外文翻译抗侧向荷载的结构体系

1、协较焙蘼鲂郴命蜉螋蟋娄讣抗侧向荷载的结构体系袁鹪韵鲋竭而哈魔啸钢圃茇常用的结构体系掸退锍氰企猹辊蝉蕲荜依驺若已测出荷载量达数千万磅重，那么在高层建筑设计中就没有多少可以进行极其复杂的构思余地了。确实，较好的高层建筑普遍具有构思简单、表现明晰的特点。剀冁馅粪昴镱嫣攥缀抬劝璜这并不是说没有进行宏观构思的余地。实际上，正是因为有了这种宏观的构思，新奇的高层建筑体系才得以发展，可能更重要的是：几年以前才出现的一些新概念在今天的技术中已经变得平常了。善筮藏响巨童莫馥荔柙钤俑如果忽略一些与建筑材料密切相关的概念不谈，高层建筑里最为常用的结构体系便可分为如下几类：疖斑瘸丽吝王铥径橘庑阽吩1 抗弯矩框架。亻韭

2、药隅砥嘎熹洁讴再笠綦2 支撑框架，包括偏心支撑框架。垸檠撺愦垡刻卦锨前雀榈冫3 剪力墙，包括钢板剪力墙。耱吱钒稹咔赕忏绚支弓炳贿4 筒中框架。啉箬矧嫉貌募奚杉鞋钱榷菽5 筒中筒结构。盘蜮怠蚣替镖褰蝤羟癸逭刮6 核心交互结构。济饯利丬兢桥辚挚均磙附洵7 框格体系或束筒体系。纱俦砧蕲纬奖渴涝筘粽胙急特别是由于最近趋向于更复杂的建筑形式，同时也需要增加刚度以抵抗几力和地震力，大多数高层建筑都具有由框架、支撑构架、剪力墙和相关体系相结合而构成的体系。而且，就较高的建筑物而言，大多数都是由交互式构件组成三维陈列。酉瑁彝邗壁删搪幄秃完垠芄将这些构件结合起来的方法正是高层建筑设计方法的本质。其结合方式需要在

3、考虑环境、功能和费用后再发展，以便提供促使建筑发展达到新高度的有效结构。这并不是说富于想象力的结构设计就能够创造出伟大建筑。正相反，有许多例优美的建筑仅得到结构工程师适当的支持就被创造出来了，然而，如果没有天赋甚厚的建筑师的创造力的指导，那么，得以发展的就只能是好的结构，并非是伟大的建筑。无论如何，要想创造出高层建筑真正非凡的设计，两者都需要最好的。舳镖伽忐弱四辞蕻氯溲崇羰虽然在文献中通常可以见到有关这七种体系的全面性讨论，但是在这里还值得进一步讨论。设计方法的本质贯穿于整个讨论。设计方法的本质贯穿于整个讨论中。铘湔贳嘞钪湫戎粥盒孕赛韭抗弯矩框架惬疯庭鄙勐短番机鞲妇涠玎抗弯矩框架也许是低，中高

4、度的建筑中常用的体系，它具有线性水平构件和垂直构件在接头处基本刚接之特点。这种框架用作独立的体系，或者和其他体系结合起来使用，以便提供所需要水平荷载抵抗力。对于较高的高层建筑，可能会发现该本系不宜作为独立体系，这是因为在侧向力的作用下难以调动足够的刚度。遏笫粒屑汽矗干屺亓疋熟了我们可以利用STRESS，STRUDL 或者其他大量合适的计算机程序进行结构分析。所谓的门架法分析或悬臂法分析在当今的技术中无一席之地，由于柱梁节点固有柔性，并且由于初步设计应该力求突出体系的弱点，所以在初析中使用框架的中心距尺寸设计是司空惯的。当然，在设计的后期阶段，实际地评价结点的变形很有必要。身耍版曲掼嗌破铮傈唪圣

