土木工程专业毕业设计外文翻译

目录 TOC \o "1-3" \h \z \u 地下空间的利用 2 高层建筑 6 Underground Space Utilization 9 High-Rise Buildings 15 地下空间的利用 全球城市化进程的加快将会对人类将来的生存方式产生重大影响。随着全球人口的增长以及更多国家要求提高生活水平，世界必须提供更多食物，能源以及矿物资源来维持此增长趋势。解决这一难题的办法有三大渠道复合而成：农业用地的保护从而得到更深入的利用；日益增长的全球城市人口；对保护和改善环境日益增长的关注，特别是关于全球气候变暖以及人口增长带来的影响。地下空间的利用，作为本章要描述的内容，将提供针对这些趋势的解决办法。 通过将特殊器材设备置于地下，城市地可被更有效地利用，这样就可释放出空间供农业和娱乐使用。类似的，在陡峭的山坡上使用阶地掩土住宅会有助于在多山地区保护宝贵的可耕平地。利用地下空间也可以提高人们在人口高密集去的居住舒适度，改善生活质量。 一城市或当地水准，地下设施的利用正日益满足当今社会对于改善环境的需求。例如不论城市还是农村都需要提高运输，实用以及娱乐服务。世界上许多城市的交通堵塞问题已经处在满足人类基本生存需求的临界点上，并且在不破坏地表环境的基础上不增加新设施或是不重新规划现有土地及周边地带上的建筑的基础上想要解决这一难题是十分困难的。 以世界上许多国家的国家水平，全球化的趋势导致对煤炭，石油，天然气的开采已达到更深的地层以下，触及更难以让人接受或是更敏感的区域。这些趋势同样导致针对能源繁衍存贮系统以及用于处理危险废料（包括化学，生物以及放射性废料）的国家设施设计的改善和提高，同样也改善了国家高速运输体系。所有这些发展均涉及地下工程。 用地压力 将设施置于地下是缓解由于世界人口增长所带来的城市化问题的一种有希望的办法。虽然世界平均人口密度并不大，但人口分布却极不均匀。世界人口密度图显示世界上大部分地方根本不适合居住。这些大方大部分是沙漠山区，或是极度严寒地带等人类不易居住区。 以中国为例，平均人口密度大概是每平方公里100人，但是10亿多的绝大部分人口居住在少于20%的国土上。这是那些可以提供粮食产品的肥沃土地。然而，由于人口增长和城市化，这些土地同样要被用于创建更广阔的运输系统，被用于工商业的发展，以及日益增长的住房需求。随着人口和经济的增长，农业用地减少，向城市人口运送食物和原材料的问题日益增长。据估计，到2000年，世界人口的70%将居住在城市。 同样的问题在日本也很明显，大约80%的土地是山区，90%的人口居住在海边平原经济发展集中在几个相关的经济中心。平原通常是最肥沃的土地，从历史上看也是人类的定居地。其他附加于人口密度的因素包括：传统低层的建筑模式，而且日本法律规定必须建造靠近阳光的坚固的维护设施。同样，为了保护家庭粮食生产能力，日本政府保护农业用地。这些历史，政策因素导致大量商业，个人向经济中心移民造成了巨大的土地使用压力。结果是市中心土地价格惊人昂贵（高达50万美圆/平米）并且很难为人们提供住房，交通，设施服务。普通公司雇员无法承担住在他们工作的市中心附近而不得不搭乘公汽单程花1.2个小时从他们负担的起的住处到公司。为了为日益扩大的大城市区域提供服务，市政当局必须升级道路并且兴建新的交通线和设施。东京市中心的土地价格如此昂贵以至于用于购买土地的花费可能会占到工程总花费的95%。 土地使用压力和由于高土地使用价格带来的相关经济影响使得对地下空间的潜在利用的研究变得相当有趣。当地表土地已被利用殆尽，地下空间将变成可开发的区域之一。这为不需深度破坏地表环境而附加需要设备提供了一种可能。虽然没有高额地价，但是建造地下设施的高额花费将是地下空间利用的一大拦路虎。因为地下设施不具有经济竞争力，因此在考虑建造前必须在美学，环境或者是社会效应方面给予综合评估，除非是一些有特殊标志性意义的设施否则将会造成现阶段国家无法承担或是很勉强承担的奢侈浪费。 地下空间规划 对地下空间利用的有效规划是发展地下设施的前奏。这个必须是为长远考虑的，并根据人们理想的工作和居住环境重构城市建筑格局。如果地下空间开发可以提供最具价值的长期效益，那么对这些资源的有效计划就应得以实施。不幸的是，在世界范围内，靠公众权力来开发近地表空间已经太迟了。紊乱的设施网络司空见惯归咎于缺乏协调以及使用设施的历史性变革以及交通系统的发展。 地下空间具有如此特征导致要做一个好的规则需要特别注意一些问题 1.一旦开始地下开挖，土地将被永久改变。地下建筑不象表面建筑那样容易拆掉。 2.开挖一片地下空间需要一大片土地作为开挖加固区。 3.土地的地理构成极大地影响了地下设施的种类，形式以及开销。但现有关于地表建筑的知识仅有很有限的内容与此相关，因此需要查阅钻探资料和以前的记录。 4.大型地下工程需要大量调查，涉及更大的建造问题，工期拖延以及预算超支等风险。 5.传统规则技术主要侧重于对于城市地形区域的二维描述。这基本上仅适合地表及上部结构但并不适合建造在处于复杂三维地理环境中的地下结构。用同一种模式来描述这种三维信息并立刻反映到规则评估中是件非常困难的事 例如，在东京，第一条地铁（Ginza线）是在现存地表层设施下作为一个影子工程线路（10m深）建成的。随着填加更多的地铁线，在更深土层中才会发现比较规整的区域。在东京，新的KeiyoJR线深达40m。一条从Marunouchi到Shinjuku的高速干线已被设计到50m深。作为比较在伦敦最深的设施大约70m深，其主要复杂部分以及排水设施至少超过25m综合日益增长的需要，有一个事实就是这类新型运输服务（例如日本的新干线子弹头列车或是法国的TGV）通常需要大量交叉隧道，笔直的队列以及平坦性。如果地下空间不是此类用途，那么城市下面将会产生非常无效率的布局。 环境利益 另一个利用地下空间的主要策略是全球日益增长的对环境问题的关注，并导致人们重新考虑城市的将来和工业的发展。在关注维持生态平衡和环境恶化以及全球有限的自然资源要考虑以下几个问题： 1.日益增长的能源消费量相对于满足将来需求的有限矿物燃料的贮备 2.由于燃烧矿物燃料对全球气候带来的影响 3.工业副产品对环境的污染 4.对于工业生产及军事演习产生的危险废物的安全处置 在提高经济增长保持工业模式的同时保护环境，延长地球上资源的寿命即使不是一个不可能的问题也是一个很复杂的问题。无论如何，高生活和高国内生产总值（GDP）不需要和资源的消耗和环境的恶化程度成比例。 地下空间的利用能从几种途径解决环境/资源的窘境。地下设施以其自身特点成为一种典型的储能设施。更重要的是，通过地下空间的利用，城市人口密度会提高但对环境的影响会减少。相对于保护绿地及耕地等的明显好处，附加于此的好处是------有充分证据显示高城市密度可以减少矿物燃料的消耗。 将来地下空间的发展 虽然在全世界范围内现有的地下设施为将来地下空间的发展提供了一些范例，但他们都在尺寸上，用途上或者对于城市整体环境缺乏考虑。作为更佳细致规划和研究的补充，未来的规划者和设计者已提出对大范围地下结构甚至从整个城市的角度综合考核，将是非常有用的。 90年代地理——一个1990年4月在日本举行的研讨博览会，主要是一个关于日本地下工业情况的论坛。一大堆关于地下的概念展示出来——从典型的运输使用设施到展望中的用于灾难时刻保护通讯网络的地下走廊。这类走廊对于在城市地铁站和中心生产去附近以及市区外安置地点间运送废弃物和能源也十分有效。这一点不仅缓解了堵塞而且提供了更加有效的能源衍生和废物循环。这些概念都是针对城市建筑的升级，将最终导致地表形成更开阔的空间以及更高效更吸引人的全局环境。 当展望将来城市建设时，地下建筑会成为主要因素——这是建筑师Paolo Soleri在过去30年的幻想杰作。在科幻小说里，未来城市常被描绘成自我供养的，气候可控制的单位，且常常位于地下以避免来自危险或环境污染等因素的侵袭。