高层建筑High-RiseBuilding

LESSON15High-RiseBuildingsBackgroundKnowledge本单元涉及的课程：《高层建筑结构》高层建筑经过长期的发展，其主要材料为钢材、钢筋混凝土，主要结构体系为框架结构、剪力墙结构体系、框架—剪力墙结构(筒体)体系、筒体结构和巨型结构等。本课文主要涉及了高层建筑的受力特点、设计理念等。Part1TheFirstDevelopmentofTallBuildingPlanforWarOffice,England,1857NewWordsandExpressionofPart1Paragraph1shaftn.电梯井theoverturningmoment倾覆力矩；倾翻力矩thesheardeflection剪力变形Itisdifficulttodefineahigh-risebuilding.Amid-risebuildinggenerallylessthan10stories(28m).Thusahigh-risebuildingisonethathasatleast10storiesormore.Althoughthebasicprinciplesofverticalandhorizontalsubsystemdesignremainthesameformid-,orhigh-risebuildings,whenabuildinggetshightheverticalsubsystemsbecomeacontrollingproblemfortworeasons.Paragraph1(theverticalsubsystemsiscontrollingproblemforhigh-risebuildings)Higherverticalloadswillrequirelargercolumns,walls,andshafts.But,moresignificantly,theoverturningmomentandthesheardeflectionsproducedbylateralforcesaremuchlargerandmustbecarefullyprovidedfor.Paragraph1(theverticalsubsystemsiscontrollingproblemforhigh-risebuildings)Theverticalsubsystemsinahigh-risebuildingtransmitaccumulatedgravityloadfromstorytostory,thusrequiringlargercolumnorwallsectionstosupportsuchloading.Inaddition,thesesameverticalsubsystemsmusttransmitlateralloads,suchaswindorseismicactions,tothefoundations..Paragraph2(lateralloadeffectsappliedontheverticalsubsystems)However,incontrasttoverticalload,lateralloadeffectsonbuildingsarenotlinearandincreaserapidlywithincreaseinheight.Forexample,underwindload,theoverturningmomentatthebaseofabuildingvariesapproximatelyasthesquareoftheheightofthebuilding,andthelateraldeflectionatthetopofabuildingmayvaryasthefourthpowerofbuildingheight,otherthingsbeingequal.Earthquakeproducesanevenmorepronouncedeffect.Paragraph2(lateralloadeffectsappliedontheverticalsubsystems)在风荷载作用下，建筑基础处的倾覆力矩大致是随建筑高度的二次方变化，建筑物顶部的水平挠度随建筑高度的四次方变化。powern.幂thepoweroffour,thefourthpower四次方Whenthestructureforamid-risebuildingisdesignedfordeadandliveload,itisalmostaninherentpropertythatthecolumns,walls,andstairorelevatorshaftscancarrymostofthehorizontalforces.Theproblemisprimarilyoneofshearresistance..Paragraph3(shearresistanceofamid-risebuilding)问题主要是剪力抵抗。Moderateadditionalbracingforrigidframesin“short”buildingscaneasilybeprovidedbyfillingcertainpanels(orevenallpanels)withoutincreasingthesizesofthecolumnsandgirdersotherwiserequiredforverticalloads.additionalbracing附加的支撑Paragraph3(shearresistanceofamid-risebuilding)如无特殊竖向承载需要，（矮建筑中）框架体系无需加大柱和梁的尺寸，只通过设置某些填充墙板（或全部填充墙）就可以轻易地实现中等强度的附加支撑（以抵抗剪力）。Unfortunately,thisisnotsoforhighrisebuildingsbecausetheproblemisprimarilyresistancetomomentanddeflectionratherthanshearalone.Specialstructuralarrangementswilloftenhavetobemadeandadditionalstructuralmaterialisalwaysrequiredforthecolumns,girders,walls,andslabsinordertomakeahighrisebuildingsufficientlyresistanttomuchhigherlateralloadsanddeformations,Paragraph4(Resistancetomomentanddeflection，andshearforhigh-risebuildings)为了使高层建筑对更高的水平荷载与变形有足够的抵抗能力，常常需要做特殊的结构布置、且柱、主梁、墙、板需要额外的结构材料。Aspreviouslymentioned,thequantityofstructuralmaterialrequiredpersquarefootoffloorofahigh-risebuildingisinexcessofthatrequiredforalowrisebuilding.Theverticalcomponentscarryingthegravityload,suchaswalls,columns,andshafts,willneedtobestrengthenedoverthefullheightofthebuilding.Paragraph5(howtheweightofstructuralsteelincreasesasthenumberofstoriesincreases)inexcessof超过；较…为多Butquantityofmaterialsrequiredforresistinglateralforcesisevenmoresignificant.ThegraphshowninFig.25.1illustrateshowtheweightofstructuralsteelinpoundspersquarefeetoffloorincreasesasthenumberofstoriesincreasesfrom1upto100.图25.1说明了当楼层从1增加到100时，楼板每平方英尺结构用钢重量的增长。Paragraph5(howtheweightofstructuralsteelincreasesasthenumberofstoriesincreases)Notethatbyusingoptimumstructuralsystemswithsuitablewidthandarrangement,theadditionalmaterialrequiredforlateralforceresistancecanbecontrolledsuchthat,evenforbuildingsof100stories,thetotalstructuralweightofsteelmaybeonlyabout34poundspersquarefoot,whereasitisnotedpreviously,somebuildingsquiteabitshorterrequiremuchmorestructuralsteel.Paragraph5(howtheweightofstructuralsteelincreasesasthenumberofstoriesincreases)现在意识到，经过合适的尺度和布局进行结构体系优化，抵抗水平力所需要的额外材料可以控制到如下程度：即使100层，结构钢材总重也可以是34磅每平方英尺，然而，以前认为某些建筑中缺少相当多的结构钢材。CurveAinFig.25.1representstheaverageunitweightofaconventionalframewithincreasingnumbersofstories.CurveBrepresentstheaveragesteelweightiftheframeisprotectedfromalllateralloads.Thegapbetweentheupperboundaryandthelowerboundaryrepresentsthepremiumforheightforthetraditionalcolumn-and-beamframe.Structuralengineershavedevelopedstructuralsystemswithaviewtoeliminatingthispremium.premium['pri:miəm]n.额外费用曲线B代表平均钢材重量，如果框架免受水平荷载影响。Paragraph5(howtheweightofstructuralsteelincreasesasthenumberofstoriesincreases)曲线A代表随着层数增加的传统框架的平均单位重量。曲线B代表平均钢材重量，如果框架免受水平荷载影响。A线代表材料用量随高度增加的趋势，B线表示，如果不受水平荷载作用，其材料重量随高度增加的趋势，中间部分表示的就是随高度增加，水平荷载引起的材料重量的增加，设计人员要合理布置，以使这个值降低Withreinforcedconcrete,thequantityofmaterialalsoincreasesasthenumberofstoriesincreases.Buthereitshouldbenotedthattheincreaseintheweightofmaterialaddedforgravityloadismuchmoresizablethanforsteel,