高層建筑展望及建筑結(jié)構(gòu)

專業(yè)英語翻譯原文：ThefutureofthetallbuildingAndstructureofbuildingsZoningeffectsonthedensityoftallbuildingsandsolardesignmayraiseethicalchallenge.Acombinedprojectofoldandnewbuildingsmaybringbackhumanscaletoourcities.Ownersandconceptualdesignerswillbechallengedinthe1980stoproduceeconomicallysound,people-orientedbuildings.In1980theLevelHouse,designedbySkidmore,OwingsandMerril1(SOM)receivedthe25-yearawardfromtheAmericanInstituteofArchitects“inrecognitionofarchitecturaldesignofenduringsignificance”.Thisawardisgivenonceayearforabuildingbetween25and35yearsold.LewisMumforddescribedtheLeverHouseas“thefirstofficebuildinginwhichmodernmaterials,modernconstruction,modernfunctionshavebeencombinedwithamodernplan”.Atthetime,thisdaringconceptcouldonlybeachievedbyvisionarymenlikeGordonBunshaft,thedesigner,andCharlesLuckman,theownerandthen-presidentofLeverBrothers.Theprojectalsoincludedafew“first”:(1)itwasthefirstsealedglasstowereverbuilt;(2)itwasthefirstofficebuildingdesignedbySOM;and(3)itwasthefirstofficebuildingonParkAvenuetoomitretailspaceonthefirstfloor.Today,afterhundredsoflook-alikeandvariationsonthegriddesign,wehavereachedwhatmaybetheepitomeoftallbuildingdesign:thenondescriptbuilding.Exceptforafewrecentlycompletedbuildingsthatseemtobepeople-orientedintheirlowerfloors,mosttallbuildingsseemtobearepletionofthedull,graph-paper-likemonolithsinmanyofourcities.Canthisbetheendofthedesign-linefortallbuildings?Probablynot.Therearedefinitesignsthataremostencouraging.Architectsandownershaverecentlybeguntodiscussthedesignproblempublicly.Perhapsweareatthethresholdofanewera.The1980smaybringforthsomenewvisionarieslikeBunshaftandLuckman.Ifso,whatkindsofrestrictionsorchallengesdotheyface?ZoningIndicationsarestrongthatcitiesmayrestrictthedensityoftallbuildings,thatis,reducethenumberoftallbuildingspersquaremile.In1980thetermgrid-lockwasusedforthefirsttimepubliclyinNewYorkCity.Itcausedaterror-likesensationinthepitofone’sstomach.Thetermreferstoasituationinwhichtrafficcomestoastandstillformanycityblocksinalldirections.Thejam-upmayevenreachtothetunnelsandbridges.Strangelyenough,suchaseventhappenedinNewYorkinayearoffuelshortagesandhighgasolineprices.Ifwearetoavoidsimilaroccurrences,itisobviousthatthedensityofpeople,places,andvehiclesmustbedrasticallyreduced.Zoningmaybetheonlylong-termsolution.Solarzoningmaybecomemoreandmorepopularascityresidentsareblockedfromthesunbytallbuildings.Regardlessofhoweffectivelyatallbuildingisdesignedtoconserveenergy,itmayatthesametimedeprivearesidentorneighborofsolaraccess.Inthe1980stherighttoseethesunmaybecomeamostinterestingethicalquestionthatmayrevolutionizethearchitecturalfabricofthecity.Mixed-usezoningbecameafinanciallyviablealternativeduringthe1970s,maybecomecommonplaceduringthe1980s,especiallyifitiscombinedwithsolarzoningtoprovideaccesstothesunforalloccupants.RenovationEmeryRothandSonsdesignedthePalaceHotelinNewYorkasanadditiontoarenovatedhistoricVillardhouseonMadisonAvenue.Itisastrikingexampleofwhatcanbedonewithsalvageableandbeautifullydetailedoldbuildings.Recyclingbothlargeandsmallbuildingsmaybecomethewayinwhichhumanismandwarmthwillbereturnedtobuildingsduringthe80’s.Ifwemustcontinuetodesignwithglassandaluminuminstarkgridpatterns,forwhateverreason,wemayfindthatacombinationofnewandoldwillbecomethegreathumanedesigntrendofthefuture.ConceptualdesignIthasbeensuggestedinarchitecturalmagazinesthattheBankofAmericaofficebuildinginSanFranciscoistoolargeforthecity’sscale.IthasalsobeensuggestedthattheJohnHancockCenterinBostoninnotonlyoutofscalebutalsooutofcharacterwiththecity.Similarstatementsandopinionshavebeenmadeaboutothersignificanttallbuildingsincitiesthroughouttheworld.Thesecommentsraisesomebasicquestionsaboutthedesignprocessandwhoreallymakethedesigndecisionsonimportantstructures-andaboutwhowillmakethesedecisionsinthe1980s.Willtheforthcomingvisionaries-architectsandowners-returntomorehumanedesigns?Willthesociologistorpsychologistplayamoreimportantroleintheyearsaheadtohelpconvincethesevisionariesthatanew,radicallydifferent,human-scaledarchitectureislongoverdue?Ifthesearevalidquestions,coulditbethatour“best”architecturaldesignersofthe60’sand70’swillbecometheworstdesignersofthe80’sand90’s?Orwilltheylearnandrespondtoavaluablelessontheyshouldhavelearnedintheir“HistoryofArchitecture”courseincollegethat“architectureusuallyreflectsthesuccessorfailureorfailureofacivilizedsociety”?Onlytimewilltell.Abuildingiscloselyboundupwithpeople,foritprovidespeoplewiththenecessaryspacetoworkandlivein.Asclassifiedbytheiruse,buildingsaremainlyoftwotypes:industrialbuildingsandcivilbuildings.Industrialbuildingsareusedbyvariousfactoriesorindustrialproductionwhilecivilbuildingsarethosethatareusedbypeoplefordwelling,emplovment,educationandothersocialactivities.Theconstructionofindustrialbuildingsisthesameasthatofcivilbuildings.However,industrialandcivilbuildingsdifferinthematerialsused,andinthestructuralformsorsystemstheyareused.Consideringonlytheengineeringessentials,thestructureofabuildingcanbedefinedastheassemblageofthosepartswhichexistforthepurposeofmaintainingshapeandstability.Itsprimarypurposeistoresistanyloadsappliedtothebuildingandtotransmitthosetotheground.Intermsofarchitecture,thestructureofabuildingisanddoesmuchmorethanthat.Itisaninseparablepartofthebuildingformandtovaryingdegreesisageneratorofthatform.Usedskillfully,thebuildingstructurecanestablishorreinforceordersandrhythmsamongthearchitecturalvolumesandplanes.Itcanbevisuallydominantorrecessive.Itcandevelopharmoniesorconflicts.Itcanbebothconfiningandemancipating.And,unfortunatelyinsomecases,itcannotbeignored.Itisphysical.Thestructuremustalsobeengineeredtomaintainthearchitecturalform.Theprinciplesandtoolsofphysicsandmathematicsprovidethebasisfordifferentiatingbetweenrationalandirrationalformsintermsofconstruction.Artistscansometimesgenerateshapesthatobviateanyconsiderationofscience,butarchitectscannot.Thereareatleastthreeitemsthatmustbepresentinthestructureofabuilding:stability,strengthandstiffness,economy.Takingthefirstofthethreerequirements,itisobviousthatstabilityisneededtomaintainshape.Anunstablebuildingstructureimpliesunbalancedforcesoralackofequilibriumandaconsequentaccelerationofthestructureoritspieces.Therequirementofstrengthmeansthatthematerialsselectedtoresistthestressesgeneratedbytheloadsandshapesofthestructure(s)mustbeadequate.Indeed,a“factorofsafety”isusuallyprovidedsothatundertheanticipatedloads,agivenmaterialisnotstressedtoalevelevenclosetoitsrupturepoint.Thematerialpropertycalledstiffnessisconsideredwiththerequirementofstrength.Stiffnessisdifferentfromstrengthinthatitdirectlyinvolveshowmuchastructurestrainordeflectsunderload.Amaterialthatisverystrongbutlackinginstiffnesswilldeformtoomuchtobeofvalueinresistingtheforcesapplied.Economyofbuildingstructurereferstomorethanjustthecostofthematerialsused.Constructioneconomyisacomplicatedsubjectinvolvingrawmaterials,fabrication,erection,andmaintenance.Designandconstructionlaborcostsandthecostsofenergyconsumptionmustbeconsidered.Speedofconstructionandthecostofmoney(interest)arealsofactors.Inmostdesignsituations,morethanonestructuralmaterialrequiresconsideration.Completivealternativesalmostalwaysexist,andthechoiceisseldomobvious.Apartfromthesethreeprimaryrequirements,severalotherfactorsareworthyofemphasis.First,thestructureorstructuralsystemmustrelatetothebuilding’sfunction.Itshouldnotbeinconflictintermsofform.Forexample,alinearfunctiondemandsalinearstructure,andthereforeitwouldbeimpropertoroofabowlingalleywithadome.Similarly,atheatermusthavelarge,unobstructedspansbutafinerestaurantprobablyshouldnot.Statedsimply,thestructuremustbeappropriatetothefunctionitistoshelter.Second,thestructuremustbefire-resistant.Itisobviousthatthestructuralsystemmustbeabletomaintainitsintegrityatleastuntiltheoccupantsaresafelyout.Buildingcodesspecifythenumberofhoursforwhichcertainpartsofabuildingmustresisttheheatwithoutcollapse.Thestructuralmaterialsusedforthoseelementsmustbeinherentlyfire-resistantorbeadequatelyprotectedbyfireproofingmaterials.Thedegreeoffireresistancetobeprovidedwilldependuponanumberofitems,includingtheuseandoccupancyloadofthespace,itsdimensions,andthelocationofthebuilding.Third,thestructureshouldintegratewellwiththebuilding’scirculationsystems.Itshouldnotbeinconflictwiththepipingsystemsforwaterandwaste,theductingsystemsforair,or(mostimportant)themovementofpeople.Itisobviousbuildingsystemsmustbecoordinatedasthedesignprogresses.Onecandesigninasequentialstep-by-stepmannerwithinanyonesystem,butthedesignofallofthemshouldmoveinaparallelmannertowardcompletion.Spatially,allthevariouspartsofabuildingareinterdependent.Fourth,thestructuremustbepsychologicallysafeaswellasphysicallysafe.Ahigh-riseframethatswaysconsiderablyinthewindmightnotactuallybedangerousbutmaymakethebuildinguninhabitablejustthesame.Lightweightfloorsystemsthataretoo:”bouncy”canmaketheusersveryuncomfortable.Largeglasswindows,uninterruptedbydividingmotions,canbequitesafebutwillappearveryinsecuretotheoccupantstandingnexttoon40floorsabovethestreet.Sometimesthearchitectmustmakedeliberateattemptstoincreasetheapparentstrengthorsolidnessofthestructure.Thisapparentsafetymaybemoreimportantthanhonestlyexpressingthebuilding’sstructure,becausetheuntrainedviewercannotdistinguishbetweenrealandperceivedsafety.Thebuildingdesignerneedstounderstandthebehaviorlfphysicalstructuresunderload.Anabilitytointuitor“feel”structuralbehaviorispossessedbythosehavingmuchexperienceinvolvingstructuralanalysis,bothqualitativeandquantitative.Theconsequentknowledgeofhowforces,stresses,anddeformationsbuildupindifferentmaterialsandshapesisvitaltothedevelopmentofthis“sense”.Structuralanalysisistheprocessofdeterminingtheforcesanddeformationsinstructuresduetospecifiedloadssothatthestructurecanbedesignedrationally,andsothatthestateofsafetyofexistingstructurescanbechecked.Inthedesignofstructures,itisnecessarytostartwithaconceptleadingtoaconfigurationwhichcanthenbeanalyzed.Thisisdonesomemberscanbesizedandtheneededreinforcingdetermined,inorderto:a)carrythedesignloadswithoutdistressorexcessivedeformations