5、驭支撑框架豕娃澎蔡镀傅组褪逖渴戢民支撑框架实际上刚度比抗弯矩框架强，在高层建筑中也得到更广泛的应用。这种体系以其结点处铰接或则接的线性水平构件、垂直构件和斜撑构件而具特色，它通常与其他体系共同用于较高的建筑，并且作为一种独立的体系用在低、中高度的建筑中。璐缌骖骨奥菇毓炒首樨闼旧尤其引人关注的是，在强震区使用偏心支撑框架。歪联啪钊揪召众竣慰禳夥颈此外，可以利用STRESS，STRUDL，或一系列二维或三维计算机分析程序中的任何一种进行结构分析。另外，初步分析中常用中心距尺寸。钛洳掣仲芳跣诓羁仅娄篆嘻剪力墙灿麻伧王阎龈疯涨驱蕞赎答剪力墙在加强结构体系刚性的发展过程中又前进了一步。该体系的特点是具有

6、相当薄的，通常是（而不总是）混凝土的构件，这种构件既可提供结构强度，又可提供建筑物功能上的分隔。趼鞣瓤祷嗦挢萌葭辽封芷疋在高层建筑中，剪力墙体系趋向于具有相对大的高宽经，即与宽度相比，其高度偏大。由于基础体系缺少应力，任何一种结构构件抗倾覆弯矩的能力都受到体系的宽度和构件承受的重力荷载的限制。由于剪力墙宽度狭狭窄受限，所以需要以某种方式加以扩大，以便提从所需的抗倾覆能力。在窗户需要量小的建筑物外墙中明显地使用了这种确有所需要宽度的体系。状搬苄流虏眦献栌狸腕我请钢结构剪力墙通常由混凝土覆盖层来加强以抵抗失稳，这在剪切荷载大的地方已得到应用。这种体系实际上比钢支撑经济，对于使剪切荷载由位于地面正上

7、方区域内比较高的楼层向下移特别有效。这种体系还具有高延性之优点，这种特性在强震区特别重要。垢匚靥篱讼钢皤撅柰猬齐笞由于这些墙内必然出同一些大孔，使得剪力墙体系分析变得错综复杂。可以通过桁架模似法、有限元法，或者通过利用为考虑剪力墙的交互作用或扭转功能设计的专门计处机程序进行初步分析统剞认颔黧琴葡米妮鹗忸蹼毓檫踯樽骇郅灾呼尥其汶福框架或支撑式筒体结构：中躏沮蛋龆玩垲炙凸砸堠鲮框架或支撑式筒体最先应用于IBM公司在Pittsburgh的一幢办公楼，随后立即被应用于纽约双子座的110层世界贸易中心摩天大楼和其他的建筑中。这种系统有以下几个显著的特征：三维结构、支撑式结构、或由剪力墙形成的一个性质上差

8、不多是圆柱体的闭合曲面，但又有任意的平面构成。由于这些抵抗侧向荷载的柱子差不多都被设置在整个系统的中心，所以整体的惯性得到提高，刚度也是很大的。裔誊辖塬叉啡瞟砺铢嬷枚务在可能的情况下，通过三维概念的应用、二维的类比，我们可以进行筒体结构的分析。不管应用那种方法，都必须考虑剪力滞后的影响。鲺婪墙跛秆白釉啥裸殁遴琦这种最先在航天器结构中研究的剪力滞后出现后，对筒体结构的刚度是一个很大的限制。这种观念已经影响了筒体结构在60层以上建筑中的应用。设计者已经开发出了很多的技术，用以减小剪力滞后的影响，这其中最有名的是桁架的应用。框架或支撑式筒体在40层或稍高的建筑中找到了自己的用武之地。除了一些美观的考

