现代建筑和结构材料

1、2 Modern Buildings and Structural Materials现代建筑和结构材料Many great buildings built in earlier ages are still in existence and in use. (许多早期建造的伟大建筑现在仍然存在和使用着) Among them are the Pantheon(1) and the Colosseum(2) in Rome, Hagia Sophia(3) in Istanbul; the Gothic churches of France and England, and the Renai

2、ssance(4) cathedrals(5), with their great domes(6), like the Duomo(7) in Florence and St. Peters(8) in Rome. (它们是罗马的潘提翁神庙和大斗兽场，伊斯坦布尔的圣索菲亚教堂；英国和法国的哥特式教堂、文艺复兴时期的天主教堂，是大圆屋顶，就象佛洛伦萨的多莫教堂和罗马的圣伯德大教堂) They are massive structures(9) with thick stone walls that counteract the thrust of their great weight. (他们

3、是用厚石墙建成的大块结构，厚石墙抵消了他们巨大的重量所产生的推力) Thrust is the pressure exerted by each part of a structure on its other parts. (推力是结构的一部分产生的作用于另一部分的压力)(1)Pantheon潘提翁神庙（公元前120124年），位于意大利罗马；(2)Colosseum罗马大斗兽场（7280年）；(3)Hagia Sophia圣索菲亚教堂（533537年），位于土耳其伊斯坦布尔；(4)Renaissance文艺复兴；(5)cathedral天主教堂；(6)Dome圆屋顶，穹顶; (7)Duom

4、o（意大利语）cathedral天主教堂；(8)St. Peters罗马圣彼得大教堂（15061626年），当时是在拉斐尔和米开朗琪罗等伟大艺术家们的亲自指导下建立起来的，是文艺复兴建筑中最完美的代表作。(9)massive(大块的，块状的，巨大的)；massive structure大体积结构/大块结构These great buildings were not the product of knowledge of mathematics and physics. (这些伟大的建筑不是数学和物理知识的产物) They were constructed instead on the basi

5、s of experience and observation, often as the result of trial and error(10). (它们不是根据经验和观察建造的，常常是反复试验的结果) One of the reasons they have survived is because of the great strength that was built into them-strength greater than necessary in most cases. (它们仍然保存完好的原因之一是建成它们的强度远大于大多数情况下所必需的强度) But the engin

6、eers of earlier times also had their failure. (但是早期的工程师也有失败的情况) In Rome, for example, most of the people lived in insulae(11), great tenement(12) blocks that were often ten stories high. (例如在罗马，大多数人居住在群屋或出租的十层高的经济公寓内) Many of them were poorly constructed and sometimes collapsed with considerable los

7、s of life(13). (这些房屋建筑结构很差，有时倒塌使其使用期大大缩短)(10)trial and error 反复试验，试错法，尝试法；(11)insula公寓，群屋，建筑群；(12)tenement经济公寓，出租的房子；(13)loss of life使用期缩短，寿命缩短；Today, however, the engineer has the advantage not only empirical information, but also of scientific data that permit him to make careful calculations in a

8、dvance. (现在工程师的优势在于不仅可以利用经验的数据，也可以利用科学的数据，这些科学的数据使得他们可以事先进行详细的计算) When a modern engineer plans a structure, he takes into account the total weight of all its component materials. (当一个现代的工程师设计一个结构时，他要考虑所有组成部分材料的总重量) This is known as the dead load(恒载), which is the weight of the structure itself. (称为静

9、载，即结构自身的重量) He must also consider the live load（活载）, the weight of all the people, cars, furniture, machines, and so on that the structure will support when it is in use. (他也必须考虑活载，即结构在使用时将要承受的所有的人、汽车、设备、机械等的重量) In structures such as bridges that will handle fast automobile traffic, he must consider

10、 the impact(冲击), the force at which the live load will be exerted on the structure. (像桥这样涉及到快速汽车交通的结构，必须考虑冲击，也即活载作用在结构上的力)He must also determine the safety factor（安全系数）, that is, an additional capability to make the structure stronger than the combination of the three other factors. (它必须确定桥的安全系数，也就是

11、说桥要有一个额外的能力，使结构能承受的力大于其他三个因素结合的力)The modern engineer must also understand the different stresses to which the materials in a structure are subjects. (现代工程师必须明白材料在结构中所承受的不同应力) These include the opposite forces of compression(压力、压缩) and tension(拉力、张力). (这些应力包括压力和拉力两个相反方向的力) In compression the material