在这种情况下，地球上的地下城市略不同于以月球或其他孤立环境为基础创建的城市。 高层建筑 前 沿 高层建筑的定义很难确定。可以说2-3层的建筑物为底层建筑，而从3-4层地10层或20层的建筑物为中层建筑，高层建筑至少为10层或者更多。 尽管在原理上，高层建筑的竖向和水平构件的设计同低层及多层建筑的设计没什么区别，但使竖向构件的设计成为高层设计有两个控制性的因素：首先，高层建筑需要较大的柱体、墙体和井筒；更重要的是侧向里所产生的倾覆力矩和剪力变形要大的多，必要谨慎设计来保证。 高层建筑的竖向构件从上到下逐层对累积的重力和荷载进行传递，这就要有较大尺寸的墙体或者柱体来进行承载。同时，这些构件还要将风荷载及地震荷载等侧向荷载传给基础。但是，侧向荷载的分布不同于竖向荷载，它们是非线性的，并且沿着建筑物高度的增加而迅速地增加。例如，在其他条件都相同时，风荷载在建筑物底部引起的倾覆力矩随建筑物高度近似地成平方规律变化，而在顶部的侧向位移与其高度的四次方成正比。地震荷载的效应更为明显。 对于低层和多层建筑物设计只需考虑恒荷载和部分动荷载时，建筑物的柱、墙、楼梯或电梯等就自然能承受大部分水平力。所考虑的问题主要是抗剪问题。对于现代的钢架系统支撑设计，如无特殊承载需要，无需加大柱和梁的尺寸，而通过增加板就可以实现。 不幸的是，对于高层建筑首先要解决的不仅仅是抗剪问题，还有抵抗力矩和抵抗变形问题。高层建筑中的柱、梁、墙及板等经常需要采用特殊的结构布置和特殊的材料，以抵抗相当高的侧向荷载以及变形。 如前所述，在高层建筑中每平方英尺建筑面积结构材料的用量要高于低层建筑。支撑重力荷载的竖向构件，如墙、柱及井筒，在沿建筑物整个高度方向上都应予以加强。用于抵抗侧向荷载的材料要求更多。 对于钢筋混凝土建筑，虽着建筑物层数的增加，对材料的要求也随着增加。应当注意的是，因混凝土材料的质量增加而带来的建筑物自重增加，要比钢结构增加得多，而为抵抗风荷载的能力而增加的材料用量却不是呢么多，因为混凝土自身的重量可以抵抗倾覆力矩。不过不利的一面是混凝土建筑自重的增加，将会加大抗震设计的难度。在地震荷载作用下，顶部质量的增加将会使侧向荷载剧增。 无论对于混凝土结构设计，还是对于钢结构设计，下面这些基本的原则都有助于在不需要增加太多成本的前提下增强建筑物抵抗侧向荷载的能力。 1.​ 增加抗弯构件的有效宽度。由于当其他条件不变时能够直接减小扭矩，并以宽度增量的三次幂形式减小变形，因此这一措施非常有效。但是必须保证加宽后的竖向承重构件非常有效地连接。 2.​ 在设计构件时，尽可能有效地使其加强相互作用力。例如，可以采用具有有效应力状态的弦杆和桁架体系；也可在墙的关键位置加置钢筋；以及最优化钢架的刚度比等措施。 3.​ 增加最有效的抗弯构件的截面。例如，增加较低层柱以及连接大梁的翼缘截面，将可直接减少侧向位移和增加抗弯能力，而不会加大上层楼面的质量，否则，地震问题将更加严重。 4.​ 通过设计使大部分竖向荷载，直接作用于主要的抗弯构件。这样通过预压主要的抗倾覆构件，可以使建筑物在倾覆拉力的作用下保持稳定。 5.​ 通过合理地放置实心墙体及在竖向构件中使用斜撑构件，可以有效地抵抗每层的局部剪力。但仅仅通过竖向构件进行抗剪是不经济的，因为使柱及梁有足够的抗弯能力，比用墙或斜撑需要更多材料和工作量。 6.​ 每层应加设充足的水平隔板。这样就会使各种抗力构件更好地在一起工作，而不是单独工作。 7.​ 在中间转换层通过大型竖向和水平构件及重楼板形成大框架，或者采用深梁体系。 应当注意的是，所有高层建筑的本质都是地面支撑的悬臂结构。如何合理地运用上面所提到的原则，就可以利用合理地布置墙体、核心筒、框架、筒式结构和其他竖向结构分体系，使建筑物取得足够的水平承载力和刚度。本文后面将对这些原理的应用做介绍。 剪力墙结构 在能够满足其他功能需求时，高层建筑中采用剪力墙可以经济地进行高层建筑的抗侧向荷载设计。例如，住宅楼需要很多隔墙，如果这些隔墙都设计为实例的，那么他们可以起到剪力墙的作用，既能抵抗侧向荷载，又能承受竖向荷载。对于20层以上的建筑物，剪力墙极为常见。如果给与足够的宽度，剪力墙能够有效地抵抗30-40层甚至更多的侧向荷载。 但是，剪力墙只能抵抗平行于墙平面的荷载（也就是说不能抵抗垂直于墙的荷载）。因此有必要经常在两个相互垂直的方向设置剪力墙，或者在尽可能多的方向布置，以用来抵抗各个方向的侧向荷载。并且，墙体设计还应考虑扭转的问题。 在设计过程中，两片或者更多的剪力墙会布置成L型或者槽形。实际上，四片内剪力墙可以被联结成矩形，以更有效地抵抗侧向荷载。如果所有外部剪力墙都连接起来，整个建筑物就像是一个筒体，将会具有很强的抵抗水平荷载和抵抗扭矩的能力。 通常混凝土就剪力墙都是实体的，并在有要求时开洞，而钢筋剪力墙常常是做成桁架式。这些桁架上可能布置成蛋单斜撑、X斜撑及K斜撑。在侧向力作用下这些桁架的组合构件受到或拉或压力。从强度和变形控制角度来说，桁架有着很好的功效，并且管道可以在构件之间穿过。当然，钢桁架墙的斜向构件在墙体上要正确放置，以免妨碍开窗、循环以及管道穿墙。 如上所述，电梯强、楼梯间及设备竖井都可以形成筒状体，常常用它们既抵抗竖向荷载又抵抗水平荷载。这些筒的横断面一般驶矩形或圆形，由于筒结构作用，筒状结构能够有效地进行各个方向上的抗弯和抗剪。不过在这样的结构设计中存在的问题是，如何保证在门洞口和其他孔洞的强度。对于钢筋混凝土结构，通过使用特殊的钢筋配置在这些孔洞的周围。对于钢剪力墙，则要求在开洞处加强节点连接，以抵抗洞口变形。 对于很多高层建筑，如果墙体和筒架进行合理地安排与连接，会起到很好的抵抗侧向荷载的作用。还要求由这些结构分体系提供的刚度在各个方向上应大体对称。 框架结构 在建筑物结构设计中，用于抵抗竖向和水平荷载的框架结构，常作为一个重要且标准的型式而被采用。它适用于低层、多层建筑物，亦可用于70-100层高的高层建筑物。同剪力墙结构相比，这种结构更适合在建筑物的内部或者外围的墙体上开设矩形孔洞。同时它还能充分利用建筑物内在任何情况下都要采用的梁和柱的刚度，但当柱子与梁刚性连接时，通过框架受弯来抵抗水平和竖向荷载会使这些柱子的承载能力变得更大。 大多情况下，框架的刚度不如剪力墙，因此对于细长的建筑物将会出现过度变形。但正是因为其柔性，使得其与剪力墙结构相比具有更大的延性，因而地震荷载下不易发生事故。例如，如果框架局部出现超应力时，那么其延性就会允许整个结构出现倒塌事故。因此，框架结构常被视为最好的高层抗震结构。另一方面，设计得好的剪力墙结构也不可能倒塌。 对于混凝土框架结构，还存在较大的分歧。的确。如果在混凝土框架设计时不进行特殊的延性设计，那么他将很难承受比设计标准值大很多倍的地震荷载的冲击。因此，很多人认为它不具备钢框架所具备的超载能力。不过最新的研究i和实验表明，当混凝土中放入充分的钢箍和节点钢筋时 ，混凝土框架框架也能表现出很好的延性。新建筑对所谓延性混凝土框架有专门的规定。然而，这些规范往往要求在框架的某处增设过多的钢筋，这就增加了施工的难度。尽管这样，混凝土框架设计还是具备既经济又实用的特性。 当然，还可以在建筑结构设计中，将框架结构和剪力墙结构结合起来使用。例如，在房屋建筑上使用框架，而在另一方向上可以使用剪力墙。 结论 以上所述就是高层建筑最普通的结构形式。在设计过程中，应尽可能经济实用地选择合理的形式。 