土木工程外文翻譯----抗側(cè)向荷載的結(jié)構(gòu)體系-建筑結(jié)構(gòu)(已改無(wú)錯(cuò)字)
2023-07-06 14:11:36 本頁(yè)面
【正文】 traight 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 pression 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. 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 ATamp。T headquarters is an example of an astonishing array of interactive elements: 1. The structural system is 94 ft () wide, 196ft(59. 7m) long, and 601ft () high. 2. Two inner tubes are provided, each 31ft(9. 4m) by 40 ft (12. 2m), centered 90 ft () apart in the long direction of the building. 3. The inner tubes are braced in the short direction, but with zero shear stiffness in the long direction. 4. A single outer tube is supplied, which encircles the building perimeter. 5. The outer tube is a momentresisting frame, but with zero shear stiffness for the center50ft () of each of the long sides. 6. A spacetruss hat structure is provided at the top of the building. 7. A similar space truss is located near the bottom of the building 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. Cellular structures A classic example of a cellular structure is the Sears Towe r, 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 plan shape, It is not unmon that some of the individual tubes one of the strengths and one of the weaknesses of the system. This special weakness of this system, particularly in framed tubes, has to do with the concept of differential column shortening. The shortening of a column under load is given by the expression △ =Σ fL/E For buildings of 12 ft () floor tofloor distances and an average pressive stress of 15 ksi (138MPa), the shortening of a column under load is 15 (12)(12)/29, 000 or 0. 074in (1. 9mm ) per story. At 50 stories, the column will have shortened to in. (94mm) less than its unstressed length. Where one cell of a bundled tube system is, say, 50stories high and an adjacent cell is, say, 100stories high, those columns near the boundary bet ween . the two systems need to have this differential deflection reconciled. Major structural work has been found to be needed at such locations. In at least one building, the Rialto Project, Melbourne, the structural engineer found it necessary to vertically prestress the lower height columns so as to reconcile the differential deflections of columns in close proximity with the post tensioning of the shorter column simulating the weight to be added on to adjacent, higher columns. 抗側(cè)向荷載的結(jié)構(gòu)體系 常用的結(jié)構(gòu)體系 若已測(cè)出 荷載量達(dá)數(shù)千萬(wàn)磅重，那么在高層建筑設(shè)計(jì)中就沒有多少可以進(jìn)行極其復(fù)雜的構(gòu)思余地了。確實(shí)，較好的高層建筑普遍具有構(gòu)思簡(jiǎn)單、表現(xiàn)明晰的特點(diǎn)。 這并不是說沒有進(jìn)行宏觀構(gòu)思的余地。實(shí)際上，正是因?yàn)橛辛诉@種宏觀的構(gòu)思，新奇的高層建筑體系才得以發(fā)展，可能更重要的是：幾年以前才出現(xiàn)的一些新概念在今天的技術(shù)中已經(jīng)變得平常了。 如果忽略一些與建筑材料密切相關(guān)的概念不談，高層建筑里最為常用的結(jié)構(gòu)體系便可分為如下幾類： 1． 抗彎矩框架。 2． 支撐框架，包括偏心支撐框架。 3． 剪力墻，包括鋼板剪力墻。 4． 筒中框架。 5． 筒中筒結(jié)構(gòu)。 6． 核心交互結(jié)構(gòu)。 7． 框格體系或束筒體系。 特別是由于最近趨向于更復(fù)雜的建筑形式，同時(shí)也需要增加剛度以抵抗幾力和地震力，大多數(shù)高層建筑都具有由框架、支撐構(gòu)架、剪力墻和相關(guān)體系相結(jié)合而構(gòu)成的體系。而且，就較高的建筑物而言，大多數(shù)都是由交互式構(gòu)件組成三維陳列。 將這
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