2022电力综合英语

PartOneCivilChapter1BuildingEngineeringChapter2BuildingMaterialsChapter3BuildingComponentsChapter4BuildingPartTwoThermalPowerPlantChapter1GeneralStatementChapter2SteamBoilerChapter3SteamTurbineChapter4PowerPlantChemistryPartThreeNewEnergyChapter1HydropowerPlantChapter2NuclearPowerPlantChapter3WindEnergyChapter4SolarEnergyPartFourProjectChapter1CoreConstructionConceptsChapter2ConstructionProjectOrganizationChapter3BiddingofConstructionProjectsPartOneCivilChapter1BuildingTypesofAbuildingiscloselyboundupwithpeople，foritprovidespeoplewiththenecessaryspacetoworkandlivein.Asclassifiedbytheiruse，therearemainlytwotypesofbuildings:industrialbuildingsandcivilbuildings.Industrialbuildingsareusedbyvariousfactoriesorindustrialproductionwhilecivilbuildingsarethosethatareusedbypeoplefordwelling，employment，educationandothersocialactivities.Asclassifiedbytheirstructuraltypes，therearemainlyfourtypesof①Framestructureswhereaframe，orskeleton，holdsuptheweightandothermaterialsareusedtoclosethebuildingup；②Masswallstructureswheresolidmaterialssuchasbrick，concreteandothertypesofmasonryareusedtobuildheavywallsthatholdupthebuilding；③Mixedbearingstructurecomposedofframestructureandbearingwallsupportingalltheweighttogether；④Spacestructureformedbyreinforcedconcreteandsteelsupporttheloads，forexample，trussstructure，cablestructure，shellstructure，etc.ThefollowingfiguresaretheschemesofdifferenttypesofFig.1-1Fabricatedsingle-storeyindustrial1.Column2.Foundation3.Rooftruss4.Roofslab5.Cornercolumn6.Windresistance7.Gablewall8.Windows9.Plinth10.Scatterwater11.Foundationbeam12.Externallongitudinalwall13.Cranebeam14.Ground15.Columnbracing16.RingbeamFig.1-2Acivil1.Foundation2.Step3.Canopy4.Scatterwater5.Plinth6.Window7.Basement8.Floor9.Stairs10.Internallongitudinalwall11.Internaltransversewall12.Partition13.Externalwall14.Drainpipe15.Wateroutlet16.Overhangeaves17.Roof18.Parapet19.DoorFig.1-3Frame1.Slab2.Mainbeam3.FillerFig.1-4Masswall1.Prefabricatedslab2.Bearingwall3.Self-supportingAsclassifiedbytheirmaterialsoftheload-carryingframe，therearemainlyfivetypesofbuildings:woodstructure，masonrystructure，reinforcedconcretestructure，steelstructureandmixedstructure.StructureofConsideringonlytheengineeringessentials，thestructureofabuildingcanbedefinedastheassemblageofthosepartswhichexistforthepurposeofmaintainingshapeandstability.Itsprimarypurposeistoresistanyloadsappliedtothebuildingandtotransmitthosetotheground.LoadTheloadscanbeclassifiedwithrespecttotheireffectonthestructure(staticordynamic)orwithrespecttotheirvariationofintensity.Loadscanalsobeclassifiedwithrespecttosomeparticularaspects.①Classificationofloadswithrespecttothestructuralresponse.Adistinctionismadebetweentwotypesofloadaccordingtotheresponseofthestructure:staticloads，whichareappliedtothestructurewithoutaccelerationsofthestructureorofstructuralelements；dynamicloads，whichcausesignificantaccelerationsofthestructure.