建筑外文翻譯---高層結(jié)構(gòu)與鋼結(jié)構(gòu)

1、<p>　　Talling building and Steel construction</p><p>　　Although there have been many advancements in building construction technology in general. Spectacular archievements have been made in the design a

2、nd construction of ultrahigh-rise buildings.</p><p>　　The early development of high-rise buildings began with structural steel framing.Reinforced concrete and stressed-skin tube systems have since been econo

3、mically and competitively used in a number of structures for both residential and commercial purposes.The high-rise buildings ranging from 50 to 110 stories that are being built all over the United States are the result

4、of innovations and development of new structual systems.</p><p>　　Greater height entails increased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acce

5、ptable limit.Excessive lateral sway may cause serious recurring damage to partitions,ceilings.and other architectural details. In addition,excessive sway may cause discomfort to the occupants of the building because thei

6、r perception of such motion.Structural systems of reinforced concrete,as well as steel,take full advantage of inherent potential stiffness </p><p>　　In a steel structure,for example,the economy can be define

7、d in terms of the total average quantity of steel per square foot of floor area of the building.Curve A in Fig .1 represents the average unit weight of a conventional frame with increasing numbers of stories. Curve B re

8、presents the average steel weight if the frame is protected from all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for height for the traditional column-and-beam frame.St

9、ru</p><p>　　Systems in steel. Tall buildings in steel developed as a result of several types of structural innovations. The innovations have been applied to the construction of both office and apartment bui

10、ldings.</p><p>　　Frame with rigid belt trusses. In order to tie the exterior columns of a frame structure to the interior vertical trusses,a system of rigid belt trusses at mid-height and at the top of the

11、building may be used. A good example of this system is the First Wisconsin Bank Building(1974) in Milwaukee.</p><p>　　Framed tube. The maximum efficiency of the total structure of a tall building, for both s

12、trength and stiffness,to resist wind load can be achieved only if all column element 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 groun

13、d. This particular structural system was probably used for the first time in the 43-story reinforced concrete DeWitt Chestnut Apartment Building in Chicago. The most significant use of this s</p><p>　　Column

14、-diagonal truss tube. The exterior columns of a building can be spaced reasonably far apart and yet be made to work together as a tube by connecting them with diagonal members interesting at the centre line of the colum

15、ns and beams. This simple yet extremely efficient system was used for the first time on the John Hancock Centre in Chicago, using as much steel as is normally needed for a traditional 40-story building.</p><p&

16、gt;　　Bundled tube. With the continuing need for larger 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 efficien

17、cy. The 110-story Sears Roebuck Headquarters Building in Chicago has nine tube, bundled at the base of the building in three rows. Some of these individual tubes terminate at different heights of the building, demonstrat

18、ing the unlimited architectural possibilities of this latest stru</p><p>　　Stressed-skin tube system. The tube structural system was developed for improving the resistance to lateral forces (wind and earthqu

19、ake) and the control of drift (lateral building movement ) in high-rise building. The stressed-skin tube takes the tube system a step further. The development of the stressed-skin tube utilizes the façade of the bui

20、lding as a structural element which acts with the framed tube, thus providing an efficient way of resisting lateral loads in high-rise buildings, and re</p><p>　　Because of the contribution of the stressed-

21、skin façade, the framed members of the tube require less mass, and are thus lighter and less expensive. All the typical columns and spandrel beams are standard rolled shapes,minimizing the use and cost of special bu

22、ilt-up members. The depth requirement for the perimeter spandrel beams is also reduced, and the need for upset beams above floors, which would encroach on valuable space, is minimized. The structural system has been used

23、 on the 54-story One </p><p>　　Systems in concrete. While tall buildings constructed of steel had an early start, development of tall buildings of reinforced concrete progressed at a fast enough rate to prov

24、ide a competitive chanllenge to structural steel systems for both office and apartment buildings.</p><p>　　Framed tube. As discussed above, the first framed tube concept for tall buildings was used for the 4

25、3-story DeWitt Chestnut Apartment Building. In this 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-m) flat-plate concrete slabs.

