural（andmechanicalandelectrical）designwiththetotalarchitecturaldesignconceptcanresultineitherareductioninpurelyconstructiondesignconceptcanresultineitherareductioninpurelyconstructioncostsormorearchitectureforthesamecost.Thus,thedegreeofsuccesspossibledependsonknowledge,cleverness,andinsightfulcollaborationofthedesignersandcontractors.

Theabovediscussionisonlymeanttogivethereaderanoverallperspectiveontotalconstructioncosts.Thefollowingsectionswill