9、虑外，桁架几乎很少涉及与外墙联系的每个建筑功能，而悬索一般设置在机械的地板上，这就令机械体系设计师们很不赞成。但是，作为一个性价比较好的结构体系，桁架能充分发挥它的性能，所以它会得到设计师们持续的支持。由于其最佳位置正取决于所提供的桁架的数量，因此很多研究已经试图完善这些构件的位置。实验表明：由于这种结构体系的经济性并不十分受桁架位置的影响，所以这些桁架的位置主要取决于机械系统的完善，审美的要求，绞呤遴郸姊浩轿萆幛摹蝴茎辏激埙煽稣睿枨藓嗦敝悄侍筒中筒结构：朽敬芒馁幄配磁喔醐淝嚷敉筒体结构系统能使外墙中的柱具有灵活性，用以抵抗颠覆和剪切力。“筒中筒”这个名字顾名思义就是在建筑物的核心承重部分又被

10、包围了第二层的一系列柱子，它们被当作是框架和支撑筒来使用。配置第二层柱的目的是增强抗颠覆能力和增大侧移刚度。这些筒体不是同样的功能，也就是说，有些筒体是结构的，而有些筒体是用来支撑的。惟湘亚呗祥圃薇哙堠记醇邙在考虑这种筒体时，清楚的认识和区别变形的剪切和弯曲分量是很重要的，这源于对梁的对比分析。在结构筒中，剪切构件的偏角和柱、纵梁（例如：结构筒中的网等）的弯曲有关，同时，弯曲构件的偏角取决于柱子的轴心压缩和延伸（例如：结构筒的边缘等）。在支撑筒中，剪切构件的偏角和对角线的轴心变形有关，而弯曲构件的偏角则与柱子的轴心压缩和延伸有关。铂撺芬锎缈虱诨刎杏柩坐恨根据梁的对比分析，如果平面保持原形（例如

11、：厚楼板），那么外层筒中柱的轴心压力就会与中心筒柱的轴心压力相差甚远，而且稳定的大于中心筒。但是在筒中筒结构的设计中，当发展到极限时，内部轴心压力会很高的，甚至远远大于外部的柱子。这种反常的现象是由于两种体系中的剪切构件的刚度不同。这很容易去理解，内筒可以看成是一个支撑（或者说是剪切刚性的）筒，而外筒可以看成是一个结构（或者说是剪切弹性的）筒。阀诗阻唬幽馐镤嚷瘠禧崞嘉太吱井裹戥佣胴喙陷牿使览核心交互式结构：讥女肌颓膜廷粮畸渚玎早肢核心交互式结构属于两个筒与某些形式的三维空间框架相配合的筒中筒特殊情况。事实上，这种体系常用于那种外筒剪切刚度为零的结构。位于Pittsburgh的美国钢铁大楼证实了

12、这种体系是能很好的工作的。在核心交互式结构中，内筒是一个支撑结构，外筒没有任何剪切刚度，而且两种结构体系能通过一个空间结构或“帽”式结构共同起作用。需要指出的是，如果把外部的柱子看成是一种从“帽”到基础的直线体系，这将是不合适的；根据支撑核心的弹性曲线，这些柱子只发挥了刚度的15%。同样需要指出的是，内柱中与侧向力有关的轴向力沿筒高度由拉力变为压力，同时变化点位于筒高度的约5/8处。当然，外柱也传递相同的轴向力，这种轴向力低于作用在整个柱子高度的侧向荷载，因为这个体系的剪切刚度接近于零。毳汀扮款臣锗谫恒逞豆枚咕把内外筒相连接的空间结构、悬臂梁或桁架经常遵照一些规范来布置。美国电话电报总局就是一

13、个布置交互式构件的生动例子。受挖梧硪什哉者疃浦青嵫谫1、 结构体系长59.7米，宽28.6米，高183.3米。腕龀祧箕捱侄特羞竟带猫榜2、 布置了两个筒，每个筒的尺寸是9.4米12.2米，在长方向上有27.4米的间隔。到赔螵蜃猬乐爽磐艹称肺析3、 在短方向上内筒被支撑起来，但是在长方向上没有剪切刚度。潜窄蚪恰拊茅镪咽丢郄辞捐4、 环绕着建筑物布置了一个外筒。千伴蕾鬣圮沅獒燹怵跳径郾5、 外筒是一个瞬时抵抗结构，但是在每个长方向的中心15.2米都没有剪切刚度。挛携枭讼桶杂陶楫鸲玮遣夤6、 在建筑的顶部布置了一个空间桁架构成的“帽式”结构。瓜脐撺猓砖炼仑嗡倒集诵皑7、 在建筑的底部布置了一个相似的

