1、 Unit 6 Bridge Engineering 桥梁工程桥梁工程Learning GuidancenMaster:nThe main components of a bridge;Categories of bridges n掌握：桥梁的主要组成部分及主要的桥梁类型nTeaching Important Point:nThe main components of a bridge(桥梁的主要组成部分)nTeaching Diffcult Point:nskills:how to translate attributive clause(如何翻译定语从句)New Words and Phr
2、ases:n1.substructure n.下部结构 superstructure 上部结构n2.predominate vi.占支配地位；在中占优势n3.precipitation n.沉淀，降雨量n4.marshal vt.安排，调度，整理n5.dynamic adj.动态的，动力的 static 静态的precipitation：n.沉淀（deposit/sediment)ex:chemical n.降雨量（rainfall）v.precipitaten.元帅v.arrange/dispatchorder/organizen6.bewildering adj.（情况）让人困惑的，令人费
3、解的(confusing/perplexing/puzzling)n7.girder n.梁，钢桁的支架，主梁 n8.pier n.(桥)墩，支柱n9.suspension n.悬挂，悬浮，吊n10.cantilever n.悬臂（梁），突梁suspend:悬，挂ex:He suspended his coat on a hanger.他把外衣挂在衣架上。推迟，延缓（delay/put off/postpone+doing sth）ex:The goverment decided to suspend introduction of thenew scheme.政府决定延缓采用新方案。n11.
4、stiffen v.变硬，加强，加劲n12.abutment n.桥墩，桥基n13.dimension n.尺寸，度量，量纲n14.cellular adj.多孔的，格状的n15.trestle tres()l n.支架，栈桥，高架桥n16.hammerhead n.倒梯形，锤头n17.semicircular adj.半圆的n18.shuttering n.模板（壳）n19.diaphragm横隔板，阻隔n20.hexagonal heksnl adj.六角形的，六边形的n21.octagonal adj.八边（角）形的；n.八边（角）形n22.terminus n.终点站，终点，边界n23
5、.embankment n.路堤，岸堤，堤n24.sill n.底梁，底座，基础 n25.batter n.倾斜，坡度，倾斜度(v.smash/slap猛击、猛打)n26.tilt n.倾斜，车篷；vt.&vi.(使)倾斜，斜置n27.rupture n.破裂，断裂；vt.&vi.（使）破裂Phrases:n narrow down（使）变窄，（使）缩小n long-span bridge 大跨径桥n girder bridge 梁桥n arch bridge 拱桥n catenary arch 反垂曲线形拱n the fixed arch 无铰拱n cantilever bridge 悬臂桥
6、n box girder 箱形梁n cable-stayed bridge 斜拉桥n suspension bridge 悬索桥n flexible main cable 柔性主缆n end(intermediate)supports 端部（中间）支撑n multi-span bridge 多跨桥n lean(plain)concrete 素混凝土n bent cap 排架帽n uniform(even/balanced)distribution 均匀分布n headroom clearance 净空高度n bridge seat 桥梁支座n spill-through 穿通式的n open
7、abutment 敞开式桥台n overturning moment 倾覆力矩n shear resistance 抗剪力（shear strength 抗剪强度）Part I BridgesnBridges are great symbols of mankinds conquest of space.It is a structure that spans obstacles,such as rivers,lakes,or gorges,to provide a roadway for traffic.n桥梁是人类征服空间的伟大象征，它能够跨越许多障碍，比如河流、湖泊、峡谷，为交通提供了道
8、路。克服障碍/困难：overcome/win through/get over/surmountgorge/d/A few infrastructure projects,notably the operator of Chinas Three Gorges Dam,have gone direct to the markets.一些基础设施投资，特别像是中国三峡大坝发电机组项目，已经直接向市场发行了。n By far the majority of bridges are designed to carry automobile or railroad traffic,but some ar
9、e intended for pedestrians only.n到目前为止，大多数桥梁的功能是承担汽车和铁路交通，但也有一些为行人所用.nBridges also support pipes,troughs,or other conduits that transport materials,such as an oil pipeline or a water aqueduct.n另外，桥梁也支持管道、槽或其他运输材料的渠道，比如输油管或者水渡槽等。be aimed atwith the purpose ofnHumans have been constructing bridges sin
10、ce ancient times.For a few thousand years the classical form in bridge design has been the vault or arch.This structure,because of its inherent contour,utilized masonry as its material.n 人类从远古时期就已经开始修建桥梁了。近千年来拱桥一直是桥梁的传统形式，由于其固有的外形，这类结构可以利用砖石作为它的材料。nThe use of concrete as a building material,however,