26、</p><p>　　Tube in tube. Another system in reinforced concrete for office buildings combines the traditional shear wall construction with an exterior framed tube. The system consists of an outer framed tube o

27、f very closely spaced columns and an interior rigid shear wall tube enclosing the central service area. The system (Fig .2), known as the tube-in-tube system , made it possible to design the world’s present tallest (714f

28、t or 218m)lightweight concrete building ( the 52-story One Shell Plaza Building in </p><p>　　Systems combining both concrete and steel have also been developed, an examle of which is the composite system dev

29、eloped by skidmore, Owings &Merril in which an exterior closely spaced framed tube in concrete envelops an interior steel framing, thereby combining the advantages of both reinforced concrete and structural steel sys

30、tems. The 52-story One Shell Square Building in New Orleans is based on this system.</p><p>　　Steel construction refers to a broad range of building construction in which steel plays the leading role. Most

31、 steel construction consists of large-scale buildings or engineering works, with the steel generally in the form of beams, girders, bars, plates, and other members shaped through the hot-rolled process. Despite the incre

32、ased use of other materials, steel construction remained a major outlet for the steel industries of the U.S, U.K, U.S.S.R, Japan, West German, France, and other steel </p><p>　　Early history. The history of

33、steel construction begins paradoxically several decades before the introduction of the Bessemer and the Siemens-Martin (openj-hearth) processes made it possible to produce steel in quantities sufficient for structure use

34、. Many of problems of steel construction were studied earlier in connection with iron construction, which began with the Coalbrookdale Bridge, built in cast iron over the Severn River in England in 1777. This and subsequ

35、ent iron bridge work, in addit</p><p>　　The technique for passing iron, heated to the plastic state, between rolls to form flat and rounded bars, was developed as early as 1800;by 1819 angle irons were rolle

36、d; and in 1849 the first I beams, 17.7 feet (5.4m) long , were fabricated as roof girders for a Paris railroad station.</p><p>　　Two years later Joseph Paxton of England built the Crystal Palace for the Lond

37、on Exposition of 1851. He is said to have conceived the idea of cage construction-using relatively slender iron beams as a skeleton for the glass walls of a large, open structure. Resistance to wind forces in the Crystal

38、 palace was provided by diagonal iron rods. Two feature are particularly important in the history of metal construction; first, the use of latticed girder, which are small trusses, a form first develope</p><p&

39、gt;　　In 1853 the first metal floor beams were rolled for the Cooper Union Building in New York. In the light of the principal market demand for iron beams at the time, it is not surprising that the Cooper Union beams clo

40、sely resembled railroad rails.</p><p>　　The development of the Bessemer and Siemens-Martin processes in the 1850s and 1860s suddenly open the way to the use of steel for structural purpose. Stronger than iro

41、n in both tension and compression ,the newly available metal was seized on by imaginative engineers, notably by those involved in building the great number of heavy railroad bridges then in demand in Britain, Europe, and

42、 the U.S.</p><p>　　A notable example was the Eads Bridge, also known as the St. Louis Bridge, in St. Louis (1867-1874), in which tubular steel ribs were used to form arches with a span of more than 500ft (15

43、2.5m). In Britain, the Firth of Forth cantilever bridge (1883-90) employed tubular struts, some 12 ft (3.66m) in diameter and 350 ft (107m) long. Such bridges and other structures were important in leading to the develop

44、ment and enforcement of standards and codification of permissible design stresses. The lack </p><p>　　The possibilities inherent in metal construction for high-rise building was demonstrated to the world by

45、the Paris Exposition of 1889.for which Alexandre-Gustave Eiffel, a leading French bridge engineer, erected an openwork metal tower 300m (984 ft) high. Not only was the height-more than double that of the Great Pyramid-re

46、markable, but the speed of erection and low cost were even more so, a small crew completed the work in a few months. </p><p>　　The first skyscrapers. Meantime, in the United States another important developm

47、ent was taking place. In 1884-85 Maj. William Le Baron Jenney, a Chicago engineer , had designed the Home Insurance Building, ten stories high, with a metal skeleton. Jenney’s beams were of Bessemer steel, though his col

48、umns were cast iron. Cast iron lintels supporting masonry over window openings were, in turn, supported on the cast iron columns. Soild masonry court and party walls provided lateral support against w</p><p>