14、空间桁架结构。唠撙站耗褛力嗨窝莳舍值河8、 由于外筒的剪切刚度在建筑的底部接近零，整个建筑基本上由两个钢板筒来支持。痪渤癖猷歃裹烟衾伺廪槟阔岩羰隈蛞嗍籴翌苏俩装警穿框格体系或束筒体系结构：贩步骱秉翰猖枵芬怊隍拮浙位于美国芝加哥的西尔斯大厦是箱式结构的经典之作，它由九个相互独立的筒组成的一个集中筒。由于西尔斯大厦包括九个几乎垂直的筒，而且筒在平面上无须相似，基本的结构体系在不规则形状的建筑中得到特别的应用。一些单个的筒高于建筑一点或很多是很常见的。事实上，这种体系的重要特征就在于它既有坚固的一面，也有脆弱的一面。萋嘭螺素墩煮骞糨脎限侯滠这种体系的脆弱，特别是在结构筒中，与柱子的压缩变形有很大的关

15、系，柱子的压缩变形有下式计算：长瘛崤磨蝗菹伺叭钚肄舞尼=fL/E胲雠潜角柘厮苋苊亩幼蔬喔对于那些层高为3.66米左右和平均压力为138MPa的建筑，在荷载作用下每层柱子的压缩变形为15（12）/29000或1.9毫米。在第50层柱子会压缩94毫米，小于它未受压的长度。这些柱子在50层的时候和100层的时候的变形是不一样的，位于这两种体系之间接近于边缘的那些柱需要使这种不均匀的变形得以调解。凳圾炳哼贴沦锑讥劲待欹校主要的结构工作都集中在布置中。在Melbourne的Rialto项目中，结构工程师发现至少有一幢建筑，很有必要垂直预压低高度的柱子，以便使柱不均匀的变形差得以调解，调解的方法近似于后拉

16、伸法，即较短的柱转移重量到较高的邻柱上。灌内酆膻岫苣嫖堍眄傥钳椒晤铟蕉的规谊圻伐洧泊赖镭Structural Systems to resist lateral loads酒蜉啮惹蛾怿凰罐杪虽抨什Commonly Used structural Systems严俭饕吼氪昱甥尤娓忘漭渴With loads measured in tens of thousands kips,there is little room in the design of high-rise buildings for excessively complex thoughts. Indeed, the better h

17、igh-rise buildings carry the universal traits of simplicity of thought and clarity of expression.憔相笪绗擘纯缙姹鸶罢绠谕It does not follow that there is no room for grand thoughts. Indeed, it is with such grand thoughts that the new family of high-rise buildings has evolved. Perhaps more important, the new con

18、cepts of but a few years ago have become commonplace in today s technology.堋莨璃肀涝蜢骰砀娲租挠乌Omitting some concepts that are related strictly to the materials of construction, the most commonly used structural systems used in high-rise buildings can be categorized as follows:耪涛竞刊砍骂侥酸肘鳔鸱瓷1. Moment-resistin

19、g frames.澧疾恋湖岸羌特掠填陧喀系2. Braced frames, including eccentrically braced frames.勹铃馓隅噎朱盟铴蘅慢崃錾3. Shear walls, including steel plate shear walls.炼楚肉苡獭春芽冲杜廪薛皙4. Tube-in-tube structures.朐奶抑隅狡洋潋眄各霰晤束5. Tube-in-tube structures.拍朝蕲滞蹊猩繇废磐裢簟奈6. Core-interactive structures.念静醪兑迥蛱笄嵛玺妾饰糯7. Cellular or bundled-tube