(serviceabilityorworkingcondition);andb)topreventcollapsebeforeaspecifiedoverloadhasbeenplacedonthestructure(safetyorultimatecondition).Sincenormallyelasticconditionswillprevailundueworkingloads,astructuraltheorybasedontheassumptionsofelasticbehaviorisappropriatefordeterminingserviceabilityconditions.Collapseofastructurewillusuallyoccuronlylongaftertheelasticrangeofthematerialshasbeenexceededatcriticalpoints,sothatanultimatestrengththeorybasedontheinelasticbehaviorofthematerialsisnecessaryforarationaldeterminationofthesafetyofastructureagainstcollapse.Nevertheless,anelastictheorycanbeusedtodetermineasafeapproximationtothestrengthofductilestructures(thelowerboundapproachofplasticity),andthisapproachiscustomarilyfollowedinreinforcedconcretepractice.Forthisreasononlytheelastictheoryofstructuresispursuedinthischapter.Lookedatcritically,allstructuresareassembliesofthree-dimensionalelements,theexactanalysisofwhichisaforbiddingtaskevenunderidealconditionsandimpossibletocontemplateunderconditionsofprofessionalpractice.Forthisreason,animportantpartoftheanalyst’sworkisthesimplificationoftheactualstructureandloadingconditionstoamodelwhichissusceptibletorationalanalysis.Thus,astructuralframingsystemisdecomposedintoaslabandfloorbeamswhichinturnframeintogirderscarriedbycolumnswhichtransmittheloadstothefoundations.Sincetraditionalstructuralanalysishasbeenunabletocopewiththeactionoftheslab,thishasoftenbeenidealizedintoasystemofstripsactingasbeams.Aldo,long-handmethodhavebeenunabletocopewiththree-dimensionalframingsystems,sothattheentirestructurehasbeenmodeledbyasystemofplanarsubassemblies,tobeanalyzedoneatatime.Themodernmatrix-computermethodshaverevolutionizedstructuralanalysisbymakingitpossibletoanalyzeentiresystems,thusleadingtomorereliablepredictionsaboutthebehaviorofstructuresunderloads.Actualloadingconditionsarealsobothdifficulttodetermineandtoexpressrealistically,andmustbesimplifiedforpurposesofanalysis.Thus,trafficloadsonabridgestructure,whichareessentiallybothofdynamicandrandomnature,areusuallyidealizedintostaticallymovingstandardtrucks,ordistributedloads,intendedtosimulatethemostsevereloadingconditionsoccurringinpractice.Themostimportantuseofstructuralanalysisisasatoolinstructuraldesign.Assuch,itwillusuallybeapartofatrial-anderrorprocedure,inwhichanassumedconfigurationwithassumeddeadloadsisanalyzed,andthemembersdesignedinaccordancewiththeresultsoftheanalysis.Thisphaseiscalledthepreliminarydesigned;sincethisdesignisstillsubjecttochange,usuallyacrude,fastanalysismethodisadequate.Atthisstage,thecostofthestructureisestimated,loadsandmemberpropertiesarerevised,andthedesignischeckedforpossibleimprovements.Thechangesarenowincorporatedinthestructure,amorerefinedanalysisisperformed,andthememberdesignisrevised.Thisprojectiscarriedtoconvergence,therapidityofwhichwilldependonthecapabilityofthedesigner.Itisclearthatavarietyofanalysismethods,rangingfrom”quickanddirtytoexact”,isneededfordesignpurposes.Anefficientanalystmustthusbeincommandoftherigorousmethodsofanalysis,mustbeawareofavailabledesignandanalysisaids,aswellassimplificationspermittedbyapplicablebuildingcodes.Anup-to-dateanalystmustlikewisebeversedinthebasesofmatrixstructuralanalysisanditsuseindigitalcomputersaswellasintheuseofavailableanalysisprogramsorsoftware譯文：高層建筑展望及建筑結(jié)構(gòu)區(qū)域規(guī)劃對(duì)高層建筑物的密度和對(duì)自然采光設(shè)計(jì)可能引起道德問題將產(chǎn)生影響。能源的有限性將繼續(xù)成為建筑設(shè)計(jì)面臨的獨(dú)特挑戰(zhàn)。新老建筑的結(jié)合將會(huì)給我們的城市帶來人情味。要設(shè)計(jì)建造出經(jīng)濟(jì)實(shí)用，以人為本的建筑物，將會(huì)是業(yè)主和概念設(shè)計(jì)師在20世紀(jì)80年代面臨的挑戰(zhàn)。1980年欲斯柯摩爾、奧英斯和米瑞爾（SOM）設(shè)計(jì)的萊弗公寓獲得了美國建筑師協(xié)會(huì)授予的25年獎(jiǎng)“以獎(jiǎng)勵(lì)具有深遠(yuǎn)意義的優(yōu)秀建筑設(shè)計(jì)”。這響?yīng)劽磕晔谟枰蛔魁g在25~35年之間的建筑物。用劉易斯.芒福德的話來說萊弗公寓是“第一座集現(xiàn)代材料、現(xiàn)代施工、現(xiàn)代功能與現(xiàn)代設(shè)計(jì)方案為一體的辦公樓”。在當(dāng)時(shí)，這樣大膽的構(gòu)思只有像設(shè)計(jì)師戈登.邦沙福特和業(yè)主—萊弗兄弟公司當(dāng)時(shí)的總裁查爾斯.盧克曼那樣富于幻想的人才能創(chuàng)造出來了。而且，這項(xiàng)工程包含了幾個(gè)”第一”：（1）它是第一座全封閉的玻璃大廈；（2）它是SOM三人合作設(shè)計(jì)的第一棟辦公樓；（3）它是公園大街第一座一層樓不設(shè)零售商場(chǎng)的辦公樓。今天，經(jīng)過眾多外觀相似而柱網(wǎng)變化的設(shè)計(jì)，我們已難以對(duì)建筑物進(jìn)行歸類，這也許是高層建筑設(shè)計(jì)的縮影。除了最近竣工的幾棟低層樓房似乎比較怡人外，在我們的許多城市中，多數(shù)高層建筑物看上去就像圖表上的柱標(biāo)，好似一塊塊單調(diào)而又笨拙的巨石。難道這就是高層建筑設(shè)計(jì)行業(yè)的終點(diǎn)嗎？也許不是。有跡象表明其發(fā)展是非常令人鼓舞的。建筑師和業(yè)主最近已開始公開討論設(shè)計(jì)問題。也許我們正處在一個(gè)新時(shí)代的開端，20世紀(jì)80年代也許會(huì)產(chǎn)生一些像邦沙福特和盧克曼那樣的幻想家。要是如此，他們會(huì)面臨什么樣的限制或挑戰(zhàn)呢？區(qū)域規(guī)劃很顯然，城市可以限制高層建筑的密度，也就是減少每平方英里高層建筑的數(shù)量。1980年，“堵塞網(wǎng)”這個(gè)術(shù)語第一次在紐約市公開使用。它的出現(xiàn)在公眾心中引起恐慌。這個(gè)詞指的是城市中四面八方的街區(qū)同時(shí)出現(xiàn)的交通停滯不動(dòng)的現(xiàn)象，堵塞甚至一直延伸到隧道里和高架橋上。奇怪的是，這種事情竟然發(fā)生在紐約燃料短缺、油價(jià)高漲的年份。很顯然，要想避免類似情況的出現(xiàn)，就必須大幅度地降低人口、降低活動(dòng)場(chǎng)所油價(jià)車輛的密度。區(qū)域規(guī)劃也許是唯一長遠(yuǎn)的解決方法。城市居民由于收到高層建筑的遮擋而見不到陽光，因此，陽光規(guī)劃將越來越受歡迎。無論高層建筑設(shè)計(jì)得如何節(jié)能，它同時(shí)有可能剝奪居住者和鄰居享受陽光的權(quán)力。20世紀(jì)80年代享受陽光的權(quán)力會(huì)成為一個(gè)十分有趣的道德問題，這個(gè)問題會(huì)徹底改變城市的建筑布局?；旌嫌猛镜姆謪^(qū)規(guī)劃在20世紀(jì)70年代還只是一種在經(jīng)濟(jì)上可行的抉擇，在20世紀(jì)80年代將會(huì)得到普及，特別是將混合功能分區(qū)規(guī)劃與陽光分區(qū)規(guī)劃相結(jié)合，讓所有的住戶都享受到陽光。