外文翻译抗侧向荷载的结构体系

外文翻译：抗侧向荷载的结构体系（中英文）Structural Systems to resist lateral loadsCommonly Used structural SystemsWith loads measured in tens of thousands kips, there is little room in the design of high-rise buildings for excessively complex thoughts. Indeed, the better high-rise buildings carry the universal traits of simplicity of thought and clarity of expression.It does not follow that there is no room for grand thoughts. Indeed, it is with such grand thoughts that the new family of high-rise buildings has evolved. Perhaps more important, the new concepts of but a few years ago have become commonplace in today s technology.Omitting some 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:1. Moment-resisting frames.2. Braced frames, including eccentrically braced frames.3. Shear walls, including steel plate shear walls.4. Tube-in-tube structures.5. Tube-in-tube structures.6. Core-interactive structures.7. Cellular or bundled-tube systems.Particularly with the recent trend toward more complex forms, 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, and related systems. Further, for the taller buildings, the majorities are composed of interactive elements in three-dimensional arrays.The method of combining these elements is the very essence of 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 development 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 structural engineer, while only fine structure, not great architecture, can be developed without the genius and the leadership of a talented architect. In any event, the best of both is needed to formulate a truly extraordinary design of a high-rise building.While comprehensive discussions of these seven systems are generally available in the literature, further discussion is warranted here .The essence of the design process is distributed throughout the discussion.Moment-Resisting FramesPerhaps 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 joints. 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 inappropriate for a stand-alone system, this because of the difficulty in mobilizing sufficient stiffness under without the genius and the leadership of a talented architect. In any event, the best of both is needed to formulate a truly extraordinary design of a high-rise building.While comprehensive discussions of these seven systems are generally available in the literature, further discussion is warranted here .The essence of the design process is distributed throughout the discussion.Moment-Resisting FramesPerhaps 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 joints. 