本为海洋图书馆设计说明建筑位于目

ThegraduationdesignfortheOceanUniversityofChinaLinYutanglibrarydesigninstructions.ConstructionislocatedinQingdaoCity,Shprovince.Purposeistomasterthemethodsandstepsof buildingstructuredesign,thearchitecturaldesign automaticallygeneratedgroundplan,standardplanefigure,topfloorplan,elevation,etc..StructurepartIcalculatedusingapinframeasaunit,iscalculatedbythesimplifiedmethod,undertheframeworkofverticalloadoftheinternalforcecalculationusingthebendingdistancedistributionmethod.Dvaluemethodisusedinhorizontaldirection.Thenaccordingtothebottomshearmethodtocalculatehorizontalseismicload,structuralinternalforceundertheactionofhorizontalload,includingbendingmoment,shearingforceandaxialforce.Then,theinternalforceiscombinedtofindthemostunfavorableinternalforce,andthecalculationofthereinforcementofthememberiscalculatedFinally,thePKPMsoftwareisusedtogeneratethebeams,columns,floors,andthefoundationandthenewkoman.:buildStructure,computation,theconstructionorganization建筑设 工程概 设计原始资 材料选 结构选 结构设 框架计算简图及梁柱线刚 恒载标准值计 风荷载计 抗震计 内力组 截面设计与配筋计 基础设 总 致 参考文 附 建筑设工程概况,50年,采光等级为三级,耐火等级为层数与层高：35.1m4.0m。设计标高±0.000设计内容 基本风压w0.6kNm2；基本雪压s0.20kNm2 抗震设防烈度为6度,设计分组为第三组,设计基本加速度值为0.05g,场地墙体：外墙和分户墙采用灰砂砖,240mm×120mm×60mm,r=18KN/m3,内290mm×290mm×140mm.r=9.8KN/m3,r=0.35KN/m2屋面结构：采用现浇钢筋混凝土肋形屋盖,刚柔性相结合屋面,屋面板厚工程概工程名称：工程位置：。2.1按照规定取的建筑面积：4492.8m2，3建筑等级：结构安全等级为二级，设计使用年限为50年，抗震设防类别为标准设的环境（主要是基础）为二b类，耐火等级为二级，地础设计等级为丙级。结构形式：层数与层高：3自然条下列房间功能：书库、借阅处、处、、阅览室还可增设学术报告厅、视听阅9±0.00039.480m表 各岩土层力学指标汇总f（kPa（MPa（kN/m3厚度（m1——27.6/318.7/439/0.5m。4、使用环境类别：b高为4m，故底面柱高为5.1m，其余各层柱高从楼面算至上一层楼面，均为4m，由此可ABBCb×h=300mm×650mmCDb×h=300mm×650mmb×h=300mm×650mm2.1左边跨梁：

左边

=EI/l=3.0×107KN/㎡×2×

×0.3×0.653/7.8m=5.3×104i右边跨=5.3×104KN.m=i左边1中跨梁：i中跨梁=EI/l=3.0×107KN/㎡×2×12×0.3×0.653/7.8m=5.3×1041上部层各柱：i=3.0×107KN/㎡×0.4×0.43/4×12=1.6×1041底层柱 i=3.0×107KN/㎡×0.4×0.43/5.1×12=1.25×104令i左上层柱=1.0则其余各杆件相对线刚度为i左右边跨=5.3×104KN.m/1.6×104KN.m=3.31i中跨梁=5.3×104KN.m/1.6×104KN.m=3.31i底层