整修改造伊莫利.羅斯和桑斯兩人合作設(shè)計(jì)的紐約王宮酒店是對(duì)麥迪遜大街上翻修后的古建筑維拉德公寓的補(bǔ)充和增色。這是一個(gè)如何對(duì)待可搶救的古建筑精品的突出實(shí)例。20世紀(jì)80年代對(duì)中西建筑物的重復(fù)利用將是人情味和溫馨回到建筑物的途徑。無論出于什么原因，如果我們必須繼續(xù)使用玻璃和鋁材進(jìn)行那種呆板的方式設(shè)計(jì)的話，我們會(huì)發(fā)現(xiàn)新老建筑的結(jié)合將成為未來富有人情味建筑設(shè)計(jì)的大趨勢(shì)。概念設(shè)計(jì)有些建筑雜志認(rèn)為位于舊金山的美洲銀行辦公大樓對(duì)于該城市來說規(guī)模過大，位于波士頓的約翰.漢考克中心不僅與該城市的規(guī)模不成比例，而且與其特點(diǎn)不符，對(duì)于世界各地主要高層建筑物的類似評(píng)論還有不少。這類評(píng)論提出了有關(guān)設(shè)計(jì)程序，和誰是重點(diǎn)項(xiàng)目設(shè)計(jì)的決策者，以及上世紀(jì)80年代的建筑設(shè)計(jì)應(yīng)由誰來決策等基本問題。未來的幻想家，即建筑師和業(yè)主會(huì)回到更富人情味的設(shè)計(jì)嗎？在今后的幾年里社會(huì)學(xué)家和心理學(xué)家會(huì)發(fā)揮他們的重要作用使這些幻想家相信一種截然不同的、合乎人體尺寸的新型建筑設(shè)計(jì)早該付諸實(shí)踐嗎？如果這些問題的突出解決有其合理性的話，那么六七十年代被我們視為“最杰出的”建筑設(shè)計(jì)師到了八九十年代就變成最差的嗎？他們?cè)诖髮W(xué)“建筑史”這門課程中應(yīng)該了解到“建筑常常反映了文明社會(huì)的成功與失敗”，他們會(huì)學(xué)到這有益的一課并對(duì)此作出反應(yīng)嗎？也許只有時(shí)間才會(huì)作出回答。建筑物與人類有著密切的關(guān)系，它能為人們?cè)谄渲泄ぷ骱蜕钐峁┍匾目臻g。根據(jù)其功能不同，建筑物主要有兩大類：工業(yè)建筑和民用建筑。工業(yè)建筑有各種工廠或制造廠，而民用建筑指的是那些人們用以居住、工作、教育或其他社會(huì)活動(dòng)的場(chǎng)所。工業(yè)建筑的建造與民用建筑相同，但兩者在所選用的材料、結(jié)構(gòu)形式和體系方面是有差別的。就工程的實(shí)質(zhì)而言，建筑結(jié)構(gòu)可定義為：以保持形狀和穩(wěn)定為目的的各個(gè)基本構(gòu)件的組合體。其基本目的是抵抗作用在建筑物上的各種荷載并把它傳到地基上。從建筑學(xué)的角度來講，建筑結(jié)構(gòu)并非僅僅如此。它與建筑風(fēng)格是不可分割的，在不同程度上是一種建筑風(fēng)格的體現(xiàn)。如能巧妙地設(shè)計(jì)建筑結(jié)構(gòu)，則可建立或加強(qiáng)建筑空間與建筑平面之間的格調(diào)與節(jié)奏。它在直觀上可以是顯性的或是隱性的。它能產(chǎn)生和諧體或?qū)φ阵w。他可能既局限又開放。不幸的是，在一些情況下，它不能被忽視。它是實(shí)際存在的。結(jié)構(gòu)設(shè)計(jì)還必須與建筑風(fēng)格相吻合。物理學(xué)和數(shù)學(xué)的原理及工具為區(qū)分在結(jié)構(gòu)上的合理和不合理的形式提供了依據(jù)。藝術(shù)家有時(shí)可以不必考慮科學(xué)就能畫出圖形，但建筑師卻不行。在建筑結(jié)構(gòu)中至少應(yīng)包括三項(xiàng)內(nèi)容：穩(wěn)定性，強(qiáng)度和剛度，經(jīng)濟(jì)性。在上述三項(xiàng)要求中，首先是穩(wěn)定性。它在保持建筑物形狀上是必不可少的。一座不穩(wěn)定的建筑結(jié)構(gòu)意味著有不平衡的力或失去平衡狀態(tài)，并且由此導(dǎo)致結(jié)構(gòu)整體或構(gòu)件產(chǎn)生加速度。強(qiáng)度的要求意味著所選擇的結(jié)構(gòu)材料足以承受由荷載產(chǎn)生的應(yīng)力并且結(jié)構(gòu)形狀必須適當(dāng)。實(shí)際上，通常都提供一個(gè)安全系數(shù)以便在預(yù)計(jì)的荷載作用下，使所選用材料的應(yīng)力不會(huì)接近破壞應(yīng)力。被稱為剛度的材料的特性，需與強(qiáng)度要求一起考慮。剛度不同于強(qiáng)度，因?yàn)樗婕昂奢d作用下結(jié)構(gòu)應(yīng)變的大小和變形的程度。它具有很高強(qiáng)度，但剛度較低的材料，在外力作用下會(huì)因變形過大而失去其使用價(jià)值。建筑結(jié)構(gòu)的經(jīng)濟(jì)性指的不僅僅是所用材料的費(fèi)用。建筑經(jīng)濟(jì)是一個(gè)復(fù)雜的問題，其中包括原材料、制作、安裝和維修等。必須考慮設(shè)計(jì)和施工中人工費(fèi)及能源消耗的費(fèi)用。施工的速度和資金成本（利息）也是需要考慮的因素。對(duì)大多數(shù)設(shè)計(jì)情況，不能僅僅考慮一種建筑材料，經(jīng)常存在一些有競(jìng)爭(zhēng)性的其他選擇，而具體應(yīng)選擇哪種并不明顯。除了這三種最基本要求之外，其他幾種因素也值得重視。首先，結(jié)構(gòu)或結(jié)構(gòu)體系必須和建筑物的功能相吻合而不應(yīng)該與建筑形式相矛盾。例如，線形功能要求線形結(jié)構(gòu)，所以若把保齡球場(chǎng)的頂部蓋