外文翻譯-抗側(cè)向荷載的結(jié)構(gòu)體系

StructuralsystemstoresistlateralloadsCommonlyusedstructuralsystemsWithloadsmeasuredintensofthousandskips,thereislittleroominthedesignofhigh-risebuildingsforexcessivelycomplexthoughts.Indeed,thebetterhigh-risebuildingscarrytheuniversaltraitsofsimplicityofthoughtandclarityofexpression.Itdoesnotfollowthatthereisnoroomforgrandthoughts.Indeed,itiswithsuchgrandthoughtsthatthenewfamilyofhigh-risebuildingshasevolved.Perhapsmoreimportant,thenewconceptsofbutafewyearsagohavebecomecommonplaceintoday’stechnology.Omittingsomeconceptsthatarerelatedstrictlytothematerialsofconstruction,themostcommonlyusedstructuralsystemsusedinhigh-risebuildingscanbecategorizedasfollows:Moment-resistingframes.科B爬r護a嘆c溝e盜d真燦f秘r初a瓣m帥e蛇s念,風衰i閃n塊c抽l莊u量d耽i閘n京g初掘e怒c被c技e旱n鐵t灣r柱i玻c濾a階l絮l振y役攪b養(yǎng)r辜a呢c孩e延d廟開f丙r沙a嫩m漏e鵝s肢.曾S當h勞e衡a僑r雷線w謹a炊l夫l堤s你,花央i王n雜c遠l育u街d叼i籮n途g紡割s舍t(yī)脫e彎e因l擾鴉p仇l榮a妻t藏e森則s堪h饑e茄a將r俱猛w戚a戲l費l暮s撈.教T兄u隆b戚e再-烈i騰n腐-梳t(yī)派u賠b左e愈崖s派t寒r磨u杠c勺t俱u圍r冶e更s即.饑T蘋u在b引e脫-脹i穴n裂-份t配u舌b濃e編愛s最t合r特u炊c腎t料u敏r雞e示s鄉(xiāng).烈C事o組r張e敬-伏i授n沖t狀e停r主a協(xié)c鐘t英i饒v虛e嬌卻s慮t回r覺u有c亡t席u叨r赴e雜s數(shù).劇C級e棵l宰l門u壞l賺a火r波踩o柴r源擱b飲u欄n日d貌l慢e聾d嘆-窄t遷u餐b規(guī)e撇冒s循y弄s毫t鼠e拿m昌s侍.公P川a豈r春t扶i鋼c兄u領(lǐng)l苦a河r附l拘y鹿養(yǎng)w苦i搞t侮h柔屋t碗h谷e路血r翠e倉c舞e豬n倉t儲奏t且r滔e鉛n床d優(yōu)緣t酸o細w子a曬r殲d竹涼m登o判r尿e程棟c充o芽m師p普l捏e荷x鬧壽f幕o本r碰m芽s四,勢錫b薪u我t配息i誤n燃獄r由e資s股p托o揮n調(diào)s只e云亡a暮l肉s牌o供盛t沾o莖拜t材h猴e畢帖n工e厲e爐d停探f脾o欲r鄙診i抄n僵c條r院e籮a墾s偽e雙d等劫s轟t抖i右f慢f膠n鋒e及s瞇s桶朽t舅o愉狹r亂e擊s勺i字s孩t并伯t韻h練e噸另f搬o森r艦c采e沫s匯研f依r可o柜m廟姑w丸i住n踢d福撤a悠n傳d動受e術(shù)a液r滿t歉h苗q消u航a封k辭e駱,添燭m兄o觀s根t銀墨h刷i搏g男h肝-碧r秀i丟s虧e刺裕b慶u射i吐l棟d各i數(shù)n創(chuàng)g引s和杰h棗a闊v蹤e患料s糖t原r屋u駕c尚t穴u而r首a斥l色茂s己y姨s樸t臺e麗m床s件特b柜u叫i概l丟t災歸u封p驅(qū)偏o旱f鳳眠c關(guān)o位m魯b毛i例n狐a應t鬼i茫o饒n躍s億乘o鴉f器氧f圖r儀a恭m變e姐s師,融削b習r膝a賽c蛇e搬d壘烤b豆e閃n廚t踐s燥,偽重s形h傲e屑a速r寇紗w盈a矮l動l楊s廈,啟碑a(chǎn)刮n胃d丟腫r懶e財l繁a洞t獲e弄d飄代s紀y禽s佛t解e餡m輛s綿.譽村F要u計r說t筒h掃e芽r欄,孩祖f因o宴r撒綠t削h信e顫跡t儉a宿l功l臉e調(diào)r睡墳b炒u跪i濟l子d奏i襪n斧g甚s連,胳寒t衡h嗎e福咱m口a戶j作o員r且i危t香i號e典s辛撥a底r史e壞光c楚o遲m少p桶o偶s錢e杏d獎筐o最f花溫i封n強t羨e植r抵a暮c檔t艘i技v翅e懂殿e榨l托e咬m堤e洞n困t咸s缺閑i繼n畏談t頸h是r懲e擊e薪-谷d騙i搶m擦e代n筆s班i亞o筒n挽a蒜l菊復a釋r述r劈a掌y企s恨.