土木专业英语英文课程PPT课件

.,1,SpecialEnglishinUrbanUndergroundEngineering(城市地下工程专业英语),LecturedByXuli主讲：李旭SchoolofArchitectureEngineering,ResourceandEnvironmentNanhuaUniversity,.,2,Lesson18BuildingMaterialsP158,课程学习指南：NewwordsanalysisElasticityilstisiti弹性elastic+ity近义词：plasticity(塑性)plastic+ityStiffness(stifnis刚度、硬度)stiff（坚硬的）+ness（n.后缀，表性质、状态）Secular(sekjul世俗的、非宗教的)形似词：secure(安全的)sikjuAbundancebndnsn.丰富、大量abundant（adj.丰富的）+ance(n.后缀)Cabinetwork(细木工，细木家具)kbinitw:k=cabinet（小木屋,内阁）+workCellular（seljul细胞的、多孔的）cell+ular(adj.后缀)Negligibleneglidblneglect+ible(adj.后缀=able)adj.可以忽略的,不予重视的Thermosetting:musetithermo(词根：热)+setting热硬化性的,热固性的Custom-designed自定义设计custom-自定义、习惯、风俗Hydrationhaidreinn.水合作用hydrat(词根：水合)+ion,hydrate,hydratable(可水合的)Pulverize（plvraizv.研磨成粉,粉化、磨成粉pulver(词根：粉)+ize（v.后缀，化）Pulverable(可磨成粉的)，pulverous(满是粉的)Inlieuof=insteadoflieulju:n.场所Impart（imp:t）im(v.前缀，=in)+partvt.给予(指抽象事物),传授,告知,透露,.,3,Lesson18BuildingMaterialsP158,NEWWORDSANDPHRASES1.elasticityilstisitin.弹性，弹力，弹性力学2.stiffnessstifnisn.坚硬,硬度劲度，刚度3.secularsekjuladj.长期的,世俗的，现世的，非宗教的4.templetempln.坦普尔(姓氏)庙，寺，神殿，教堂5.pyramidpirmidn.金字塔,叠罗汉金字塔,四面体(角锥、棱椎),6.stackstkn.堆,一堆,堆栈v.堆叠，成堆，整齐地堆起7.slatesleitn.板岩,石板,石片,石板瓦，v.铺石板岩adj.含板岩的8.timbertimbn.木材，木料，原木9.coniferkunifn.植松类,针叶树，松柏类植物10.abundancebndnsn.丰富，充裕，大量11.sprucespru:sn.云杉,云杉木adj.整洁的12.cabinetworkkbinitw:kn木工，细木家具13.cellularseljuladj.细胞的，分格的，多孔状的,.,4,Lesson18BuildingMaterials,14.graingreinn.谷物,谷类,谷粒,细粒,颗粒，纹理，粒面15.siliconsiliknn.化硅，硅元素16.Manganesemgni:zn.锰(元素符号为Mn)Magnesiummni:zjmn.镁(元素符号为Mg)Calciumklsimn.钙17.seashellsi:eln.海贝壳海贝，贝壳18.negligibleneglidbladj.可以忽略的,不予重视的，微不足道的19.syntheticsineticadj.合成的,人造的,综合的20.resinrezinn.树脂,胶质,人造树脂vt.涂树脂于21.thermosetting:musetiadj.热硬化性的,热凝性的,热固性的22.elasticmodulusmdjulsn.(系数,模数)弹性模量23.douglasfirdglsf:n.植冷杉,枞树n.道格拉斯(男子名)美国松24.ultimatetensilestrength极限抗拉(张)强度ltimitadj.最后的,最终的,根本的tensailadj.可拉长的,物张力的,拉力的stre25.masonrymeisnrin.石工术,砌筑;砌砖;砖石建筑;砖石结构;圬工26.cementmortar水泥砂浆bricklaidwithmortar砂浆砌砖cementmortarscreeding水泥砂浆找平cementmortarwaterproofingsystem水泥砂浆防水做法,.,5,Lesson18BuildingMaterialsT1,Materialsforbuildingmusthavecertainphysicalpropertiestobestructurallyuseful(建筑材料必然有某些在结构上有用的物理性质).Primarily,theymustbeabletocarryaload,orweight,withoutchangingshapepermanently.Whenaloadisappliedtoastructuremember,itwilldeform;thatis,awirewillstretchorabeamwillbend.However,whentheloadisremoved,thewireandthebeamcomebacktotheoriginalpositions.Thismaterialpropertyiscalledelasticity.Ifamaterialwerenotelasticandadeformationwerepresentinthestructureafterremovaloftheload,repeatedloadingandunloadingeventuallywouldincreasethedeformationtothepointwherethestructurewouldbecomeuseless.Allmaterialsusedinarchitecturalstructures,suchasstoneandbrick,wood,steel,aluminum,reinforcedconcrete,andplastics,behaveelasticallywithinacertaindefinedrangeofloading.Iftheloadingisincreasedabovetherange,twotypesofbehaviorcanoccur:brittleandplastic.Intheformer,thematerialwillbreaksuddenly.Inthelatter,thematerialbeginstoflowatacertainload(yieldstrength),ultimatelyleadingtofracture.Asexamples,steelexhibitsplasticbehavior,andstoneisbrittle.Theultimatestrengthofamaterialismeasuredbythestressatwhichfailure(fracture)occurs.,.,6,Lesson18BuildingMaterialsT2,Asecondimportantpropertyofabuildingmaterialisitsstiffness.Thispropertyisdefinedbytheelasticmodulus,whichistheratioofthestress(forceperunitarea),tothestrain(deformationperunitlength).Theelasticmodulus,therefore,isameasureoftheresistanceofamaterialtodeformationunderload.Fortwomaterialsofequalareaunderthesameload,theonewiththehigherelasticmodulushasthesmallerdeformation.Structuralsteel,whichhasanelasticmodulusof30millionpoundspersquareinch(psi),or2,100,000kilogramspersquarecentimeter,is3timesasstiffasaluminum,10timesasstiffasconcrete,and15timesasstiffaswood.Masonry.Masonryconsistsofnaturalmaterials,suchasstone,ormanufacturedproducts,suchasbrickandconcreteblocks.Masonryhasbeenusedsinceancienttimes;mudbrickswereusedinthecityofBabylonforsecularbuildings,andstonewasusedforthegreattemplesoftheNileValley.TheGreatPyramidinEgypt,standing481feet(147meters)high,isthemostspectacularmasonryconstruction.Masonryunitsoriginallywerestackedwithoutusinganybondingagent,butallmodernmasonryconstructionusesacementmortarasabondingmaterial.Modernstructuralmaterialsincludestone,bricksofburntclayorslate,andconcreteblocks.,.,7,Lesson18BuildingMaterialsT3,Masonryisessentiallyacompressivematerial;itcannotwithstandatensileforce,thatis,apull.Theultimatecompressivestrengthofbondedmasonrydependsonthestrengthofthemasonryunitandthemortar.Theultimatestrengthwillvaryfrom1,000to4,000psi(70to280kg/sqcm),dependingontheparticularcombinationofmasonryunitandmortarused.Timber.Timberisoneoftheearliestconstructionmaterialsandoneofthefewnaturalmaterialswithgoodtensileproperties.Hundredsofdifferentspeciesofwoodarefoundthroughouttheworld,andeachspeciesexhibitsdifferentphysicalcharacteristics.Onlyafewspeciesareusedstructurallyasframingmembersinbuildingconstruction.IntheUnitedStates,forinstance,outofmorethan600speciesofwood,only20speciesareusedstructurally.Thesearegenerallytheconifers,orsoftwoods,bothbecauseoftheirabundanceandbecauseoftheeasewithwhichtheirwoodcanbeshaped.ThespeciesoftimbermorecommonlyusedintheUnitedStatesforconstructionareDouglasfir,Southernpine,spruce,andredwood.Theultimatetensilestrengthofthesespeciesvariesfrom5,000to8,000psi(350to560kg/sqcm).Hardwoodsareusedprimarilyforcabinetworkandforinteriorfinishessuchasfloors.,.,8,Lesson18BuildingMaterialsT4,Becauseofthecellularnatureofwood,itisstrongeralongthegrainthanacrossthegrain.Woodisparticularlystrongintensionandcompressionparalleltothegrain,andithasgreatbendingstrength.Thesepropertiesmakeitideallysuitedforcolumnsandbeamsinstructures.Woodisnoteffectivelyusedasatensilememberinatruss,however,becausethetensilestrengthofatrussmemberdependsuponconnectionsbetweenmembers.Itisdifficulttodeviseconnectionswhichdonotdependontheshearortearingstrengthalongthegrain,althoughnumerousmetalconnectorshavebeenproducedtoutilizethetensilestrengthoftimbers(虽然生产了许多利用木材抗拉强度的金属连接器，但很难设计与沿木材顺纹方向抗剪强度或抗扯裂强度关系不大的接头).Steel.Steelisanoutstandingstructuralmaterial.Ithasahighstrengthonapound-for-poundbasiswhencomparedtoothermaterials,eventhoughitsvolume-for-volumeweightismorethantentimesthatofwood(钢材是一种极好的结构材料。与其它材料同强度单位相比时，它的抗拉强度更高，尽管同体积单位时相比，它的密度比木材的十倍还大).Ithasahighelasticmodulus,whichresultsinsmalldeformationsunderload.ItcanbeformedbyrollingintovariousstructuralshapessuchasI-beams,plates,andsheets;italsocanbecastintocomplexshapes;anditisalsoproducedintheformofwirestrandsandropesforuseascablesinsuspensionbridges,.,9,Lesson18BuildingMaterialsT5,andsuspendedroofs,aselevatorropes,andaswiresforprestressingconcrete.Steelelementscanbejoinedtogetherbyvariousmeans,suchasbolting,riveting,orwelding.Carbonsteelsaresubjecttocorrosionthroughoxidationandmustbeprotectedfromcontactwiththeatmospherebypaintingthemorembeddingtheminconcrete.Abovetemperaturesofabout700(371),steelrapidlylosesitsstrength,andthereforeitmustbecoveredinajacketofafireproofmaterial(usuallyconcrete)toincreaseitsfireresistance.Theadditionofalloyingelements,suchassiliconormanganese,resultsinhigherstrengthsteelswithtensilestrengthsupto250,000psi(17,500kgs/sqcm)(添加象硅或锰这样的合金元素，会得到抗拉强度达250000磅/平方英寸的高强钢筋).Thesesteelsareusedwherethesizeofastructuralmemberbecomescritical,asinthecaseofcolumnsinaskyscraper.Aluminum.Aluminumisespeciallyusefulasabuildingmaterialwhenlightweight,strength,andcorrosionresistanceareallimportantfactors.Becausepurealuminumisextremelysoftandductile,alloyingelements,suchasmagnesium,silicon,zinc,andcopper,mustbeaddedtoittoimpartthestrengthrequiredforstructuraluse.Structuralaluminumalloysbehave,.,10,Lesson18BuildingMaterialsT6,elastically.Theyhaveanelasticmodulusonethirdasgreatassteelandthereforedeformthreetimesasmuchassteelunderthesameload.theunitweightofanaluminumalloyisonethirdthatofsteel,andthereforeanaluminummemberwillbelighterthanasteelmemberofcomparablestrength.Theultimatetensilestrengthofaluminumalloysrangesfrom20,000to60,000psi(1,400to4,200kgs/sqcm).Aluminumcanbeformedintoavarietyofshapes;itcanbeextrudedtoformI-beams,drawntoformwireandrods,androlledtoformfoilandplates.Aluminummemberscanbeputtogetherinthesamewayassteelbyriveting,bolting,and(toalesserextent)bywelding.Apartfromitsuseforframingmembersinbuildingsandprefabricatedhousing,aluminumalsofindsextensiveuseforwindowframesandfortheskinofthebuildingincurtain-wallconstruction.Concrete.Concreteisamixtureofwater,sandandgravel,andportlandcement.Crushedstone,manufacturedlightweightstone,andseashellsareoftenusedinlieuofnaturalgravel.Portlandcement,whichisamixtureofmaterialscontainingcalciumandclay,isheatedinakilnandthenpulverized.,.,11,Lesson18BuildingMaterialsT7,ConcretederivesitsstrengthfromthefactthatpulverizedPortlandcement,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.,.,12,Lesson18BuildingMaterialsT8,ReinforcedConcrete.Reinforcedconcretehassteelbarsthatareplacedinaconcretemembertocarrytensileforces.Thesereinforcingbars,whichrangeindiameterfrom0.25inch(0.64cm)to2.25inches(5.7cm),havewrinklesonthesurfacestoensureabondwiththeconcrete.Althoughreinforcedconcretewasdevelopedinmanycountries,itsdiscoveryusuallyisattributedtoJosephMonnier,aFrenchgardener,whousedawirenetworktoreinforceconcretetubesin1868.Thisprocessisworkablebecausesteelandconcreteexpandandcontractequallywhenthetemperaturechanges.Ifthiswerenotthecase,thebondbetweenthesteelandconcretewouldbebrokenbyachangeintemperaturesincethetwomaterialswouldresponddifferently.Reinforcedconcretecanbemoldedintoinnumerableshapes,suchasbeams,columns,slabs,andarches,andisthereforeeasilyadaptedtoaparticularformofbuilding(钢筋混凝土可被浇铸成各种形状，例如梁、柱、板和拱，因此它易适合用于建筑的特殊结构).Reinforcedconcretewithultimatetensilestrengthsinexcessof10,000psi(700kg/sqcm)ispossible,althoughmostcommercialconcreteisproducedwithstrengthsunder6,000psi(420kg/sqcm).,.,13,Lesson18BuildingMaterialsT9,Plastics.Plasticsarerapidlybecomingimportantconstructionmaterialsbecauseofthegreatvariety,strength,durability,andlightness(由于品种多、强度高、耐久性好以及密度小，塑料正迅速成为越来越重要的建筑材料).Aplasticisasyntheticmaterialorresinwhichcanbemoldedintoanydesiredshapeandwhichusesanorganicsubstanceasabinder.Organicplasticsaredividedintotwogeneralgroups:thermosettingandthermoplastic.Thethermosettinggroupbecomesrigidthroughachemicalchangethatoccurswhenheatisapplied;onceset,theseplasticscannotberemolded.Thethermoplasticgroupremainssoftathightemperaturesandmustbecooledbeforebecomingrigid;thisgroupisnotusedgenerallyasastructuralmaterial.Theultimatestrengthofmostplasticmaterialsisfrom7,000to12,000psi(490to840kg/sqcm),althoughnylonhasatensilestrengthupto60,