1、Lesson 4 Tall Buildings nFazlur Rahman khannDr. Fazlur Rahman Khan was one of the greatest structural engineers of the twentieth century. nHe has been called “the Einstein of the structural engineering” and “the father of the modern skyscraper”nAlthough there have been many advancements in building
2、construction technology in general, spectacular achievements have been made in the design and construction of ultrahigh-rise buildings. nThe early development of high-rise buildings began with structural steel framing. nReinforced concrete and stressed-skin tube systems have since been economically
3、and competitively used in a number of structures for both residential and commercial purposes. 薄壳筒体nThe high-rise buildings ranging from 50 to 110 stories that are being built all over the United States are the result of innovations and development of new structural systems.nGreater height entails i
4、ncreased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acceptable limit. nExcessive lateral sway may cause serious recurring damage to partitions, ceilings, and other architectural details. In addition, excessive sway may cause discomfort to
5、the occupants of the building because of their perception of such motion. nStructural systems of reinforced concrete, as well as steel, take full advantage of the inherent potential stiffness of the total building and therefore do not require additional stiffening to limit the sway. nIn a steel stru
6、cture, for example, the economy can be defined in terms of the total average quantity of steel per square foot of floor area of the building. nCurve A in Fig. 1 represents the average unit weight of a conventional frame with increasing numbers of stories. nCurve B represents the average steel weight
7、 if the frame is protected from all lateral loads. nThe gap between the upper boundary and the lower boundary represents the premium for height for the traditional column-and-beam frame.nStructural engineers have developed structural systems with a view to eliminating this premium. 一一 Systems in ste
8、el.nTall buildings in steel developed as a result of several types of structural innovations.nThe innovations have been applied to the construction of both office and apartment buildings. Frames with rigid belt trusses.nIn order to tie the exterior columns of a frame structure to the interior vertic
9、al trusses, a system of rigid belt trusses at mid-height and at the top of the building may be used. nA good example of this system is the First Wisconsin Bank Building (1974) in Milwaukee. 刚性带式桁架US Bank Center n Street 777 East Wisconsin Avenue Height 183 m Floors 42 Year 1973 Framed tube.nThe maxi
10、mum efficiency of the total structure of a tall building, for both strength and stiffness, to resist wind load can be achieved only if all column elements can be connected to each other in such a way that the entire building acts as a hollow tube or rigid box in projecting out of the ground. 凸出框筒nTh
11、is particular structural system was probably used for the first time in the 43-story reinforced concrete DeWitt Chestnut Apartment Building in Chicago. nThe most significant use of this system is in the twin structural steel towers of the 110-story World Trade Center building in New York.a three dim
12、ensional space structure composed of three, four, or possibly more frames, braced frames, or shear walls, joined at or near their edges to form a vertical tube-like structural system capable of resisting lateral forces in any direction by cantilevering from the foundation. A framed tube structure is
13、 a new addition to the structural systems. Khan is generally credited with its invention in the 1960s.Completed in: 1965 Location: Chicago, Illinois, USA Function / usage: Apartment building Column-diagonal truss tube.nThe exterior columns of a building can be spaced reasonably far apart and yet be
14、made to work together as a tube by connecting them with diagonal members intersecting at the center line of the columns and beams. nThis simple yet extremely efficient system was used for the first time on the John Hancock Center in Chicago, using as much steel as is normally needed for a traditiona
15、l 40-story building.nThe John Hancock Building (Chicago, Illinois). nThis 100-story building is one of a new generation of high-rise structures. The main building is 1127 ft. high and consists of a tapered tube with continuous X-bracing on all four sides. Bundled tube.nWith the continuing need for l
16、arger and taller buildings, the framed tube or the column-diagonal truss tube may be used in a bundled form to create larger tube envelopes while maintaining high efficiency.nThe 110-story Sears Roebuck Headquarters Building in Chicago has nine tubes, bundled at the base of the building in three row
17、s. nSome of these individual tubes terminate at different heights of the building, demonstrating the unlimited architectural possibilities of this latest structural concept.n The Sears tower, at a height of 1450 ft (442 m), is the worlds tallest building.nWorlds tallest building from 1974 - 1996; su
18、rpassed by the Petronas Towers in Kuala Lumpur, Malaysia. n-nUntil Taipei 101 was topped out in 2004, the Sears Tower held title to the worlds highest roof and highest occupied floor. Stressed-skin tube system.nThe tube structural system was developed for improving the resistance to lateral forces (
19、wind or earthquake) and the control of drift (lateral building movement) in high-rise building. nThe stressed-skin tube takes the tube system a step further. This薄壳筒体nThe development of the stressed-skin tube utilizes the facade of the building as a structural element which acts with the framed tube
20、, thus providing an efficient way of resisting lateral loads in high-rise buildings, and resulting in cost-effective column-free interior space with a high ratio of net to gross floor area.nBecause of the contribution of the stressed-skin facade, the framed members, of the tube require less mass, an
21、d are thus lighter and less expensive. nAll the typical columns and spandrel beams are standard rolled shapes, minimizing the use and cost of special built-up members. 窗下墙的托梁nThe depth requirement for the perimeter spandrel beams is also reduced, and the need for upset beams above floors, which woul
22、d encroach on valuable space, is minimized. nThe structural system has been used on the 54-story One Mellon Bank Center in Pittsburgh.upset adj.让人心烦的、混乱的One Mellon Bank Center二二 Systems in concrete.nWhile tall buildings constructed of steel had an early start, development of tall buildings of reinfo
23、rced concrete progressed at a fast enough rate to provide a competitive challenge to structural steel systems for both office and apartment buildings.Framed tube.nAs discussed above, the first framed tube concept for tall buildings was used for the 43-story DeWitt Chestnut Apartment Building. nIn th
24、is building, exterior columns were spaced at 5.5ft (1. 68m) centers, and interior columns were used as needed to support the 8-in. -thick (20-cm) flat-plate concrete slabs.Tube in tube.nAnother system in reinforced concrete for office buildings combines the traditional shear wall construction with a
25、n exterior framed tube. nThe system consists of an outer framed tube of very closely spaced columns and an interior rigid shear wall tube enclosing the central service area. nThe system (Fig. 2), known as the tube-in-tube system, made it possible to design the worlds present tallest (714 ft or218m)
26、lightweight concrete building (the 52-story One Shell Plaza Building in Houston) for the unit price of a traditional shear wall structure of only 35 stories.nThe 50-story One Shell Plaza Building, when completed in 1971, was the tallest concrete building in the world. nTowering at 217.7 m (714 ft),
27、One Shell Plaza still reigns as the tallest lightweight concrete building in the world. nSystems combining both concrete and steel have also been developed, an example of which is the composite system developed by Skidmore, Owings & Merrill in which an exterior closely spaced framed tube in concrete
28、 envelops an interior steel framing, thereby combining the advantages of both reinforced concrete and structural steel systems. nThe 52-story One Shell Square Building in New Orleans is based on this system. 1. New words analysisSpectacular=spectat(词根，观、看词根，观、看)+cular(adj.后缀后缀)Spectator(观众观众)=specta
29、t+orResidential（住宅的）（住宅的）=resident（住宅、居民）（住宅、居民）+ial(adj.后缀后缀)Perimeter(周长周长)=peri(词根，周边的，绕一圈的词根，周边的，绕一圈的)+meter(米，长米，长度单位度单位)Encroach（蚕食）（蚕食）=en(绕，使绕，使化化)+croach(吃吃)Reinforced concrete 钢筋混凝土钢筋混凝土 Reinforced-被加强的被加强的Prestresses concrete 预应力混凝土预应力混凝土 prestressed（预应力的）（预应力的）=pre(前缀，预、先前缀，预、先)+stressed
30、(被施加应力的被施加应力的)词缀介绍：词缀介绍：ultra, super, supra, sur, meta 均有超、上之意。如：均有超、上之意。如：ultrasound(超声波超声波)，metachemistry(超级化学超级化学) 长句、难句分析长句、难句分析Exam. 1 reinforced concrete and stressed-tube systems have since been economically and competitively used in a number of structures for both residential and commercial
31、purposes.分析 本处翻译难点是专业词组stressed-tube systems (薄壳筒体结构体系)以及economically and competitively used 的翻译处理。译文：从此，钢筋混凝土和薄壳筒体结构体系由于造价经济和竞争力强而在许多住宅和商业建筑的得到广泛应用。Exam. 2 Framed tube. The maximum efficiency of the total structure of a tall building, for both strength and stiffness, to resist wind load can be achi
32、eved only if all the column elements can be connected to each other in such a way that the entire building acts as a hollow tube or a rigid box in projecting out of the ground.分析 本句是一典型长句，句子结构相对复杂， 主句主语和谓语之间有一表目的的独立介词短语，主句有一if条件状语从句， if条件状语从句中还有that引导的宾语从句。可以采用编号法翻译。参考翻译 框架式筒体结构。从强度和刚度两方面考虑，高层建筑整体结构的最有效的抗风荷载效果只有通过以下结构组合形式方可实现：所有的柱单元按照使建筑整体成为伸出地面的空心筒体起作用的方式相互连接。