49、;　　Though the new construction form was to remain centred almost entirely in America for several decade, its impact on the steel industry was worldwide. By the last years of the 19th century, the basic structural shapes-

50、I beams up to 20 in. ( 0.508m) in depth and Z and T shapes of lesser proportions were readily available, to combine with plates of several widths and thicknesses to make efficient members of any required size and strengt

51、h. In 1885 the heaviest structural shape produced through hot-r</p><p>　　Coincident with the introduction of structural steel came the introduction of the Otis electric elevator in 1889. The demonstration of

52、 a safe passenger elevator, together with that of a safe and economical steel construction method, sent building heights soaring. In New York the 286-ft (87.2-m) Flatiron Building of 1902 was surpassed in 1904 by the 375

53、-ft (115-m) Times Building ( renamed the Allied Chemical Building) , the 468-ft (143-m) City Investing Company Building in Wall Street, the 612-ft</p><p>　　The rapid increase in height and the height-to-widt

54、h ratio brought problems. To limit street congestion, building setback design was prescribed. On the technical side, the problem of lateral support was studied. A diagonal bracing system, such as that used in the Eiffel

55、Tower, was not architecturally desirable in offices relying on sunlight for illumination. The answer was found in greater reliance on the bending resistance of certain individual beams and columns strategically designed

56、into the </p><p>　　World War I brought an interruption to the boom in what had come to be called skyscrapers (the origin of the word is uncertain), but in the 1920s New York saw a resumption of the height ra

57、ce, culminating in the Empire State Building in the 1931. The Empire State’s 102 stories (1,250ft. [381m]) were to keep it established as the hightest building in the world for the next 40 years. Its speed of the erectio

58、n demonstrated how thoroughly the new construction technique had been mastered. A depot acro</p><p>　　The worldwide depression of the 1930s and World War II provided another interruption to steel constructio

59、n development, but at the same time the introduction of welding to replace riveting provided an important advance.</p><p>　　Joining of steel parts by metal are welding had been successfully achieved by the e

60、nd of the 19th century and was used in emergency ship repairs during World War I, but its application to construction was limited until after World War II. Another advance in the same area had been the introduction of hi

61、gh-strength bolts to replace rivets in field connections.</p><p>　　Since the close of World War II, research in Europe, the U.S., and Japan has greatly extended knowledge of the behavior of different types o

62、f structural steel under varying stresses, including those exceeding the yield point, making possible more refined and systematic analysis. This in turn has led to the adoption of more liberal design codes in most countr

63、ies, more imaginative design made possible by so-called plastic design ?The introduction of the computer by short-cutting tedious paperwork,</p><p><b>　　高層結(jié)構(gòu)與鋼結(jié)構(gòu)</b></p><p>　　近年來，盡管一

64、般的建筑結(jié)構(gòu)設計取得了很大的進步，但是取得顯著成績的還要屬超高層建筑結(jié)構(gòu)設計。</p><p>　　最初的高層建筑設計是從鋼結(jié)構(gòu)的設計開始的。鋼筋混凝土和受力外包鋼筒系統(tǒng)運用起來是比較經(jīng)濟的系統(tǒng)，被有效地運用于大批的民用建筑和商業(yè)建筑中。50層到100層的建筑被定義為超高層建筑。而這種建筑在美國得廣泛的應用是由于新的結(jié)構(gòu)系統(tǒng)的發(fā)展和創(chuàng)新。</p><p>　　這樣的高度需要增大柱和梁的尺寸

65、，這樣以來可以使建筑物更加堅固以至于在允許的限度范圍內(nèi)承受風荷載而不產(chǎn)生彎曲和傾斜。過分的傾斜會導致建筑的隔離構(gòu)件、頂棚以及其他建筑細部產(chǎn)生循環(huán)破壞。除此之外，過大的搖動也會使建筑的使用者們因感覺到這樣的的晃動而產(chǎn)生不舒服的感覺。無論是鋼筋混凝土結(jié)構(gòu)系統(tǒng)還是鋼結(jié)構(gòu)系統(tǒng)都充分利用了整個建筑的剛度潛力，因此不能指望利用多余的剛度來限制側(cè)向位移。</p><p>　　在鋼結(jié)構(gòu)系統(tǒng)設計中，經(jīng)濟預算是根據(jù)每平方英寸地板面積

