道桥专业英语(一)ppt课件.ppt

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1、道路与桥梁工程专业英语第一讲 绪论 一.专业英语是什么（what）？ 二. 为什么要学习专业英语（why）？ 三.怎么样学习专业英语（how）？第一讲 绪论 一.专业英语是什么（what）？1、概念专业英语：English for special purpose,简称ESP。专业：针对相应专业知识，专业术语，专业常识，所以应以专业知识理论为基础。英语：国际语言，便于交流，包括学术交流、文献参阅、文章撰写等。 第一讲 绪论 一.专业英语是什么（what）？2、特点2.1 语言特点语言简练，表达明确，不重润饰 The shoulder width of urban and rural freewa

2、ys is dependent upon the number of lanes of the facility. The right side shoulder for both urban and rural freeways shall be 10 feet. This width allows for emergency parking of vehicles on the right hand shoulder. The left side shoulder is dependent on the number of freeway lanes. 第一讲 一.专业英语是什么（what

3、）？2、特点2.1 语言特点逻辑严谨，概念清晰，关系分明Asphalt is called a bituminous material because it contains bitumen, a hydrocarbon material soluble in carbon disulfate(一个易溶于二硫化碳烃类物质). The tar(焦油） obtained from the destructive distillation of soft coal also contains bitumen. Both petroleum asphalt and coal tar are refer

4、red to as bituminous materials.第一讲 绪论 一.专业英语是什么（what）？2、特点2.2 语法特点非人称的语气和客观的态度，常用It结构 It is important, though, to design freeways, urban and rural, that provide a consistent roadway for drivers.第一讲 绪论 一.专业英语是什么（what）？2、特点2.2 语法特点多用被动结构A freeway may be defined as a divided highway facility having two

5、 or more lanes for the exclusive use of traffic in each direction and full control of access and egress.高速公路可定义为每个方向具有两条或两条以上汽车专用车道，并且进出口完全控制的被分隔的公路设施。第一讲 绪论 一.专业英语是什么（what）？2、特点2.2 语法特点多用动词非谓语结构In general, the design speed of freeways should be similar to the desired running speed during off peak h

6、ours, keeping in mind a reasonable and prudent speed.第一讲 绪论 一.专业英语是什么（what）？2、特点2.2 语法特点祈使语句和公式化表达方式在理论分析和公式推导中常采用Assume that，Suppose that，Let等祈使语气表达方式。 So, next let us look at how to use SYNCHRO to do signal timing and simulation work.因此，接下来让我们看看如何使用SYNCHRO来进行信号配时和交通仿真工作。第一讲 绪论 一.专业英语是什么（what）？2、特点

7、2.2 语法特点条件句较多条件句多用于条件论述、理论分析和公式推导中，最常用的是If语句。The huge investment in the highway infrastructure will be erased quickly if proper maintenance and rehabilitation procedures are enforced and funded.若合理的养护和修护计划得以资助并实施，就可迅速取消用于公路基础建设的巨大投资。第一讲 绪论 一.专业英语是什么（what）？2、特点2.2 语法特点多用长句One of the effects of oxidat

8、ion is that the binder loses flexibility and therefore becomes harder and more susceptible to the abrasive effects of traffic; an oxidized binder is thus likely to wear away in preference to particles of coarse aggregate set in the surface, allowing the chippings to protrude from the surface and imp

9、rove the skidding resistance.第一讲 绪论 一.专业英语是什么（what）？2、特点2.2 语法特点省略句较多为了简洁，有时省略掉句子中的一些成分，如状语从句中的主语和谓语、定语从句中的关联词which或that, 从句中的助动词等。If not well managed, the procedure for construction may be more expensive. 如果管理不善，这一施工方法还可能更费钱。 常见的省略（状语从句中的主语和谓语的）句型有：As already discussed 前已讨论 If possible 如果可能的话As des

10、cribed above 如前所述 If so 倘若如此As explained before 前已解释 When necessary 必要时As indicated in Fig.1 如图1所示 When needed 需要时As previously mentioned 前已述及 Where feasible 在实际可行的场合If necessary 如果必要的话 Where possible 在可能的情况下第一讲 绪论 一.专业英语是什么（what）？2、特点2.2 语法特点大量使用名词化结构名词化特点主要是指在专业文献中广泛使用能表示动作和状态的名词，或是起名词作用的非限定动词。In

11、the initial stages of road design it is usual for several alternative route proposals to be considered but only outline details of road center lines and estimates of speeds and flows are available.在道路设计的初始阶段，通常有多种备选的路线方案需要考虑，但这时只有道路中线的概要数据和车速及流量的预测值。第一讲 绪论 一.专业英语是什么（what）？2、特点2.3 词汇特点专业词汇2.4 结构特点每一自

12、然段落中，总有一个语句概括出该段落的重点。这个语句或在段落之首，或在段落之尾，较少出现在段落中间。若干个自然段会形成一个逻辑（或结构）段落，用以从不同角度来解说某一层面的核心内容。全篇则由若干个逻辑段落组成，从不同层面来阐述文章标题所标明的中心思想。实际上，专业文献中通常采用的标题、子标题、编号等形式，就是对文章结构的逻辑划分 Highway engineering is an engineering discipline branching from civil engineering which involves the design, construction and maintenan

13、ce of highway systems. Highway engineering became prominent towards the latter half of the 20th Century after World War 2. Standards of highway engineering are continuously being improved. Highway engineers must take into account future traffic flows, design of highway intersections/interchanges, ge