=1.25×104KN.m/1.6×104KN.m2恒载标准值计防水层（刚性）30厚细石混凝土防 1.0KM/防水层（柔性）三毡四油铺小石 0.4KM/找坡层：40厚水泥石灰焦渣砂浆3‰ 找平层：15厚水泥砂浆 0.015m×20KN/m3=0.30KN/㎡找坡层：40厚水泥石灰焦渣砂浆3‰找平0.04m×14KN/m3=0.56KM/保温层：80厚矿渣水泥 0.08m×14.5KN/m3=1.16KM/㎡结构层：100厚现浇钢筋混凝土板0.1m×25KN/m3=3KN/㎡水磨石地面（10㎜面层、20㎜水泥砂浆打底、素水泥浆结合一道结构层：120厚现浇钢筋混凝土板 0.10m×25KN/m3=3KN/㎡抹灰层：10㎜厚混合砂 0.01m×17KN/m3=0.17KN/大理石面层，水泥砂浆擦缝、30厚1：3干硬性水泥砂浆，面上撒2㎜厚素水泥水泥浆结合层一 1.16KN/结构层：1200.1m×25KN/结构层：1200.1m×25KN/m3=3KN/抹灰层：100.01×17KN/m3=0.17KN/横梁自重b×h=300×650梁自重 25KN/m3×0.3m×（0.65m-抹灰层：10厚混合砂 合计柱尺 b×h=400㎜×400柱自重 25KN/m3×0.4m×0.4m=4抹灰层：10厚混合砂 (4m-1.8m)×0.36KN/㎡=0.79KN/m外水泥粉刷外涂涂料：（4m-1.8m）×0.5KN/㎡合计纵墙 （5.1-2.4-0.4）×0.24×18N/m3=7.34 (5.1-2.4)×0.5kN/㎡=1.35kN/m水泥粉刷 （5.1-2.4）×0.36kN/㎡纵墙 2.4×0.24m×18KN/m3铝合金窗 水泥粉刷内 2.4×0.36kN/㎡（5.1-2.4-0.4）×0.24×18N/m3=7.34：(5.1-2.4)×0.5kN/㎡=1.35kN/m（5.1-2.4）×0.36kN/㎡（8）3.4×0.24×18KN/m3水泥粉 3.4×2×0.36KN/㎡=2.45内隔墙 3.4×0.24×18KN/m3水泥粉刷 3.4×2×0.36KN/㎡楼面：2.0KN/㎡走廊：2.5KN/Sk=1.0×0.2kN/㎡=0.2KN/㎡屋面活荷载于雪荷载不同时考虑，两2.25.99kN/㎡×1.95×（1-2a2a3）×2=6.49kN/㎡×[1-

(a

a(+ ×1.5×2=6.49kN/㎡×[1- 2.0×1.95×2×（1-2a2+a3）=6.95kN/m恒载 3.83kN/㎡×1.95×（1-2a2+a3活载 0.9×2.0×1.95×2×（1-2a2+a3）=6.25梁自重 4.23kN/A-B屋面梁：恒载=梁自重+板传荷载=4.23kN/m+20.81kN/m活荷载=板传荷 楼面梁：恒载=梁自重+板传荷载=4.23kN/m+13.30kN/m活荷载=板传荷载 =6.255.99kN/㎡×1.95×（1-2a2a3）×2=6.49kN/㎡×[1-

(a

(+ ×1.5×2=6.49kN/㎡×[1- 2.0×1.95×2×（1-2a2+a3）=6.95kN/m恒载 3.83kN/㎡×1.95×（1-2a2+a3活载 0.9×2.0×1.95×2×（1-2a2+a3）=6.25梁自重 4.23kN/A-B屋面梁：恒载=梁自重+板传荷载=4.23kN/m+20.81kN/m活荷载=板传荷 楼面梁：恒载=梁自重+板传荷载=4.23kN/m+13.30kN/m活荷载=板传荷载 =6.25（4）C-D

(a

(+ ×1.5×2=6.49kN/㎡×[1- 2.0×1.95×2×（1-2a2+a3）=6.95kN/m 3.83kN/㎡×1.95×（1-2a2+a3）×2=13.30kN/m 0.9×2.0×1.95×2×（1-2a2+a3）=6.25kN/m梁自重 4.23kN/A-B屋面梁：恒载=梁自重+板传荷载=4.23kN/m+20.81kN/m活荷载=板传荷 楼面梁：恒载=梁自重+板传荷载=4.23kN/m+13.30kN/m活荷载=板传荷载 =6.25女儿墙自重：（600，1000.6m18KN/m3+25KN/0.1m0.24m+(0.7m2+0.24m)0.5KN/=4.01KN／m×7.8m＋4.23KN／m×﹙7.8m-=6.95kN/m×7.8m=54.21标准层柱活载=板传活载（4）B=4.23kN/m(7.8m-0.4m)+5.99kN/m58顶层柱活载=板传荷载=2.0kN/m×8

×1.95×3.9/2×4+2kN/m27.8×4/4=标准层柱恒载=梁自重＋板传荷载=4.23/m×﹙7.8m－0.4m﹚＋3.83KN/m标准层柱活载=板传荷载2.3使用二次分配法计算框架弯2.9试中WO－基本风 2.344443.1风荷载作用下的位移验iii 2 h2ABCD∑2.5Dii 2 h2ABCD∑Dij－j∑μj－jnn和。J层侧

jjj

jj12.3.2风荷载作用下框架侧移计2.631.32×10-23.24×10-18.19×10- 3.3风荷载内力计D值法修正）其步骤如下：（1） Mb(Mi1,jMi,j) ir