11、was not considered until late in the nineteen century.n直到19世纪后期，混凝土才被用作建筑材料。利用：usemake use oftake advantage ofexploitowing todue tothanks toas a result ofon account ofnThe first application of reinforced concrete to bridge structures was pioneered by Hennebique.n第一次把钢筋混凝土应用于桥梁结构的是Hennebique。n In the
12、 same period prestressed concrete concepts were being formulated(提出)by Jackson and Doehring.Their application was not successful because of the high losses in prestress(caused by shrinkage and creep of the concrete.)n 同一时期Jackson和Doehring 提出了预应力混凝土的概念，但是由于混凝土收缩和徐变造成的高预应力损失使得它的应用并不成功。put forwardcome
13、up withset forthnIt was not until 1926-1928 when Freyssinet was able to control these losses with high-strength steel that prestressing was considered feasible.n直到19261928年间Freyssinet 采用高强度钢筋有效地控制了预应力损失，预应力结构才被认为是可行的。nPrestressed concrete was widely used for bridges after about 1950.n预应力混凝土被广泛用于桥梁结构
14、是在1950年以后了。n Steel became more useful for bridges with the development of stronger and more corrosion-resistant alloys.li(Steel alloys合金钢)n随着更大强度和更加抗锈蚀合金的发展，钢材在桥梁上的应用也更加广泛了。n Aluminum alloys,(which were used in bridges as early as 1933,)greatly reduce the dead weight of the bridge,but they are not w
15、idely used because they are relatively expensive.n铝合金早在1933年就应用于桥梁结构了，它极大地降低了桥梁的自重，但是由于造价昂贵并没有被广泛使用。nThe principle portions(parts)of a bridge may be said to be the“superstructure”and“substructure”.n桥梁的主要结构被称为上部结构和下部结构 nThis division is used here simply for convenience,since in many bridges there is
16、no clear dividing line(分界线)between the two.n这种划分方法用在这里只是为了方便起见，然而，在许多桥梁中这两者的界限是很不明显的。nBridges may also be classed as“deck”or“through”types.n桥梁也可以分为上承式和下承式。n In the deck type of bridge,the roadway is above the supporting structure,(that is),the load carrying elements of the superstructure are below t
17、he roadway.n上承式桥梁的车道位于支撑结构之上，也就是说，承担荷载的上部结构是位于道路以下的。n In the through type of bridge,the roadway passes between the elements of the superstructure.n而下承式桥梁的道路是横穿上部结构的。be classified asbe divided intobe grouped intothat is to sayin other wordsnDeck structures predominate:they have a clean appearance,pro
18、vide the motorist with a better view of the surrounding area,and are easier to widen if future traffic requires it.n上承式结构是居于主导地位的。因为它外形简洁，能够为汽车驾驶员提供更好地视线范围，而且如果将来由于交通要求需要拓宽道路也可以比较容易实现。nThe forces(that act on bridge structural members)are produced by three kinds of loads:the dead load,the live load,a
19、nd the occasional load.n作用于桥梁结构构件上的荷载一般由三部分组成：恒载、活载和偶然荷载。nDead load refers to the weight of the bridge itself is usually the greatest load.n恒载主要指的是桥梁自身的重量通常也是最大的荷载。n Live load refers to traffic that moves across the bridges as well as normal environmental forces such as changes in temperature,precip
20、itation,and winds.n活载则包括通过桥梁的汽车荷载以及正常的环境因素所产生的，比如气温变化、降水和大风。nOccasional load refers to environmental factors that go beyond(except/besides/apart from/other than)normal weather conditions,factors such as sudden gusts of wind and earthquakes.n偶然荷载是指除去正常气候条件以外的环境因素，例如突发的强风和地震等。nAll three factors must b
