土木專業(yè)畢業(yè)設(shè)計(jì)外文翻譯---高層建筑

1、<p>　　High-Rise Buildings</p><p>　　Introduction</p><p>　　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 bui

2、lding probably ranges between 3 or 4 stories up to 10 or 20 stories or more . </p><p>　　Although the basic principles of vertical and horizontal subsystem design remain the same for low- , medium- , or high-

3、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 ov

4、erturning moment and the shear deflections produced by lateral forces are much larger and must be carefully provided for .</p><p>　　The vertical subsystems in a high-rise building transmit accumulated gravit

5、y 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 foundat

6、ions. 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 ba</p><

7、;p>　　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

8、 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 the si

9、zes of the columns and girders otherwise required for vertical loads</p><p>　　Unfortunately , this is not is for high-rise buildings because the problem is primarily resistance to moment and deflection rathe

10、r than shear alone . Special structural arrangements will often have to be made and additional structural material is always required for the columns , girders , walls , and slabs in order to made a high-rise buildings s

11、ufficiently resistant to much higher lateral deformations . </p><p>　　As previously mentioned , the quantity of structural material required per square foot of floor of a high-rise buildings is in excess of

12、that required for low-rise buildings . The vertical components carrying the gravity load , such as walls , columns , and shafts , will need to be strengthened over the full height of the buildings . But quantity of mater

13、ial required for resisting lateral forces is even more significant .</p><p>　　With reinforced concrete , the quantity of material also increases as the number of stories increases . But here it should be not

14、ed that the increase in the weight of material added for gravity load is much more sizable than steel , whereas for wind load the increase for lateral force resistance is not that much more since the weight of a concrete

15、 buildings helps to resist overturn . On the other hand , the problem of design for earthquake forces . Additional mass in the upper floors will give r</p><p>　　In the case of either concrete or steel design

16、 , there are certain basic principles for providing additional resistance to lateral to lateral forces and deflections in high-rise buildings without too much sacrifire in economy . </p><p>　　Increase the ef

17、fective width of the moment-resisting subsystems . This is very useful because increasing the width will cut down the overturn force directly and will reduce deflection by the third power of the width increase , other th

18、ings remaining cinstant . However , this does require that vertical components of the widened subsystem be suitably connected to actually gain this benefit.</p><p>　　Design subsystems such that the component

19、s are made to interact in the most efficient manner . For example , use truss systems with chords and diagonals efficiently stressed , place reinforcing for walls at critical locations , and optimize stiffness ratios for

20、 rigid frames . </p><p>　　Increase the material in the most effective resisting components . For example , materials added in the lower floors to the flanges of columns and connecting girders will directly d

21、ecrease the overall deflection and increase the moment resistance without contributing mass in the upper floors where the earthquake problem is aggravated . </p><p>　　Arrange to have the greater part of vert

22、ical loads be carried directly on the primary moment-resisting components . This will help stabilize the buildings against tensile overturning forces by precompressing the major overturn-resisting components . </p>

23、<p>　　The local shear in each story can be best resisted by strategic placement if solid walls or the use of diagonal members in a vertical subsystem . Resisting these shears solely by vertical members in bending

24、is usually less economical , since achieving sufficient bending resistance in the columns and connecting girders will require more material and construction energy than using walls or diagonal members . </p><p

25、>　　Sufficient horizontal diaphragm action should be provided floor . This will help to bring the various resisting elements to work together instead of separately . </p><p>　　Create mega-frames by joining

26、 large vertical and horizontal components such as two or more elevator shafts at multistory intervals with a heavy floor subsystems , or by use of very deep girder trusses .</p><p>　　Remember that all high-r

27、ise buildings are essentially vertical cantilevers which are supported at the ground . When the above principles are judiciously applied , structurally desirable schemes can be obtained by walls , cores , rigid frames, t

28、ubular construction , and other vertical subsystems to achieve horizontal strength and rigidity . Some of these applications will now be described in subsequent sections in the following . </p><p>　　The vert

29、ical 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 tran

30、smit 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 exampl

31、e under wind load , the overturning moment at the ba</p><p>　　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 , wa

32、lls , 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 fill

33、ing certain panels ( or even all panels ) without increasing the sizes of the columns and girders otherwise required for vertical loads</p><p>　　With reinforced concrete , the quantity of material also incre

