专业英语[土木工程专业(路桥方向)]

1、Lesson 1 Careers in Civil Engineering Many civil engineers, among them the top people in the field work in design. As we have seen ,civil engineers work on many diferent kinds of structures , so it is normal practice for an engineer to specialize in just one kind . In designing buildings ,engineers

2、often work as consultants to architectural or construction firm.Dams, bridges, water supply systems and other large project ordinarily employ several engineers whose work is coordinated by a system enginneer who is in charge of the entire project . In many cases engineers from other disciplines are

3、involved .In dam project , for example , electrical and mechanical engineers work on the design of the powerhouse and its equipment. In other cases , civil engineers are assigned to work on a project in another field ; in the space program , for instance ,civil engineers were necessary in the design

4、 and construction of such structures as launching pads and rocket storage facilities . Construction is a complicated process on almost all engineering projects. It involves scheduling the work and utilizing the equipment and the materials so that costs are kept as low as possible . Safty factors mus

5、t also be taken into account , since construction can be very dangerous . Many civil engineers therefore specialize in the construction phase.11许多土木工程师在设计领域工作,他们中的许多人是这个行业的佼佼者。正如我们所见，土木工程师研究许多不同的结构, 因此工程师专门研究一类结构是通常的做法（一般的惯例）。在建筑设计中, 工程师经常作为建筑或结构公司的顾问。水坝、桥梁、给水系统, 和其它大项目通常；聘用几位系统工程师（总工程师） ，他们的工作是协助负责

6、整个项目。在许多情况下, 也需要（涉及）其它学科的工程师。例如,在水坝项目中, 电子和机械工程师负责发电站及其设备的设计。在其它情况下, 土木工程师被分配到其它领域的项目上工作; 例如,在空间项目中, 需要土木工程师设计和施工诸如发射台和火箭存贮设施这样的结构。12在几乎所有土木工程项目中，施工是复杂的过程。它包括项目的进度安排和设备的使用以及材料，以便使得造价尽可能降低。必须考虑安全因素，因为施工很危险。许多土木工程师因此专门研究施工阶段。Lesson 2 Modern Buildings And Structural MaterialsToday , however , the engin

7、eer has the advantage not only of empirical information , but also of scientific data that permit him to make careful calculations in advance . When a modern engineer plans a structure , he takes into account the total weight of all its component materials . This is konwn as the dead load , which is

8、 the weight of the structure itself . He must also consider the live load , the weight of all the people , cars , furniture , machines and so on that the structure will support when it is in use . In structures such as bridges that will handle fast automobile traffic , he must consider the impact ,

9、the force at which the live load will be exerted on the structure . He must also determine the safety factor , that is , an additional capability to make the structure stronger than the combination of the three often factors . The principle construction materials of earlier times were wood and mason

10、ry brick , stone , or tile , and similar materials . The courses or layers were bound together with mortar or bitumen , a tarlike substance , or some other binding agent . The Greeks and Romans sometimes used iron rods or clamps to strengthen their buildings . The columns of the Parthenon in Athens

11、, for example , have holes drilled in them for iron bars that have now rusted away . The Romans also used a natural cement calles pozzolana , made from volcanic ash , that became as hard as stone under water .3但是，现在的工程师具备许多有利条件，不仅有经验资料，而且有科学数据供他预先做详细计算。一个现代工程师当他设计一座建筑物时，他要考虑这座建筑物所有组成材料的总重量，这就是所谓的静荷载

12、，即建筑物自身的重量。他还必须考虑动荷载，即在建筑物投入使用时它要承受的人，车辆，设备、机器等等的重量。对于象桥梁这种需要承担高速汽车交通的构筑物，他必须考虑到冲力，即动荷载将借以作用于结构物的那种力。他还必须确定出安全系数，即附加的承载能力，以使建筑物的承载能力比上述三个因素结合起来还要强些。7现代最引人注目的工程事故之一1940年塔科马海峡大桥的倒塌，就是由于没有非常仔细地考虑这些因素中的最后一个因素。在一场暴风雨中，当每小时高达65公里的强劲狂风冲击这座桥时，狂风引起了沿着桥面方向的波动；同时还产生了一种使路面塌落的横向运动。幸亏工程师们从错误中汲取了教训，所以现在的通常做法是将按比例缩

