1、Unit1(2)Reinforced Concrete 钢筋混凝土钢筋混凝土1.2.3.4.5.6.7.Review 加强，加固压缩压缩使嵌入使结合易碎的，脆弱的粘附变形 rate of contraction rate of expansion tensile strength compressive strength elastic modulusyield strength hot-rolled reinforcing barPhrases收缩率膨胀率膨胀率抗拉强度抗压强度抗压强度弹性模量弹性模量屈服应力屈服应力热轧钢筋Reinforced concrete(1)DefinitionIt
2、 also called ferroconcrete in some countries,is concrete in which reinforced bars or fibers have been incorporated to(掺入)strengthen a material that would otherwise be brittle(易碎的/脆弱的).钢筋混凝土即在混凝土中掺入钢筋和纤维，来增大脆弱材料的强度。Reinforced concrete was invented in the latter half of the 19th century.Concrete and r
3、einforced concrete are used as building materials in every country.Reinforced concrete is a dominant structural material in engineering construction in many countries,including the United States and Canada.钢筋混凝土发明于19世纪后半期。在世界上的许多国家，混凝土和钢筋混凝土被用作建筑材料。在包括美国，加拿大的许多国家，钢筋混凝土在工程结构中是一种主导结构材料。mainprimarydomi
4、nating1.The band played many songs,including some of my favourites.这个乐队唱了很多的歌,包括我喜欢的一些歌.2.The islands of the southern Pacific Ocean,including Australia,New Zealand,and New Guinea 太平洋南部岛屿，包括澳大利亚、新西兰及新几内亚The universal nature of reinforced concrete construction stems from the wide availability of reinf
5、orcing bars and the constituents of concrete,gravel,sand and cement，the relatively simple skills required in concrete construction,and the economy of reinforced concrete compared to other forms of construction.钢筋混凝土结构通用的特性源于钢筋以及混凝土的组成部（砂，石子，水泥）很容易获得，以及混凝土施工过程中相对简单的技术和与其他结构形式相比的经济性。derive fromorigina
6、te fromcome ofavailable:可获得的；可利用的；闲暇的;空闲的；I am available in the afternoon.我下午有空。The information is freely available on the Internet.信息可在因特网上任意获取。Concrete and reinforced concrete are used in bridge,buildings of all sorts(各种各样),underground structures,water tanks,television towers,offshore oil explorat
7、ion and production structures(近海石油开采和生产结构),dams,and even in ships.混凝土和钢筋混凝土被应用在桥梁和各类建筑中，地下结构，水箱，电视塔，近海石油开采和生产结构，大坝，甚至还用在船舶上。Its ApplicationSteel bars are embedded in concrete to make reinforced concrete in concrete beams and structures where tension will develop,the proper adhesion between the steel
8、 and the concrete is of the greatest importance,and bars should be of a sufficiently small diameter to offer an adequate area of contact with the concrete;note that the smaller the diameter of the bars,the greater their surface area for any given percentage of reinforcement.钢筋嵌入混凝土中形成钢筋混凝土，可用于有拉力产生的
9、混凝土梁和结构中。钢筋和混凝土之间形成强大的黏结力使得钢筋不能从混凝土中滑出。而且，钢筋的直径必须足够小从而为钢筋和混凝土提供充足的接触面积。这表明了对于配筋率的结构，钢筋的直径越小，它们的接触面积越大。.the more.,the more.句型常表示越就越,The more he gets,the more he wants.他越来越贪。The harder you work,the greater progress you will make.你越用功,进步就越大。The more English you practise,the better your English is.你练习英语
10、越多,你的英语就越好。钢筋混凝土梁Reinforced Concrete beamConcrete and steel form such a strong bondthe force that unites themthat no relative movements of the steel bars and the surrounding concrete occur.This bond is provided by the relatively large chemical adhesion which develops at the steel-concrete interface,