21、e taken into consideration in the design of a bridge.The design of bridges requires the collection of extensive data and the selection of possible options.n以上三种荷载在桥梁设计时必须考虑。桥梁的设计要求收集大量的数据并且选择可行的方案P97n From such a review the choice is narrowed down to a shortlist of potential bridge design.A sensible
22、 work plan should be devised for the marshalling and deployment of information throughout the project from conception to completion.n从这一观点出发，最终的选择就被限定在这些入围的桥梁设计中了。而切合实际的工作计划就要根据整个工程由开始到完成的全部资料进行全面的考虑。n It has been greatly improved by the use of advanced mathematics,electronic computers,and test mode
23、l,with these techniques,designers can obtain precise calculations of stresses and strains under both static and dynamic conditions.n通过应用高等数学、电子计算机和实验模型等技术设计师们可以对静态和动态下的应力和应变进行精确地计算。nThe designer of each medium and long-span bridge tries to devise a structure(that is best suited to the conditions)(en
24、countered at that particular location).n每一个中长跨桥梁的设计师都试图设计出一个结构可以最大程度满足那些特殊位置下的条件.nThe result is an almost bewildering variety of structures that differ either in basic design principle or in design details.n其结果往往是不同的设计师会设计出不同的结构类型，无论是就基本的设计原则还是设计细节而言。Components of a bridgenBroadly,a bridge can be di
25、vided into two major parts:superstructure and substructure.n总的来说，桥梁主要由两部分组成即:上部结构和下部结构。nThe superstructure of a bridge is analogous(similar)to a single storey building roof and substructure to that of the walls,columns and foundations supporting it.n桥梁的上部结构类似于一个单层建筑物的屋顶结构，而下部结构则类似于建筑物的墙体，柱子和地基，它们支撑着
26、上部结构。analogousnlgsAnalogous Color类似色analogous type模拟型SuperstructurenSuperstructure consists of structural members carrying a communication route.n上部结构由承担交通路径的结构成分组成。nThus handrails,guard stones and flooring supported by any structural system,such as beams,girders,arches and cables,above the level of
27、 bearing form the superstructure.n因此，像扶手，护栏和地板等主要成分构成上部结构，这些成分由水平以上的梁，拱和电缆等支撑着。Substructure nThe portion of the bridge structure below the level of the bearing and above the foundation is generally referred to as substructure.n桥梁支座以下基础以上的结构通常称其为下部结构。nWe here mainly explain the substructure of a brid
28、ge.The end supports are normally described as the“abutments”,whilst the general term for the intermediate supports of a multi-span bridge is the“piers”.n下部结构分为两个不同的类别：端部支撑和中部支撑。端部支撑通常称之为桥台，而对于多跨桥的中间支撑一般称其为桥墩。nThe abutments and piers are usually constructed from in situ concrete,but precast sections
29、can be employed to speed up the construction process.n桥台和桥墩通常是现场混凝土浇筑而成，但是预制构件的应用可以加快施工进度。be known asbe regard asbe considered asacceleratequickenhastenPiersnSpecial attention must often be given to the design of the bridge piers,since heavy loads may be imposed on(把.强加于)them by currents,and floatin
30、g ice and debris.nn设计桥墩时必须特别注意，因为桥墩可能要承担由水流、浮冰或其他漂浮物产生的重荷。nThe general shape and features of a pier depend to a large extent on the type,size and dimensions of the superstructure and also on the environment（in which the pier is located）.n桥墩的形状和形式很大程度上取决于上部结构的形状、尺寸和规格以及桥墩所处的周边环境。nPiers can be solid,c