Mb(Mi1,jMi,j) ir MlM Vb l

N(VbVbk其中il.ir分别代表节点左右梁的线刚度bMl.M b代表节点左右梁的弯 Ni为柱的层间轴2.7Hi∑iyMMiyMM3448022420515.4712.8MblMbMblNN3--2--719--4重力荷载代表值计12350% 67半层墙体自重1250%楼面均布活活载：50%×2KN/㎡×912.634561250%楼面均布活活载：50%×2KN/㎡×912.63456横向框架侧移刚度的计ibicD

12ic计算，式中系数c 表可查得。（根据梁柱的线刚度比k的不同矩再乘以不同的增大系数。梁截面惯性矩取值见下表，表中I0为梁矩形部分的截面惯2.9ibNb2lEcl1.5Ecl2Ecl33.0 BC3.0 CD3.0 2.10icNmm2bmm2mm4EcIcN3.040013.04002.112.12kib（一般层 （一般层 kDciEIC kib（底层k0.5（底层 kki1ki1i2i3 kkki1k k2.14A/D=kc 2D=kCc30.420.410.42.15B/C=kc 2D=kCc30.420.410.42.16DA轴B轴C轴D轴12.17层123横向水平作用下框架结构的内力和侧移计结构水平作用计算的底部剪力法，按式T1

计算基本周期T1.UT为结构顶点的假想位移,单位为m,即假想把集中在各楼层处的重力荷载代表值Gi作为 UT=(U)k UGi=Gk （ΔU）i=UGi／k

k

jUGii层的层间剪力,2.18321框架结构非承重墙影响系数ψT0.7,则 横向水平作用计算及楼层剪力计40m,Geq=0.85Gi

=a1Geq由场地类别二类,设计分组为第二组,查表Tg=0.40s抗震设防烈度为6度,设计基本加速度值为0.05g，设防查表αmax=0.12因为：Tg<T1=0.58s<5Tg η2=1.0(阻尼调整系数 Tg

0.4a1

(T)2max=0.58

FEK1Geq0.0680.85Gi0.0680.8549202.95

1因为1.4T=1.40.40s=0.56s＜T=0.58s,所以考虑顶部附加作用，顶部附加1g用系数δn各质点的水平作用按下列过程计算，将Sn和FEK代入得

Gin

GinGjHjj1

GjHjj1nn具体计算过程见下表，各楼 剪力按Vi=k

Fk表2.19各层横向作用及楼层剪nGiHi/GkHK34241各质点水平作用及了楼层剪力沿屋高分布图2.15各质 作用分布图2.16剪力沿房屋高度分布水平作用下框架位移计nn水 作用下框架结构的层间位移ui和顶点位移ui分别按公式(ui)Vi/nn和u

(ui

计算，计算过程如表（11）表中e为各层的层间弹性位移角

表2.20横向水平作用下的位移计3211/612<1/550满足式中uh=1/550由表D值法计算。计算柱的反弯点高度mnK查表得到柱反弯点系数yo据上下横梁线刚度比值来查得修正值y1，根据上下层高度变化查得修正值y2，y3反弯点yh=(yoy1y2y3)h2.21中柱（C轴边柱（D轴3同中柱（B轴同边柱（A轴a1y1a1y1a2y2a2y22同中柱（B轴同边柱（A轴a1y1a1y1a2y2a2y21同中柱（B轴同边柱（A轴a1y1a1y1a2y2a2y2同中柱（B轴同边柱（A轴柱端及梁端弯矩的计上柱

=V(1

y

MD=Vyh

ViADVikyMMui34241BCVikyMMui34241

ilb

irbiMb=(mi+1,j+Mi1j)ib

Mb=(mi+1,j+M

irbilbMlbM l

Ni=k

(Vb-Vb)kb, ilir分别表示节点左右梁的线刚度；Mbl，Mr分别表示节点左右梁的弯矩；Nib, 2.23blbl边柱N中柱N3-22-1377-4.8梁端剪力计2.17梁端剪力图2.18水平荷载作用下框架弯矩2.242.25截面设计与配筋计

f=14.3KN/

f=1.43KN/ctct

f360N/

f270N/yy2.26yy12.27承载力调整系数梁0.150.15框架梁配筋计AC（1）2.192.28ⅠⅡⅢⅣⅤb×REM(kNMRE.Mo fbh 11s0.5(112sARE fsy22222%(As梁的斜截面强度计2.29A区BB区bREV/SrREV0.7Psv配筋 框架柱的配筋计以第一层框架柱B轴上柱计算，柱的截面尺寸为 fc=14.3N／底层柱N