20、systems.碟控推明藤囝帧概颔架描寒Particularly with the recent trend toward more complex forms, but in response also to the need for increased stiffness to resist the forces from wind and earthquake, most high-rise buildings have structural systems built up of combinations of frames, braced bents, shear walls, an

21、d related systems. Further, for the taller buildings, the majorities are composed of interactive elements in three-dimensional arrays.泛矿蔓然唆扛肫镂驹龀鸦但The method of combining these elements is the very essence of the design process for high-rise buildings. These combinations need evolve in response to en

22、vironmental, functional, and cost considerations so as to provide efficient structures that provoke the architectural development to new heights. This is not to say that imaginative structural design can create great architecture. To the contrary, many examples of fine architecture have been created

23、 with only moderate support from the structural engineer, while only fine structure, not great architecture, can be developed without the genius and the leadership of a talented architect. In any event, the best of both is needed to formulate a truly extraordinary design of a high-rise building.襞躐健漂

24、斡坝程蛀贝倔冗读While comprehensive discussions of these seven systems are generally available in the literature, further discussion is warranted here .The essence of the design process is distributed throughout the discussion.某罱悄嬗非泯汆犁捉梧驳士饪魄的箍住尻踹俗泮皈钙旋Moment-Resisting Frames要书茂挂镏滓蓿氓堠漾颍舷Perhaps the most commo

25、nly used system in low-to medium-rise buildings, the moment-resisting frame, is characterized by linear horizontal and vertical members connected essentially rigidly at their joints. Such frames are used as a stand-alone system or in combination with other systems so as to provide the needed resista

26、nce to horizontal loads. In the taller of high-rise buildings, the system is likely to be found inappropriate for a stand-alone system, this because of the difficulty in mobilizing sufficient stiffness under lateral forces.椋胃坏缂嗣髁吻亦垒朵汶揆 Analysis can be accomplished by STRESS, STRUDL, or a host of oth

27、er appropriate computer programs; analysis by the so-called portal method of the cantilever method has no place in todays technology.筌寇类棵住稽饱蜢椁毳昊怕Because of the intrinsic flexibility of the column/girder intersection, and because preliminary designs should aim to highlight weaknesses of systems, it i

28、s not unusual to use center-to-center dimensions for the frame in the preliminary analysis. Of course, in the latter phases of design, a realistic appraisal in-joint deformation is essential.旄镜巡虱先阋绺凤钟爱伙绸俏匙莴龊冱犀佬钍云麻肥食Braced Frames苓插啵蚊纯颗薷秣吁遴课擘The braced frame, intrinsically stiffer than the moment resi

29、sting frame, finds also greater application to higher-rise buildings. The system is characterized by linear horizontal, vertical, and diagonal members, connected simply or rigidly at their joints. It is used commonly in conjunction with other systems for taller buildings and as a stand-alone system

30、in low-to medium-rise buildings.攻太涯先蛰弗闶菩聊铋阈骚While the use of structural steel in braced frames is common, concrete frames are more likely to be of the larger-scale variety.黄镔盘塞钝糇岸萨纡罚泸癫Of special interest in areas of high seismicity is the use of the eccentric braced frame.耐蜥识檬绅被敕坡大勇嵯浒Again, analysis

31、 can be by STRESS, STRUDL, or any one of a series of two or three dimensional analysis computer programs. And again, center-to-center dimensions are used commonly in the preliminary analysis.遢镡瞢牌云围彐谘彬蒺与诒 搛耆鼗镙馊傈帆醭盖绲缂撅Shear walls唤锴荨庙缕饮艽坎歃湓碧丛The shear wall is yet another step forward along a progressio

32、n of ever-stiffer structural systems. The system is characterized by relatively thin, generally (but not always) concrete elements that provide both structural strength and separation between building functions.谱脸狭钛翘巷很和喑宦宝锹In high-rise buildings, shear wall systems tend to have a relatively high asp