Underground Space Utilization The rapid growth of world civilization will have a significant impact on the way humans live in the future. As the global population increases and more countries demand a higher standard of living, the difficulty of doing this is compounded by three broad trends: the conversion of agricultural land to development uses; the increasing urbanization of the world`s population; and growing concern for the maintenance and improvement of the environment, especially regarding global warming and the impact of population growth. Underground space utilization, as this chapter describes, offers opportunities for helping address these trends. By moving certain facilities and function underground, surface land in urban areas can be used more effectively , thus freeing space for agricultural and recreational purpose. Similarly, the use of terraced earth sheltered housing. Using underground space also enables humans to live more comfortably in densely populated areas while improving the quality of live. On an urban or local level, the use of underground facilities is rising to accommodate the complex demands of today`s society while improving the environment . For example, both urban and rural areas are requiring improved transportation, utility, and recreational services. The state of traffic congestion in many urban areas of the world is at a critical level for the support of basic human living, and it is difficult if not impossible to add new infrastructure at ground level without causing an unacceptable deterioration of the surface environment or an unacceptable relocation of existing land uses and neighborhoods. On a national level in countries around the world, global trends are causing the creation and extension of mining developments and oil or gas recovery at greater depths and in more inaccessible or sensitive locations. Three trends have also led to the developments of improved designs for energy generation and storage systems as well as national facilities for dealing with hazardous waste (including chemical, biological, and radioactive waste ), and improved high-speed national transportation systems .All these developments involve use of the underground . Land Use Pressures Placing facilities underground is a promising method for helping ease land use pressures caused by the growth and urbanization of the world`s population. Although the average population density in the world is not large, the distribution of population is very uneven. A map of population density in the world is not large ,areas of the world are essentially uninhabited . These areas are for the most part deserts ,mountainous regions, or regions of severe cold that do not easily support human habitation. If one examines China ,for example ,the average population density is approximately 100 persons per square kilometer, but the vat majority of the one billion-plus population lives on less than 20 percent of the land area. this is the fertile land that can support food production. However, due to population growth, urbanization, and economic growth, this same land must now support extensive transportation systems, industrial and commercial development, and increasing demands for housing, As the population and economy grow, the land available for agriculture shrinks, and the problems of transporting food and raw materials to an urban population increase. By the year 2000 it is estimated that 70 percent of the world`s population will inhabit urban areas. The same trend are evident in Japan, where approximately 80 percent of the