父T壞h局e肯刺m乖e節(jié)t矮h聯(lián)o省d您鏡o能f論欺c奇o符m奉b腳i臥n槳i億n荒g女鍋t匯h扇e課s銳e掀及e顆l濟e幫m則e裳n芹t澇s澆爛i視s逢得t痕h緞e蜓顛v禁e奮r本y領(lǐng)源e拐s聯(lián)s燈e陽n百c總e土愚o滿f鉤獎t促h約e振散d烘e火s吉i學g擋n找乏p矛r奧o巡c校e祖s毯s邀耗f傳o抱r問貢h牲i紡g兄h馳-幣r剖i叢s混e恐染b茶u貌i抽l店d特i蕉n降g泉s享.靜孕T稀h禾e岔s炒e色創(chuàng)c句o倒m畏b專i遵n妹a美t艘i腫o緊n品s臭毯n些e撥e藍d約丘e缺v騎o第l殿v斃e仁衣i窮n特粒r枯e爽s掉p培o諸n茶s掙e石春t粗o宣津e叮n遼v將i襖r殃o掩n探m瘡e搞n坐t廚a飄l付,富射f憲u菜n摧c琴t胖i膝o賄n占a粱l當,撐陳a貸n督d米共c蹦o仆s票t蚊或c挪o泛n橡s縮i喘d逝e轟r洞a暈t裝i皺o潮n鞋s規(guī)兵s絕o麻真a兩s堆茶t德o渣視p途r卸o叢v紅i蜓d脅e葡得e智f埋f藍i鞋c冒i貸e儀n媽t憂煉s碰t籃r購u鮮c霞t艘u肥r僚e命s街詳t沸h截a勁t麗降p赴r解o聯(lián)v脊o勸k戰(zhàn)e賭蠢t漠h旗e辛拳a拜r發(fā)c卷h漲i令t嶺e免c古t屬u扔r命a督l竄楚d勤e框v偏e略l膽o畢p頓m僻e秤n香t勤貪t觸o軌兇n扶e籍w物渡h蘆e裂i連g單h師t動s誕.按焰T魚h火i肺s戀井i瞞s鉆騙n違o慈t阿矛t照o療果s黑a跌y址椅t偶h滾a束t考趨i很m楚a傅g牽i終n疑a賊t稀i每v省e縣顏s診t漲r緊u能c鵲t增u墊r扛a奪l畫白d賄e懸s灣i厲g欲n桿眼c忌a戀n王堆c宋r倡e胳a殘t跌e浮也g項r相e顏a簡t以效a鑒r漏c之h弦i級t霧e尖c帶t噴u響r拼e敲.杜格T息o吧犁t毒h過e太熔c逆o恒n萌t閑r年a青r住y樣,奪都m六a脊n撲y悟輪e響x誕a粘m綠p倉l候e儲s伍拐o惜f橡慰f冷i支n逐e宣演a副r晚c炸h沈i倆t謠e慧c皺t軍u術(shù)r秘e唐趁h描a羊v怒e慎狀b雞e雕e甘n悉旅c心r裝e池a亞t外e撤d榮燙w惕i走t御h揀吹o批n崗l嬸y臉償m湖o摟d身e跨r擦a膽t跳e欠酷s痕u推p廁p逮o嬸r子t踩添f宣r秀o捏m請牽t德h林e矩般s飯t勇r極u啞c脊t黎u酒r廊a闊l斷晃e蛙n牧g拴i爽n繩e憐e衫r覆,旱富w印h跨i哪l據(jù)e遙售o爬n榮l宴y餅賴f能i腎n橡e撿稅s范t肉r通u格c致t搬u腿r政e線,練邀n槽o母t芒螞g奸r行e膨a花t有父a鎖r裂c準h醫(yī)i茂t掀e餓c仇t克u跑r建e遞,置宣c煤a軍n油傍b擁e川炮d秋e理v暢e筍l棍o奮p吸e障d辟則w例i劫t菌h愚o風u碎t鐮怪t亦h滔e燕鍬g尼e茅n盞i滾u是s翁討a右n過d曉固t竟h捧e割俊l克e淘a禁d派e亡r竹s碧h謎i扮p棒亡o送f詞品a增蜻t垂a返l各e瘋n蓄t粥e爛d麥掉a愿r予c予h樸i拴t眨e舅c換t自.顯幟I主n妥醫(yī)a處n胳y那怕e駛v理e紙n支t存,軍象t幅h違e蠶宗b課e匙s訊t僵幅o吩f財恨b蔬o貍t批h菊憤i勢s秘邁n浙e傘e昨d粗e端d逆屋t疲o傘賤f傘o武r晌m歸u東l接a恭t性e鑰失a俊慣t持r鏟u慨l珠y得躺e丙x編t遇r孫a某o輝r鍋d蜂i糧n曲a善r喬y悲租d笨e盯s僵i斥g穴n弱頓o弟f突槳a疤玉h豪i柏g氏h侍-舅r斑i掀s刺e吼簽b臉u百i油l晚d驚i展n薪g托.振W策h杯i厲l劑e袖宗c種o泛m濱p棗r目e須h份e奴n巷s菠i解v列e略仙d顆i格s并c王u熊s螞s錢i覽o槳n冊s呆賢o邊f(xié)崇至t租h伐e炸s錯e比彈s賞e奔v顛e棋n吼鐮s泰y經(jīng)s透t深e南m怠s政辛a瞞r撞e材算g誤e按n嗚e甲r噸a武l禁l彈y舌繡a愁v驅(qū)a離i破l返a灑b歡l恨e壓帳i霧n廳為t售h笨e廁綁l抄i鑒t碑e傍r順a皆t企u眨r譯e沉,耀稠f頭u岡r吉t馬h俱e竹r若們d義i擱s紐c因u擱s指s盛i甩o鄉(xiāng)n漁舉i業(yè)s協(xié)視w塑a遣r名r診a仁n疼t猛e賊d升屬h齒e驢r熱e震德.兇T遺h伯e敞映e衡s奶s慚e片n圣c濃e寫濾o且f槍而t轉(zhuǎn)h陽e域繁d叫e正s話i宗g鞏n班覆p簽r幻o守c像e懶s鋤s瓣冬i田s陪孟d撥i包s簽t躺r堅i笛b枯u繩t訴e監(jiān)d鍬疊t舉h媽r絨o頸u靠g蟲h錦o端u搶t帽舊t籍h銀e棄曾d警i零s孫c桑u低s仇s傻i盲o步n情.條M缺o屋m犬e份n殘t席-淹R抵e被s睛i隱s雁t續(xù)i純n怨g蝴艘F辯r燭a撫m級e坡s泄P潑e訪r洲h燃a嘉p免s狂柏t雜h蒸e妹園m攔o秧s弄t即拘c化o辨m化m誘o系n丘l側(cè)y剖圍u既s姑e重d販要s雄y挑s疲t嗎e火m駕以i奏n劫最l沉o腿w并-姥t毛o與輪m糊e寄d勇i艇u勞m疊-從r繪i男s膛e化壟b順u扒i深l示d介i糕n間g茂s箭,名鳳t錯h想e違鞋m逐o憤m析e畫n掀t原-分r重e盯s駕i敘s搜t脫i劈n出g蒼罵f察r譯a奏m漸e錘,猜疫i廉s銜慮c廟h研a蹲r霞a招c干t高e已r屑i昨z挖e懶d閱遮b稀y脂賞l泰i照n上e貌a昂r準兇h碰o宅r撫i格z缺o脈n稅t廈a被l醫(yī)辨a妨n督d護本v益e癢r漠t臨i賴c首a銳l鋼粉m取e牲m還b苗e捷r昏s渴佩c提o酬n遠n劑e烤c刮t慕e師d臥器e輩s在s恭e此n寺t比i煎a怠l夜l綿y痕沫r摧i北g根i鵲d題l差y澇網(wǎng)a綿t柳稈t綁h按e臂i告r毅級j權(quán)o賓i買n肝t項s籌.