求B取 0.25βcfcbho=0.25×1.0×14.3N／㎡B：Nb=α1fcbhoξs=14.3N／㎡N＞NbM，N组合为 内力组合 lo=1.0H=4.7mζ＝0.5fcA／N=0.5×14.3N／mm2×﹙400mm﹚2／1392.43KN=0.82因为 所以ζ2＝ Nb1

Ne0.431fcbho

fs(1b)(hoas

1

1 As=Asˊ=[Nγe－αf 1 3内力组合 lo=1.0H=5.1mζ＝0.5fcA／N=0.5×14.3N／mm2×﹙400mm﹚2／1792.46KN=0.74因为 所以ζ2＝ii Nb1

Ne0.431fcbho

fs(1b)(hoas

1

1 As=Asˊ=[Nγe－αf 1 3B轴柱：最不利内力组合（M=252.20KN·m V

f

Asv ＋1 f 按构造配箍取复式箍 B设计，选粘土层为持力层，fa=260KN/m22.2m，取基础1000m=20kNm3,回填土G=10kN/m3.(d=2.0,bB基础尺寸及埋置深ａ.271.2+1.0=2.2m,100fafakdm(d0.5)=260+2×20×(2.2-0.5)=328.4oA Nkmax,o

faG

1.2A0=4.728Mk=-141.17kN Nk=1539.27Gk=10×1.0×2.6×2.6=108.16747kNek

MkNk

=1792.46kNl6

Nk

1792.46108.16160.0039

)

2.6 k,min

PPk,maxPk,min=290.57 Pk=290.57kPa＜faPk,max=284.10kPa＜fa＜1.2Mk=-747kN

Nk=1792.46ek

MkNk

=747kNl6

Nk

1792.46108.16160.0049

)