land area is mountainous,90 percent of the population lives on the coastal plains, and economic development is concentrated in relatively few economic development is concentrated in relatively few economic centers .The flat-lying land is generally the most fertile and is historically the region of settlement . Other factors adding to population density include the traditional building style , which is low-rise , and Japanese law that contain strong provisions for maintenance of access to sunlight .Also ,to retain domestic food production capability , the Japanese government has protected agricultural land from development. The combination of these historical and political factors together with a strong migration of businesses and individuals to the economic centers has created enormous land use pressure. The result is an astronomically high cost of land in city centers (as high as US $500,00 per square meter) and difficulty in an providing housing, transportation, and utility services for the population. Typical business employees cannot afford to live near the city center where they work and may have to commute one to two hours each way from an affordable area. To service the expanding metropolitan area, public agencies must upgrade roads and build new transit lines and utilizes. Land costs for such work are so high that in central Tokyo, the cost of land may represent over 95 percent of the total cost of a project. The problem of land use pressures and related economic effects of high land prices are of great interest in the study of the potential uses of underground space. When surface space is fully utilized, underground space becomes one of the few development zones available. It offers the possibility of the adding needed facilities without further degrading the surface environment. Without high land prices, however, the generally higher cost of constructing facilities underground is a significant deterrent to their environmental, or social grounds-luxuries which many developing nation cannot afford at present and which developed nations are reluctant to undertake except in areas of special significance. Planning of Underground Space Effective planning for underground utilization should be an essential precursor to the development of major underground facilities. This planning must consider long-term needs while providing a frame work for reforming urban areas into desirable and effective environments in which to live and work. If underground development is to provide the most valuable long-term benefit possible , then effective zones beneath public rights-of-way in older cities around the world. The tangled wed of utilizes commonly found is due to a lack of coordination and the historical evolution in utility provision and transit system development. The underground has several characteristics that make good planning especially problematical: ​ Once underground excavations are made, the ground is permanently altered. Underground structures are not as easily dismantled as surface buildings. ​ An underground excavation may effectively a large zone of the stability of the excavation. ​ The underground geologic structure greatly affects the type, size, and costs of facilities that can be constructed, but the knowledge of a region`s can only be inferred from a limited