66、上的鋼材的數(shù)量確定的。圖示1中的曲線A顯示了常規(guī)框架的平均單位的重量隨著樓層數(shù)的增加而增加的情況。而曲線B顯示則顯示的是在框架被保護而不受任何側(cè)向荷載的情況下的鋼材的平均重量。上界和下界之間的區(qū)域顯示的是傳統(tǒng)梁柱框架的造價隨高度而變化的情況。而結(jié)構(gòu)工程師改進結(jié)構(gòu)系統(tǒng)的目的就是減少這部分造價。</p><p>　　鋼結(jié)構(gòu)中的體系：鋼結(jié)構(gòu)的高層建筑的發(fā)展是幾種結(jié)構(gòu)體系創(chuàng)新的結(jié)果。這些創(chuàng)新的結(jié)構(gòu)已經(jīng)被廣泛地應用于辦公大

67、樓和公寓建筑中。</p><p>　　剛性帶式桁架的框架結(jié)構(gòu)：為了聯(lián)系框架結(jié)構(gòu)的外柱和內(nèi)部帶式桁架，可以在建筑物的中間和頂部設置剛性帶式桁架。1974年在米望基建造的威斯康森銀行大樓就是一個很好的例子。</p><p>　　框架筒結(jié)構(gòu)： 如果所有的構(gòu)件都用某種方式互相聯(lián)系在一起，整個建筑就像是從地面發(fā)射出的一個空心筒體或是一個剛性盒子一樣。這個時候此高層建筑的整個結(jié)構(gòu)抵抗風荷載的所有強度和

68、剛度將達到最大的效率。這種特殊的結(jié)構(gòu)體系首次被芝加哥的43層鋼筋混凝土的德威特紅棕色的公寓大樓所采用。但是這種結(jié)構(gòu)體系的的所有應用中最引人注目的還要屬在紐約建造的100層的雙筒結(jié)構(gòu)的世界貿(mào)易中心大廈。</p><p>　　斜撐桁架筒體： 建筑物的外柱可以彼此獨立的間隔布置，也可以借助于通過梁柱中心線的交叉的斜撐構(gòu)件聯(lián)系在一起，形成一個共同工作的筒體結(jié)構(gòu)。這種高度的結(jié)構(gòu)體系首次被芝加哥的John Hancock 中

69、心大廈采用。這項工程所耗用的剛才量與傳統(tǒng)的四十層高樓的用鋼量相當。</p><p>　　筒體： 隨著對更高層建筑的要求不斷地增大。筒體結(jié)構(gòu)和斜撐桁架筒體被設計成捆束狀以形成更大的筒體來保持建筑物的高效能。芝加哥的110層的Sears Roebuck 總部大樓有9個筒體，從基礎(chǔ)開始分成三個部分。這些獨立筒體中的終端處在不同高度的建筑體中，這充分體現(xiàn)出了這種新式結(jié)構(gòu)觀念的建筑風格自由化的潛能。這座建筑物1450英尺（

70、442米）高，是世界上最高的大廈。</p><p>　　薄殼筒體系統(tǒng)：這種筒體結(jié)構(gòu)系統(tǒng)的設計是為了增強超高層建筑抵抗側(cè)力的能力（風荷載和地震荷載）以及建筑的抗側(cè)移能力。薄殼筒體是筒體系統(tǒng)的又一大飛躍。薄殼筒體的進步是利用高層建筑的正面（墻體和板）作為與筒體共同作用的結(jié)構(gòu)構(gòu)件，為高層建筑抵抗側(cè)向荷載提供了一個有效的途徑，而且可獲得不用設柱，成本較低，使用面積與建筑面積之比又大的室內(nèi)空間。</p>&l