2.6 k,min

t取as=60h0=1000-60=940tC30

f1.71N/atac=500ab=500+2×9400=2380am=(2380+500)/2=1440

A(lach)b(bbch

0.94)2=0.274 取h0.7hft(bch0)h0=1592.715＞

基础尺寸及埋置深MPn(la)2(2bb yHRB400f360Nmm2y

0.9h0f

=343.951060.9940360=1129.33选用16@150(As=1340mm2);另一方向选用16@150As=1340mm2的对指导老师和给我帮助过的每一个同学充满了感谢此外，也要感谢室友，班级同学在我设计艰难时期给鼓励和支持再次感谢在百忙中抽出时间来为我们答辩的各位老师及评委，建筑结构荷载规范（GB50009－2001），，中国建筑工业混凝土结构设计规范（GB50010－2002），，中国建筑工建筑抗震设计规范（GB50011－2001），，中国建筑工业建筑地础设计规范（GB50007－2002），，中国建筑工梁兴文.混凝土结构设计原理（第二版）[M].：中国建筑工业梁兴文.混凝土结构设计（第二版）[M].：中国建筑工业王小红，罗建阳.建筑结构CAD—PKPM软件应用[M].：中国建筑工业High-Rise:Inthispaper,fornoadditionalcostunderthepremiseoftoomanybuildingstoresistlateralloadstoenhancethecapacityoftheapplicationofsomeprincipleintroduced.Kayward:High-RiseBuildings,Shear-WallSystems,Rigid-FrameItisdifficulttodefineahigh-risebuilding.Onemaysaythatalow-risebuildingrangesfrom1to2stories.Amedium-risebuildingprobablyrangesbetween3or4storiesupto10or20storiesormore.Althoughthebasicprinciplesofverticalandhorizontalsubsystemdesignremainthesameforlow-,medium-,orhigh-risebuildings,whenabuildinggetshighthevertical eacontrollingproblemfortworeasons.Higherverticalloadswillrequirelargercolumns,walls,andshafts.But,moresignificantly,theoverturningmomentandthesheardeflectionsproducedbylateralforcesaremuchlargerandmustbecarefullyprovidedfor.Theverticalsubsystemsinahigh-risebuildingtransmitaccumulatedgravityloadfromstorytostory,thusrequiringlargercolumnorwallsectionstosupportsuchloading.Inadditionthesesameverticalsubsystemsmusttransmitlateralloads,suchaswindorseismicloads,tothefoundations.However,incontrasttoverticalload,lateralloadeffectsonbuildingsarenotlinearandincreaserapidlywithincreaseinheight.Forexampleunderload,theoverturningmomentatthebaseofbuildingsvariesapproximayasthesquareofabuildingsmayvaryasthefourthpowerofbuildingsheight,otherthingsbeingequal.Earthquakeproducesanevenmorepronouncedeffect.Whenthestructureforalow-ormedium-risebuildingisdesignedfordeadandliveload,itisalmostaninherentpropertythatthecolumns,walls,andstairorelevatorshaftscancarrymostofthehorizontalforces.Theproblemisprimarilyoneof .additionbracingforrigidframesin“short”buildingscaneasilybeprovidedbyfillingcertainpanels(orevenallpanels)withoutincreasingthesizesofthecolumnsandgirdersotherwiserequiredforverticalloads.Unfortunay,thisisnotisforhigh-risebuildingsbecausetheproblemisprimarilytomomentanddeflectionratherthanshearalone.Specialstructuralarrangementswilloftenhavetobemadeandadditionalstructuralmaterialisalwaysrequiredforthecolumns,girders,walls,andslabsinordertomadeahigh-risebuildingssufficientlyresistanttomuchhigherlateraldeformations.Aspreviouslymentioned,thetyofstructuralmaterialrequiredpersquarefootoffloorofahigh-risebuildingsisinexcessofthatrequiredforlow-risebuildings.Theverticalcomponentscarryingthegravityload,suchaswalls,columns,andshafts,willneedtobestrengthenedoverthefullheightofthebuildings.Buttyofmaterialrequiredforresistinglateralforcesisevenmoresignificant.Withreinforcedconcrete,thetyofmaterialalsoincreasesasthenumberofstoriesincreases.Buthereitshouldbenotedthattheincreaseintheweightofmaterialaddedforgravityloadismuoresizablethansteel,whereasforwindloadtheincreaseforlateralforceisnotthatmuoresincetheweightofaconcretebuildingshelpstoresistoverturn.Ontheotherhand,theproblemofdesignforearthquakeforces.Additionalmassintheupperfloorswillgiverisetoagreateroveralllateralforceundertheofseismiceffects.Inthecaseofeitherconcreteorsteeldesign,therearecertainbasicprinciplesforprovidingadditionaltolateraltolateralforcesanddeflectionsinhigh-risebuildingswithouttoomuchsacrifireineconomy.Increasetheeffectivewidthofthemoment-resistingsubsystems.Thisisveryusefulbecauseincreasingthewidthwillcutdowntheoverturnforcedirectlyandwillreducedeflectionbythethirdpowerofthewidthincrease,otherthingsremainingcinstant.However,thisdoesrequirethatverticalcomponentsofthewidenedsubsystembesuitablyconnectedtoactuallygainthisbenefit.Designsubsystemssuchthatthecomponentsaremadetointeractinthemostefficientmanner.Forexample,usetrusssystemswithchordsanddiagonalsefficientlystressed,placereinforcingforwallsatcriticallocations,andoptimizestiffnessratiosforrigidframes.Increasethematerialinthemosteffectiveresistingcomponents.Forexamplematerialsaddedinthelowerfloorstotheflangesofcolumnsandconnectinggirderswilldirectlydecreasetheoveralldeflectionandincreasethemomentwithoutcontributingmassintheupperfloorswheretheearthquakeproblemisaggravated.Arrangetohavethegreaterpartofverticalloadsbecarrieddirectlyontheprimarymoment-resistingcomponents.Thiswillhelpstabilizethebuildingsagainsttensileoverturningforcesby