14、ometric alignment and design, highway pavement materials and design, structural design of pavement thickness, and pavement maintenance. Most developed nations have extensive highway networks. The most appropriate location, alignment, and shape of a highway are selected during the design stage. Highw

15、ay design involves the consideration of three major factors (human, vehicular, and roadway) and how these factors interact to provide a safe highway. Human factors include reaction time for braking and steering, visual acuity for traffic signs and signals, and car-following behavior. Vehicle conside

16、rations include vehicle size and dynamics that are essential for determining lane width and maximum slopes, and for the selection of design vehicles. Highway engineers design road geometry to ensure stability of vehicles when negotiating curves and grades and to provide adequate sight distances for

17、undertaking passing maneuvers along curves on two-lane, two-way roads.vehicle dynamics 汽车的动力汽车的动力lane width车道宽度车道宽度maximum slopes 最大纵坡度最大纵坡度design vehicles设计车辆设计车辆design vehicles视距视距two-lane, two-way roads双向双车道双向双车道道路Geometric Design Highway and transportation engineers must meet many safety, servic

18、e, and performance standards when designing highways for certain site topography. Highway geometric design primarily refers to the visible elements of the highways. Highway engineers who design the geometry of highways must also consider environmental and social effects of the design on the surround

19、ing infrastructure（基础设施）（基础设施）.Geometric Design There are certain considerations that must be properly addressed in the design process to successfully fit a highway to a sites topography and maintain its safety. Some of these design considerations include Design speed, Design traffic volume, Number

20、of lanes, Level of Service (LOS), Sight Distance, super-elevation, and grades, Cross section, Lane width, Horizontal and vertical clearance. The operational performance of a highway can be seen through drivers reactions to the design considerations and their interaction.Level of Service (LOS)服务水平服务水

21、平Sight Distance-视距视距 super-elevation-超高超高Grade-纵坡度纵坡度 cross section-横断面横断面 lane width-车道宽车道宽MaterialsThe materials used for roadway construction have progressed with time, dating back to the early days of the Roman Empire. Advancements in methods with which these materials are characterized and appl

22、ied to pavement structural design has accompanied this advancement in materials. There are two major types of pavement surfaces -Portland cement concrete (PCC) and hot-mix asphalt (HMA). Portland cement concrete (PCC)-普通硅酸盐水泥普通硅酸盐水泥hot-mix asphalt (HMA)-热拌沥青混合料热拌沥青混合料Flexible Pavement DesignA flexib

23、le, or asphalt, pavement typically consists of three or four layers. For a four layer flexible pavement, there is a surface course, base course, and subbase course constructed over a compacted, natural soil subgrade. When building a three layer flexible pavement, the subbase layer is not used and th

24、e base course is placed directly on the natural subgrade. Flexible Pavement柔性路面柔性路面 surface course-面层面层Layers-结构层结构层 base course -基层基层subbase course-底基层底基层 soil subgrade-土基土基A flexible pavements surface layer is constructed of hot-mix asphalt (HMA). Unstabilized aggregates are typically used for the

25、 base course; however, the base course could also be stabilized with asphalt, Portland cement, or another stabilizing agent. The subbase is generally constructed from local aggregate material, while the top of the subgrade is often stabilized with cement or lime. With a flexible pavement, the highes

26、t stress occurs at the surface and the stress decreases as the depth of the pavement increases. Therefore, the highest quality material needs to be used for the surface, while lower quality materials can be used as the depth of the pavement increases. Stress-应力；应力；The term flexible is used because o

27、f the asphalts ability to bend and deform slightly, then return to its original position as each traffic load is applied and removed. It is possible for these small deformations to become permanent, which can lead to rutting in the wheel path over an extended time. The service life of a flexible pav

28、ement is typically designed in the range of 15 to 20 years. traffic load车辆荷载车辆荷载Rutting车辙车辙service life使用寿命使用寿命Rigid Pavement Rigid pavements are generally used in constructing airports and major highways, such as those in the interstate highway system. Like flexible pavements, rigid highway pavemen

29、ts are designed as all-weather, long-lasting structures to serve modern day high-speed traffic. Rigid pavements -刚性路面；刚性路面；all-weather-全天候；全天候；long-lasting-持久的；持久的；Rigid PavementOffering high quality riding surfaces for safe vehicular travel, they function as structural layers to distribute vehicula

30、r wheel loads in such a manner that the induced stresses transmitted to the subgrade soil are of acceptable magnitudes. Portland cement concrete (PCC) is the most common material used in the construction of rigid pavement slabs. The reason for its popularity is due to its availability and the econom

31、y. Rigid pavements must be designed to endure frequently repeated traffic loadings. The typical designed service life of a rigid pavement is between 30 and 40 years, lasting about twice as long as a flexible pavement.二二. 为什么要学习专业英语（为什么要学习专业英语（why）？）？1、Reading2、Translation and Interpretation（笔译和口译）（笔译和口译）3、Writing三三.怎么样学习专业英语（怎么样学习专业英语（how）？）？1、掌握专业词汇；、掌握专业词汇；2、大量阅读专业学科论文；、大量阅读专业学科论文；3、学会进行英文论文的检索、学会进行英文论文的检索(第第3章）；章）；4、尝试着翻译（第四章）和写作（第五章）。、尝试着翻译（第四章）和写作（第五章）。