实用土木工程英语 中国建材工业出版社 Unit 7 SteelStructure

1、 Specialized English for Civil Engineering实用土木工程专业英语实用土木工程专业英语中国建材工业出版社中国建材工业出版社 Unit 7 Steel Structures 第七章第七章 钢结构钢结构Main contentsMain contents Text A Text A Steel Members Steel Members 钢构件钢构件 Translate some important Translate some important sentences sentences 翻译句子翻译句子 Special difficulties Specia

2、l difficulties 难点讲解难点讲解 Translation Skills -Translation Skills -词类转换词类转换 Writing Skills -Writing Skills -英文摘要的连贯性英文摘要的连贯性Text A Steel Members Translate Text A into Chinese.Tension members are found in bridge and roof trusses , towers, bracing systems, and in situation where they are used as tie rods

3、（连杆）. The selection of a section to be used as a tension member is one of the simplest problems encountered in design. 受拉构件可以在桥梁和屋架、塔、支撑系统以及用作连杆时见到。用作受拉构件的截面选择是设计中遇到的最简单问题之一。 As there is no danger of buckling, the designer needs only to compute the factored force（分解力）to be carried by the member and

4、divide that force by a design stress to determine the effective cross-sectional area required. 因为没有屈曲的危险，设计者只需要计算由该构件承受的分解力，并将该力除以设计应力以确定所需的有效横截面面积。 Then it is necessary to select a steel section that provides the required area. Though these introductory calculations for tension members are quite si

5、mple, they do serve the important tasks of getting students started with design ideas and getting their “feet wet” regarding the massive LRFD Manual. 然后有必要选择一个钢截面，它提供了需要的面积。尽管这些关于受拉构件的介绍性的计算非常简单，但它们确实完成了这样一个重要的目标，即使学生开始有设计的概念，并使他们涉足于大量的LRFD手册。 Load Resistance Factor Design (LRFD) 钢结构设计规范(荷载抗力系数设计 )V

6、arious structural steel shapesVarious structural steel shapes Tension Members 受拉构件受拉构件 One of the simplest forms of tension members is the circular rod, but there is some difficulty in connecting it to many structures. The rod has been used frequently in the past, but has only occasional uses today

7、in bracing systems, light trusses, and in timber construction. 受拉构件最简单的形式之一是圆钢，但是将其与很多结构连接有一些困难。过去常常采用圆钢，但是如今只偶然用于支撑系统、轻质桁架以及木结构。Rod 圆钢One important reason rods are not popular with designers is that they have been used improperly so often in the past that they have a bad name; however, if designed

8、and installed correctly, they are satisfactory for many situations.圆钢不受设计者青睐的一个重要原因是由于人们过去对它的不当使用而导致其口碑不好；但是如果正确地设计和安装，它们在很多情况下是令人满意的。 The average size rod has very little stiffness and may quite easily sag under its own weight, injuring the appearance of the structure. The threaded rods formerly us

9、ed in bridges often worked loose and rattled. 平均尺寸的圆钢几乎没有刚度，并且在自重下很容易下垂，因而破坏了结构的外观。以前用于桥梁的有螺纹的圆钢常常松掉，并发出嘎嘎声。 Another disadvantage of rods is the difficulty of fabricating them with the exact lengths required and the consequent difficulties of installation. 圆钢的另一个缺点是难以按需要的精确长度来制作，随之发生的是安装的困难。When rod

10、s are used in wind bracing, it is a good practice to produce initial tension in them, as this will tighten up the structure and reduce rattling and swaying. To obtain initial tension the member may be detailed shorter than their required lengths, a method that gives the steel fabricator very little

11、trouble. 当圆钢被用作抗风支撑时，一个很好的做法是使它们产生初张力，因为这将拉紧结构，并减少发出嘎嘎声和摇晃。为获得初张力，杆件可以设计得比它们需要的长度短，该法对钢材的制作者来说几乎没什么困难。 A common rule of thumb used is to detail the rods about 1/16 in short for each 20 ft. of length. Another very satisfactory method involves tightening the rods with some sort of sleeve nut（轴套螺母）or t

12、urnbuckle （套筒螺母）. 一个常用的经验法是设计该圆钢时每20英尺的长度缩短约1/16英寸, 另一个非常令人满意的方法包括采用某种套筒螺母拉紧圆钢。The preceding discussion on rods should illustrate why rolled shapes（轧制型钢）such as angles have supplanted rods for most applications. In the early days of steel structures, tension members consisted of rods, bars, and perh