71、t;p>　　由于薄殼立面的貢獻，整個框架筒的構(gòu)件無需過大的質(zhì)量。這樣以來使得結(jié)構(gòu)既輕巧又經(jīng)濟。所有的典型柱和窗下墻托梁都是軋制型材，最大程度上減小了組合構(gòu)件的使用和耗費。托梁周圍的厚度也可適當?shù)臏p小。而可能占據(jù)寶貴空間的墻上鐓梁的尺寸也可以最大程度地得到控制。這種結(jié)構(gòu)體系已被建造在匹茲堡洲的One Mellon銀行中心所運用。</p><p>　　鋼筋混凝土中的各體系：雖然鋼結(jié)構(gòu)的高層建筑起步比較早，但是鋼

72、筋混凝土的高層建筑的發(fā)展非?？欤瑹o論在辦公大樓還是公寓住宅方面都成為剛結(jié)構(gòu)體系的有力競爭對手。</p><p>　　框架筒：像上面所提到的，框架筒構(gòu)思首次被43層的迪威斯公寓大樓所采用。在這座大樓中，外柱的柱距為5.5英尺（1.68米）。而內(nèi)柱則需要支撐8英寸厚的無梁板。</p><p>　　筒中筒結(jié)構(gòu)：另一種針對于辦公大樓的鋼筋混凝土體系把傳統(tǒng)的剪力墻結(jié)構(gòu)與外框架筒相結(jié)合。該體系由柱距很

73、小的外框架與圍繞中心設備區(qū)的剛性剪力墻筒組成。這種筒中筒結(jié)構(gòu)（如插圖2）使得當前世界上最高的輕質(zhì)混凝土大樓（在休斯頓建造的獨殼購物中心大廈）的整體造價只與35層的傳統(tǒng)剪力墻結(jié)構(gòu)相當。</p><p>　　鋼結(jié)構(gòu)與混凝土結(jié)構(gòu)的聯(lián)合體系也有所發(fā)展。Skidmore ,Owings 和Merrill共同設計的混合體系就是一個好例子。在此體系中，外部的混凝土框架筒包圍著內(nèi)部的鋼框架，從而結(jié)合了鋼筋混凝土體系與鋼結(jié)構(gòu)體系各

74、自的優(yōu)點。在新奧爾良建造的52層的獨殼廣場大廈就是運用了這種體系。</p><p>　　鋼結(jié)構(gòu)是指在建筑物結(jié)構(gòu)中鋼材起著主導作用的結(jié)構(gòu)，是一個很寬泛的概念。大部分的鋼結(jié)構(gòu)都包括建筑設計，工程技術(shù)、工藝。通常還包括以主梁、次梁、桿件，板等形式存在的鋼的熱軋加工工藝。上個世紀七十年代，除了對其他材料的需求在增長，鋼結(jié)構(gòu)仍然保持著對于來自美國、英國、日本、西德、法國等國家的鋼材廠鋼材的大量需求。</p>

75、<p>　　發(fā)展歷史：早在Bessemer和Siemens-Marton(開放式爐)工藝出現(xiàn)以前，鋼結(jié)構(gòu)就已經(jīng)有幾十年的歷史了。而直到此工藝問世之后才使得鋼材可以大批生產(chǎn)出來供結(jié)構(gòu)所用。對鋼結(jié)構(gòu)諸多問題的研究開始于鐵結(jié)構(gòu)的使用，當時很著名的研究對象是1977年在英國建造的橫跨斯沃河的Coalbrook dale 大橋。這座大橋以及后來的鐵橋設計再加上蒸汽鍋爐、鐵船身的設計都刺激了建筑安裝設計以及連接工藝的發(fā)展。鐵結(jié)構(gòu)對材料的需

76、求量較小是優(yōu)勝于磚石結(jié)構(gòu)的主要方面。長久以來一直用木材制作的三角桁架也換成鐵制的了。承受由直接荷載產(chǎn)生的重力作用的受壓構(gòu)件常用鑄鐵制造，而承受由懸掛荷載產(chǎn)生的推力作用的受拉構(gòu)件常用熟鐵制造。</p><p>　　把鐵加熱到塑性狀態(tài)，使之從卷狀轉(zhuǎn)化為扁平狀與圓狀之間的某一狀態(tài)的工藝，早在1800年就得以發(fā)展了。隨后，1819年角鋼問世，1894年第一個工字鋼被建造出來作為巴黎火車站的頂梁。此工字鋼長17.7英尺）（