33、ect ratio, that is, their height tends to be large compared to their width. Lacking tension in the foundation system, any structural element is limited in its ability to resist overturning moment by the width of the system and by the gravity load supported by the element. Limited to a narrow overtur

34、ning, One obvious use of the system, which does have the needed width, is in the exterior walls of building, where the requirement for windows is kept small.参桠懔湮鄂影茂桃铥骋绊黻Structural steel shear walls, generally stiffened against buckling by a concrete overlay, have found application where shear loads

35、are high. The system, intrinsically more economical than steel bracing, is particularly effective in carrying shear loads down through the taller floors in the areas immediately above grade. The sys tem has the further advantage of having high ductility a feature of particular importance in areas of

36、 high seismicity.馄挝布佬低篝簸广遑诌谬疙The analysis of shear wall systems is made complex because of the inevitable presence of large openings through these walls. Preliminary analysis can be by truss-analogy, by the finite element method, or by making use of a proprietary computer program designed to conside

37、r the interaction, or coupling, of shear walls.狻穹粤股俎逄耍仂碰柚勿纳篡茸踮憨草鞒佞盼珂瓞醑竹Framed or Braced Tubes累诖菪节是沟鼢逖椴徼装舶The concept of the framed or braced or braced tube erupted into the technology with the IBM Building in Pittsburgh, but was followed immediately with the twin 110-story towers of the World Trade

38、Center, New York and a number of other buildings .The system is characterized by three dimensional frames, braced frames, or shear walls, forming a closed surface more or less cylindrical in nature, but of nearly any plan configuration. Because those columns that resist lateral forces are placed as

39、far as possible from the cancroids of the system, the overall moment of inertia is increased and stiffness is very high.喋藕睫脱枉瓠缘关逭夹必鲋The analysis of tubular structures is done using three-dimensional concepts, or by two- dimensional analogy, where possible, whichever method is used, it must be capabl

40、e of accounting for the effects of shear lag.昔懑槎湍展姗应獐釜槐勺惊The presence of shear lag, detected first in aircraft structures, is a serious limitation in the stiffness of framed tubes. The concept has limited recent applications of framed tubes to the shear of 60 stories. Designers have developed variou

41、s techniques for reducing the effects of shear lag, most noticeably the use of belt trusses. This system finds application in buildings perhaps 40stories and higher. However, except for possible aesthetic considerations, belt trusses interfere with nearly every building function associated with the

42、outside wall; the trusses are placed often at mechanical floors, mush to the disapproval of the designers of the mechanical systems. Nevertheless, as a cost-effective structural system, the belt truss works well and will likely find continued approval from designers. Numerous studies have sought to

43、optimize the location of these trusses, with the optimum location very dependent on the number of trusses provided. Experience would indicate, however, that the location of these trusses is provided by the optimization of mechanical systems and by aesthetic considerations, as the economics of the st

44、ructural system is not highly sensitive to belt truss location.迷诘椟孕个贵砌驭愧笨焯倨Tube-in-Tube Structures韬橛髹几暝轼谧廛绚惦向怖The tubular framing system mobilizes every column in the exterior wall in resisting over-turning and shearing forces. The termtube-in-tubeis largely self-explanatory in that a second ring of

45、 columns, the ring surrounding the central service core of the building, is used as an inner framed or braced tube. The purpose of the second tube is to increase resistance to over turning and to increase lateral stiffness. The tubes need not be of the same character; that is, one tube could be fram

46、ed, while the other could be braced.吭锰叙戴力泰呢窀浅贪吗涵In considering this system, is important to understand clearly the difference between the shear and the flexural components of deflection, the terms being taken from beam analogy. In a framed tube, the shear component of deflection is associated with t

47、he bending deformation of columns and girders (i.e, the webs of the framed tube) while the flexural component is associated with the axial shortening and lengthening of columns (i.e, the flanges of the framed tube). In a braced tube, the shear component of deflection is associated with the axial def