滅律S判u弓c遙h炭挑f嫂r紅a竭m貢e搞s砌敗a攝r促e熱態(tài)u犧s憐e難d麥史a孤s奪顆a金工s里t摩a調(diào)n倍d趨-舉a橡l唯o蕩n主e躁綢s冰y匠s熱t(yī)剖e鄙m芒沖o斬r弄版i翁n睡腥c弄o孟m廳b抄i族n對a舅t男i健o壁n朝熱w付i壁t離h銀孔o睛t約h抓e泉r倦立s李y君s仿t吼e短m脂s徐芹s深o圍患a惕s產(chǎn)讀t揭o拉妖p址r佛o跌v麗i剩d賽e水往t藏h衡e道鴨n僑e母e晌d蹤e圓d菌鞠r幻e錄s市i貿(mào)s該t投a夏n度c揚e岸般t蘿o腰盼h荷o枝r蘭i恭z距o舞n間t卻a陷l墻貞l介o挖a杰d綢s渡.奶銷I國n家景t毀h既e知質(zhì)t騾a盜l聲l你e文r糧動o跨f公甜h錫i珍g節(jié)h潑-乏r瓶i蓄s驅(qū)e濤罪b踐u偽i招l(wèi)清d朋i憐n音g剩s塔,疤證t貢h恰e燒刑s融y膜s叨t激e繪m開褲i造s扇劍l殼i迷k披e舟l妹y拔衣t堪o辟不b刊e蛇先f斬o中u棟n此d償悔i往n脹a害p桌p著r扯o厲p劉r鉤i定a惑t猴e芹內(nèi)f數(shù)o盜r甚膨a橡賤s齊t陵a恩n陰d呀-藍a池l士o佛n省e邀鋒s誰y愧s輔t單e墨m鏡,妖絲t境h倆i搏s乖寧b刪e蜻c糧a喬u秧s敘e紹鞋o朋f貸葉t殖h倒e捆父d范i藏f通f棗i棚c腹u處l帆t敲y勾軟i暴n澤溪m愚o難b宿i備l堡i奧z譽i瘋n螺g慢等s維u聾f越f繁i留c胡i驅(qū)e饅n做t馬惠s旨t賄i緒f嗽f他n饞e寶s劣s院揀u陣n煩d舌e賤r鏟縣l籮a待t綢e虎r搜a登l撤祖f策o軍r鏡c轟e盡s濱.AnalysiscanbeaccomplishedbySTRESS,STRUDL,orahostofotherappropriatecomputerprograms;analysisbytheso-calledportalmethodofthecantilevermethodhasnoplaceintoday’stechnology.Becauseoftheintrinsicflexibilityofthecolumn/girderintersection,andbecausepreliminarydesignsshouldaimtohighlightweaknessesofsystems,itisnotunusualtousecenter-to-centerdimensionsfortheframeinthepreliminaryanalysis.Ofcourse,inthelatterphasesofdesign,arealisticappraisalin-jointdeformationisessential.BracedFramesThebracedframe,intrinsicallystifferthanthemoment–resistingframe,findsalsogreaterapplicationtohigher-risebuildings.Thesystemischaracterizedbylinearhorizontal,vertical,anddiagonalmembers,connectedsimplyorrigidlyattheirjoints.Itisusedcommonlyinconjunctionwithothersystemsfortallerbuildingsandasastand-alonesysteminlow-tomedium-risebuildings.Whiletheuseofstructuralsteelinbracedframesiscommon,concreteframesaremorelikelytobeofthelarger-scalevariety.Ofspecialinterestinareasofhighseismicityistheuseoftheeccentricbracedframe.Again,analysiscanbebySTRESS,STRUDL,oranyoneofaseriesoftwo–orthreedimensionalanalysiscomputerprograms.Andagain,center-to-centerdimensionsareusedcommonlyinthepreliminaryanalysis.ShearwallsTheshearwallisyetanotherstepforwardalongaprogressionofever-stifferstructuralsystems.Thesystemischaracterizedbyrelativelythin,generally(butnotalways)concreteelementsthatprovidebothstructuralstrengthandseparationbetweenbuildingfunctions.Inhigh-risebuildings,shearwallsystemstendtohavearelativelyhighaspectratio,thatis,theirheighttendstobelargecomparedtotheirwidth.Lackingtensioninthefoundationsystem,anystructuralelementislimitedinitsabilitytoresistoverturningmomentbythewidthofthesystemandbythegravityloadsupportedbytheelement.Limitedtoanarrowoverturning,Oneobvioususeofthesystem,whichdoeshavetheneededwidth,isintheexteriorwallsofbuilding,wheretherequirementforwindowsiskeptsmall.Structuralsteelshearwalls,generallystiffenedagainstbucklingbyaconcreteoverlay,havefoundapplicationwhereshearloadsarehigh.Thesystem,intrinsicallymoreeconomicalthansteelbracing,isparticularlyeffectiveincarryingshearloadsdownthroughthetallerfloorsintheareasimmediatelyabovegrade.Thesystemhasthefurtheradvantageofhavinghighductilityafeatureofparticularimportanceinareasofhighseismicity.Theanalysisofshearwallsystemsismadecomplexbecauseoftheinevitablepresenceoflargeopeningsthroughthesewalls.Preliminaryanalysiscanbebytruss-analogy,bythefiniteelementmethod,orbymakinguseofaproprietarycomputerprogramdesignedtoconsidertheinteraction,orcoupling,ofshearwalls.FramedorBracedTubesTheconceptoftheframedorbracedorbracedtubeeruptedintothetechnologywiththeIBMBuildinginPittsburgh,butwasfollowedimmediatelywiththetwin110-storytowersoftheWorldTradeCenter,NewYorkandanumberofotherbuildings.Thesystemischaracterizedbythree–dimensionalframes,bracedframes,orshearwalls,formingaclosedsurfacemoreorlesscylindricalinnature,butofnearlyanyplanconfiguration.Becausethosecolumnsthatresistlateralforcesareplacedasfaraspossiblefromthecancroidsofthesystem,theoverallmomentofinertiaisincreasedandstiffnessisveryhigh.Theanalysisoftubularstructuresisdoneusingthree-dimensionalconcepts,orbytwo-dimensionalanalogy,wherepossible,whichevermethodisused,itmustbecapableofaccountingfortheeffectsofshearlag.Thepresenceofshearlag,detectedfirstinaircraftstructures,isaseriouslimitationinthestiffnessofframedtubes.Theconcepthaslimitedrecentapplicationsofframedtubestotheshearof60stories.Designershavedevelopedvarioustechniquesforreducingtheeffectsofshearlag,mostnoticeablytheuseofbelttrusses.Thissystemfindsapplicationinbuildingsperhaps40storiesandhigher.However,exceptforpossibleaestheticconsiderations,belttrussesinterferewithnearlyeverybuildingfunctionassociatedwiththeoutsidewall;thetrussesareplacedoftenatmechanicalfloors,mushtothedisapprovalofthedesignersofthemechanicalsystems.Nevertheless,asacost-effectivestructuralsystem,thebelttrussworkswellandwilllikelyfindcontinuedapprovalfromdesigners.Numerousstudieshavesoughttooptimizethelocationofthesetrusses,withtheoptimumlocationverydependentonthenumberoftrussesprovided.Experiencewouldindicate,however,thatthelocationofthesetrussesisprovidedbytheoptimizationofmechanicalsystemsandbyaestheticconsiderations,astheeconomicsofthestructuralsystemisnothighlysensitivetobelttrusslocation.Tube-in-TubeStructuresThetubularframingsystemmobilizeseverycolumnintheexteriorwallinresistingover-turningandshearingforces.Theterm‘tube-in-tube’islargelyself-explanatoryinthatasecondringofcolumns,theringsurroundingthecentralservicecoreofthebuilding,isusedasaninnerframedorbracedtube.Thepurposeofthesecondtubeistoincreaseresistancetooverturningandtoincreaselateralstiffness.Thetubesneednotbeofthesamecharacter;thatis,onetubecouldbeframed,whiletheothercouldbebraced.Inconsideringthissystem,isimportanttounderstandclearlythedifferencebetweentheshearandtheflexuralcomponentsofdeflection,thetermsbeingtakenfrombeamanalogy.Inaframedtube,theshearcomponentofdeflectionisassociatedwiththebendingdeformationofcolumnsandgirders(i.e,thewebsoftheframedtube)whiletheflexuralcomponentisassociatedwiththeaxialshorteningandlengtheningofcolumns(i.e,theflangesoftheframedtube).Inabracedtube,theshearcomponentofdeflectionisassociatedwiththeaxialdeformationofdiagonalswhiletheflexuralcomponentofdeflectionisassociatedwiththeaxialshorteningandlengtheningofcolumns.Followingbeamanalogy,ifplanesurfacesremainplane(i.e,thefloorslabs),thenaxialstressesinthecolumnsoftheoutertube,beingfartherformtheneutralaxis,willbesubstantiallylargerthantheaxialstressesintheinnertube.However,inthetube-in-tubedesign,whenoptimized,theaxialstressesintheinnerringofcolumnsmaybeashigh,orevenhigher,thantheaxialstressesintheouterring.Thisseeminganomalyisassociatedwithdifferencesintheshearingcomponentofstiffnessbetweenthetwosystems.Thisiseasiesttounder-standwheretheinnertubeisconceivedasabraced(i.e,shear-stiff)tubewhiletheoutertubeisconceivedasaframed(i.e,shear-flexible)tube.CoreInteractiveStructuresCoreinteractivestructuresareaspecialcaseofatube-in-tubewhereinthetwotubesarecoupledtogetherwithsomeformofthree-dimensionalspaceframe.Indeed,thesystemisusedoftenwhereintheshearstiffnessoftheoutertubeiszero.TheUnitedStatesSteelBuilding,Pittsburgh,illustratesthesystemverywell.Here,theinnertubeisabracedframe,theoutertubehasnoshearstiffness,andthetwosystemsarecouplediftheywereconsideredassystemspassinginastraightlinefromthe“hat”structure.Notethattheexteriorcolumnswouldbeimproperlymodelediftheywereconsideredassystemspassinginastraightlinefromthe“hat”tothefoundations;thesecolumnsareperhaps15%stifferastheyfollowtheelasticcurveofthebracedcore.Notealsothattheaxialforcesassociatedwiththelateralforcesintheinnercolumnschangefromtensiontocompressionovertheheightofthetube,withtheinflectionpointatabout5/8oftheheightofthetube.Theoutercolumns,ofcourse,carrythesameaxialforceunderlateralloadforthefullheightofthecolumnsbecausethecolumnsbecausetheshearstiffnessofthesystemisclosetozero.Thespacestructuresofoutriggergirdersortrusses,thatconnecttheinnertubetotheoutertube,arelocatedoftenatseverallevelsinthebuilding.TheAT&Theadquartersisanexampleofanastonishingarrayofinteractiveelements:Thestructuralsystemis94ft(28.6m)wide,196ft(59.7m)long,and601ft(183.3m)high.Twoinnertubesareprovided,each31ft(9.4m)by40ft(12.2m),centered90ft(27.4m)apartinthelongdirectionofthebuilding.Theinnertubesarebracedintheshortdirection,butwithzeroshearstiffnessinthelongdirection.Asingleoutertubeissupplied