34、ases as the number of stories increases . But here it should be noted that the increase in the weight of material added for gravity load is much more sizable than steel , whereas for wind load the increase for lateral fo

35、rce resistance is not that much more since the weight of a concrete buildings helps to resist overturn . On the other hand , the problem of design for earthquake forces . Additional mass in the upper floors will give r&l

36、t;/p><p>　　In the case of either concrete or steel design , there are certain basic principles for providing additional resistance to lateral to lateral forces and deflections in high-rise buildings without too

37、 much sacrifire in economy . Increase the effective width of the moment-resisting subsystems . This is very useful because increasing the width will cut down the overturn force directly and will reduce deflection by the

38、third power of the width increase , other things remaining cinstant . However , t</p><p>　　Remember that all high-rise buildings are essentially vertical cantilevers which are supported at the ground . When

39、the above principles are judiciously applied , structurally desirable schemes can be obtained by walls , cores , rigid frames, tubular construction , and other vertical subsystems to achieve horizontal strength and rigid

40、ity . Some of these applications will now be described in subsequent sections in the following . </p><p>　　Shear-Wall Systems</p><p>　　When shear walls are compatible with other functional requi

41、rements , they can be economically utilized to resist lateral forces in high-rise buildings . For example , apartment buildings naturally require many separation walls . When some of these are designed to be solid , they

42、 can act as shear walls to resist lateral forces and to carry the vertical load as well . For buildings up to some 20storise , the use of shear walls is common . If given sufficient length ,such walls can economically re

43、s</p><p>　　However , shear walls can resist lateral load only the plane of the walls ( i.e.not in a diretion perpendicular to them ) . There fore ,it is always necessary to provide shear walls in two perpend

44、icular directions can be at least in sufficient orientation so that lateral force in any direction can be resisted . In addition , that wall layout should reflect consideration of any torsional effect . </p><p

45、>　　In design progress , two or more shear walls can be connected to from L-shaped or channel-shaped subsystems . Indeed , internal shear walls can be connected to from a rectangular shaft that will resist lateral forc

46、es very efficiently . If all external shear walls are continuously connected , then the whole buildings acts as tube , and connected , then the whole buildings acts as a tube , and is excellent Shear-Wall Seystems resist

47、ing lateral loads and torsion . </p><p>　　Whereas concrete shear walls are generally of solid type with openings when necessary , steel shear walls are usually made of trusses . These trusses can have single

48、 diagonals , “X”diagonals , or“K”arrangements . A trussed wall will have its members act essentially in direct tension or compression under the action of view , and they offer some opportunity and deflection-limitation p

49、oint of view , and they offer some opportunity for penetration between members . Of course , the inclined members o</p><p>　　In many high-rise buildings , a combination of walls and shafts can offer excellen

50、t resistance to lateral forces when they are suitably located ant connected to one another . It is also desirable that the stiffness offered these subsystems be more-or-less symmertrical in all directions .</p>&l

51、t;p>　　Rigid-Frame Systems</p><p>　　In the design of architectural buildings , rigid-frame systems for resisting vertical and lateral loads have long been accepted as an important and standard means for de

52、signing building . They are employed for low-and medium means for designing buildings . They are employed for low- and medium up to high-rise building perhaps 70 or 100 stories high . When compared to shear-wall systems

53、, these rigid frames both within and at the outside of a buildings . They also make use of the stiffness in bea</p><p>　　Frequently , rigid frames will not be as stiff as shear-wall construction , and theref

54、ore may produce excessive deflections for the more slender high-rise buildings designs . But because of this flexibility , they are often considered as being more ductile and thus less susceptible to catastrophic earthqu

55、ake failure when compared with ( some ) shear-wall designs . For example , if over stressing occurs at certain portions of a steel rigid frame ( i.e.,near the joint ) , ductility will allow the </p><p>　　In

56、the case of concrete rigid frames ,there is a divergence of opinion . It true that if a concrete rigid frame is designed in the conventional manner , without special care to produce higher ductility , it will not be able

57、 to withstand a catastrophic earthquake that can produce forces several times lerger than the code design earthquake forces . therefore , some believe that it may not have additional capacity possessed by steel rigid fra

58、mes . But modern research and experience has indicated th</p><p>　　Of course , it is also possible to combine rigid-frame construction with shear-wall systems in one buildings ，F(xiàn)or example , the buildings ge