13、aps cables. 前面关于圆钢的讨论应该阐明为什么诸如角钢的轧制型钢已在多数应用中代替了圆钢。在早期的钢结构中，受拉构件包括圆钢、型钢以及可能的索。Today, although the use of cables is increasing for suspended-roof（悬索屋顶）structures, tension members usually consist of single angles, double angles, tees, channels（槽钢）, W sections （W型钢）, or sections built up from plates（薄钢板

14、）or rolled shapes.今天尽管索在悬索屋顶结构中的使用不断增加，受拉构件通常包括单角钢、双角钢、T形钢、槽钢、W型钢，或由薄钢板或轧制型钢组合成的型钢。Channels 槽钢 W sections W型钢Tees T型钢 single angles 单角钢 double angles 双角钢Colored plates 彩色薄钢板 These members look better than the old ones, are stiffer, and are easier to connect. Another type of tension section often use

15、d is the welded tension plate or flat bar（扁钢）, which is very satisfactory for use in transmission towers, signs, foot bridges, and similar structures. 这些构件看上去比旧的更好、更结实、更容易连接。另一种常用的受拉构件是焊接的受拉薄钢板或者是扁钢，它在用于发射塔、广告牌、人行桥以及类似的结构中是非常令人满意的。flat bar 扁钢 Although single structural shapes are a little more econo

16、mical than built-up sections, the latter are occasionally used when the designer is unable to obtain sufficient area or rigidity from single shapes. 尽管单个结构型钢比组合的型钢稍微更经济一些，但是当设计者采用单个型钢无法得到足够的面积或刚度时，偶然也会采用后者。Where built-up sections are used it is important to remember that field connections will have

17、to be made and paint applied; therefore, sufficient space must be available to accomplish these things.在采用组合型钢处，要记住的重一点是将不得不进行现场连接，并进行涂漆；因此，必须获得足够的空间来完成这些事情。 Members consisting of more than one section need to be tied together. Tie plates(also called tie bars) located at various intervals or perfora

18、ted cover plates serve to hold the various pieces in their correct positions. 由几个截面组成的构件需要连接在一起。以不同的间隔设置的连接板（也称为连杆）或多孔盖板用以保持不同的构件均在其恰当的位置上。 These plates serve to correct any unequal distribution of loads between the various parts. They also keep the slenderness ratios (to be discussed) of the indivi

19、dual parts within limitation and they may permit easier handling of the built-up members. 这些板用以调整不同部分之间的荷载分配的不平衡。它们也使单个部分的长细比（将要讨论）保持在限制的范围内，这样他们可以允许较容易地处理组合构件。 Long individual members such as angles may be inconvenient to handle due to flexibility, but when four angles are laced together into one m

20、ember, the member has considerable stiffness. 长长的单个构件如角钢，由于易弯性可能处理时有困难，但是当四根角钢绑扎成一根构件时，该构件具有相当大的刚度。None of the intermittent tie plates may be considered to increase the effective areas of the sections. As they do not theoretically carry portions of the force in the main sections, their sizes are usu

21、ally governed by specifications and perhaps by some judgment on the designers part.可以不考虑间断的连接板对截面的有效面积的增加。因为他们理论上不承受主截面中的部分力，它们的尺寸通常由规范以及可能根据设计者的某些判断来决定。Perforated cover plates are an exception to this rule, as part of their areas can be considered as being effective in resisting axial load.多孔盖板则是该规

22、则的例外，因为它们的部分面积在抵抗轴向荷载时可认为是有效的。 Steel cables are made with special steel alloy wire ropes which are cold-drawn to the desired diameter. The resulting wires with strengths of about 200,000 to 250,000 psi can be economically used for suspension bridges, cable supported roofs, ski lifts , and other simi

23、lar applications. 钢索是由冷拉至需要直径的特种合金钢丝绳制成的。形成的具有强度约为200,000到250,000磅/平方英寸的钢丝能经济地用于悬索桥、悬索屋顶、运送滑雪者上山坡的吊索设备以及其它类似的应用。Steel cables 钢索 Normally, the designer uses a manufacturers catalog to select a cable tension member . From the catalog the yield stress of the steel and the cable size required for the de