77、5.4米）。</p><p>　　1851年英國的Joseph Paxtond為倫敦博覽會建造了水晶宮。據(jù)說當時他已有這樣的骨架結(jié)構(gòu)構(gòu)思：用比較細的鐵梁作為玻璃幕墻的骨架。此建筑的風荷載抵抗力是由對角拉桿所提供的。在金屬結(jié)構(gòu)的發(fā)展歷史中，有兩個標志性事件：首先是從木橋發(fā)展而來的格構(gòu)梁由木制轉(zhuǎn)化為鐵制；其次是鍛鐵制的受拉構(gòu)件與鑄鐵制的受壓構(gòu)件受熱后通過鉚釘連接工藝的發(fā)展。</p><p>　

78、　十九世紀五六十年代，Bessemer 與 Siemens-Martin工藝的發(fā)展使鋼材的生產(chǎn)能滿足結(jié)構(gòu)的需求。鋼的受拉強度與受壓強度都好于鐵。這種新型的金屬常被有想象力的工程師所利用，尤其倍受那些參與過英國、歐洲以及美國的道橋建設的工程師的喜愛。</p><p>　　其中一個很好的例子就是Eads大橋（也被稱為路易斯洲大橋）（1867-1874）。在這座大橋中，每隔500英尺（152.5米）設有由鋼管加強肋形成

79、的拱。英國的Firth of Forth懸索橋設有管件支撐，直徑大約為12英尺（3.66米），長度為350英尺（107）米。這些大橋以及其他結(jié)構(gòu)在引導鋼結(jié)構(gòu)的發(fā)展，規(guī)范的實施，許用應力的設計方面起到了很重要的作用。1907年Quebec懸索大橋的偶然破壞揭露了二十世紀初期由于缺乏足夠的理論知識，甚至是缺乏足夠的理論研究的基礎(chǔ)知識，而導致在應力分析方面出現(xiàn)了很多的不足。但是，這樣的損壞卻很少出現(xiàn)在金屬骨架的辦公大樓中。因為盡管在缺乏縝密的

80、分析的情況下，這些建筑也表現(xiàn)出了很高的實用性。在上個世紀中葉，沒有經(jīng)過任何特殊合金強化、硬化過的普通碳素鋼已經(jīng)被廣泛地使用了。</p><p>　　在1889年巴黎召開的世界博覽會上，金屬結(jié)構(gòu)表現(xiàn)出了在超高層建筑運用上的內(nèi)在潛力。在這次會上，法國著名的橋梁設計師埃非爾展示了他的杰作-300米高的露天開挖的鐵塔。無論是它的高度（比著名的金字塔的兩倍還高），架設的速度-人數(shù)不多的工作人員僅用幾個月的時間就完成了整個工

81、程任務，還是很低的工程造價都使它脫穎而出。</p><p>　　首批摩天大廈：在剛結(jié)構(gòu)發(fā)展的同時，美國的另一個是也蓬勃的發(fā)展起來了。1884-1885年，芝加哥的工程師Maj.William Le Baron Jennny設計了家庭保險公司大廈。這座大廈也是金屬結(jié)構(gòu)的，有十層高。大廈的梁是鋼制的，而柱是鑄鐵所制。鑄鐵制的過梁支撐著窗洞口上方的砌體，同時也需要鑄鐵制的柱支撐著。實心砌體的天井與界墻提供抵抗風載的側(cè)向

82、支撐。不到十年的功夫，芝加哥和紐約已經(jīng)有超過30座辦公大樓是利用這種結(jié)構(gòu)。鋼材在這些結(jié)構(gòu)中起了非常大的作用。這種結(jié)構(gòu)利用鉚釘把梁與柱連接在一起。有時為了抵抗風荷載還是在豎向構(gòu)件和橫向構(gòu)件的連接點出貼覆上節(jié)點板來加固結(jié)構(gòu)。此外，輕型的玻璃幕墻結(jié)構(gòu)代替了老式的重質(zhì)砌體結(jié)構(gòu)。</p><p>　　盡管幾十年來之中建筑形式主要是在美國發(fā)展的，但是它卻影響著全世界鋼材工業(yè)的發(fā)展。十九世紀的最后幾年，基本結(jié)構(gòu)形狀工字型鋼的厚