48、ormation of diagonals while the flexural component of deflection is associated with the axial shortening and lengthening of columns.楂割绯蛞柽噫槐陂仁硪悒语Following beam analogy, if plane surfaces remain plane (i.e, the floor slabs),then axial stresses in the columns of the outer tube, being farther form the n

49、eutral axis, will be substantially larger than the axial stresses in the inner tube. However, in the tube-in-tube design, when optimized, the axial stresses in the inner ring of columns may be as high, or even higher, than the axial stresses in the outer ring. This seeming anomaly is associated with

50、 differences in the shearing component of stiffness between the two systems. This is easiest to under-stand where the inner tube is conceived as a braced (i.e, shear-stiff) tube while the outer tube is conceived as a framed (i.e, shear-flexible) tube.舌岂箫轺伯秧顺彀铴樱祷蟾制轰赉桐陛绸镜鲑羼赌佃莛Core Interactive Structur

51、es噙璃鸥胞揣昝抱痰头槐夜侵Core interactive structures are a special case of a tube-in-tube wherein the two tubes are coupled together with some form of three-dimensional space frame. Indeed, the system is used often wherein the shear stiffness of the outer tube is zero. The United States Steel Building, Pittsbu

52、rgh, illustrates the system very well. Here, the inner tube is a braced frame, the outer tube has no shear stiffness, and the two systems are coupled if they were considered as systems passing in a straight line from the “hat” structure. Note that the exterior columns would be improperly modeled if

53、they were considered as systems passing in a straight line from the “hat” to the foundations; these columns are perhaps 15% stiffer as they follow the elastic curve of the braced core. Note also that the axial forces associated with the lateral forces in the inner columns change from tension to comp

54、ression over the height of the tube, with the inflection point at about 5/8 of the height of the tube. The outer columns, of course, carry the same axial force under lateral load for the full height of the columns because the columns because the shear stiffness of the system is close to zero.帅立躬蚁阎蛛娉

55、萸讣送蛏卧 The space structures of outrigger girders or trusses, that connect the inner tube to the outer tube, are located often at several levels in the building. The AT&T headquarters is an example of an astonishing array of interactive elements:备芾僚温嫩忏轾乌璞柞咣渚1. The structural system is 94 ft (28.6m) wi

56、de, 196ft(59.7m) long, and 601ft (183.3m) high.使例濂鳝懿因娥纬逆栏沼嘶2. Two inner tubes are provided, each 31ft(9.4m) by 40 ft (12.2m), centered 90 ft (27.4m) apart in the long direction of the building.貂衔活缜窒叭貉举晟孙惜以3. The inner tubes are braced in the short direction, but with zero shear stiffness in the long

57、 direction.岑祟蝴堙酵栋官裰囤速剜嫁4. A single outer tube is supplied, which encircles the building perimeter.笱硫错虏囫参魂狺爱鸩趱戥5. The outer tube is a moment-resisting frame, but with zero shear stiffness for the center50ft (15.2m) of each of the long sides.潞抨赙帑珠靛辊馈旎寝跫拮6. A space-truss hat structure is provided at th

58、e top of the building.孵沔兕遒榘暌嚅啼丹氯滁苣7. A similar space truss is located near the bottom of the building给祸躇荼慢褥肆疹缠象乓窜8. The entire assembly is laterally supported at the base on twin steel-plate tubes, because the shear stiffness of the outer tube goes to zero at the base of the building.触砗阚囚翕悯莫围沫嗒敞圣编淇魄

59、嫖则角甄指纪殴说控Cellular structures蚂桢善蹑哝计捃丌娲鼙噎钩A classic example of a cellular structure is the Sears Tower, Chicago, a bundled tube structure of nine separate tubes. While the Sears Tower contains nine nearly identical tubes, the basic structural system has special application for buildings of irregular shape, as the several tubes need not be similar in