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 inappropriate for a stand-alone system, this because of the difficulty in mobilizing sufficient stiffness under lateral forces.Analysis can be accomplished by STRESS, STRUDL, or a host of other appropriate computer programs; analysis by the so-called portal method of the cantilever method has no place in todays technology.Because of the intrinsic flexibility of the column/girder intersection, and because preliminary designs should aim to highlight weaknesses of systems, it is not unusual to use center-to-center dimensions for the frame in the preliminary analysis. Of course, in the latter phases of design, a realistic appraisal in-joint deformation is essential.Braced FramesThe braced frame, intrinsically stiffer than the moment resisting frame, finds also greater application to higher-rise 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 as a stand-alone system in low-to medium-rise buildings.While the use of structural steel in braced frames is common, concrete frames are more likely to be of the larger-scale variety.Of special interest in areas of high seismicity is the use of the eccentric braced frame.Again, analysis can be by STRESS, STRUDL, or any one of a series of two or three dimensional analysis computer programs. And again, center-to-center dimensions are used commonly in the preliminary analysis.Shear wallsThe shear wall is yet another step forward along a progression of ever-stiffer structural systems. The system is characterized by relatively thin, generally (but not always) concrete elements that provide both structural strength and separation between building functions.In high-rise 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 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 in the exterior walls of building, where the requirement for windows is kept small.Structural steel shear walls, generally stiffened against buckling by a concrete overlay, have found application where shear loads are high. The system, 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 high ductility a feature of particular importance in areas of high seismicity.The analysis of shear wall systems is made complex because of the inevitable presence of large openings through these 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.Framed or Braced TubesThe 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 towers 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 nature, but of nearly any plan configuration. Because those columns that resist lateral forces are placed as far as possible from the cancroids of the system, the overall moment of inertia is increased and stiffness is very high.The analysis of tubular structures is done using three-dimensional concepts, or by two- dimensional analogy, where possible, whichever method is used, it must be capable of accounting for the effects of shear lag.The presence of shear lag, detected first in aircraft structures, is a serious 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, 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 every building function associated