1、Unit6(2)Bridge Engineering 桥梁工程桥梁工程Learning GuidancenMaster:nCategories of bridges n掌握：主要的桥梁类型nTeaching Important Point:nCategories of bridges (桥梁的主要类型)nTeaching Diffcult Point:nskills:how to translate attributive clause(如何翻译定语从句)1.2.3.4.5.6.7.Review下部结构 上部结构桥墩多孔的高架桥路堤破裂，断裂1.2.3.4.5.6.7.Review沉淀，降雨量
2、 安排,整理悬挂，悬浮底梁，底座尺寸模板梁girder bridge arch bridgecantilever bridgesuspension bridgecable-stayed bridgelong-span bridge multi-span bridge Phrases 梁桥 拱桥 悬臂桥 悬索桥斜拉桥大跨径桥 多跨桥“八仙”之一的张果老十分惊讶，约了柴王爷一同来试桥。张果老倒骑毛驴在前，驴背褡裢里装着日、月；柴王爷推小车在后，运载着五岳名山。行于桥中心，将桥压得摇摇欲坠。鲁班见势不妙，一纵身跳入水中，用手将桥托住，石桥安然无恙。桥身经过这样的重压，也就更加稳固。于是，桥面上留下了
3、清晰的驴蹄印、车道沟；桥底留下鲁班的手印。赵州桥：又名安济桥,安济桥是目前世界最古老的现存完好的大跨度单孔敞肩坦弧石拱桥。赵州桥位于河北石家庄赵县，建于公元605年，由著名的匠师李春设计和建造，距今已有1400年的历史，是当今世界上现存最早和保存最完整的石拱桥。赵州桥，又名安济桥，位于河北赵县的洨河上，长50.82米，跨径37.02米，高7.23米，这是李春对拱肩进行的重大改进，把以往桥梁建筑中采用的实肩拱改为敝肩拱，即在大拱两端各设两个小拱，靠近大拱脚的小拱净跨为38米，另一拱的净跨为2.8米。这种大拱加小拱的敝肩拱具有优异的技术性能，首先，可以增加泄洪能力，减轻洪水季节由于水量增加而产生的
4、洪水对桥的冲击力。古代佼河每逢汛期，水势较大，对桥的泄洪能力是个考验，四个小拱就可以分担部分洪流。据计算四个小拱可增加过水面积16%左右，大大降低洪水对大桥的影响，提高大桥的安全性。其次，敝肩拱比实肩拱可节省大量土石材料，减轻桥身的自重。据计算四个小拱可以节省石料26立方米，减轻自身重量700吨，从而减少桥身对桥台和桥基的垂直压力和水平推力，增加桥梁的稳固。第三、增加了造型的优美，四个小拱均衡对称，大拱与小拱构成一幅完整的图画，显得更加轻巧秀丽，体现建筑和艺术的完整统一。第四、符合结构力学理论，敝肩拱式结构在承载时使桥梁处于有利的状况，可减少主拱圈的变形，提高了桥梁的承载力和稳定性。Categ
5、ories of bridges Girder bridges(梁式桥梁式桥)A girder bridge is perhaps the most common and most basic bridge.梁式桥或许是最常见和最基本的桥梁。A log or piece of other material across a creek is an example of a girder bridge in its simplest form.横跨小河的一块木头或者一根其他材料都是最简单形式的梁式桥。That piece of materialcalled a girder or beamres
6、ts directly on the ground on each side or is supported on heavy foundations known as piers.这段材料就被称为梁它直接搁置在水域的两侧，或者支撑在很重的基础之上也就是众所周知的柱。rest on:把.建立在.(build on/upon repose on)依靠、依赖（rely on/depend on）靠在.（lean on/lean against）Girder bridges come in two basic varieties:plate and box girders.Simple or con
7、tinuous beam-type bridges can be made of timber,steel,concrete,prestressed concrete or other materials.梁式桥梁包括两个基本类型：板梁和箱梁。简支梁式桥梁或者连续梁桥可以由木材、钢材、混凝土、预应力混凝土或其他材料所构成。The precast,prestressed beam type is a popular bridge type.These bridges can be found both as overpasses and as bridges.预制装配式预应力梁桥是常见的一类桥型
8、，可以修建成为立交桥或者跨河桥。This type of bridge became popular in the 1950s.这类桥19世纪50年代后被广泛运用。Prestress indicates that the reinforcing is stressed before loading,thereby(hence/therfore)placing the entire concrete beam section in compression or at a low value tension stress.预应力就是指在荷载施加之前给予混凝土的预压力，从而使整个混凝土梁截面处于受压