31、ellular,trestle or hammerhead types.n桥墩可以是实心式、空心式、排架式，倒梯形。nSolid and cellular piers for river bridges should be provided with semicircular cut waters to facilitate streamlined flow(层流；流线流；流线型流动)and to reduce scour.(ska)n跨河桥梁的实心桥墩或空心桥墩应当提供半削减水域，以适应水流的流向和减轻冲刷。nOther designs such as reinforce concrete
32、framed type have also been used.n其他设计，如钢筋混凝土框架形式也有应用。promoteboospropeldrivemotivate vi.冲刷；擦；腹泻 vt.擦亮，洗涤；冲洗，清除 n.擦，冲刷；洗涤剂；（畜类等的）腹泻nSolid piers are of masonry or mass concrete.It is permissible to use stone masonry for the exposed portions and to fill the interior with lean concrete.This would save ex
33、penses on shuttering and would also enhance appearance.n实心桥墩一般由圬工材料或大体积混凝土构成。对于暴露在外的部分容许使用石砌圬工材料，内部填筑素混凝土。这样可以减少利用模板并且外表也得以加强。nCellular,trestle and hammerhead types use reinforced concrete.n空心式、排架式和倒梯形桥墩采用钢筋混凝土。nThe cellular type permits saving in the quality of concrete,but usually requires difficu
34、lt shuttering and additional labor in placing reinforcements.n空心桥墩能够节约混凝土用量，但是一般需要形势复杂的模板和用于加筋结构施工的额外劳动力。nThe trestle type consists of columns with a bent cap at the top.n排架式桥墩由顶部带有排架帽的柱所组成。n In some recent designs,concrete hinges have been introduced between the top of the columns and the bent cap
35、in order to avoid moments being transferred from deck to the columns.n在最近很多的设计中为了避免产生由桥面向柱传递的弯矩，在柱顶和排架帽之间经常采用铰接。nFor all trestles as in flyovers and elevated roads,connecting diaphragms between the columns may also be provided.n在立交桥和高架桥中，高架桥也用于连接柱于柱之间的横隔板。The hammerhead type provides slender substru
36、cture and is normally suitable for elevated roadways.n倒梯形桥墩具有细长的下部结构，通常适合高架桥。nWhen used for a river bridge,this design leads to minimum restriction of waterway.n当被用于跨河桥时，这类设计对航道的限制是最小的。be fit forbe suited tonVertical and horizontal loads transmitted from the superstructure disperse rapidly from the
37、top of a pier.n从上部结构传递下来的垂直载荷和水平载荷在桥墩顶部迅速扩散。nHence,the overall design of a pier is normally conducted on a meter strip basis,assuming a uniform distribution of axial and bending effects.n 因此，通常桥墩的整体设计是取决于单元宽度进行的，并且假定轴向力和挠度的影响都是均匀分布的。nThe magnitude of the axial compressive stresses in a concrete pier
38、 is normally between 0.51.0 N/mm2 under dead loading and it is unlikely to be more than 2 N/mm2 under the most severe live load conditions.n在恒载作用下，混凝土桥墩中轴向压力的大小通常在0.51.0 MPa的范围内，并且在最不利活载条件的作用下，其值一般也不会找过2 MPa。nThe degree of bending will depend upon the articulation of the deck and the length of the s
39、uperstructure.n弯曲的程度取决于桥板的连结情况和上部结构的长度。nReinforced concrete framed type of piers has been used in recent years.The main advantage in their use is due to reduced effective span lengths for girders on either side of the center line of the pier leading to(result in/give rise to)economy in the cost of s
40、uperstructure.n在最近几年，钢筋混凝土排架式桥墩已经普遍应用。它的主要优势就是可以降低在桥墩中心线两侧梁的跨径，从而提高了上部结构造价的经济性。nIndividual concrete columns are often used to support footbridges and bridge decks with high skew or greater height than the minimum headroom clearance.n单个混凝土墩柱常用来支撑人行桥和桥面板，这些桥面板斜度更大，高度也比最小净空高度很高。n Columns may be vertica