13、小的桥梁模型放在风洞中检验它们的空气动力学抵抗力。Lesson 5 philosophy of structural design Specially , the structural design of any structure first involves the establishment of the loading and other design conditions that must be resisted by the structure and therefor must be considered in its design . Then comes the analy

14、sis (or computation) of the internal gross forces (thrust , shears , bending moments and twisting moments), stress intensities , strains , deflections and reactions produced by the loads , temperature , shrinkage , creep , or other design conditions . Finally comes the proportioning and selection of

15、 materials of the members and connections so as to resist adequately the effects produced by the design conditions . The criteria used to judge whether particular proportions will result in the desired behavior reflect accumulated knowledge (theory , field and model tests , and practical experience

16、) , intuition and judgment . For most common civil engineering structures such as bridges and buildings , the usual practice in the past has been to design on the basis of a comparison of allowable stress intensities with those produced by the service loadings and other design conditions . This trad

17、itional basis for design is called elastic design because the allowing to the yield point of the material should not be exceeded at the most highly stressed points of the structure . Of course , the selection of the allowable stresses may also be modified by a consideration of the possibility of fai

18、lure due to fatigue , buckling , or brittle fracture or by consideration of the permissible deflections of the structure . The allowance-stress approach has an improtant disadvantage in which it does not provide a uniform overload capacity for all parts and all types of structures . As a result , th

19、ere is today a rapidly growing tendency to base the design on the ultimate strength and serviceability of the structure , with the older allowable-stress approach serving as an alternative basis for design the newer approach currently goes under the name of strength design in reinforce-concrete-desi

20、gn literature and plastic design in steel-design literature . When proportioning is done on the strength basis , the anticipated service loading is first multiplied by a suitable laod factor (greater than 1 ) , the magnitude of which depends upon the uncertainty of the loading , the possibility of i

21、ts changing during the life of the structure , and for a combination of loading , the likelihood , frequency and duration of the particular combination . In this approach for reinforced-concrete design , the theorectical capacity of a structural element is reduced by a capacity-reduction factor to p

22、rovide for small adverse variations in material strengths , workmanship and dimensions . The strcuture is then proportioned so that , depending on the governing conditions , the increased load would (1) cause a fatigue or a buckling or a brittle-fracture failure or just produce yielding at one inter

23、nal section ( or simultaneous yileding at several sections) or cause elastic-plastic displacement of the structure or cause the entire structure to be on the point of collapse.专门的，任何结构物的结构设计首先包括荷载以及其他结构所必须承受的设计条件的确立，并且因此，这些条件必须被考虑到设计中。然后需要进行总内力(轴力，剪力，弯矩，和扭矩)，应力强度，应变，挠度，和反作用力的分析(或计算)，它们是由于荷载，温度，干缩，徐变

24、或其它设计条件所引起的。最后是结构构件以及连接件截面尺寸和材料的确定，使得结构能充分抵抗由上述设计条件所引起的作用效应。用于判断(结构设计)是否非常合适的标准将导致一个由积累的知识(原理，学术领域，模型试验，实践经验)，直觉，判断所反映的期望的行为。对于绝大多数土木工程结构来说，例如桥梁和建筑，过去通常的设计方法是基于结构所受荷载或其他设计条件所产生的应力与材料自身的容许应力强度相比较(容许应力法)。这种传统的设计原理叫做弹性设计，因为容许应力强度(值)的选择与材料应力应变的屈服点相一致，而并非超过结构的最高应力点。当然， 当需要考虑由于疲劳，纵向弯曲(平面外失稳)，脆性断裂，以及关于结构允许