pressingthemajoroverturn-resistingcomponents.Thelocalshearineachstorycanbebestresistedbystrategicplacementifsolidwallsortheuseofdiagonalmembersinaverticalsubsystem.Resistingtheseshearssolelybyverticalmembersinbendingisusuallylesseconomical,sinceachievingsufficientbendinginthecolumnsandconnectinggirderswillrequiremorematerialandconstructionenergythanusingwallsordiagonalmembers.Sufficienthorizontaldiaphragmactionshouldbeprovidedfloor.Thiswillhelptobringthevariousresistingelementstoworktogetherinsteadofseparay.Createmega-framesbyjoininglargeverticalandhorizontalcomponentssuchastwomoreelevatorshaftsatmultistoryintervalswithaheavyfloorsubsystems,orbyuseofverydeepgirdertrusses.Rememberthatallhigh-risebuildingsareessentiallyverticalcantileverswhicharesupportedattheground.Whentheaboveprinciplesarejudiciouslyapplied,structurallydesirableschemescanbeobtainedbywalls,cores,rigidframes,tubularconstruction,andotherverticalsubsystemstoachievehorizontalstrengthandrigidity.Someoftheseapplicationswillnowbedescribedinsubsequentsectionsinthefollowing.Shear-WallWhenshearwallsarecompatiblewithotherfunctionalrequirements,theycanbeeconomicallyutilizedtoresistlateralforcesinhigh-risebuildings.Forexample,apartmentbuildingsnaturallyrequiremanyseparationwalls.Whensomeofthesearedesignedtobesolid,theycanashearwallstoresistlateralforcesandtocarrytheverticalloadaswell.Forbuildingsuptosome20storise,theuseofshearwallsiscommon.Ifgivensufficientlength,suchwallscaneconomicallyresistlateralforcesupto30to40storiesormore.However,shearwallscanresistlateralloadonlytheplaneofthewalls(i.e.notindiretionperpendiculartothem).Therefore,itisalwaysnecessarytoprovideshearwallsintwoperpendiculardirectionscanbeatleastinsufficientorientationsothatlateralforceinanydirectioncanberesisted.Inaddition,thatwalllayoutshouldreflectconsiderationofanytorsionaleffect.Indesignprogress,twoormoreshearwallscanbeconnectedtofromL-shapedorchannel-shapedsubsystems.Indeed,internalshearwallscanbeconnectedtofromarectangularshaftthatwillresistlateralforcesveryefficiently.Ifallexternalshearwallsarecontinuouslyconnected,thenthewholebuildingsactsastube,andconnected,thenthewholebuildingsactsasatube,andisexcellentShear-WallSeystemsresistinglateralloadsandtorsion.Whereasconcreteshearwallsaregenerallyofsolidtypewithopeningswhennecessary,steelshearwallsareusuallymadeoftrusses.Thesetrussescanhavesinglediagonals,“X”diagonals,or“K”arrangements.Atrussedwallwillhaveitsmembersactessentiallyindirecttensionorcompressionundertheactionofview,andtheyoffersomeopportunityanddeflection-limitationpointofview,andtheyoffersomeopportunityforpenetrationbetweenmembers.Ofcourse,theinclinedmembersoftrussesmustbesuitableplacedsoasnottointerferewithrequirementsforwiondowsandforcirculationservicepenetrationsthoughthesewalls.Asstatedabove,thewallsofelevator,staircase,andutilityshaftsformnaturaltubesandarecommonlyemployedtoresistbothverticalandlateralforces.Sincetheseshaftsarenormallyrectangularorcircularincross-section,theycanofferanefficientmeansforresistingmomentsandshearinalldirectionsduetotubestructuralaction.Butaprobleminthedesignoftheseshaftsisprovidedsufficientstrengtharounddooropeningsandotherpenetrationsthroughtheseelements.Forreinforcedconcreteconstruction,specialsteelreinforcementsareplacedaroundsuchopening.Insteelconstruction,heavierandmorerigidconnectionsarerequiredtoresistrackingattheopenings.Inmanyhigh-risebuildings,acombinationofwallsandshaftscanofferexcellenttolateralforceswhentheyaresuitablylocatedantconnectedtooneanother.Itisalsodesirablethatthestiffnessofferedthesesubsystemsbemore-or-lesssymmertricalinalldirections.Rigid-FrameInthedesignofarchitecturalbuildings,rigid-framesystemsforresistingverticalandlateralloadshavelongbeenacceptedasanimportantandstandardmeansfordesigningbuilding.Theyareemployedforlow-andmediummeansfordesigningbuildings.Theyareemployedforlow-andmediumuptohigh-risebuildingperhaps70or100storieshigh.Whencomparedtoshear-wallsystems,theserigidframesbothwithinandattheoutsideofabuildings.Theyalsomakeuseofthestiffnessinbeamsandcolumnsthatarerequiredforthebuildingsinanycase,butthecolumnsaremadestrongerwhenrigidlyconnectedtoresistthelateralaswellasverticalforcesthoughframebending.Frequently,rigidframeswillnotbeasstiffasshear-wallconstruction,andthereforemayproduceexcessivedeflectionsforthemoreslenderhigh-risebuildingsdesigns.Butbecauseofthisflexibility,theyareoftenconsideredasbeingmoreductileandthuslesssusceptibletocatastrophicearthquakefailurewhencomparedwith(some)shear-walldesigns.Forexample,ifoverstressingoccursatcertainportionsofasteel