9、状态或者低拉应力状态。Since concrete is strong in compression and relatively weak in tension,this procedure creates a more effective concrete section.因为混凝土抗压强度较高而抗拉强度很弱，这种操作产生了更加有效地混凝土截面。Examples钢桁梁桥南京长江大桥钢桁梁桥南京长江大桥 连续梁桥杭州钱塘江二桥连续梁桥杭州钱塘江二桥 简支梁桥简支梁桥 飞云江桥飞云江桥简支梁桥简支梁桥 开封开封黄河桥黄河桥泰山科技学院泰山科技学院 A strong point in favor
10、 of arch bridges in their pleasing appearance and aesthetic elegance.拱桥的优点就是造型美观优雅。Arch bridges can be made of bricks or stone blocks that are held together by the compressive force characteristic of the arch because tensile strength is not necessarily required for arch construction.拱桥可以用砖石等块材修建，他们受
11、到压力的作用而结合的很紧密。因为建造拱桥对抗拉强度几乎是没有要求的。Arch bridges（拱桥）（拱桥）in favor of:有利于（be propitious to）支持/赞同（agree with/approve of）Reinforced concrete and steel arches are altogether much lighter structures.钢筋混凝土拱桥或钢拱桥都是非常轻的结构类型。The structure consists basically of the arch,the deck and usually some supports from th
12、e arch to the deck.结构的基本组成就是拱、桥面和一些位于拱与桥面之间的支撑构件。Arches may be grouped into circular,parabolic and catenary arch in terms of the shape of arch.拱根据不同的外形一般分为圆弧形、抛物线和悬链线拱。With regard to structural articulation the arch can fixed or hinged.有关的节点可以固接或铰接。Three types of arches are used:the fixed arch,the t
13、wo-hinged arch and the three-hinged arch.以下三种类型的拱被经常采用：无铰拱、双铰拱和三铰拱。according toin accordance withon the basis ofin line within the light ofwith respect toaboutconcerningThe main supporting structure in an arch bridge is one or more curved elements.拱桥的主要支撑结构是一个或多个弧形构件。The dead and live forces that ac
14、t on the arch bridge are transmitted along the curved line of the arch into abutments or supporting structures at either end.拱桥所承担的恒载和活载通过弧形构件传递到桥墩或两端的支撑构件上。世界第一钢拱桥世界第一钢拱桥泰山科技学院泰山科技学院桁架拱桥悉尼港桥桁架拱桥悉尼港桥 桁架拱桥三门上叶桥桁架拱桥三门上叶桥泰山科技学院泰山科技学院桁式组合拱桥恩施混水河桥桁式组合拱桥恩施混水河桥 泰山科技学院泰山科技学院肋拱桥肋拱桥 永定河桥永定河桥泰山科技学院泰山科技学院无锡民主桥无
15、锡民主桥 泰山科技学院泰山科技学院箱形拱桥宜宾岷江大桥箱形拱桥宜宾岷江大桥 箱形拱桥巫山龙门桥箱形拱桥巫山龙门桥 泰山科技学院泰山科技学院Zhaozhou Bridge1.1 混凝土结构一般概念和特点Cantilever bridges(悬臂桥悬臂桥)To solve the problem of increasing the span distance,other alternatives to beam and arch bridges included suspension and cantilever bridges.为了解决持续增加的跨径问题，除了梁桥和拱桥外，可以选择的有悬臂桥和悬
16、索桥。Among the largest cantilever bridges in the United States is the Commodore Barry Bridge.在美国跨度最大的悬臂桥是Commodore John Barry桥Commodore Barry BridgeA cantilever bridge is a bridge built using cantilevers,a cantilever is a structure or beam that is unsupported at one end but supported at the other,like
17、 diving boards.悬臂桥是采用了悬臂结构的桥型，悬臂是一端支撑而另一端没有支撑的结构，就像跳水板。When anchored firmly,a cantilever is a very strong structure.如果锚固牢固悬臂是强度很高的一种结构。It consists of three parts:the outer beams,the cantilever,and the central beam.它由三部分组成：边梁、悬臂和中梁。This configuration made longer spans possible and wider clearance ben