25、挠度等因素而产生失效的可能性，容许应力值的选择同样要被修正。在容许应力法中，有一个重要的缺陷就是它不能对各种类型的结构以及(结构的)各个部分提供统一的过载能力。结果，今天对于基于结构极限强度和适用性的设计理论有了一个迅速的成长趋势，同时，老的容许应力法作为备用的设计方法来做参考。这个新的设计方法目前在钢筋混凝土规范中叫强度设计(法)，在钢结构规范中叫塑性设计(法)。当我们给予基于强度理论一个合适的比例参数(安全系数)时，如果在适当的荷载因素下预期的工况荷载首先增大(>1)，荷载增大量依赖于荷载的不确定性，在结构生命期中变化的可能性，并且鉴于荷载的组合目的，这个可能性，频率，作用持续时间也

26、是一个特殊组合。在钢筋混凝土结构设计的这种方法中，由于材料强度，制作工艺，截面尺寸等一些小的误差引起承载能力折剪系数使得结构构件的理论承载能力降低。根据结构的控制条件，即增长的荷载将(1)引起疲劳，纵向弯曲，或脆性断裂破坏，或者(2)仅仅引起内部一个截面(或者同时几个截面)的屈服，或者(3)引起结构的弹塑性位移，或者(4)引起结构的整体倾覆，所以，结构是要相称的。Lesson 7 transportation system Transportation system in a developed nation consists of a network of modes that have e

27、volved over many years . The system consists of vehicals , guideways , terminal facilities and control systems ; these operate according to established procedures and schedules in the air , on land , and on water . The system also requires interaction with the user , the operator and the environment

28、 . The systems that are in place reflect the multitude of decisions made by shipper , carriers , government , individual travelers , and affected nonusers concerning the investment in or the use of transportation . The transportation system that has evolved has produced a variety of modes that compl

29、ement each other . The nations transportation system can be considered to be in a state of equilibrium at any given point in time as a result of market forces , government actions and transportation technology . As these change over time , the transportation system also will be modified . During rec

30、ent decades , changes in gasoline prices , regulation by government , and new technology have affected the relative improtance of each mode . The passenger or shipper thinks of each mode in terms of the level of service provided . Each mode offers a unique set of service characteristics at a given p

31、rice : travel time , frequency , comfort , convenience ,reliability and safety . The traveler or shipper selects the mode based on how these attributes are valued.在发达国家，交通运输系统由一个形成多年的方式的网组成。这个系统由车辆，导轨，站场设施和控制系统组成，这些部分通过以建立的规程和日程表在天空，在陆地，在水中各自正常运转着。这个系统也要求用户，操作员，和环境的相互作用。现在的运输体系可以反映出与投资和使用有关的多方决定，包括运

32、输业主，承运商，政府，每个出行者以及受影响的非使用者等。交通运输系统已经被创造出多种相互补充的模式。国家的运输系统可以通过一些及时给与的根据市场压力，政府管理，运输新工艺调整的要点所考虑。随着时间变化，运输系统也将改变。在最近的几十年里，油价，政府的调控，和新技术的变化已经对运输业造成了很大影响。乘客和发货人考虑每一种方式无论提供的服务水平。每种方式在给定的价格下提供一种独特的服务特点：行程时间，频率，舒适性，方便性，可靠性和安全性。旅客和发货人基于这个属性有多值选择运输方式。Lesson 9 design of the alignment The alignment of a highway

33、 is composed of vertical and horizontal elements . The vertical alignment includes straight ( tangent ) highway grades and the parabolic curvers that connect these grades the horizantal alignment includes the straight ( tangent ) sections of the roadway and the circular curves that connect their cha

34、nge in direction . The design of the alignment depends primarily on the design speed selected for the highway . The least costly alignment is one that generally takes the form of the natural topography . It is not always possible to select the lowest cost alternatibe because the designer has to adhe

35、re to certain standards that may not exist on the natural topography . It is the vertical and horizontal layout of the highway . It is also important that both horizantal and vertical alignments be designed to conplement each other , since this will result in a safer and more attractive highway . On

