外文翻译高层建筑及结构设计.docx

外文翻译高层建筑及结构设计.docx

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外文翻译高层建筑及结构设计

附录：

毕业设计外文翻译

院（系）建筑工程学院

专业土木工程

班级070710班

姓名张波

学号070710317

导师周雪峰

2011年4月15日

英文：

High-RiseBuildingsandStructuralDesign

Abstract：

Itisdifficulttodefineahigh-risebuilding.Onemaysaythatalow-risebuildingrangesfrom1to2stories.Amedium-risebuildingprobablyrangesbetween3or4storiesupto10or20storiesormore.Althoughthebasicprinciplesofverticalandhorizontalsubsystemdesignremainthesameforlow-,medium-,orhigh-risebuildings,whenabuildinggetshightheverticalsubsystemsbecomeacontrollingproblemfortworeasons.Higherverticalloadswillrequirelargercolumns,walls,andshafts.But,moresignificantly,theoverturningmomentandthesheardeflectionsproducedbylateralforcesaremuchlargerandmustbecarefullyprovidedfor.

KeyWords：

High-RiseBuildingsStructuralDesignFrameworkShearSeismicSystem

Introduction

Theverticalsubsystemsinahigh-risebuildingtransmitaccumulatedgravityloadfromstorytostory,thusrequiringlargercolumnorwallsectionstosupportsuchloading.Inadditionthesesameverticalsubsystemsmusttransmitlateralloads,suchaswindorseismicloads,tothefoundations.However,incontrasttoverticalload,lateralloadeffectsonbuildingsarenotlinearandincreaserapidlywithincreaseinheight.Forexampleunderwindload,theoverturningmomentatthebaseofbuildingsvariesapproximatelyasthesquareofabuildingsmayvaryasthefourthpowerofbuildingsheight,otherthingsbeingequal.Earthquakeproducesanevenmorepronouncedeffect.

Whenthestructureforalow-ormedium-risebuildingisdesignedfordeadandliveload,itisalmostaninherentpropertythatthecolumns,walls,andstairorelevatorshaftscancarrymostofthehorizontalforces.Theproblemisprimarilyshearresistance.Moderateadditionbracingforrigidframesin“short”buildingscaneasilybeprovidedbyfillingcertainpanels（orevenallpanels）withoutincreasingthesizesofthecolumnsandgirdersotherwiserequiredforverticalloads.

Unfortunately,thisisnotisforhigh-risebuildingsbecausetheproblemisprimarilyresistancetomomentanddeflectionratherthanshearalone.Specialstructuralarrangementswilloftenhavetobemadeandadditionalstructuralmaterialisalwaysrequiredforthecolumns,girders,walls,andslabsinordertomadeahigh-risebuildingssufficientlyresistanttomuchhigherlateraldeformations.

Aspreviouslymentioned,thequantityofstructuralmaterialrequiredpersquarefootoffloorofahigh-risebuildingsisinexcessofthatrequiredforlow-risebuildings.Theverticalcomponentscarryingthegravityload,suchaswalls,columns,andshafts,willneedtobestrengthenedoverthefullheightofthebuildings.Butquantityofmaterialrequiredforresistinglateralforcesisevenmoresignificant.

Withreinforcedconcrete,thequantityofmaterialalsoincreasesasthenumberofstoriesincreases.Buthereitshouldbenotedthattheincreaseintheweightofmaterialaddedforgravityloadismuchmoresizablethansteel,whereasforwindloadtheincreaseforlateralforceresistanceisnotthatmuchmoresincetheweightofaconcretebuildingshelpstoresistoverturn.Ontheotherhand,theproblemofdesignforearthquakeforces.Additionalmassintheupperfloorswillgiverisetoagreateroveralllateralforceundertheofseismiceffects.

Inthecaseofeitherconcreteorsteeldesign,therearecertainbasicprinciplesforprovidingadditionalresistancetolateraltolateralforcesanddeflectionsinhigh-risebuildingswithouttoomuchsacrifireineconomy.

1、Increasetheeffectivewidthofthemoment-resistingsubsystems.Thisisveryusefulbecauseincreasingthewidthwillcutdowntheoverturnforcedirectlyandwillreducedeflectionbythethirdpowerofthewidthincrease,otherthingsremainingcinstant.However,thisdoesrequirethatverticalcomponentsofthewidenedsubsystembesuitablyconnectedtoactuallygainthisbenefit.

2、Designsubsystemssuchthatthecomponentsaremadetointeractinthemostefficientmanner.Forexample,usetrusssystemswithchordsanddiagonalsefficientlystressed,placereinforcingforwallsatcriticallocations,andoptimizestiffnessratiosforrigidframes.

3、Increasethematerialinthemosteffectiveresistingcomponents.Forexample,materialsaddedinthelowerfloorstotheflangesofcolumnsandconnectinggirderswilldirectlydecreasetheoveralldeflectionandincreasethemomentresistancewithoutcontributingmassintheupperfloorswheretheearthquakeproblemisaggravated.