with the outside wall; the trusses are placed often at mechanical floors, mush to the disapproval of the designers of the mechanical systems. Nevertheless, as a cost-effective structural system, the belt truss works well and will likely find continued approval from designers. Numerous studies have sought to optimize the location of these trusses, with the optimum location very dependent on the number of trusses provided. Experience would indicate, however, that the location of these trusses is provided by the optimization of mechanical systems and by aesthetic considerations, as the economics of the structural system is not highly sensitive to belt truss location.Tube-in-Tube StructuresThe tubular framing system mobilizes every column in the exterior wall in resisting over-turning and shearing forces. The termtube-in-tubeis largely self-explanatory in that a second ring of columns, the ring 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 not be of the same character; that is, one tube could be framed, while the other could be braced.In considering this system, is important to understand clearly the difference between the shear and the flexural components of 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 flexural 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 component of deflection is associated with the axial deformation of diagonals while the flexural component of deflection is associated with the axial shortening and lengthening of columns.Following beam analogy, if plane surfaces remain 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-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 component of stiffness between the two systems. This is easiest to under-stand where the inner tube is conceived as a braced (i.e, shear-stiff) tube while the outer tube is conceived as a framed (i.e, shear-flexible) tube.Core Interactive StructuresCore interactive structures are a special case of a tube-in-tube wherein the two tubes are coupled together with some form of three-dimensional space frame. Indeed, the system is used often wherein the shear stiffness of the outer tube is zero. The United States Steel Building, Pittsburgh, illustrates the system very well. Here, the inner tube is a braced frame, the outer tube has no shear stiffness, and the two systems are coupled if they were considered as systems passing in a straight line from the “hat” structure. Note that the exterior columns would be improperly modeled if they were considered as systems passing in a straight 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 compression 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 AT&T headquarters is an example of an astonishing array of interactive elements:1. The structural system is 94 ft (28.6m) wide, 196ft(59.7m) long, and 601ft (183.3m) high.2. Two inner tubes are provided, each 31ft(9.4m) by 40 ft (12.2m), centered 90 ft (27.4m) 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 moment-resisting frame, but with zero shear stiffness for the center50ft (15.2m) of each of the long sides.6. A space-truss hat structure is provided at the top of the building.7. A similar space truss is located near the bottom of the building8. 