36、e factor that should be considered to achieve compatibility is the proper balancing of the grades of tangents with curvatures of horizintal curves and the lacation of horizantal and vertical curves with respect to each other . For example , a design that achieves horizontal curves with large radii a

37、t the expense of steep or long grades is a poor design . Similarly , if sharp horizaontal curves are placed at or near the top of pronounced crest vertical curves or at or near the bottom of a pronounced sag vertical curve , a hazardous condition will be created at these sections of the highway . Th

38、us , it is important that coordination of the vertical and horizontal alignments be considered at the early stages of preliminary design .Transition curves are placed between tangents and circular curves or between two adjacent cirular curves having substantially different radii . The use of transit

39、ion curves provides a vehicle path that gradually increases or decreases the radial force as the vehical enters or leaves a circular curve . If the transition curve is a spiral , the degree of curve between the tangent and the circular curve varies from zero at the tangent end to the degree of the c

40、ircular curve at the curve end . When the transition is placed between two circular curves , the degree of curve varies from that of the first circular curve to that of the second circular .竖直曲线和水平曲线的布置组成了高速公路的线形，竖曲线包括直的纵坡线和连接纵坡线的抛物线.平曲线包括直线段和连接它们并改变方向的圆曲线段.线形的设计主要依赖于高速公路设计速度的选择，与自然地形相符合的线形造价最小。通常这种

41、情况是不可能的，然而，因为设计师必须遵循一定的设计标准，而这些标准也许并不能适应地形。重要的是既定部分的线形必须遵循一致的标准来避免高速路在竖直和水平定线时产生突变，同样，竖曲线和平曲线在设计是要相互补充协调，这样才能设计出一条安全的和更有吸引力的高速公路。为了达到这一点，一个应该考虑的因素是适当地保持直线坡度和平曲线曲率的平衡，处理好平曲线和竖曲线间的相互位置。例如，在较大半径的陡坡上设置平曲线是一种较差的设计，同理，如果在一个明显的凸形竖曲线的顶部或附近设置小半径平曲线，或在明显的凹形竖曲线底部或附近设置小半径平曲线，这将导致这里是一个危险部分。因而在初步设计阶段把竖曲线和平曲线的协调综合

42、考虑是很重要的。 缓和曲线设置在直线段与圆曲线段之间或两个不同半径的圆曲线之间，缓和曲线的作用是在车辆进入或离开圆曲线时为车辆提供一个逐渐增加或降低的向心力，设置直线段与圆曲线之间的缓和曲线的曲率由直线段末端的0变化到圆曲线段的接点时与圆曲线同样的曲率，当要设置两个圆曲线时，缓和曲线的曲率从与一个圆曲线相同的曲率变化到与第二个圆曲线相同的曲率。 Lesson 11 pavement Highway pavements are divided into two main categories : rigid and flexible . The wearing surface of a rigi

43、d pavement usually is constructed of Portland cement concrete such that it acts like a beam over any irregularities in the underlying supporting material . The wearing surface of flexible pavements , on the other hand ,usually is constructed of bituminous material such that they remain in contact wi

44、th the underlying material even when minor irregularities occur . Flexible pavements usually consist of a bituminous surface underlaid with a layer of granular material and a layer of a suitable mixture of coarse and fine materials . Traffic loads are transferred by the wearing surface to the underl

45、ying supporting materials through the interlocking of aggregates , the frictional effect of granular materials , and cohesion of the fine materials .Located immediately above the surbgrade , the subbase component consists of material of a superior quality to that which generally is used for subgrade

46、 construction . The requirments for subbase materials usually are given in terms of the gradation , plastic charateristics , and strength . When the quality of the subgrade material meets the requirements of the subbase material , the subbase component may be omitted . In cases where suitable subbas

47、e material is not readily available , the available material can be treated with other materials to achieve the necessary properties . This process of treating soil to improve their engineering properties is known as stablization .高速公路路面分为两大类：刚性和柔性。一个刚性路面磨损表面通常是波特兰水泥混凝土建造的，其受力与梁类似，承受支撑材料以下的任何变形。对柔性路