4、Arrangetohavethegreaterpartofverticalloadsbecarrieddirectlyontheprimarymoment-resistingcomponents.Thiswillhelpstabilizethebuildingsagainsttensileoverturningforcesbyprecompressingthemajoroverturn-resistingcomponents.

5、Thelocalshearineachstorycanbebestresistedbystrategicplacementifsolidwallsortheuseofdiagonalmembersinaverticalsubsystem.Resistingtheseshearssolelybyverticalmembersinbendingisusuallylesseconomical,sinceachievingsufficientbendingresistanceinthecolumnsandconnectinggirderswillrequiremorematerialandconstructionenergythanusingwallsordiagonalmembers.

6、Sufficienthorizontaldiaphragmactionshouldbeprovidedfloor.Thiswillhelptobringthevariousresistingelementstoworktogetherinsteadofseparately.

7、Createmega-framesbyjoininglargeverticalandhorizontalcomponentssuchastwoormoreelevatorshaftsatmultistoryintervalswithaheavyfloorsubsystems,orbyuseofverydeepgirdertrusses.

Rememberthatallhigh-risebuildingsareessentiallyverticalcantileverswhicharesupportedattheground.Whentheaboveprinciplesarejudiciouslyapplied,structurallydesirableschemescanbeobtainedbywalls,cores,rigidframes,tubularconstruction,andotherverticalsubsystemstoachievehorizontalstrengthandrigidity.Someoftheseapplicationswillnowbedescribedinsubsequentsectionsinthefollowing.

Shear-WallSystems

Whenshearwallsarecompatiblewithotherfunctionalrequirements,theycanbeeconomicallyutilizedtoresistlateralforcesinhigh-risebuildings.Forexample,apartmentbuildingsnaturallyrequiremanyseparationwalls.Whensomeofthesearedesignedtobesolid,theycanactasshearwallstoresistlateralforcesandtocarrytheverticalloadaswell.Forbuildingsuptosome20storise,theuseofshearwallsiscommon.Ifgivensufficientlength,suchwallscaneconomicallyresistlateralforcesupto30to40storiesormore.

However,shearwallscanresistlateralloadonlytheplaneofthewalls（i.e.notinadiretionperpendiculartothem）.Therefore,itisalwaysnecessarytoprovideshearwallsintwoperpendiculardirectionscanbeatleastinsufficientorientationsothatlateralforceinanydirectioncanberesisted.Inaddition,thatwalllayoutshouldreflectconsiderationofanytorsionaleffect.

Indesignprogress,twoormoreshearwallscanbeconnectedtofromL-shapedorchannel-shapedsubsystems.Indeed,internalshearwallscanbeconnectedtofromarectangularshaftthatwillresistlateralforcesveryefficiently.Ifallexternalshearwallsarecontinuouslyconnected,thenthewholebuildingsactsasatube,andisexcellentShear-WallSystemsresistinglateralloadsandtorsion.

Whereasconcreteshearwallsaregenerallyofsolidtypewithopeningswhennecessary,steelshearwallsareusuallymadeoftrusses.Thesetrussescanhavesinglediagonals,“X”diagonals,or“K”arrangements.Atrussedwallwillhaveitsmembersactessentiallyindirecttensionorcompressionundertheactionofview,andtheyoffersomeopportunityanddeflection-limitationpointofview,andtheyoffersomeopportunityforpenetrationbetweenmembers.Ofcourse,theinclinedmembersoftrussesmustbesuitableplacedsoasnottointerferewithrequirementsforwindowsandforcirculationservicepenetrationsthoughthesewalls.

Asstatedabove,thewallsofelevator,staircase,andutilityshaftsformnaturaltubesandarecommonlyemployedtoresistbothverticalandlateralforces.Sincetheseshaftsarenormallyrectangularorcircularincross-section,theycanofferanefficientmeansforresistingmomentsandshearinalldirectionsduetotubestructuralaction.Butaprobleminthedesignoftheseshaftsisprovidedsufficientstrengtharounddooropeningsandotherpenetrationsthroughtheseelements.Forreinforcedconcreteconstruction,specialsteelreinforcementsareplacedaroundsuchopening.Insteelconstruction,heavierandmorerigidconnectionsarerequiredtoresistrackingattheopenings.

Inmanyhigh-risebuildings,acombinationofwallsandshaftscanofferexcellentresistancetolateralforceswhentheyaresuitablylocatedantconnectedtooneanother.Itisalsodesirablethatthestiffnessofferedthesesubsystemsbemore-or-lesssymmertricalinalldirections.

Rigid-FrameSystems

Inthedesignofarchitecturalbuildings,rigid-framesystemsforresistingverticalandlateralloadshavelongbeenacceptedasanimportantandstandardmeansfordesigningbuilding.Theyareemployedforlow-andmediummeansfordesigningbuildings.Theyareemployedforlow-andmediumuptohigh-risebuildingperhaps70or100storieshigh.Whencomparedtoshear-wallsystems,theserigidframesbothwithinandattheoutsideofabuildings.Theyalsomakeuseofthestiffnessinbeamsandcolumnsthatarerequiredforthebuildingsinanycase,butthecolumnsaremadestrongerwhenrigidlyconnectedtoresistthelateralas