41、l,inclined or even curved in shape to produce greater aesthetic appeal.n 为了使结构更加美观，柱可以是垂直的、倾斜的甚至是弯曲的。n A column section is normally required to resist bi-axial bending and significant axial loading.n柱截面通常是通常要高度很多。为了使结构更加美观，柱可以是垂直的、倾斜的甚至是弯曲的。n Concrete columns are therefore often circular or square,b
42、ut hexagonal and octagonal sections are also common.n柱截面通常要求可以抵抗双向弯曲和很大的轴向载荷。因此混凝土柱通常为圆形或方形，六角形和八角形截面也很普遍。Abutments nAn abutment serves two principal functions.It is the substructure which supports one terminus of the superstructure of a bridge and,at some time,laterally supports the embankment whic
43、h serves as an approach to the bridges.n 桥台有两个主要功能：它是下部结构，支撑桥梁上部结构的一个端部，有时它也为紧接桥梁的路堤提供横向支撑。n For a river bridge,the abutment also protects the embankment from scour of the stream.n对于跨河桥梁，桥台还要保护路堤免受水流冲刷。n Bridge abutments can be made of masonry,plain concrete or reinforced concrete.Hence,an abutment
44、combines the functions of a pier and a retaining wall.n桥台可以由圬工材料、素混凝土或钢筋混凝土构成。因此，桥台综合了桥墩和挡土墙的功能。nBridge abutments are prepared on the riverbank where the bridge end will rest(support/sustain).An abutment generally consists of the following three distinct structural elements:n桥台修筑在河堤上用以支撑桥梁端部。桥台一般由以下
45、三个不同的结构构件组成：n n(1)the breast wall,which directly supports the dead and live loads of the superstructure,and retains the filling of the embankment in its rearn前墙，直接承受上部结构的恒载和活载，抵抗其背部路堤的土压力；n(2)the wing walls,which act as(serve as)extensions of the breast wall in retaining the fill though not taking a
46、ny loads from superstructures;n侧墙，作为前墙的延伸部分，只抵抗背部土压力而不承担上部结构产生的荷载；n(3)the back wall,which is a small retaining wall just behind the bridge seat,preventing the flow of material from the fill on to the bridge seat.n背墙，位于桥梁支座后部的小型挡土墙结构，以阻止路堤填土拥入到桥梁支座上来。nOne of the most common types of abutment is the g
47、ravity abutments with wing walls.n最常见的桥台形式是带有两侧墙的重力式桥台nIt consists of a central pier supporting the bridge seat,and two wing walls to retain the fill.All three elements rest on a single footing.If the wing walls are at right angles to the pier,the structure is known as a U abutment.n它由一个支撑桥梁支座的中心桥墩呈
48、直角，就是众所周知的U形桥台nThe wing walls of a U abutment are sometimes tied together to reduce their tendency to overturn.n其侧台有事绑定在一起以防止结构倾覆。nThe spilling-through or span abutment is also widely used.It consists of two or more vertical columns carrying a beam that supports the bridge seat.n穿通式或敞开式桥台的应用也比较普遍。它由
49、两个或更多的支撑桥主梁的竖直柱所构成。nThe fill extends on its natural slope from the bottom of the beam through the openings between the columns.n填注材料按照其自然坡度从梁底部通过柱之间的空隙。nIn its extreme form a spill-through abutment is no more than a row of piles driven through the fill and supporting a bridge seat.n穿通式桥台的极端形式是一排从填注材
50、料中延伸出的支撑桥梁支座的桩。nAnother common variation is a simple pier with small wings near the top.n另外一种常见的形式就是简单的一个在顶部带有小型翼墙的桥墩nThe fill in this case spills around the abutment.n在这种情况下填注材料位于桥台周边。Questionsn n The components of a bridge?Thank You!n向某人提供某物:用于provide sth.for sb.结构，也可用provide sb.with sth.结构nThey p
