土木工程专业外文翻译建筑工程.docx

土木工程专业外文翻译建筑工程.docx

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土木工程专业外文翻译建筑工程

ConstructionEngineering

Abstract:

Constructionengineeringisaspecializedbranchofcivilengineeringconcernedwiththeplanning,execution,andcontrolofconstructionoperationsforsuchprojectsashighways,buildings,dams,airports,andutilitylines.Planningconsistsofschedulingtheworktobedoneandselectingthemostsuitableconstructionmethodsandequipmentfortheproject.Executionrequiresthetimelymobilizationofalldrawings,layouts,andmaterialsonthejobtopreventdelaystothework.Controlconsistsofanalyzingprogressandcosttoensurethattheprojectwillbedoneonscheduleandwithintheestimatedcost.

Keywords:

planning,Execution,Control,Preparationofsite,Earthmoving,Foundationtreatment,Steelerection,Concreteconstruction,Asphaltpavingandsoon.

Constructionengineeringisaspecializedbranchofcivilengineeringconcernedwiththeplanning,execution,andcontrolofconstructionoperationsforsuchprojectsashighways,buildings,dams,airports,andutilitylines.

Planningconsistsofschedulingtheworktobedoneandselectingthemostsuitableconstructionmethodsandequipmentfortheproject.Executionrequiresthetimelymobilizationofalldrawings,layouts,andmaterialsonthejobtopreventdelaystothework.Controlconsistsofanalyzingprogressandcosttoensurethattheprojectwillbedoneonscheduleandwithintheestimatedcost.

Planning.Theplanningphasestartswithadetailedstudyofconstructionplansandspecifications.Fromthisstudyalistofallitemsofworkisprepared,andrelateditemsarethengroupedtogetherforlistingonamasterschedule.Asequenceofconstructionandthetimetobeallottedforeachitemisthenindicated.Themethodofoperationandtheequipmenttobeusedfortheindividualworkitemsareselectedtosatisfythescheduleandthecharacteroftheprojectatthelowestpossiblecost.

Theamountoftimeallottedforacertainoperationandtheselectionofmethodsofoperationandequipmentthatisreadilyavailabletothecontractor.Afterthemasterorgeneralconstructionschedulehasbeendrawnup,subsidiarydetailedschedulesorforecastsarepreparedformthemasterschedule.Theseincludeindividualschedulesforprocurementofmaterial,equipment,andlabor,aswellasforecastsofcostandincome.

Execution.Thespeedyexecutionoftheprojectrequirestheprojectrequiresthereadysupplyofallmaterials,equipment,andlaborwhenneeded.Theconstructionengineerisgenerallyresponsibleforinitiatingthepurchaseofmostconstructionmaterialsandexpeditingtheirdeliverytotheproject.Somematerials,suchasstructuralsteelandmechanicalequipment,requirepartialorcompletefabricationbyasupplier.Forthesefabricatedmaterialstheengineermustprepareorcheckallfabricationdrawingsforaccuracyandcaseofassemblyandofteninspectthesupplier’sfabrication.

Otherconstructionengineeringdutiesarethelayoutoftheworkbysurveyingmethods,thepreparationofdetaildrawingstoclarifythedesignengineer’sdrawingsfortheconstructioncrews,andtheinspectionoftheworktoensurethatitcomplieswithplansandspecifications.

Onmostlargeprojectsitisnecessarytodesignandprepareconstructiondrawingsfortemporaryconstructionfacilities,suchasdrainagestructures,accessroads,officeandstoragebuildings,formwork,andcofferdams.Otherproblemsaretheselectionofelectricalandmechanicalequipmentandthedesignofstructuralfeaturesforconcretematerialprocessingandmixingplantsandcompressedair,water,andelectricaldistributionsystems.

Control.Progresscontrolisobtainedbycomparingactualperformanceontheworkagainstthedesiredperformancesetuponthemasterordetailedschedules.Sincedelayononefeatureoftheprojectcouldeasilyaffecttheentirejob,itisoftennecessarytoaddequipmentorcrewstospeedupthework.

Costcontrolisobtainedbycomparingactualunitcostsforindividualworkitemsagainstestimatedorbudgetedunitcosts,whicharesetupatthebeginningofthework.Aunitcostisobtainedbydividingthetotalcostofanoperationbythenumberofunitsinthatoperation.

Typicalunitsarecubicyardsforexcavationorconcreteworkandtonsforstructuralsteel.Theactualunitcostforanyitematanytimeisobtainedbydividingtheaccumulatedcostschargedtothatitembytheaccumulatedunitsofworkperformed.

Individualworkitemcostsareobtainedbyperiodicallydistributingjobcosts,suchaspayrollandinvoicestovariousworkitemaccounts.Payrollandequipmentrentalchargesaredistributedwiththeaidoftimecardspreparedbycrewforemen.Thecardsindicatethetimespentbythejobcrewsandequipmentonthedifferentelementofthework.Theallocationofmaterialcostsisbasedonthequantityofeachtypeofmaterialusedforeachspecificitem.