11、by the natural roughness of the mill scale of hot-rolled reinforcing bars,and by the closely spaced rib-shaped surface deformations with which reinforcing bars are furnished in order to provide a high degree of interlocking of the two materials.Still another advantage is that the steel is therefore
12、completely surrounded by the concrete and the steel does not rust in concrete.混凝土和钢筋之间形成一种强大的粘合力，这个力能够将它们粘合在一起使得周围混凝土和钢筋不产生相对滑移。这种粘合力是钢筋和混凝土表面产生的相对较大的化学附着力，由热轧钢筋工厂的原始粗糙度以及表面间隔较小的带肋钢筋所提供的，是为了使两种材料有很高的联结。另一个优点是钢筋与周围的混凝土充分接触，钢筋在混凝土中不会生锈。1.1 混凝土结构一般概念和特点its advantagesA.the relatively low costB.good weat
13、her and fire resistance(抗火性)C.good compressive strength D.excellent formability of concreteE.the high tensile strengthF.much greater ductility(延展性)and toughness(韧性)of steel1.成本相对较低2.适用各种天气状况，抗火性良好3.较高的抗压强度4.混凝土极易成形5.较高的抗拉强度6.极好的延展性和钢的韧性1.1 混凝土结构一般概念和特点 Its classificationReinforced concrete can be cl
14、assified as(把分类为):precast concrete 预制钢筋混凝土 cast in-situ concrete 现浇钢筋混凝土 prestressed concrete 预应力钢筋混凝土1.1 混凝土结构一般概念和特点(1)definationThe construction that uses steels and concrete of very high strength in combination is known as(称为)prestressed concrete.把钢筋和混凝土使用很强的力结合在一起就被称为预应力混凝土。Prestressed Concrete
15、The development of early cracks in reinforced concrete due to non-compatibility in the strains of steel and concrete was perhaps the starting point for the development of a new material“prestressed concrete”.由于钢筋混凝土应变的不兼容性而导致混凝土早起裂缝的出现很可能是研发像预应力混凝土这样新型材料的出发点。第一章 绪论1.1 混凝土结构一般概念和特点(2)Two methods to p
16、restress concretepre-tensioned method：is to leave channels in a concrete beam that correspond to(与相符合/相应)the shapes of the steel bars.When the bars are run through the channels,they are then bonded to(结合)the concrete by filling the channels with grout,a thin mortar of binding agent.先张法:在混凝土梁中留下对应钢筋形
17、状的孔道。当钢筋穿过孔道时，用水泥浆填满混凝土梁的孔道，钢筋就会与混凝土梁黏合在一起。conform toaccord withmeet withpost-tensioned method：the prestressed steel bars are placed in the lower part of a form that corresponds to the shape of the finished structure,and the concrete is poured(浇灌)around them.后张法后张法:把预应力钢筋放在与成品结构形状对应的模板较低的把预应力钢筋放在与成品
18、结构形状对应的模板较低的位置，并把混凝土浇灌在其周围。位置，并把混凝土浇灌在其周围。Historical development of reinforced concrete 1.First stage:1850 to the late nineties Application of R.C component.Capacity is calculated by elastic analysis method.allowable stress design principal.第一阶段：第一阶段：从钢筋混凝土的发明至本世纪初从钢筋混凝土的发明至本世纪初钢筋和混凝土的强度都比较低钢筋和混凝土的强
19、度都比较低主要用于建造中小型主要用于建造中小型楼板楼板(Slabs)、梁、梁(Beams)、柱、柱(Columns)、拱、拱(Arches)和基础和基础(Foundation)等构件。等构件。计算理论：计算理论：结构结构内力内力(Inner Forces)和构件和构件截面截面(Section)计算均套计算均套用用弹性理论弹性理论(Elastic Theory)，采用，采用容许应力设计方法容许应力设计方法(Allowable Stress Design)。2.Second stage:the early twenties to the second world war Space structu
20、re and prestressed concrete,thin shells structure.Capacity calculation:plastic analysis method,failure state design principle 第二阶段：第二阶段：从本世纪从本世纪2020年代到第二次世界大战前后年代到第二次世界大战前后混凝土和钢筋强度的不断提高混凝土和钢筋强度的不断提高19281928年法国杰出的土木工程师年法国杰出的土木工程师E.E.Freyssnet发明了发明了预应力混凝土预应力混凝土(Prestressed Concrete)，使得混凝土结构可以用来建造大跨度，使