18、eath.这种构造可以获得更长的跨径和更宽的净空。The cantilever bridge was a popular type of bridge in the first half of the twentieth century,but at present,some commentators believe that the cable-stayed bridge will replace it for comparable spanning distances.在20世纪前半期，悬臂梁桥是一种非常普遍的桥梁形式。但目前，一些评论家认为：斜拉桥将由于有更大的跨越能力而取代悬臂桥。钢斜
19、钢斜拉桥拉桥东营东营黄河黄河桥桥 混凝土斜拉桥混凝土斜拉桥-夷陵长江大桥夷陵长江大桥组合梁斜拉桥组合梁斜拉桥-南浦大桥南浦大桥泰山科技学院泰山科技学院组合梁斜拉桥组合梁斜拉桥-上海杨浦大桥上海杨浦大桥Suspension bridges are used for very long spans or for shorter spans(where intermediate piers cannot be built.)悬索桥应用于那些无法修筑中间墩台的大跨径或稍短一些跨径的桥梁结构。Of all the bridge types in use today,the suspension brid
20、ge allows for the longest spans.在当今使用的所有桥梁形式中，悬索桥具有最大的跨径能力。Suspension bridges悬索桥结构示意图悬索桥结构示意图悬索吊杆塔架锚固锚固泰山科技学院泰山科技学院The principal structural elements of a suspension bridge are:flexible main cables,towers,anchorages,hangers,deck and stiffening girder.悬索桥主要的结构组成包括：柔性主缆、塔架、锚锭、吊杆、桥面板和加劲梁。Some primitive
21、examples of suspension bridges use vines and ropes for cables.一些原始的悬索桥使用藤或绳索作为缆索。A typical suspension bridge is a continuous girder with one or more towers erected above piers in the middle of the span.典型的悬索桥是连续梁结构，一个或多个主塔竖立在跨径中部的墩台上。The girder itself is usually a truss or box girder though in short
22、er spans,plate girders are not uncommon.梁本身通常采用钢桁架或是箱梁，板梁的情况也不少见。At both ends of the bridge large anchors or counter weights are placed to hold the ends of the cables.在悬索桥的两端设置大型的锚锭结构用以固定缆索。Suspension bridges,when well designed and proportioned,are clearly the most aesthetically pleasing of all brid
23、ges.如果悬索桥设计合理，比例得当，那么，毫无疑问在所有桥形中，它是最美观的。1.1 混凝土结构一般概念和特点大贝尔特桥大贝尔特桥香港青马大桥香港青马大桥明石海峡大桥明石海峡大桥金门大桥金门大桥The categories of bridges Summary(总结）总结）Translate the following sentences into Chinese or English.1.Some bridges are intended for pedestrians only.2.The use of concrete as a building material,however,wa
24、s not considered until the nineteenth century.3.The application of reinforced concrete was not successful because of the high losses in prestress caused by shrinkage and creep of the concrete.4.The principal portions of a bridge may be said to be the“superstructure”and“substructure”.5.Occasional loa
25、d refers to environmental factors that go beyond normal weather conditions,factors such as sudden gusts of wind and earthquakes.Exerecises6.桥梁支座以下基础以上的结构通常称其为下部结构。7.设计桥墩时必须特别注，因为桥墩可能要承担由水流、浮水或其他漂浮物产生的重荷。8.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结构，内部填注素混凝土。9.最常见的桥台形式是带有两个侧墙的重力式桥台。10.拱桥可以用砖石等块材修建，它们受到压力的作用而结合的很紧。Thank you！52 ！
