【正文】 高 286英寸（ 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(shí)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。 房屋高度與高寬比的不斷增加也帶來了許多的問題。為了控制道路的阻塞，要對(duì)建筑的縮進(jìn)設(shè)計(jì)進(jìn)行限定。側(cè)向支 撐的設(shè)置也是其中一項(xiàng)技術(shù)問題，例如，埃非爾鐵塔所采用的對(duì)角支撐體系對(duì)于要靠太陽光來照明的辦公大廈就不實(shí)用了。而只有考慮到具體的單獨(dú)梁與單獨(dú)柱的抗彎能力以及梁柱相交處的剛度的框架設(shè)計(jì)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(fēng)荷載的對(duì)角支撐又重新被利用起來了。芝加哥的 John Hancock 中心就是一個(gè)很顯著的例子。外部的對(duì)角支撐成為此結(jié)構(gòu)立面的一個(gè)很顯眼的部分。 第一次世界大戰(zhàn)暫時(shí)中斷了所謂摩天大廈（當(dāng)時(shí)這個(gè)詞并沒有確定）的蓬勃發(fā)展，但是二十世紀(jì)二十年代又恢復(fù)了這一趨勢(shì)。 1931 年建造的帝國(guó)大廈把詞 潮流推向了頂峰。 102 層高 1250 英尺（ 381 米）的帝國(guó)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(dāng)時(shí)的技術(shù)所掌握。 次項(xiàng)工程所需要的梁是由 Bayonne 海灣對(duì)岸的軍械庫所提供的。是由用精密儀器控制的駁船和卡車負(fù)責(zé)運(yùn)輸?shù)?。由九架起重機(jī)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(gè)工程的最終完成只用了一年零 45 天。 二十世紀(jì)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(shí)，焊接代替了鉚釘連接則是一個(gè)很重要的發(fā)展。 十九世紀(jì)末，利用焊接把各個(gè)鋼零件相連接已取得了很好的成績(jī)，并在第一次世界大戰(zhàn)中被運(yùn)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(shí)在連接領(lǐng)域中又一進(jìn)步就是高強(qiáng)螺栓代替了鉚釘。 二戰(zhàn)結(jié)束后，歐洲，美國(guó)，日本等國(guó)都擴(kuò)大了對(duì)在不定應(yīng)力（包括超過屈服點(diǎn)的情況）作用下各種結(jié)構(gòu)鋼的性質(zhì)的研究，并進(jìn)行了更為精確、系統(tǒng)的分析。此后，許多國(guó)家采用了一些更為自由靈活的設(shè)計(jì)規(guī)范和更為理想化的彈性設(shè)計(jì)規(guī)范。計(jì)算機(jī)在工程上的運(yùn)用代替了冗長(zhǎng)的手工計(jì)算，從而更加促進(jìn) 了鋼結(jié)構(gòu)的發(fā)展，并大大的減低了造價(jià)。 (來自 為期兩天的 混凝土技術(shù)可持續(xù)發(fā)展 國(guó)際研討會(huì)上 ， 四月 1920,2020) 附件 2：外文原文 （ 電子或 復(fù)印件） Talling building and Steel construction Although there have been many advancements in building construction technology in general. Spectacular achievements have been made in the design and construction of ultrahighrise buildings. The early development of highrise buildings began with structural steel framing. Reinforced concrete and stressedskin tube systems have since been economically and petitively used in a number of structures for both residential and mercial purposes. The highrise 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. Greater height entails increased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acceptable limit. Excessive lateral sway may cause serious recurring damage to partitions, ceilings and other architectural details. In addition, excessive sway may cause disfort to the occupants of the building because their perception of such motion. Structural systems of reinforced concrete ,as well as steel, take full advantage of inherent potential stiffness of the total building and therefore require additional stiffening to limit the sway. In a steel structure, 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. 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 buildings. 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 midheight and at the top of the building may be used. A good example of this system is the First Wisconsin Bank Building (1974) in Milwaukee. Framed tube. The maximum 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 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 ground. This particular structural system was probably used for the first time in the 43story reinforced concrete DeWitt Chestnut Apartment Building in Chicago. The most significant use of this system is in the twin structural steel towers of the 110story World Trade Center building in New York. Columndiagonal 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 columns 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 40story building. Bundled tube. With the continuing need for larger and taller buildings, the framed tube or the columndiagonal truss tube may be used in a bundled form to create larger tube envelopes while maintaining high efficiency. The 110story Sears Roebuck Headquarters Building in Chicago has nine tube, bundled at the base of the building in three rows. Some of