59、ometry may be such that rigid frames can be used in one direction while shear walls may be used in the other direction。</p><p>　　Structural Systems to resist lateral loads</p><p>　　Omitting some

60、 concepts that are related strictly to the materials of construction, the most commonly used structural systems used in high-rise buildings can be categorized as follows:</p><p>　　1.Moment-resisting frames.&

61、lt;/p><p>　　2.Braced frames, including eccentrically braced frames.</p><p>　　3.Shear walls, including steel plate shear walls.</p><p>　　4.Tube-in-tube structures.</p><p>　

62、　5.Tube-in-tube structures.</p><p>　　6.Core-interactive structures.</p><p>　　7.Cellular or bundled-tube systems.</p><p>　　Particularly with the recent trend toward more complex form

63、s, but in response also to the need for increased stiffness to resist the forces from wind and earthquake, most high-rise buildings have structural systems built up of combinations of frames, braced bents, shear walls, a

64、nd related systems. Further, for the taller buildings, the majorities are composed of interactive elements in three-dimensional arrays.</p><p>　　The method of combining these elements is the very essence of

65、the design process for high-rise buildings. These combinations need evolve in response to environmental, functional, and cost considerations so as to provide efficient structures that provoke the architectural developmen

66、t to new heights. This is not to say that imaginative structural design can create great architecture. To the contrary, many examples of fine architecture have been created with only moderate support from the structura&l

67、t;/p><p>　　Perhaps the most commonly used system in low-to medium-rise buildings, the moment-resisting frame, is characterized by linear horizontal and vertical members connected essentially rigidly at their jo

68、ints. Such frames are used as a stand-alone system or in combination with other systems so as to provide the needed resistance to horizontal loads. In the taller of high-rise buildings, the system is likely to be found i

69、nappropriate for a stand-alone system, this because of the difficulty in mobilizi</p><p>　　The braced frame, intrinsically stiffer than the moment –resisting frame, finds also greater application to higher-r

70、ise buildings. The system is characterized by linear horizontal, vertical, and diagonal members, connected simply or rigidly at their joints. It is used commonly in conjunction with other systems for taller buildings and

71、 as a stand-alone system in low-to medium-rise buildings.</p><p>　　While the use of structural steel in braced frames is common, concrete frames are more likely to be of the larger-scale variety.</p>

72、<p>　　Of special interest in areas of high seismicity is the use of the eccentric braced frame.</p><p>　　Again, analysis can be by STRESS, STRUDL, or any one of a series of two –or three dimensional ana

73、lysis computer programs. And again, center-to-center dimensions are used commonly in the preliminary analysis.</p><p>　　The shear wall is yet another step forward along a progression of ever-stiffer structur

74、al systems. The system is characterized by relatively thin, generally (but not always) concrete elements that provide both structural strength and separation between building functions.</p><p>　　In high-rise

75、 buildings, shear wall systems tend to have a relatively high aspect ratio, that is, their height tends to be large compared to their width. Lacking tension in the foundation system, any structural element is limited in

76、its ability to resist overturning moment by the width of the system and by the gravity load supported by the element. Limited to a narrow overturning, One obvious use of the system, which does have the needed width, is i

77、n the exterior walls of building, where the requ</p><p>　　Structural steel shear walls, generally stiffened against buckling by a concrete overlay, have found application where shear loads are high. The syst

78、em, intrinsically more economical than steel bracing, is particularly effective in carrying shear loads down through the taller floors in the areas immediately above grade. The sys tem has the further advantage of having

79、 high ductility a feature of particular importance in areas of high seismicity.</p><p>　　The analysis of shear wall systems is made complex because of the inevitable presence of large openings through these

80、walls. Preliminary analysis can be by truss-analogy, by the finite element method, or by making use of a proprietary computer program designed to consider the interaction, or coupling, of shear walls.</p><p>

81、;　　Framed or Braced Tubes</p><p>　　The concept of the framed or braced or braced tube erupted into the technology with the IBM Building in Pittsburgh, but was followed immediately with the twin 110-story tow

82、ers of the World Trade Center, New York and a number of other buildings .The system is characterized by three –dimensional frames, braced frames, or shear walls, forming a closed surface more or less cylindrical in natur

83、e, but of nearly any plan configuration. Because those columns that resist lateral forces are placed as far </p><p>　　The analysis of tubular structures is done using three-dimensional concepts, or by two- d