Whenthecomparisonofactualandestimatedunitcostsindicatesanoverrun;ananalysisismadetopinpointthecause.Iftheoverrunisinequipmentcosts,itmaybethattheequipmenthasinsufficientcapacityorthatitisnotworkingproperly.Iftheoverrunisinlaborcosts,itmaybethatthecrewshavetoomanymen,lackofpropersupervision,orarebeingdelayedforlackofmaterialsorlayout.Insuchcasestimestudiesareinvaluableinanalyzingproductivity.

Constructionoperationsaregenerallyclassifiedaccordingtospecializedfields.Theseincludepreparationoftheprojectsite,earthmoving,foundationtreatment,steelerection,concreteplacement,asphaltpaving,andelectricalandmechanicalinstallations.Proceduresforeachofthesefieldsaregenerally,thesame,evenwhenappliedtodifferentprojects,suchasbuildings,dams,orairports.However,therelativeimportanceofeachfieldisnotthesameinallcases.

Preparationofsite.Thisconsistsoftheremovalandclearingofallsurfacestructuresandgrowthfromthesiteoftheproposedstructure.Abulldozerisusedforsmallstructuresandtrees.Largerstructuresmustbedismantled.

Earthmoving.Thisincludesexcavationandtheplacementofearthfill.Excavationfollowspreparationofthesite,andisperformedwhentheexistinggrademustbebroughtdowntoanewelevation.Excavationgenerallystartswiththeseparatestrippingoftheorganictopsoil,whichislaterreusedforlandscapingaroundthenewstructure.Thisalsopreventscontaminationofthenonorganicmaterialwhichisbelowthetopsoilandwhichmayberequiredforfill.Excavationmaybedonebyanyofseveralexcavators,suchasshovels,draglines,clamshells,cranes,andscrapers.

Efficientexcavationonlandrequiresadryexcavationarea,becausemanysoilsareunstablewhenwetandcannotsupportexcavatingandhaulingequipment.Dewateringbecomesamajoroperationwhentheexcavationliesbelowthenaturalwatertableandinterceptsthegroundwaterflow.Whenthisoccurs,dewateringandstabilizingofthesoilmaybeaccomplishedbytrenches,whichconductseepagetoasumpfromwhichthewaterispumpedout.Dewateringandstabilizingofthesoilmayinothercasesbeaccomplishedbywellpointsandelectroosmosis.

Somematerials,suchasrock,cementedgravels,andhardclays,requireblastingtoloosenorfragmentthematerial.Blastholesaredrilledinthematerial;explosivesarethenplacedintheblastholesanddetonated.Thequantityofexplosivesandtheblast-holespacingaredependentuponthetypeandstructureoftherockandthediameteranddepthoftheblastholes.

Afterplacementoftheearthfill,itisalmostalwayscompactedtopreventsubsequentsettlement.Compactionisgenerallydonewithsheep’s-foot,grid,pneumatic-tired,andvibratory-typerollers,whicharetowedbytractorsoverthefillsitisbeingplaced.Hand-held,gasoline-drivenrammersareusedforcompactionclosetostructureswhereisnoroomforrollerstooperate.

Foundationtreatment.Whensubsurfaceinvestigationrevealsstructuraldefectsinthefoundationareatobeusedforastructure,thefoundationmustbestrengthened.Waterpassages,cavities,fissures,faults,andotherdefectsarefilledandstrengthenedbygrouting.Groutingconsistsofinjectionoffluidmixturesunderpressure.Thefluidssubsequentlysolidifyinthevoidsofthestrata.Mostgroutingisdonewithcementandmixtures,butothermixtureingredientsareasphalt,cementandclay,andprecipitatingchemicals.

Steelerection.Theconstructionofasteelstructureconsistsoftheassemblyatthesiteofmill-rolledorshop-fabricatedsteelsection.Thesteelsectionsmanyconsistofbeams,columns,orsmalltrusseswhicharejoinedtogetherbyriveting,bolting,orwelding.Itismoreeconomicaltoassemblesectionsofthestructureatafabricatingshopratherthaninthefield,butthesizeofpreassembledunitsislimitedbythecapacityoftransportationanderectionequipment.Thecraneisthemostcommontypeoferectionequipment,butwhenastructureistoohighorextensiveinareatobeerectedbyacrane,itisnecessarytoplaceoneormorederricksonthestructuretohandlethesteel.Inhighstructuresthederrickmustbeconstantlydismantledandreerectedtosuccessivelyhigherlevelstoraisethestructure.Forriverbridgesthesteelmaybehandledbycranesonbarges,or,ifthebridgeistoohigh,bytravelingderrickswhichrideonthebridgebeingerected,Cablesforlongsuspensionbridgesareassembledinplacebyspecialequipmentthatpullsthewirefromareel,setupatoneanchorage,acrosstotheoppositeanchorage,repeatingtheoperationuntilthebundleofwiresisoftherequiredsize.

Concreteconstruction.Concreteconstructionconsistsofseveraloperations:

forming,concreteproduction,placement,andcuring.Formi