24、sign force are determined. It is also possible to select clevises（马蹄钩）or other devices to use for connectors（连接器）at the cable ends. 通常，为选择索的受拉构件，设计者采用制造商的产品目录。从产品目录中可以确定钢材的屈服应力和设计力所需要的索的尺寸。也有可能选择马蹄钩或其他的装置用作索端的连接器。Axially Loaded Compression Members轴向受力的受压构件轴向受力的受压构件 There are several types of compres

25、sion members, the column being the best known. Among the other types are the top chords of trusses, bracing members, the compression flanges of rolled beams and built-up beam sections,and members that are subjected simultaneously to bending and compressive loads. 有多种受压构件，其中柱子是最知名的。在其他的类型中有桁架的上弦杆、支撑杆

26、件、轧制梁和组合梁截面的受压翼缘以及同时承受弯曲荷载和压力荷载的构件Truss 桁架Compression Members 受压构件 Columns are usually thought of as being straight vertical members whose lengths are considerably greater than their thicknesses. Short vertical members subjected to compressive loads are often called struts（支柱）or simply compression m

27、embers; however, the terms column and compression member will be used interchangeably in the pages that follow. 柱子通常被认为是直的竖向构件，其长度比它的厚度大得多。承受压力的短的竖向构件常常称为支柱或简单地称为受压构件；但是术语柱子和受压构件在下面的页面中将被交替地使用。 There are three general modes by which axially loaded columns can fail. These are flexural buckling, local

28、 buckling and torsional buckling. These modes of buckling are briefly defined below. (1)Flexural buckling (also called Euler buckling is the primary type of buckling. Members are subject to flexure or bending when they become unstable. 轴向受力的柱子发生失效有三种一般的模式。它们是弯曲屈曲、局部屈曲和扭转屈曲。这些屈曲模式简单地定义如下： （1）弯曲屈曲（也称为

29、欧拉屈曲）是主要的屈曲类型。当构件变得不稳定时，它们易于弯曲。 (2)Local buckling occurs when some part or parts of the cross section of a column are so thin that they buckle locally in compression before the other modes of buckling can occur. The susceptibility（敏感性）of a column to local buckling is measured by the width-thickness

30、ratios of the parts of its cross section. （2）局部屈曲发生在柱子某部分的横截面太薄了以至于在其它屈曲模式发生之前它们便受压局部屈曲。柱子对局部屈曲的敏感性可以通过 该 部 分 的 横 截 面 的 宽 厚 比 来 测 得 。 (3)Torsional buckling may occur in columns that have certain cross-sectional configurations（外形）. These columns fail by twisting(torsion) or by a combination of torsio

31、nal and flexural buckling.（3）扭转屈曲可以发生在具有某种横截面外形的柱子中。这些柱子由于扭曲（扭转）或扭转屈曲与弯曲屈曲的组合而失效。Buckling-restrained brace防屈曲支撑 The longer a column becomes for the same cross section the greater becomes its tendency to buckle and the smaller becomes the load it will support. The tendency of a member to buckle is us

32、ually measured by its slenderness ratio, which has previously been defined as the ratio of the length of the member to its least radius of gyration（回转半径）. 相同横截面的柱子越长，则屈曲的趋势越大，它能承受的荷载将越小。构件屈曲的趋势通常根据其长细比来测定，它在先前已定义为构件的长度与它最小的回转半径之比。The tendency to buckle is also affected by such factors as the types o

33、f end connections, eccentricity of load application, imperfection（缺陷）of column material, initial crookedness（弯曲）of column, residual stresses from manufacture, etc.屈曲的趋势也受到诸如端部连接的类型、荷载施加的偏心距、柱子材料的缺陷、柱子的初始弯曲、制造引起的残余应力等因素的影响。 The loads supported by a building column are applied by the column section ab

34、ove and by the connections of other members directly to the column. The ideal situation is for the loads to be applied uniformly across the column, with the center of gravity（重心）of the loads coinciding with the center of gravity of the column. 建筑物中的柱子承受的荷载是由其上方的柱子部分和直接与柱子相连的其他构件施加的。理想的情况是该荷载均匀地施加在柱子

35、上，荷载的重心与柱子的重心一致。Furthermore, it is desirable（希望）for the column to have no flaws（缺陷）, to consist of a homogeneous（均匀的）material, and to be perfectly straight, but these situations are obviously impossible to achieve.而且希望柱子没有缺陷、由均匀的材料组成以及是完全笔直的，但是这些情形显然不可能达到。 Loads that are exactly centered（居中）over a c