83、度已經(jīng)達到20英寸（0.508米），非對稱的Z字型鋼和T型鋼可以與有一定寬度和厚度的板相聯(lián)結(jié)，使得構(gòu)件具體符合要求的尺寸和強度。1885年最重的型鋼通過熱軋生產(chǎn)出來，每英寸不到100磅（45千克）。到二十世紀六十年代這個數(shù)字已經(jīng)達到每英寸700磅（320千克）。</p><p>　　緊隨著鋼結(jié)構(gòu)的發(fā)展，1988年第一部電梯問世了。安全載客電梯誕生，以及安全經(jīng)濟的鋼結(jié)構(gòu)設計方法的發(fā)展促使建筑高度迅猛增加。1902年

84、在紐約建造的高286英寸（87.2米）的Flatiron大廈不斷地被后來的建筑所超越。這些建筑分別是高375英尺（115米）的時代大廈（1904），（后來改名為聯(lián)合化工制品大廈）。1908年在華爾街建造的高468英尺（143米）的城市投資公司大廈，高612 英尺（187米）的星爾大廈，以及700英尺（214米）的都市塔和780英尺高（232米）的Woll worth大廈。</p><p>　　房屋高度與高寬比的不

85、斷增加也帶來了許多的問題。為了控制道路的阻塞，要對建筑的縮進設計進行限定。側(cè)向支撐的設置也是其中一項技術(shù)問題，例如，埃非爾鐵塔所采用的對角支撐體系對于要靠太陽光來照明的辦公大廈就不實用了。而只有考慮到具體的單獨梁與單獨柱的抗彎能力以及梁柱相交處的剛度的框架設計才是可靠的。隨著現(xiàn)代內(nèi)部采光體系的不斷發(fā)展，抵抗風荷載的對角支撐又重新被利用起來了。芝加哥的John Hancock 中心就是一個很顯著的例子。外部的對角支撐成為此結(jié)構(gòu)立面的一個很

86、顯眼的部分。</p><p>　　第一次世界大戰(zhàn)暫時中斷了所謂摩天大廈（當時這個詞并沒有確定）的蓬勃發(fā)展，但是二十世紀二十年代又恢復了這一趨勢。1931年建造的帝國大廈把詞潮流推向了頂峰。102層高1250英尺（381米）的帝國大廈在后來的40年一直保持著世界最高的地位。它的建造速度充分證明了這種新的結(jié)構(gòu)形式已經(jīng)被當時的技術(shù)所掌握。次項工程所需要的梁是由Bayonne海灣對岸的軍械庫所提供的。是由用精密儀器控制的

87、駁船和卡車負責運輸?shù)?。由九架起重機將這些梁提升到指定的位置。由工業(yè)軌道裝置把鋼材和其他材料移到每一層上去。先是螺栓連接緊接著鉚釘連接，最后是裝修，整個工程的最終完成只用了一年零45天。</p><p>　　二十世紀三十年代席卷全世界的大蕭條以及第而次世界大戰(zhàn)使鋼結(jié)構(gòu)的發(fā)展又一次受到了阻礙。但是與此同時，焊接代替了鉚釘連接則是一個很重要的發(fā)展。</p><p>　　十九世紀末，利用焊接把各個

88、鋼零件相連接已取得了很好的成績，并在第一次世界大戰(zhàn)中被運用于救生船的修理。但直到第二次世界大戰(zhàn)后才用于建筑結(jié)構(gòu)中。同時在連接領(lǐng)域中又一進步就是高強螺栓代替了鉚釘。</p><p>　　二戰(zhàn)結(jié)束后，歐洲，美國，日本等國都擴大了對在不定應力（包括超過屈服點的情況）作用下各種結(jié)構(gòu)鋼的性質(zhì)的研究，并進行了更為精確、系統(tǒng)的分析。此后，許多國家采用了一些更為自由靈活的設計規(guī)范和更為理想化的彈性設計規(guī)范。計算機在工程上的運用代