number of site investigation borings and previous records. ​ Large underground projects may require massive investments with relatively high risks of construction problem, delay, and cost overruns. ​ Traditional planning techniques have focused on two-dimensional representations of regions and urban areas . This is generally adequate for surface and aboveground construction but it is not adequate for the complex three-dimensional geology and built structures often found underground . Representation of this three-dimensional information in a form that can readily be interpreted for planning and evaluation is very difficult. In Tokyo, for example, the first subway line (Ginza Line) was installed as a shallow line (10 meters deep) immediately beneath the existing layer of surface utilities. As more subway lines have been added, uncluttered zones can only be found at the deeper underground levels. The new Keiyo JR line in Tokyo is 40 meter deep. A new underground super highway from Marunouchi to Shinjuku has been proposed at a 50-meter depth. For comparison, the deepest installations in London are at approximately a 70-meter depth although the main complex of works and sewers is at less than 25 neters. Compounding these issues of increasing demand is the fact newer transportation services (such as the Japanese Shinkansen bullet trains or the French TGV) ofen require larger cross-section tunnels, straighter alignments, and flatter grades. If space is not reserved for this type of use, very inefficient layouts of the beneath urban areas can occur. Environmental Benefits Another major trigger for under ground space usage is the growing international concern over the environment, which has led to attempts to rethink the future of urban and industrial development. The major concerns in balancing economic development versus environmental degradation and world natural resource limitations revolve around several key issues. These are: ​ The increasing consumption of energy compared to the limited reserves of fossil fuels available to meet future demand. ​ The effect on the global climate of burning fossil fuels. ​ The pollution of the environment from the by-products of industrial development ​ The safe disposal of hazardous wastes generated by industrial and military activites. Preserving the environment from the by-products of industrial development economic growth and maintaining individual life styles will be complex if not impossible. However, a high standard of living and high gross domestic product do not have to be proportionately dependent on resource consumption and environmental degradation. Underground space utilization can help solve the environmental/resource dilemma in several ways . Underground facilities are typically energy conserving in their own right. More importantly, by using addition to the obvious benefit of preserving green space and agricultural land, there is strong evidence that higher urban density can lower fuel resource consumption The Future of Underground Space Development Although existing underground facilities throughout the world provide some models for future development, they are all limited in scale, in their lack of a comprehensive vision for the total city environment. As a complement to more detailed planning and research studies, it is useful