36、olumn are referred to as axial or concentric（同轴的）loads. The dead loads may or may not be concentrically placed over an interior building column and the live loads may never be centered. 在柱子上精确居中的荷载称为轴向或同轴荷载。恒载可能或不一定同轴地置于建筑屋内部的柱子上，而活载可能永远也不会居中。For an outside column the load situation is probably even

37、 more eccentric（偏心）, as the center of gravity of the loads will usually fall well on（恰好落在）the inner side of the column. In other words, it is doubtful that a perfect axially loaded column will ever be encountered in practice.外部柱子的荷载情形甚至可能更偏心，因为荷载的重心通常恰好落在柱子的内侧。换句话说，在实际中曾遇到一个完全轴向受荷的柱子是令人怀疑的。 The othe

38、r desirable situations are also impossible to achieve because of the following: imperfections of cross-sectional dimensions, residual stresses, holes punched for bolts, erection stresses, and transverse loads. It is difficult to take into account all of these imperfections in a formula. 由于下列的原因，其他希望

39、的情形也是不可能达到：横截面尺寸的缺陷；残余应力；螺栓冲孔；安装应力；横向荷载。很难在一个公式中考虑所有的这些缺陷。Slight imperfections in tension members and beams can be safely disregarded as they are of little consequence. On the other hand, slight defects in columns may be of major significance. A column that is slightly bent at the time it is put in

40、place may have significant bending moments equal to the column load times the initial lateral deflection. 受拉构件和梁中微小的缺陷可以安全地忽略掉，因为它们几乎没有什么后果。相反，柱子中微小的缺陷可能意义重大。柱子就位时的轻微弯曲可能产生很大的弯距，它等于柱子上的荷载乘以初始的横向挠度。 Obviously, a column is a more critical member in a structure than is a beam or tension member because

41、minor imperfections in materials and dimensions mean a great deal. The fact can be illustrated by a bridge truss that has some of its members damaged by a truck. 显然，比起梁或受拉构件，结构中的柱子是较为关键的构件，因为材料和尺寸中较小的缺陷意味着很多。该事实可通过一个桥梁桁架来说明，其有一些被卡车损坏的构件。The bending of tension members probably will not be serious as

42、the tensile loads will tend to straighten those members; but the bending of any compression members is a serious matter , as compressive loads will tend to magnify the bending in those members.受拉构件的弯曲可能不是严重的问题，因为拉力往往使这些构件伸直；但是任何受压构件的弯曲则是一个严重的问题。因为压力往往扩大了这些构件中的弯曲。 Answer the following content questio

43、ns ： （1） Where can tension members be found? （1）受拉构件可以在哪些地方被见到？ Tension members are found in bridge and roof trusses, towers, bracing systems, and in situation where they are used as tie rods. 受拉构件在桥梁和屋架、塔、支撑系统以及用作连杆时被见到。 （2） Why rods are not popular with designers? （2）为什么圆钢不受设计者欢迎？ One important re

44、ason why rods are not popular with designers is that they have been used improperly so often in the past that they have a bad name; however, if designed and installed correctly, they will be satisfied for many situations. 圆钢不受设计者欢迎的一个重要原因是过去常常被不恰当地使用，以至于落得坏名声；但是如果正确地设计和安装，它们在很多情况下是令人满意的。 （3） Where a

45、re tie plates located in a structure? （3）连接板位于结构的什么位置？ Tie plates（also called tie bars）located at various intervals or perforated cover plates serve to hold the various pieces in their correct positions. 位于不同的间隔的连接板（也称为连杆）或多孔盖板用以保持不同的构件均在其恰当的位置上。 （4） What are the three modes by which axially loaded

46、columns can fail. ? （4）轴向受力的柱子发生失效的三种模式是什么？ These are flexural buckling, local buckling and torsional buckling. 它们是弯曲屈曲、局部屈曲和扭转屈曲。Translate some important sentences Translate some important sentences 翻译句子翻译句子 (1) One of the simplest forms of tension members is the circular rod, but there is some dif

47、ficulty in connecting it to many structures. (2) In the early days of steel structures, tension members consisted of rods, bars, and perhaps cables. (3) Short vertical members subjected to compressive loads are often called struts or simply compression members. (4) A column that is slightly bent at

48、the time it is put in place may have significant bending moments equal to the column load times the initial lateral deflection. (5) Obviously, a column is a more critical member in a structure than is a beam or tension member because minor imperfections in materials and dimensions mean a great deal.