21、得混凝土结构可以用来建造大跨度计算理论：计算理论：前苏联著名的混凝土结构专家格沃兹捷夫前苏联著名的混凝土结构专家格沃兹捷夫（.）开始考虑混凝土）开始考虑混凝土塑性性能塑性性能(Plastic Behavior)的破损阶段设计法，的破损阶段设计法，5050年代又提出更为合理的年代又提出更为合理的极限状态极限状态设计方法设计方法(Limit State Design)，奠定了现代钢筋混凝土结构的基，奠定了现代钢筋混凝土结构的基本计算理论。本计算理论。3.Third stage:the second world war to now industrialization construction me
22、thod.limit state design principle based on probability theory Materials:high strength concrete and reinforcement.Structure:high-rise and off-shore structure第三阶段：第三阶段：二战以后到现在二战以后到现在随着建设速度加快，对材料性能和施工技术提出更高要求，出现装配随着建设速度加快，对材料性能和施工技术提出更高要求，出现装配式式(fabricated)钢筋混凝土结构、泵送商品混凝土等工业化生产技术。钢筋混凝土结构、泵送商品混凝土等工业化生产技
23、术。高强高强(high-strength)混凝土和高强钢筋的发展、计算机的采用和先进施混凝土和高强钢筋的发展、计算机的采用和先进施工机械设备的发明，建造了一大批超高层建筑、大跨度工机械设备的发明，建造了一大批超高层建筑、大跨度桥梁桥梁(Bridge)、特长跨海特长跨海隧道隧道(Tunnel)、高耸结构等大型工程，成为现代、高耸结构等大型工程，成为现代土木工程土木工程(Civil Engineering)的标志。的标志。设计计算理论：设计计算理论：发展了以发展了以概率理论概率理论(Probability Theory)为基础的极限为基础的极限状态设计法，基础理论问题大都得到解决，而新型混凝土材料
24、及其复状态设计法，基础理论问题大都得到解决，而新型混凝土材料及其复合结构形式的出现又不断提出新的课题，并不断促进混凝土结构的发合结构形式的出现又不断提出新的课题，并不断促进混凝土结构的发展。展。上海东方明珠塔 a flock of sheep/birdsa herd of cattle/deer/elephantsa swarm of bees/antsa cluster of grapes/flowers 1.the mechanics of reinforced concrete2.what is pre-tensioned method and post-tensioned method
25、 Summary(总结）总结）Exercises:1.What is reinforced concrete?2.When was the reinforced concrete invented?3.Reinforced concrete is usually used in which area?4.What are the two methods to prestress concrete?5.Whats the advantage of reinforced concrete?6.How many kinds can the reinforced concrete be classif
26、ied?Translate the following sentences into Chinese or English.1.The advantage of reinforced concrete structures over steel ones are their heavy weight that makes them more stable under wind load,they hardly experience corrosion and can last longer in a fire without rapid loss of strength due to thei
27、r concrete cover to rebars.2.Concrete and reinforced concrete are used in bridge,buildings of all sorts,underground structures,water tanks,television towers,offshore oil exploration and production structures,dams,and even in ships.3.For structural applications it is normal practice to incorporate st
28、eel bars to resist any tensile forces or to apply compressive forces to the concrete to counteract these tensile forces.4.混凝土是一种广泛使用的人造材料，可定义为由胶结介质胶结而成的固体物质，它的主要成分包括水泥，石子，砂和水。5.如果世贸大厦由钢筋混凝土建造，当时就不可能在受到打击时倒塌的那样快。Sothat/suchthat用法相同点：都表示“如此以致”的意思，连接一个表示结果的状语从句表示结果的状语从句。不同点：such后边要用名词（这个名词前面可以带形容词，也可以不
29、带）。so后边可加形容词或副词。1)sucha(an)adj.单数可数名词thatclause He is such a clever boy that everybody likes him.他非常聪明，大家都非常喜欢他。2)suchadj.复数可数名词thatclause They are such interesting novels that I want to read them once again.这些小说非常有趣，我想再读一遍。3)suchadj.不可数名词thatclause He has made such great progress that the teachers are pleased with him.他进步得很快，老师们对他感到很满意 soadj.adv.thatclause（so的后面跟形容词或副词）He runs so fast that nobody can catch up with him.他跑得非常快，没人能追上他。so that引导目的状语从句目的状语从句时，表示“以便；为了She bought a digital camera online so that she would save a lot of time.为了节省时间，她从网上购买了数码相机。