48、面磨损表面另一方面，通常是沥青材料建造，使他们在与基本材料保持联系，即使轻微的变形发生。柔性路面通常包括一个颗粒物质层和一个合适的粗，细料沥青混合料面层隐伏。交通负荷是由面层到底层辅助材料移送通过聚合联锁，粒状物料的摩擦作用，以及优良的材料凝聚力。位于正上方的路基，底基层组成部分包括一个优质的材料一般是用于路基建设。为底基层材料的要求通常给出的层次，塑料的特性来看，和力量。当路基材料的质量满足了底基层材料的要求，底基层组成部分可以省略。在适当的情况下，底基层材料尚不齐备，现有的材料可与其它材料处理，以实现必要的属性。这种对待土工程特性，以改善他们的过程被称为稳定。 Lesson 12 bitu

49、minous surface courses The bituminous surface course has to provide resistance to the effects of repeated loading by tyres and to the effects of the environment . In addition , it must offer adequate skid resistance in wet weather as well as comfortable vehical ride . It must also be resistant to ru

50、tting and to cracking . It is also desirable that surface course is impermeable , except in the case of porous asphalt . Porous asphalt ( PA ) is a uniformly graded material which is designed to provide large air voids so that water can drain to the verges within the layer thickness . If the wearing

51、 course is to be effective , the basecourse below must be waterproof and the PA must have the ability to retain its open textured properties with time . Thick binder films are required to resist water damage and ageing of the binder . In use ,this material minimizes vehical spray , provides a quiet

52、ride and lower rolling resistance to traffic than dense mixtures . It is often specified for environmental reasons but stone mastic asphlt ( SMA ) and specialist thin surfacings are generally favoured in current UK practice . There have been high profile instances where a PA wearing course has faile

53、d early in its life . The Highways Agency does not recommend the use of a PA at traffic levels above 6 000 commercial vehicals per day . 1沥青面层必须能够抵抗轮胎重荷载作用和环境作用的影响，此外他必须在雨天能够提供足够的抗滑力以及提供行车舒适性，他还能够抵抗车辙和开裂能力，我们还希望面层是不透水的，除非是透水性路面。 4透水性沥青路面是用均匀级配材料，其特点是提供大的空斜率将水在结构层厚度范围内排到边缘，如果磨耗层太透水了，那么下面的基层必须是防水的，并且透

54、水性路面必须保持开发结构特质以及延长结合料使用寿命，需要较厚的吸附沥青膜来抵抗水损害和组织结合料的老化，在使用中，这种材料能最大限度的降低水雾，与密集配结合料相比，他能够提供低噪音路面，并减少路面并减少滚动摩阻力，通常由于特定的环境因素，但是目前在英国施工中，沥青瑪蹄脂碎石和指定的薄面层通常是首选，在早期使用中，在高等级公路中透水性沥青磨耗层在早期使用中会发生破坏，公路局不建议在日载重车超过6000辆的公路上采用透水性沥青面层。Lesson 14 Freeways Dsign speeds for interchange rangs depend on the type of ramp sel

55、ected , for example , loop , diamond , or direct , and the low-volume ,running speed of the intersecting highway . Usually , the design speed is established by the most restrictive element of the ramp , typically , the sharpest curve . Whatever design speed is selected , adequate transitions from th

56、e freeway proper and at the ramp terminal or merge point should be developed . It has been estimated that 8 billion hours of excess travel occur each year because of navigational errors that are partly due to inadequate signing , amounting to an average of 34 hours per year for every person in the U

57、nited states . Appropriate highway information systems are needed to ensure that motorists have adequate time to acquire and process the information for control , guidance , and navigation . On the other hand , the lack of signs or misleading signs can contribute to driver confusion , loss of attention , and erratic maneuvers .立交匝道的设计速度取决于砸到的选择类型，例如，环形、菱形、直线型以及低交通量，相交交通干线的运行速度。 通