49、 Key: (1)受拉构件最简单的形式是圆钢，但是它和许多构件很难连接起来。 (2)在早期的钢结构中，受拉构件由圆钢、型钢以及可能的索缆线构成。 (3)承受压缩荷载的垂直短构件通常被称为钢支柱或者简单称为受压构件。 (4)柱子就位时的轻微弯曲可能产生明显弯矩，它等于柱荷载乘以初始的横向挠度。 (5)显然柱是结构中比梁或受拉构件更关键的构件，因为其重要性在于材料和尺寸的缺陷微小。Special difficulties Special difficulties 难点讲解难点讲解 1 One important reason why rods are not popular with design

50、ers is that they have been used improperly so often in the past that they have a bad name. 译文：圆钢不受设计者青睐的一个重要原因是由于过去人们对它的不当使用而导致其口碑不好。 be popular with可表示“受到的青睐”“受到的欢迎”。例如： The courses seem to be popular with entrepreneurs. 这些课程似乎广受企业家的欢迎。 2 These plates serve to correct any unequal distribution of lo

51、ads between the various parts. 译文：这些钢板适用于矫正不同部分载荷的分布不均。 serve可表示“提供”“为服务”“适合”“对有用”。例如： A simple example will serve to illustrate the point. 一个简单的例子可以说明这一点。 3 The longer a column becomes for the same cross section, the greater becomes its tendency to buckle and the smaller becomes the load it will su

52、pport. 译文：相同横截面的柱子越长，则屈曲的趋势越大，它能承受的荷载将越小。 （1）the more., the more.句型常表示“越就越”，是一个复合句，其中前面的句子是状语从句，后面的句子是主句。 例如： The higher the ground is, the thinner air becomes. 离地面越高,空气就越稀薄。 （2）这种句型中的比较部分通常是状语、宾语、表语， 也可以是主语。例如： The more air there is inside the tyre, the greater pressure there is in it. 轮胎里空气越多，承受的压

53、力就越大。 （3）若表示“越越不”，常用the more. the less句型。例如： I am finding info of the unis in the Internet, but the more I find, the less confidence I own. 我在网上找寻大学的信息，但越找越没信心。 （4）若表示“越不就越”，可用the less. the more.句型。例如： The less he worried, the better he worked. 他越不烦恼，工作就干得越好。 4 Loads that are exactly centered over a

54、 column are referred to as axial or concentric loads. 译文：在柱上精确居中的载荷被称为轴向载荷或同轴载荷。 refer to可表示 “参考”“涉及”“查阅”“提到”。例如： We can refer to these duplicated chromosomes as making up a doublet. 我们称这些复制的染色体为双体。 Newspapers now refer to such sites. 现在报纸也参考这些网站的内容。Translation Skills 词类转换由于语法结构和表达习惯的差异，在英汉翻译过程中词类并不

55、总是对等。例如英语中的名词翻译为汉语不一定仍是名词；动词、形容词等在翻译过程中也可能会转化为其他词类。因此译者需要结合实际情况，对词类进行必要的转换处理，使译文更为流畅。 【例1】An increase in gasoline consumption and a reduction in speed are noticeable when grades are increased. 和英语相比，汉语是以动词为主导的语言。英语科技类文章中大量使用的名词，很多都可以转化为相应的动词。因此这里的increase和reduction均可以动词形式译出。同时句子中的形容词noticeable可以在翻译时

56、转化为副词。 译文：很显然，坡度增加，油耗增加，速度降低。（比较：坡度增加时，油耗的增加和速度的降低是很明显的。） 【例2】The engineering properties and behavior of the soils are their concern. 这里的concern是名词，译为动词更符合汉语习惯。 译文：他们关注的是土壤的工程属性和状态。（比较：土壤的工程属性和状态是他们的关注。）Writing Skills 英文摘要的连贯性 摘要在本质上是一篇浓缩后的小文章，因此需要一系列连贯的语言手段来保证内在的逻辑性。而有一些英文摘要只是对信息进行罗列，对中文摘要逐句的机械翻译，连接较少，文章欠缺连贯性，导致流畅度不够。 以下是一段关于混凝土复合材料强度的论文摘要： T