②Classificationoftheloadswithrespecttothevariationtimeoftheirintensity.Deadloadsactonthestructureforthewholeofitslifewithnegligiblevariationsofintensity；liveloadsactonthestructurewithinstantaneousvalueswhichcanbenoticeablydifferentfromeachother；exceptionalloadsarethoseloadswhichareveryunlikelytoactonthestructure，suchasthoseduetocollision，explosions，firesandearthquakesinnon-seismicareas.StructuralStructureofbuildingsiscombinedwithvariousstructuralmemberssuchasbeams，columns，floors，wallsandtrusses.Columnsareverticalcompressionmembersofastructuralframeintendedtosupporttheload-carryingbeams.Theytransmitloadsfromtheupperfloorstothelowerlevelsandthentothesoilthroughthefoundations.Wewillconsiderafewtypesofcolumns.Withskeleton-frameconstruction，exteriorwallsneedcarrynoloadotherthantheirownweight，andthereforetheirprincipalfunctionistokeepwindandweatheroutofthebuilding—hencethenamecurtainwall.Withmasswallstructure，exteriorwallsneedcarryverticalandhorizontalload—hencethenamebearingwall.Planetrussiscomposedbyagroupofbarsarrangedinatriangleonaplane.Underthejointedloads，theinternalforcesintrussstructureonlywillbetheaxialstress(tensilestress，orcompressivestress).ConstructionofConstructionengineeringisaspecializedbranchofcivilengineeringconcernedwiththeplanning，execution，andcontrolofconstructionoperationsforvariousprojects.Planningconsistsofschedulingtheworktobedoneandselectingthemostsuitableconstructionmethodsandequipmentfortheproject.Executionrequiresthetimelymobilizationofalldrawings，layouts，andmaterialsonthejobpreventdelaystothework.ControlconsistsofanalyzingprogressandcosttoensurethattheprojectwillbedoneonscheduleandwithintheestimatedConstructionoperationsaregenerallyclassifiedaccordingtospecializedfields.Theseincludepreparationoftheprojectsite，earthmoving，foundationtreatment，constructionofload-carryingframeandelectricalandmechanicalinstallations.However，therelativeimportanceofeachfieldisnotthesameinallcases.Wordsandaxisstress轴向应力bearingwall承重墙canopykænəpɪ/n.雨篷column/'kɒləm/n.柱columnbracing柱间支承compressivestress压应力curtainwall幕墙deadload永久荷载(恒荷载)exteriorwall外墙fillerwall填充墙gablewall山墙internalforceliveload可变荷载(活荷载)longitudinalwall纵向挡板masonry/'meɪsənrɪ/n.砌体planetruss平面桁架plinth/plɪnθ/a.柱基skeleton/'skelɪtən/n.骨架slab/slæb/n.厚板，平板stirrup/'stɜːrəp/箍筋tensilestress拉应力transversewall横切墙Chapter2BuildingMaterialsforbuildingmusthavecertainphysicalpropertiestobestructurallyuseful.Primarily，theymustbeabletocarryaload，orweight，withoutchangingshapepermanently.Whenaloadisappliedtoastructuremember，itwilldeform.Thatis，awirewillstretchorabeamwillbend.However，whentheloadisremoved，thewireandthebeamcomebacktotheoriginalposition.Thismaterialpropertyiscalledelasticity.Ifamaterialwerenotelasticandadeformationwerepresentinthestructureafterremovaloftheload，repeatedloadingandunloadingeventuallywouldincreasethedeformationtothepointwherethestructurewouldbecomeuseless.Allmaterialsusedinarchitecturalstructures，suchasstone，brick，wood，steel，aluminum，reinforcedconcrete，andplastics，behaveelasticallywithinacertaindefinedrangeofloading.Iftheloadingisincreasedabovetherange，twotypesofbehaviorcanoccur:brittleandplastic.Intheformerthematerialwillbreaksuddenly.Inthelatter，thematerialbeginstoflowatacertainload(yieldstrength)，ultimatelyleadingtofracture.Forexample，steelexhibitsplasticbehavior，andstoneisbrittle.Theultimatestrengthofamaterialismeasuredbythestressatwhichfailure(fracture)occurs.Masonryconsistsofnaturalmaterials，suchasstoneormanufacturedproducts，suchasbrickandconcreteblocks.Masonryhasbeenusedsinceancienttimes.MudbrickswereusedinthecityofBabylonforsecularbuildings，andstonewasusedforthegreattemplesoftheNileValley.TheGreatPyramidinEgypt，standing481feet(147meters)high，isthemostspectacularmasonryconstruction.Masonryunitsoriginallywerestackedwithoutusinganybondingagent，butallmodernmasonryconstructionusesacementmortarasabondingmaterial.Modernstructuralmaterialsincludestones，bricksandconcreteblocks.Masonryisessentiallyacompressivematerial，anditcan'twithstandatensileforce，thatis，apull.Theultimatecompressivestrengthofbondedmasonrydependsonthestrengthofthemasonryunitandthemortar.Timberisoneoftheearliestconstructionmaterialsandoneofthefewnaturalmaterialswithgoodtensileproperties.Hundredsofdifferentspeciesofwoodarefoundthroughouttheworld，andeachspeciesexhibitsdifferentphysicalcharacteristics.Onlyafewspeciesareusedstructurallyasframingmembersinbuildingconstruction.Becauseofthecellularnatureofwood，itisstrongeralongthegrainthanacrossthegrain.Woodisparticularlystrongintensionandcompressionparalleltothegrain，andithasgreatbendingstrength.Thesepropertiesmakeitideallysuitedforcolumnsandbeamsinstructures.Woodisnoteffectivelyusedasatensilememberinatrussbecausethetensilestrengthofatrussmemberdependsuponconnectionsbetweenmembers.Itisdifficulttodeviseconnectionswhichdonotdependontheshearortearingstrengthalongthegrain，althoughnumerousmetalconnectorshavebeenproducedtoutilizethetensilestrengthoftimbers.Steelisanoutstandingstructuralmaterial.Ithasahighstrengthonapoundfor-poundbasiswhencomparedtoothermaterials，eventhoughitsvolume-forvolumeweightismorethantentimesthatofwood.Ithasahighelasticmodulus，whichresultsinsmalldeformationsunderload.ItcanbeformedbyrollingintovariousstructuralshapessuchasI-beams，plates，andsheets；italsocanbecastintocomplexshapes；andisalsoproducedintheformofwirestrandsandropesforuseascablesinsuspensionbridgesandsuspendedroofs，aselevatorropes，andaswiresforprestressedconcrete.Steelelementscanbejoinedtogetherbyvariousmeans，suchasbolting，riveting，orwelding.Carbonsteelsaresubjecttocorrosionthroughoxidationandmustbeprotectedfromcontactwiththeatmospherebypaintingthemorembeddingtheminconcrete.Abovetemperatureofabout371°C，steelrapidlylosesitsstrength，andthereforeitmustbecoveredinajacketofafireproofmaterialtoincreaseitsfireAluminumisespeciallyusefulasabuildingmaterialwhenlightweight，strength，andcorrosionresistanceareallimportantfactors.Becausepurealuminumisextremelysoftandductile，alloyingelements，suchasmagnesium，silicon，zinc，andcopper，mustbeaddedtoittoimpartthestrengthrequiredforstructuraluse.Structuralaluminumalloysbehaveelastically.Theyhaveanelasticmodulusonethirdasgreatassteelandthereforedeformthreetimesasmuchassteelunderthesameload.Theunitweightofanaluminumalloyisonethirdthatofsteel，andthereforeanaluminummemberwillbelighterthanasteelmemberofcomparablestrength.Aluminumcanbeformedintoavarietyofshapes，anditcanbeextrudedtoformI-beams，drawntoformwireandrods，androlledtoformfoilandplates.Aluminummemberscanbeputtogetherinthesamewayassteelbyriveting，bolting，and(toalesserextent)bywelding.Apartfromitsuseforframingmembersinbuildingsandprefabricatedhousing，aluminumalsofindsextensiveuseforwindowframesandfortheskinofthebuildingincurtain-wallconstruction.Concreteisamixtureofwater，sandandgravel，andPortlandcement.Crushedstone，manufacturedlightweightstone，andseashellsareoftenusedinlieuofnaturalgravel.Portlandcement，whichisamixtureofmaterialscontainingcalciumandclay，isheatedinakilnandthenpulverized.Portlandcement，whenmixedwithwater，hardensbyaprocesscalledhydration.Inanidealmixture，concreteconsistsofaboutthreefourthssandandgravel(aggregate)byvolumeandonefourthcementpaste.Thephysicalpropertiesofconcretearehighlysensitivetovariationsinthemixtureofthecomponents，soaparticularcombinationoftheseingredientsmustbecustom-designedtoachievespecifiedresultsintermsofstrengthorshrinkage.Whenconcreteispouredintoamoldorform，itcontainsfreewater，notrequiredforhydration，whichevaporates.Astheconcretehardens，itreleasesthisexcesswateroveraperiodoftimeandshrinks.Asaresultofthisshrinkage，finecracksoftendevelop.Inordertominimizetheseshrinkagecracks，concretemustbehardenedbykeepingitmoistforatleast5days.Thestrengthofconcreteincreasesintimebecausethehydrationprocesscontinuesforyears；asapracticalmatter，thestrengthat28daysisconsideredstandard.Concretedeformsunderloadinanelasticmanner.Althoughitselasticmodulusisonetenththatofsteel，similardeformationswillresultsinceitsstrengthisalsoaboutonetenththatofsteel.Concreteisbasicallyacompressivematerialandhasnegligibletensilestrength.ReinforcedReinforcedconcretehassteelbarsthatareplacedinaconcretemembertocarrytensileforces.Thesereinforcedbarshavewrinklesonthesurfacestoensureabondwiththeconcrete.Althoughreinforcedconcretewasdevelopedinmanycountries，itsdiscoveryisusuallyattributedtoJosephMonnier，aFrenchgardener，whousedawirenetworktoreinforceconcretetubesin1868.Thisprocessisworkablebecausesteelandconcreteexpandandcontractequallywhenthetemperaturechanges.Ifthiswerenotthecase，thebondbetweenthesteelandconcretewouldbebrokenbyachangeintemperaturesincethetwomaterialswouldresponddifferently.Reinforcedconcretecanbemoldedintoinnumerableshapes，suchasbeams，columns，slabs，andarches，andisthereforeeasilyadaptedtoaparticularformofPlasticsarerapidlybecomingimportantconstructionmaterialsbecauseofgreatvariety，strength，durability，andlightness.Aplasticisasyntheticmaterialwhichcanbemoldedintoanydesiredshapeandwhichusesanorganicsubstanceasabinder.Organicplasticsaredividedintotwogeneralgroups:thermosettingandthermoplastic.Thethermosettinggroupbecomesrigidthroughachemicalchangethatoccurswhenheatisapplied；onceset，theseplasticscannotberemolded.Thethermoplasticgroupremainssoftathightemperatureandmustbecooledbeforebecomingrigid；thisgroupisnotusedgenerallyasastructuralmaterial.Wordsandaggregate/'æɡrɪɡət/n.alloy/'ælɔɪ/n.bond/bɒnd/n.黏结clay/kleɪ/n.黏土crushkrʌʃ/v.压碎durability/ˌdjʊərə'bɪlətɪ/n.耐久性evaporate/ɪ'væpəreɪt/v.蒸发，挥发finecrack微裂缝grain/ɡreɪn/n.纹理hydrationhaɪ'dreɪʃən/n.水化作用kilnkɪln/n.(用来煅烧或烘干砖等的)窑，炉oxidation/ˌɒksɪ'deɪʃən/n.氧化prestressedconcrete预应力混凝土reinforcedconcrete钢筋混凝土thermosetting/ˌθɜːməʊ'setɪŋ/n.热固性weld/weld/v.焊接Chapter3BuildingMaterialsandstructuralformsarecombinedtomakeupthevariouspartsofabuilding，includingthesoilandfoundations，load-carryingframe，skin，partitions，floors，andstairs，suchasthoseshowninFig.3-1.Thebuildingalsohasmechanicalandelectricalsystems，suchaselevators，heatingandcoolingsystems，andlightingsystems.Thesuperstructureisthepartofabuildingaboveground；andthesubstructureandfoundationsarethepartsofabuildingbelowground.Fig.3-1Componentsofa1.Foundation2.Externalwall3/4.Internalwall5.Floor6.Roof7.Groundfloor8.Door9.Window10.Stair11.Step12.Canopy13.ScatterwaterSoilsandAllbuildingsaresupportedontheground，andthereforethenatureofthesoilbecomesanextremelyimportantconsiderationinthedesignofanybuilding.Thedesignofafoundationdependsonmanysoilfactors，suchasthetypeofsoil，soilstratification，thicknessofsoillayersandtheircompaction，andgroundwaterconditions.Soilsrarelyhaveasinglecomposition；theygenerallyaremixturesinlayersofvaryingthickness.Forevaluation，soilsaregradedaccordingtoparticlesize，whichincreasesfromsilttoclaytosandtograveltorock.Duetoboththecompactionandfloweffects，buildingstendtosettle.Uniformsettlementsarenotsoserious，butunevensettlementscanhavedamagingeffects—thebuildingmaylean，wallsandpartitionsmaycrack，windowsanddoorsmaybecomeinoperative，andintheextreme，abuildingmaycollapse.Becausesuchmovementscanoccurduringandafterconstruction，carefulanalysisofthebehaviorofsoilsunderabuildingisvital.Thegreatvariabilityofsoilshasledtoavarietyofsolutionstotheproblem.Whenthefirmsoilexistsclosetothesurface，thesimplestsolutionistorestcolumnsonasmallslabofconcrete.Whenthesoilissofter，itisnecessarytospreadthecolumnloadoveragreaterarea；inthiscase，acontinuous-slabofconcreteunderthewholebuildingisused.Incaseswhenthesoilnearthesurfaceisunabletosupporttheweightofthebuilding，pilesofsteelorconcretearedrivendowntofirmsoil.Load-carryingUntilthelate19thcentury，theexteriorwallsofabuildingwereusedasbearingwallstosupportthefloors.Thisconstructionisstillusedinframeconstructionforhouses.Bearing-wallconstructionlimitedtheheightofbuildings.Becauseoftheenormouswallthicknessrequired，skeletonconstruction，consistingofsteelbeamsandcolumns，wasfirstusedin1889.Asaconsequenceofskeletonconstruction，theenclosingwallsbecomea“curtainwall”ratherthanasupportingfunction.Masonrywasthecurtainwallmaterialuntilthe1930s，whenlightmetalandglasscurtainwallswereused.Aftertheintroductionofthesteelskeleton，theheightofbuildingscontinuedtoincreaserapidly.Theskinofabuildingconsistsofbothtransparentelements(windows)andopaqueelements(walls).Windowsaretraditionallyglass，althoughplasticsarebeingused.Thewallelements，whichareusedtocoverthestructureandaresupportedbyit，arebuiltofvarietyofmaterials:bricks，precastconcrete，stones，opaqueglass，plastics，steel，andaluminum.Theconstructionofthefloorsinabuildingdependsonthebasicstructuralframethatisused.Insteelskeletonconstruction，floorsareeitherslabsofconcreterestingonsteelbeamsoradeckconsistingofcorrugatedsteelwithaconcretetopping.Inconcreteconstruction，thefloorsareeitherslabsofconcreterestingonconcretebeamsoraseriesofcloselyspacedconcretebeams(ribs)intwodirectionstoppedwithathinconcreteslab.Thekindoffloorsthatisuseddependsonthespanbetweenthesupportingcolumnsorwallsandthefunctionofthespace.WordsandExpressionscompaction/kəm'pækʃən/n.压实deckdek/n.甲板，舱面，桥面，层面partitionpɑː'tɪʃən/n.分开，分割，隔墙，隔板Chapter4BuildingBuildingconstructionisaspecializedbranchofcivilengineeringconcernedwiththeplanning，executionandcontrolofconstructionoperationsforsuchprojectsashighways，buildings，dams，airports，andutilitylines.Planningconsistsofschedulingtheworktobedoneandselectingthemostsuitableconstructionmethodsandequipmentsfortheproject.Executionrequiresthetimelymobilizationofalldrawings，layoutsandmaterialsonthejobtopreventdelaystothework.Controlconsistsofanalyzingprogressandcosttoensurethattheprojectwillbedoneonscheduleandwithintheestimatedcost.PreparationofThisconsistsoftheremovalandclearingofallsurfacestructuresandgrowthfromthesiteoftheproposedstructure.Abulldozerisusedforsmallstructures，andlargerstructuresmustbeThisincludesexcavationandplacementofearthfilling.Excavationfollowspreparationofthesite，andisperformedwhentheexistinggrademustbebroughtdowntoanewelevation.Excavationgenerallystartswiththeseparatestrippingoftheorganictopsoilwhichislaterreusedforlandscapingaroundthenewbuilding.Thisalsopreventscontaminationoftheinorganicmaterialwhichisbelowthetopsoilandwhichmayberequiredforfilling.Excavationmaybedonebyanyofseveralexcavators(seeFig.4-1)，suchasshovels，draglines，clamshells，cranes，andscrapers.Efficientexcavationonlandrequiresadryexcavationarea，becausemanysoilsareunstablewhenwetandcannotsupportexcavatingandhaulingequipment.Dewateringbecomesamajoroperationwhentheexcavationliesbelowthenaturalwatertableandinterceptsthegroundwaterflow.Whenthisoccurs，dewateringandstabilizingofthesoilmaybeaccomplishedbytrenches，whichconductseepagetoasumpfromwhichthewaterispumpedout.Dewateringandstabilizingofthesoilmayinothercasesbeaccomplishedbywellpoints.Somematerials，suchasrocks，cementedgravels，andhardclays，requireblastingtoloosenorfragment.Blastholesaredrilledinthematerial；explosivesarethenplacedintheblastholesanddetonated.Thequantityofexplosivesandtheblast-holespacingaredependentuponthetypeandstructureoftherockandthediameteranddepthoftheblastholes.Fig.4-1SketchmapofseveralAfterplacementoftheearthfill，itisalmostalwayscompactedtopreventsubsequentsettlement.Compactionisgenerallydonewithsheep's-foot，grid，pneumatic-tired，andvibratory-typeroller，whicharetowedbytractorsoverthefillasitisbeingplaced.Hand-held，gasoline-drivenrammersareusedforcompactionclosetostructureswherethereisnoroomforrollerstooperate.FoundationWhensubsurfaceinvestigationrevealsstructuraldefectsinthefoundationareatobeusedforastructure，thefoundationmustbestrengthened.Waterpassages，cavities，fissures，faults，andotherdefectsarefilledandstrengthenedbygrouting.Groutingconsistsofinjectionoffluidmixturesunderpressure.Thefluidssubsequentlysolidifyinthevoidsofthestrata.Mostgroutingisdonewithcementandwatermixtures，butothermixtureingredientsareasphalt，cementandclay，andprecipitatingchemicals.SteelTheconstructionofasteelstructureconsistsoftheassemblyatthesiteofmill-rolledorshop-fabricatedsteelsections.Thesteelsectionsmayconsistofbeams，columns，orsmalltrusseswhicharejoinedtogetherbyriveting，bolting，orwelding.Itismoreeconomicaltoassemblesectionsofthestructureatafabricatingshopratherthaninthefield，butthesizeofpreassembledunitsislimitedbythecapacityoftransportationanderectionequipment.ConcreteConcreteconstruction(seeFig.4-2)consistsofseveraloperations:forming，concreteproduction，placement，andcuring.Formingisrequiredtocontainandsupportthefluidconcretewithinitsdesiredfinaloutlineuntilitsolidifiesandcansupportitself.Theformismadeoftimberorsteelsectionsoracombinationofbothandisheldtogetherduringtheconcreteplacingbyexternalbracesorinternalties.Theformsandtiesaredesignedtowithstandthetemporaryfluidpressureoftheconcrete.Fig.4-2SketchmapofconcreteTheusualpracticeforverticalwallsistoleavetheformsinpositionforatleastonedayaftertheconcreteisplaced.Theyareremovedwhentheconcretehassolidifiedorset.Slip-forming(seeFig.4-3)isamethodwheretheformisconstantinmotion，justaheadoftheleveloffreshconcrete.Theformisliftedupwardbymeansofjackswhicharemountedonverticalrodsembeddedintheconcreteandarespacedalongtheperimeterofthestructure.Slipformsareusedforhighstructuressuchassilos，tanks，orchimneys.Fig.4-3Sketchmapofslip-1.Supportbar2.Elevator3.Hydraulicjack4.Rib5.Ribsupporting6.Framework7.Operation8.Trussoftable9.Railing10.Externaltripod11.Externalscaffoldcradle12.Internalscaffold13.ConcretewallConcretemaybeobtainedfromcommercialbatchplantswhichdeliveritinmixtrucks(seeFig.4-4)ifthejobisclosetosuchaplant，oritmaybeproducedatthejobsite.Concreteproductionatthejobsiterequirestheerectionofamixingplant，andofcementandaggregatereceivingandhandlingplants.Aggregatesaresometimesproducedatornearthejobsite.Thisrequiresopeningaquarryanderectingprocessingequipmentsuchascrushersandscreens.Fig.4-4SketchmapofamixConcreteisplacedbycuttingdirectlyfromthemixtruck，wherepossible，orfrombucketshandledbymeansofcranesorcableways，oritcanbepumpedintoplacebyspecialconcretepumps.Curingofexposedsurfacesisrequiredtopreventevaporationofmixwaterortoreplacemoisturethatdoesevaporate.Theproperbalanceofwaterandcementisrequiredtodevelopfulldesignstrength.WordsandExpressionsas-built/'æz'bilt/建成的，竣工的commissioningtest启用试验，试运行derrick/'derɪk/n.悬臂式起重机gridɡrɪd/n.groutingɡraʊtɪŋ/n.mixtrucks混凝土搅拌车pneumatic-tiedroller气胎碾pre-commissioningtest启用前试验precompression/ˌpriːkəm'preʃən/n.预先压缩prefabrication/ˌpriːfæbrɪ'keɪʃən/n.预先制造sheep'sfootroller羊足碾silo/'saɪləʊ/n.筒仓，竖井slipform动模板，滑模(施工法)sump/sʌmp/n.水坑trench/trentʃ/n.沟渠vibratory-typeroller震动碾SupplementaryReadingReinforcingSteels（钢筋）forComparedwithconcrete，steelisahighstrengthmaterial.Theusefulstrengthofordinaryreinforcingsteelsintensionaswellascompressioni.e.theyieldstrengthisaboutfifteentimesthecompressivestrengthofcommonstructuralconcreteandwelloveronehundredtimesitstensilestrength.Ontheotherhand，steelisahighcostmaterialcomparedwithconcrete.Itfollowsthatthetwomaterialsarebestusedincombinationiftheconcreteismadetoresistthecompressivestressesandthecompressiveforce，longitudinal(纵向的)steelreinforcingbarsarelocatedclosetothetensionfacetoresistthetensionforce，andusuallyadditionalsteelbarsaresodisposedthattheyresisttheinclinedtensionstressesthatarecausedbytheshearforceinthebeams.However，reinforcementisalsousedforresistingcompressiveforceprimarilywhereitisdesiredtoreducethecross-sectionaldimensionsofcompressionmembers，asinthelowerfloorcolumnsofmultistorybuildings.Evenifnosuchnecessityexists，aminimumamountofreinforcementisplacedinallcompressionmemberstosafeguardthemagainsttheeffectsofsmallaccidentalbendingmomentsthatmightcrackandevenfailanunreinforcedmember.Formosteffectivereinforcingactionisessentialthatsteelandconcretedeformtogether，i.e.thattheremustbeasufficientlystrongbondbetweenthetwomaterialstoensurethatnorelativemovementsofthesteelbarsandthesurroundingconcreteoccur.Thisbondisprovidedbytherelativelylargechemicaladhesion(黏结力)whichdevelopsatthesteelconcreteinterfacebythenaturalroughnessofthemillscaleofhot-rolledreinforcingbars(热轧钢筋)，andbythecloselyspacedrib-shapedsurfacedeformationswithwhichreinforcingbarsarefurnishedinordertoprovideahighdegreeofinterlocking(咬合)ofthetwomaterials.Additionalfeatureswhichmakeforthesatisfactoryjointperformanceofsteelandconcretearethefollowing:Thethermalexpansioncoefficients(线膨胀系数)ofthetwomaterials，about6.5X10-6/Kforsteelvs.anaverageof5.5X10-6/Kforconcretearesufficientlyclosetoforestallcrackingandotherundesirableeffectsofdifferentialthermaldeformations.Whilethecorrosionresistanceofbaresteelispoor，theconcretewhichsurroundsthesteelreinforcementprovidesexcellentcorrosionprotection，minimizingcorrosionproblemsandcorrespondingmaintenancecosts.Thefireresistanceofunprotectedsteelisimpairedbyitshighthermalconductivityandbythefactthatitsstrengthdecreasessizablyathightemperatures.Converselythethermalconductivityofconcreteisrelativelylow.Thus，damagecausedbyevenprolongedfireexposureifanyisgenerallylimitedtotheouterlayerofconcreteandamoderateamountofconcretecoverprovidessufficientt