,whichencirclesthebuildingperimeter.Theoutertubeisamoment-resistingframe,butwithzeroshearstiffnessforthecenter50ft(15.2m)ofeachofthelongsides.Aspace-trusshatstructureisprovidedatthetopofthebuilding.AsimilarspacetrussislocatednearthebottomofthebuildingTheentireassemblyislaterallysupportedatthebaseontwinsteel-platetubes,becausetheshearstiffnessoftheoutertubegoestozeroatthebaseofthebuilding.CellularstructuresAclassicexampleofacellularstructureistheSearsTower,Chicago,abundledtubestructureofnineseparatetubes.WhiletheSearsTowercontainsninenearlyidenticaltubes,thebasicstructuralsystemhasspecialapplicationforbuildingsofirregularshape,astheseveraltubesneednotbesimilarinplanshape,Itisnotuncommonthatsomeoftheindividualtubesoneofthestrengthsandoneoftheweaknessesofthesystem.Thisspecialweaknessofthissystem,particularlyinframedtubes,hastodowiththeconceptofdifferentialcolumnshortening.Theshorteningofacolumnunderloadisgivenbytheexpression△=ΣfL/EForbuildingsof12ft(3.66m)floor-to-floordistancesandanaveragecompressivestressof15ksi(138MPa),theshorteningofacolumnunderloadis15(12)(12)/29,000or0.074in(1.9mm)perstory.At50stories,thecolumnwillhaveshortenedto3.7in.(94mm)lessthanitsunstressedlength.Whereonecellofabundledtubesystemis,say,50storieshighandanadjacentcellis,say,100storieshigh,thosecolumnsneartheboundarybetween.thetwosystemsneedtohavethisdifferentialdeflectionreconciled.Majorstructuralworkhasbeenfoundtobeneededatsuchlocations.Inatleastonebuilding,theRialtoProject,Melbourne,thestructuralengineerfounditnecessarytoverticallypre-stressthelowerheightcolumnssoastoreconcilethedifferentialdeflectionsofcolumnsincloseproximitywiththepost-tensioningoftheshortercolumnsimulatingtheweighttobeaddedontoadjacent,highercolumns.抗側(cè)向荷載的結(jié)構(gòu)體系常用的結(jié)構(gòu)體系若已測出荷載量達數(shù)千萬磅重，那么在高層建筑設計中就沒有多少可以進行極其復雜的構(gòu)思余地了。確實，較好的高層建筑普遍具有構(gòu)思簡單、表現(xiàn)明晰的特點。這并不是說沒有進行宏觀構(gòu)思的余地。實際上，正是因為有了這種宏觀的構(gòu)思，新奇的高層建筑體系才得以發(fā)展，可能更重要的是：幾年以前才出現(xiàn)的一些新概念在今天的技術(shù)中已經(jīng)變得平常了。如果忽略一些與建筑材料密切相關(guān)的概念不談，高層建筑里最為常用的結(jié)構(gòu)體系便可分為如下幾類：抗彎矩框架。支撐框架，包括偏心支撐框架。剪力墻，包括鋼板剪力墻。筒中框架。筒中筒結(jié)構(gòu)。核心交互結(jié)構(gòu)?？蚋耋w系或束筒體系。特別是由于最近趨向于更復雜的建筑形式，同時也需要增加剛度以抵抗幾力和地震力，大多數(shù)高層建筑都具有由框架、支撐構(gòu)架、剪力墻和相關(guān)體系相結(jié)合而構(gòu)成的體系。而且，就較高的建筑物而言，大多數(shù)都是由交互式構(gòu)件組成三維陳列。將這些構(gòu)件結(jié)合起來的方法正是高層建筑設計方法的本質(zhì)。其結(jié)合方式需要在考慮環(huán)境、功能和費用后再發(fā)展，以便提供促使建筑發(fā)展達到新高度的有效結(jié)構(gòu)。這并不是說富于想象力的結(jié)構(gòu)設計就能夠創(chuàng)造出偉大建筑。正相反，有許多例優(yōu)美的建筑僅得到結(jié)構(gòu)工程師適當?shù)闹С志捅粍?chuàng)造出來了，然而，如果沒有天賦甚厚的建筑師的創(chuàng)造力的指導，那么，得以發(fā)展的就只能是好的結(jié)構(gòu)，并非是偉大的建筑。無論如何，要想創(chuàng)造出高層建筑真正非凡的設計，兩者都需要最好的。雖然在文獻中通常可以見到有關(guān)這七種體系的全面性討論，但是在這里還值得進一步討論。設計方法的本質(zhì)貫穿于整個討論。設計方法的本質(zhì)貫穿于整個討論中?？箯澗乜蚣芸箯澗乜蚣芤苍S是低，中高度的建筑中常用的體系，它具有線性水平構(gòu)件和垂直構(gòu)件在接頭處基本剛接之特點。這種框架用作獨立的體系，或者和其他體系結(jié)合起來使用，以便提供所需要水平荷載抵抗力。對于較高的高層建筑，可能會發(fā)現(xiàn)該本系不宜作為獨立體系，這是因為在側(cè)向力的作用下難以調(diào)動足夠的剛度。我們可以利用STRESS，STRUDL或者其他大量合適的計算機程序進行結(jié)構(gòu)分析。所謂的門架法分析或懸臂法分析在當今的技術(shù)中無一席之地，由于柱梁節(jié)點固有柔性，并且由于初步設計應該力求突出體系的弱點，所以在初析中使用框架的中心距尺寸設計是司空慣的。當然，在設計的后期階段，實際地評價結(jié)點的變形很有必要。支撐框架支撐框架實際上剛度比抗彎矩框架強，在高層建筑中也得到更廣泛的應用。這種體系以其結(jié)點處鉸接或則接的線性水平構(gòu)件、垂直構(gòu)件和斜撐構(gòu)件而具特色，它通常與其他體系共同用于較高的建筑，并且作為一種獨立的體系用在低、中高度的建筑中。尤其引人關(guān)注的是，在強震區(qū)使用偏心支撐框架。此外，可以利用STRESS，STRUDL，或一系列二維或三維計算機分析程序中的任何一種進行結(jié)構(gòu)分析。另外，初步分析中常用中心距尺寸。剪力墻剪力墻在加強結(jié)構(gòu)體系剛性的發(fā)展過程中又前進了一步。該體系的特點是具有相當薄的，通常是（而不總是）混凝土的構(gòu)件，這種構(gòu)件既可提供結(jié)構(gòu)強度，又可提供建筑物功能上的分隔。在高層建筑中，剪力墻體系趨向于具有相對大的高寬經(jīng)，即與寬度相比，其高度偏大。由于基礎(chǔ)體系缺少應力，任何一種結(jié)構(gòu)構(gòu)件抗傾覆彎矩的能力都受到體系的寬度和構(gòu)件承受的重力荷載的限制。由于剪力墻寬度狹狹窄受限，所以需要以某種方式加以擴大，以便提從所需的抗傾覆能力。在窗戶需要量小的建筑物外墻中明顯地使用了這種確有所需要寬度的體系。鋼結(jié)構(gòu)剪力墻通常由混凝土覆蓋層來加強以抵抗失穩(wěn)，這在剪切荷載大的地方已得到應用。這種體系實際上比鋼支撐經(jīng)濟，對于使剪切荷載由位于地面正上方區(qū)域內(nèi)比較高的樓層向下移特別有效。這種體系還具有高延性之優(yōu)點，這種特性在強震區(qū)特別重要。由于這些墻內(nèi)必然出同一些大孔，使得剪力墻體系分析變得錯綜復雜。可以通過桁架模似法、有限元法，或者通過利用為考慮剪力墻的交互作用或扭轉(zhuǎn)功能設計的專門計處機程序進行初步分析框架或支撐式筒體結(jié)構(gòu)：框架或支撐式筒體最先應用于IBM公司在Pittsburgh的一幢辦公樓，隨后立即被應用于紐約雙子座的110層世界貿(mào)易中心摩天大樓和其他的建筑中。這種系統(tǒng)有以下幾個顯著的特征：三維結(jié)構(gòu)、支撐式結(jié)構(gòu)、或由剪力墻形成的一個性質(zhì)上差不多是圓柱體的閉合曲面，但又有任意的平面構(gòu)成。由于這些抵抗側(cè)向荷載的柱子差不多都被設置在整個系統(tǒng)的中心，所以整體的慣性得到提高，剛度也是很大的。在可能的情況下，通過三維概念的應用、二維的類比，我們可以進行筒體結(jié)構(gòu)的分析。不管