84、imensional analogy, where possible, whichever method is used, it must be capable of accounting for the effects of shear lag.</p><p>　　The presence of shear lag, detected first in aircraft structures, is a se

85、rious limitation in the stiffness of framed tubes. The concept has limited recent applications of framed tubes to the shear of 60 stories. Designers have developed various techniques for reducing the effects of shear lag

86、, most noticeably the use of belt trusses. This system finds application in buildings perhaps 40stories and higher. However, except for possible aesthetic considerations, belt trusses interfere with nearly e</p>&

87、lt;p>　　The tubular framing system mobilizes every column in the exterior wall in resisting over-turning and shearing forces. The term‘tube-in-tube’is largely self-explanatory in that a second ring of columns, the ring

88、 surrounding the central service core of the building, is used as an inner framed or braced tube. The purpose of the second tube is to increase resistance to over turning and to increase lateral stiffness. The tubes need

89、 not be of the same character; that is, one tube could be framed, whil</p><p>　　In considering this system, is important to understand clearly the difference between the shear and the flexural components of

90、deflection, the terms being taken from beam analogy. In a framed tube, the shear component of deflection is associated with the bending deformation of columns and girders (i.e, the webs of the framed tube) while the flex

91、ural component is associated with the axial shortening and lengthening of columns (i.e, the flanges of the framed tube). In a braced tube, the shear comp</p><p>　　Following beam analogy, if plane surfaces re

92、main plane (i.e, the floor slabs),then axial stresses in the columns of the outer tube, being farther form the neutral axis, will be substantially larger than the axial stresses in the inner tube. However, in the tube-in

93、-tube design, when optimized, the axial stresses in the inner ring of columns may be as high, or even higher, than the axial stresses in the outer ring. This seeming anomaly is associated with differences in the shearing

94、 component of st</p><p><b>　　高層建筑</b></p><p><b>　　前沿</b></p><p>　　高層建筑的定義很難確定。可以說2-3層的建筑物為底層建筑，而從3-4層地10層或20層的建筑物為中層建筑，高層建筑至少為10層或者更多。</p><p>　　

95、盡管在原理上，高層建筑的豎向和水平構(gòu)件的設(shè)計(jì)同低層及多層建筑的設(shè)計(jì)沒什么區(qū)別，但使豎向構(gòu)件的設(shè)計(jì)成為高層設(shè)計(jì)有兩個(gè)控制性的因素：首先，高層建筑需要較大的柱體、墻體和井筒；更重要的是側(cè)向里所產(chǎn)生的傾覆力矩和剪力變形要大的多，必要謹(jǐn)慎設(shè)計(jì)來保證。</p><p>　　高層建筑的豎向構(gòu)件從上到下逐層對累積的重力和荷載進(jìn)行傳遞，這就要有較大尺寸的墻體或者柱體來進(jìn)行承載。同時(shí)，這些構(gòu)件還要將風(fēng)荷載及地震荷載等側(cè)向荷載傳給基

96、礎(chǔ)。但是，側(cè)向荷載的分布不同于豎向荷載，它們是非線性的，并且沿著建筑物高度的增加而迅速地增加。例如，在其他條件都相同時(shí)，風(fēng)荷載在建筑物底部引起的傾覆力矩隨建筑物高度近似地成平方規(guī)律變化，而在頂部的側(cè)向位移與其高度的四次方成正比。地震荷載的效應(yīng)更為明顯。</p><p>　　對于低層和多層建筑物設(shè)計(jì)只需考慮恒荷載和部分動荷載時(shí)，建筑物的柱、墻、樓梯或電梯等就自然能承受大部分水平力。所考慮的問題主要是抗剪問題。對于現(xiàn)

97、代的鋼架系統(tǒng)支撐設(shè)計(jì)，如無特殊承載需要，無需加大柱和梁的尺寸，而通過增加板就可以實(shí)現(xiàn)。</p><p>　　不幸的是，對于高層建筑首先要解決的不僅僅是抗剪問題，還有抵抗力矩和抵抗變形問題。高層建筑中的柱、梁、墻及板等經(jīng)常需要采用特殊的結(jié)構(gòu)布置和特殊的材料，以抵抗相當(dāng)高的側(cè)向荷載以及變形。</p><p>　　如前所述，在高層建筑中每平方英尺建筑面積結(jié)構(gòu)材料的用量要高于低層建筑。支撐重力荷載