to examine the visions of extensive underground complexes, even entire cities, that have been proposed by futuristic planners and designers. Geotech`90, a conference and exhibition held in Tokyo in April 1990, was a major forum for the underground industry in Japan. More than a dozen underground concepts were displayed, ranging from the typical transit and utility uses to underground corridors that are envisioned as places for a communication network protected during disasters. Such corridors could also effectively transport both waste and energy between substations in the city and central generation and disposal sites outside the city. This approach not only relieves congestion but also can provide more efficient energy generation and recycling of waste materials. These concepts are all intended to permit a major upgrade of the city infrastructure that will eventually enable the surface to be rebuilt with more open space and a more efficient, attractive overall environment. When completely new cities are envisioned for the future, the underground often is a major component, as illustrated by the work of the architect Paolo Soleri over the last 30 years. In science fiction future cities often are depicted as self-contained, climate-controlled units frequently located underground for protection from the elements and possibly from a hazardous or polluted environment. In this case, underground cities on earth differ little from bases created on the moon or other isolated environments. High-Rise Buildings Introduction It is difficult to define a high-rise building . One may say that a low-rise building ranges from 1 to 2 stories . A medium-rise building probably ranges between 3 or 4 stories up to 10 or 20 stories or more . Although the basic principles of vertical and horizontal subsystem design remain the same for low- , medium- , or high-rise buildings , when a building gets high the vertical subsystems become a controlling problem for two reasons . Higher vertical loads will require larger columns , walls , and shafts . But , more significantly , the overturning moment and the shear deflections produced by lateral forces are much larger and must be carefully provided for . The vertical subsystems in a high-rise building transmit accumulated gravity load from story to story , thus requiring larger column or wall sections to support such loading . In addition these same vertical subsystems must transmit lateral loads , such as wind or seismic loads , to the foundations. However , in contrast to vertical load , lateral load effects on buildings are not linear and increase rapidly with increase in height . For example under wind load , the overturning moment at the base of buildings varies approximately as the square of a buildings may vary as the fourth power of buildings height , other things being equal. Earthquake produces an even more pronounced effect. When the structure for a low-or medium-rise building is designed for dead and live load , it is almost an inherent property that the columns , walls , and stair or elevator shafts can carry most of the horizontal forces . The problem is primarily one of shear resistance . Moderate addition bracing for rigid frames in“short”buildings can easily be provided by filling certain panels ( or even all panels ) without increasing