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 structuresA classic example of a cellular structure is the Sears Tower, 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 uncommon 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=fL/EFor buildings of 12 ft (3.66m) floor-to-floor distances and an average compressive 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 3.7 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 between .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 pre-stress 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. 抗侧向荷载的结构体系结构系统抵抗横向荷载常用的结构体系与负载检测成千上万kips ，很少有房的设计，高层建筑的过于复杂的想法。事实上，更好的高层建筑中的普遍特征简单的思路和清晰的表达。但这并不意味着没有余地大的想法。事实上，这是与这种大的思想，新的家庭高层建筑的发展。也许更重要的是，新概念，但在几年前已经司空见惯在当今的技术。忽略了一些概念，有关的材料严格的建设，最常用的结构系统用于高层建筑可归纳如下：1 .矩抗张。2 .支撑框架，包括偏心支撑框架。3 .剪力墙，包括钢板剪力墙。4 .筒中筒结构。5 .筒中筒结构。6 .核心的互动结构。7 .蜂窝或捆绑管系统。特别是最近的趋势更为复杂的形式，但在反应还需要增加刚度抵制军队从风和地震，最高层建筑结构体系已经建立起来的组合框架，支撑bents ，剪力墙，和相关系统。此外，在高建筑物，多数是由互动元素在三维阵列。结合的方法，这些要素是非常重要，设计过程中的高层建筑。这些组合的需要演变为响应环保，功能和成本的考虑，以便提供有效的结构，挑起建筑发展到一个新的高度。这并不是说，富有想象力的结构设计可以创造伟大的建筑。与此相反，许多例子，罚款架构已经建立，只有适度的支持，结构工程师，而只有精细结构，而不是伟大的建筑，可开发的天才和领导才能的的建筑师。在任何情况下，最好都需要制定一个真正特殊的设计高层建筑。虽然全面的讨论，这七个系统通常适用于文学，值得进一步讨论的是在这里。本质的设计过程是分布在整个讨论。矩抗框架也许，最常用的系统在低到中等高楼大厦，目前抗内，特点是线性的横向和纵向联系成员基本上是在其关节僵硬。这种帧被用作一个独立的系统或与其他系统，以便提供必要的抵抗水平荷载。在高的高层建筑，该系统很可能会发现不合适的一个独立的系统，这个，因为难以调动足够的刚度下的天才和领导才能的建筑师。在任何情况下，最好都需要制定一个真正特殊的设计高层建筑。虽然全面的讨论，这七个系统通常适用于文学，值得进一步讨论的是在这里。本质的设计过程是分布在整个讨论。矩抗框架也许，最常用的系统在低到中等高楼大厦，目前抗内，特点是线性的横向和纵向联系成员基本上是在其关节僵硬。这种帧被用作一个独立的系统或与其他系统，以便提供必要的抵抗水平荷载。在高的高层建筑，该系统很可能会发现不合适的一个独立的系统，这个，因为难以调动足够的刚度下的侧向力。分析可以通过压力， STRUDL ，或主机的其他适当的计算机程序;分析，所谓的门户方法悬臂法没有发生在今天的技术。由于固有的灵活性柱/梁相交，并且由于初步设计的目标应该是突出的弱点的系统，这是不寻常使用中心到中心尺寸为框架的初步分析。当然，在后者的设计阶段，一个现实的评估关节变形是必不可少的。支撑框架的支撑框架，内在比目前更严厉的抗内，发现也更广泛地应用到更高的高楼大厦。该系统的特点是线性横向，纵向和对角线成员，连接简单，或在其关节僵硬。这是常用的与其他系统的高大建筑物和作为一个独立的系统在低到中等高楼大厦。虽然使用结构钢支撑框架中是很常见，混凝土框架结构更可能的较大规模的品种。特别感兴趣的领域的高地震活动是利用偏心支撑框架。再次，分析可通过压力， STRUDL ，或任何一个一系列两年或三年量纲分析的计算机程序。再次，中心到中心尺寸常用的初步分析。剪力墙该剪力墙是又向前迈出的一步沿着进步的时候，更严厉的结构系统。该系统的特点是比较薄，通常（但并不总是）具体内容，提供了结构强度和建设职能分开。在高层建筑中，剪力墙体系往往有一个相对高纵横比，也就是说，他们的身高往往是比较大的宽度。张力缺乏系统的基础，任何结构性因素是有限的能力抵抗倾覆力矩的宽度系统和重力负载支持因素。限于狭隘倾覆，一个明显的使用该系统，它具有必要的宽度，是在外墙建设，那里的要求是保持小窗户。剪力墙结构钢，一般加筋对屈曲的一个具体的覆盖，已发现的应用在剪切载荷是很高的。该系统，更经济的内在比钢支撑，特别是有效地执行剪切载荷下通过高楼层的地区立即级以上。该系统的TEM的进一步利用具有高韧性的功能特别重要的地区的地震活动。分析剪力墙体系是复杂的，因为不可避免的存在大开口通过这些墙壁。初步分析可能的桁架类推，有限元法，或利用专有的计算机程序设计考虑的互动，或耦合的剪力墙。框架或支撑管的概念框架或支撑，或演变成支撑管的技术与IBM大厦在匹兹堡，但随后立即与双110层塔楼的世界贸易中心，纽约和其他一些建筑。系统特点是立体框架，支撑框架或剪力墙结构，形成一个封闭的表面或多或少圆柱的性质，但几乎所有计划配置。因为这些栏目的抵制侧向力放在尽可能从cancroids的制度，但总的转动惯量的增加和刚度是非常高的。分析管状结构进行三维概念，或二维类推，在可能的情况下，两者方法，它必须能够核算的影响剪力滞后。在场的情况下剪力滞后，发现第一次在飞机结构，是一种严重的限制，刚度框架管。有限的概念最近应用框架管剪切60故事。设计师们已经制定了各种技术减轻剪力滞影响，最明显的使用带桁架。该系统的应用在建筑物发现也许40stories及以上。然而，除了可能的审美考虑，带桁架干扰几乎每一个建设职能与外墙;的桁架放在往往机械楼层，玉米粥的反对设计师的机械系统。然而，作为一个符合成本效益的结构系统，带桁架运作良好，并有可能找到继续批准设计师。无数的研究已经设法优化所在地的这些桁架，与最佳位置非常依赖数量的桁架提供。经验表明，然而，这些位置所提供桁架优化机械系统和审美的考虑，作为经济学的结构体系是高度敏感，不带支架的位置。筒中筒结构管状框架系统动员每栏外墙抵制过度转向和剪切力。该termtube在tubeis基本上不言自明的，第二次环列，环围绕中心服务核心的建设，是作为一种内在的框架或支撑管。的目的，第二管是增加阻力的转折点，增加侧向刚度。管子不必进行同一性质，也就是说，一个管可以制定，而其他可能支撑。在审议这一系统，重要的是要清楚了解之间的差异剪切和弯曲部分的挠度，正在采取的条款从梁类推。在框筒，剪切部分挠度与弯曲变形的柱子和梁（即网的框筒） ，而弯曲部分与轴向缩短和延长栏（即法兰的对框筒）。在支撑管，剪切挠度的组成部分是与轴向变形的对角线而弯曲部分的挠度与轴向缩短和延长栏。继梁类推，如果飞机的表面保持飞机（即楼板），然后轴向应力栏目外管，正在进一步形成轴线，将大大大于轴向应力内胎。然而，在筒中筒的设计，在优化，轴向应力内圈栏可作为高，甚至更高，比轴向应力外环。这种似是而非的异常与不同的剪切部分的刚度两个系统之间。这是最简单的不足立场在内胎设想作为支撑（即剪切激烈），而管外管被视为一个框架（即剪切灵活）管。核心互动结构核心的互动式结构是一种特殊情况的筒中筒，其中两个管耦合与某种形式的三维空间内。事实上，该系统是经常使用，其中剪切刚度的外管是零。美国钢铁大厦，匹兹堡，说明了系统的非常好。在这里，内胎是一个支撑框架，外管没有剪切刚度和两个系统耦合如果他们被视为系统通过直线的“帽子”的结构。请注意，外部栏将不当模仿如果他们被视为系统通过直线的“帽子”的基础;这些列，也许是15 ，更严厉的，因为它们遵循弹性曲线的支撑核心。还注意到，轴向力与侧向力的内在列从紧张压缩的高度，管，与拐点在5月8日的高度管。外柱，当然，执行相同的轴向力侧向载荷下的充分高度的列，因为列，因为剪切刚度的系统是接近于零。空间结构支腿或桁架梁，连接内胎的外管，位于往往在几个层面的建设。 AT T的总部是一个例子，一个惊人的一系列互动内容：1 .结构体系是94英尺（二十八点六米）宽， 196英尺（五十九点七米）长，六零一英尺（一百八十三点三米）高。2 .两个内胎提供，每个三十一英尺（九点四米） 40英尺（一十二点二米） ，中心九零英尺（二十七点四米）除了在长期的方向建设。3 .在内胎已作好在短期内的方向，但与零剪切刚度的长期方向。4 .一个单一的供应外管，其中环绕周边的建设。5 .外管是目前抗框架，但与零剪切刚度的center50ft （十五点二米）每个只要双方。6 .空间桁架结构的帽子提供顶部的建设。7 .类似的空间桁架位于底部的建设8 .整个大会是横向支持的基础上对双钢板管，因为剪切刚度的外管到零的基础上建设。细胞结构一个典型的例子了蜂窝结构的西尔斯大厦，芝加哥，捆绑筒结构的9个独立管。虽然西尔斯大厦包含九个几乎完全相同管的基本结构体系具有特殊的申请建筑形状不规则，如几个管不必形状类似的计划，这并不少见，一些个人管的优势之一，并一个弱点的系统。这一个特殊的弱点这一制度，特别是在管内，已经这样做的概念差别柱缩短。缩短一栏下，给出了负载的表达 = fL /电子建筑物的12英尺（三点六六米）落地式地板的距离，平均压应力15 ksi （ 138MPa ） ，缩短一栏下的负荷是15 （ 12 ）（ 12 ） / 29000或0.074in （一点九毫米）的故事。在50层，该列将缩短到3.7英寸（ 94毫米）小于其轻声长度。如果一个细胞的捆绑管系统，也就是说， 50stories高，相邻的细胞，也就是说， 100stories高，这些柱子之间的边界附近。两个系统需要有这种差别偏转调和。主要结构的工作被认为是需要在这些地点。至少在一个建设，里亚托项目，墨尔本，结构工程师认为有必要纵向预应力低高度栏，以便核对鉴别挠度栏接近与后张的短栏模拟重量要添加到相邻，更高栏。付：外文翻译 电火花加工 电火花加工法对加工超韧性的导电材料（如新的太空合金）特别有价值。这些金属很难用常规方法加工，用常规的切削刀具不可能加工极其复杂的形状，电火花加工使之变得相对简单了。在金属切削工业中，这种加工方法正不断寻找新的应用领域。塑料工业已广泛使用这种方法，如在钢制模具上加工几乎是任何形状的模腔。 电火花加工法是一种受控制的金属切削技术，它使用电火花切除（侵蚀）工件上的多余金属，工件在切削后的形状与刀具（电极）相反。切削刀具用导电材料（通常是碳）制造。电极形状与所需型腔想匹配。工件与电极都浸在不导电的液体里，这种液体通常是轻润滑油。它应当是点的不良导体或绝缘体。 用伺服机构是电极和工件间的保持0.00050.001英寸（0.010.02mm）的间隙，以阻止他们相互接触。频率为20000Hz左右的低电压大电流的直流电加到电极上，这些电脉冲引起火花，跳过电极与工件的见的不导电的液体间隙。在火花冲击的局部区域，产生了大量的热量，金属融化了，从工件表面喷出融化金属的小粒子。不断循环着的不导电的液体，将侵蚀下来的金属粒子带走，同时也有助于驱散火花产生的热量。 在最近几年，电火花加工的主要进步是降低了它加工后的表面粗糙度。用低的金属切除率时，表面粗糙度可达24vin.(0.050.10vin)。用高的金属切除率如高达15in3/h(245.8cm3/h)时，表面粗糙度为1000vin.(25vm)。 需要的表面粗糙度的类型，决定了能使用的安培数,电容,频率和电压值。快速切除金属（粗切削）时，用大电流,低频率,高电容和最小的间隙电压。缓慢切除金属（精切削）和需获得高的表面光洁度时，用小电流,高频率,低电容和最高的间隙电压。 与常规机加工方法相比，电火花加工有许多优点。 1 . 不论硬度高低，只要是导电材料都能对其进行切削。对用常规方法极难切削的硬质合金和超韧性的太空合金，电火化加工特别有价值。 2 . 工件可在淬火状态下加工，因克服了由淬火引起的变形问题。 3 . 很容易将断在工件中的丝锥和钻头除。 4 . 由于刀具（电极）从未与工件接触过，故工件中不会产生应力。 5 . 加工出的零件无毛刺。 6 . 薄而脆的工件很容易加工，且无毛刺。 7 . 对许多类型的工件，一般不需第二次精