12、 is pressed or pushed together; in tension the material pulled apart or stretched, like a rubber band. (在压力作用下，材料被压或推在一起；在拉力作用下，材料象橡皮筋一样被拉开或伸长) In addition to tension and compression, another force is at work, namely shear(剪力、剪切), which we defined as the tendency of a material to fracture along the

13、lines of stress. (除了拉力和压力外，工作中的另一种力叫剪力我们定义为材料沿着应力线断裂的趋势) The shear might occur in a vertical plane, but it also might run along the horizontal axis of the beam, the neutral plane(中性面), where there is neither tension nor compression. (剪切可能发生在竖直面内，也可能沿着梁的水平轴发生，既没有拉力也没有压力的截面叫中性面)Altogether, three force

14、s can act on a structure (三个力可以作用在一个结构上): vertical-those that act up or down; horizontal-those that act sideways; and those that act upon it with a rotating or turning motion. (竖直方向的力向上或向下，水平方向上的力作用于一侧，那些作用于其上的力产生旋转或转动运动) Forces that act at an angle are a combination of horizontal and vertical force

15、s. (以一定角度作用的力是水平力和竖直力的合力) Since the structures designed by civil engineers are intended to be stationary or stable, these forces must be kept in balance. (土木工程师设计的结构要想保持静止或稳定，这些力必须保持平衡) The vertical forces, for example, must be equal to each other. If a beam supports a load above, the beam itself mu

16、st have sufficient strength to counterbalance that weight. (例如竖直力必须彼此相等，如果一个梁承受其上的荷载，梁本身必须有足够的强度来平衡它的重量) The horizontal forces must also equal each other so that there is not too much thrust either to the right or to the left. (水平力也必须相等，以至于没有太多向左或向右的推力) And forces that might pull the structure aroun

17、d must be countered with forces that pull in the opposite direction. (拉结构的力必须抵消相反方向的拉力)One of the most spectacular engineering failures of modern times, the collapse of the Tacoma Narrows Bridge in 1940, was the result of not considering the last of these factors carefully enough. (当代最引人注意的工程失败的实例是1

18、940年（美国）塔科马港跨达达尼尔海峡大桥的坍塌，他是没有仔细充分地考虑这些因素的结果) When strong gusts of wind, up to sixty-five kilometers an hour, struck the bridge during a storm, they set up waves along the roadway of the bridge and also a lateral motion that cause the roadway to fall. (在一场暴风雨中，当强阵风以65km/h的速度撞击桥时，暴风掀起的波浪沿桥面运动，引起了桥面的侧向

19、运动，造成了桥面坍塌) Fortunately, engineers learn from mistakes, so it now common practice to test scale models of bridges in wind tunnels(14) for aerodynamic resistance. (幸运的是工程师们从这次失败中吸取了教训，现在根据空气动力学阻力特性在风洞内进行桥梁模型试验是很普通的事)(14)wind tunnel (test) 风洞(试验)The principal construction materials of earlier times we

20、re wood and masonry brick(圬工砖), stone, or tile(瓦), and similar materials. (早期的主要建筑材料是木材和圬工砖、石、瓦或类似材料) The courses or layers were bound together with mortar(砂浆) or bitumen(15), a tar-like substance or some other binding agent. (层与层间用砂浆、沥青、焦油类的物质或其他粘结剂将他们结合在一起) The Greeks and Romans sometimes used iro

21、n rods or clamps(16) to strengthen their buildings. (希腊和罗马人有时用铁棒或夹钳来加固他们的建筑) The columns of the Parthenon(17) in Athens, for example, have holes drilled in them for iron bars that have now rusted away. (比如在雅典的帕提侬神庙的柱子内就有钻孔，孔内有已经腐朽的铁棒) The Romans also used a natural cement(水泥) called pozzolana(火山灰，白榴

22、火山灰), made from volcanic ash(火山灰), that become as hard as stone under water. (罗马人使用一种来自的天然水泥，叫火山灰，这种水泥在水中会变得像石头一样坚硬)(15) bitumen沥青；asphalt, pitch(16) clamp夹子，夹钳，卡紧(17)Parthenon帕提侬神庙指古希腊雅典城邦的保护神雅典娜·帕提侬的神庙，是古希腊全盛时期建筑与雕刻的主要代表作。Both steel and cement, the two most important construction materials of

23、 modern times, were introduced in the nineteenth century. (钢(制品)和水泥当代最著名的两种建筑材料被采用是在19世纪) Steel, basically an alloy of iron and a small amount of carbon, had been made up to that time by a laborious process that restricted it to such special uses as sword blades. (钢是铁和少量碳组成的合金。在那个时期，钢只能在实验室中生产，专用于刀刃

24、) After the invention of the Bessemer process(18) in 1956, steel was available in large quantities at low prices. (直到1856年贝色麦法发明以后，钢得以低价大量利用) The enormous advantage of steel is its tensile strength(19); that is, it does not lose its strength when it is under a calculated degree of tension, a force w

25、hich, as we have seen, tends to pull apart many materials. (钢的最大优点是它的抗拉强度，也就是说他在计算的拉伸度内强度不会损失，这个拉力如我们看到的一样企图将许多材料拉开) New alloys have further increased the strength of steel and eliminated some of its problems, such as fatigue(疲劳), which is a tendency for it to weaken as a result of continual changes

26、 in stress. (新的合金增加了钢的强度，消除了它的一些问题，比如疲劳问题，即在连续变化应力作用下材料性能恶化的趋势)(18)Bessemer process贝色麦法，又称酸性底吹转炉炼钢法，由英国冶金学家Henry Bessemer 在1856年首创。这是一种不需外热的、可大量生产的炼钢方法。(19)tensile strength抗拉强度； compression strength; compressive strength抗压强度； shear strength; shearing strength抗剪强度；Modern cement, called Portland cemen

27、t(20), was invented in 1824. (现代水泥叫硅酸盐水泥，发明于1824年) It was a mixture of limestone(石灰石) and clay(粘土), which is heated and then ground into a powder. (他是石灰石和粘土被加热后磨成的粉末状的混合物) It is mixed at or near the construction site with sand, aggregate(21) (small stones, cruhshed rock, or gravel), and water to mak

28、e concrete(22). (在施工现场或其附近,水泥同砂子、骨料（小石子、碎石或砾石）、水混合制成砼) Different proportions of the ingredients(混合物成分，配料) produce concrete with different strength and weight. (混凝土成品混合物成份比例不同，强度和重量也不同) Concrete is very versatile; it can be poured, pumped, or even sprayed into all kinds of shapes. (砼具有良好的可塑性，他能被灌注、泵送

29、甚至喷射成各种形状) And whereas steel has great tensile strength, concrete has great strength under compression. (这样一来，钢有很高的抗拉强度，混凝土有很高的抗压强度) Thus, the two substances complement each other. (因此这两种材料彼此互补)(20)Portland cement硅酸盐水泥；波特兰水泥；普通水泥 Portland-slag cement；slag Portland cement矿渣硅酸盐水泥 Portland fly-ash ceme

30、nt粉煤灰硅酸盐水泥 (21) aggregate骨料；fine aggregate细骨料；coarse aggregate粗骨料 (22) reinforced concrete钢筋砼； prestressed concrete预应力砼； asphalt concrete沥青砼； crushed concrete碎石砼； bubble concrete泡沫砼； bulk concrete大体积砼； blown-out concrete充气砼，多孔砼；high-early strength concrete 早强砼；design of concrete mix 砼配合比设计age of con

31、crete 砼龄期They also complement each other in another way: they have almost the same rate of contraction and expansion. (他们也用另一种方式互补，他们的伸缩比几乎相同) They therefore can work together in situations where both compression and tension are factors. (因此当只考虑拉压时他们能在一起工作) Steel rods are embedded in concrete to mak

32、e reinforced concrete in concrete beams or structures where tension will develop. (在砼梁或结构的受拉区砼中埋入钢筋制成钢筋砼) Concrete and steel also form such a strong bond-the force that unites them-that the steel cannot slip within the concrete. (砼和钢形成一个强有力的骨架，钢在砼内不能滑动，因为有力将他们结合在一起) Still another advantage is that s

33、teel does not rust in concrete. (另一个优点是砼对钢不腐蚀) Acid corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid. (因为酸腐蚀钢，而砼具有酸的相反物碱的化学反应)Prestressed concrete is an improved form of reinforcement. (预应力砼是钢筋砼的一种改进形式) Steel rods are bent into the shapes to give them the necessary degree of tensile strength. (在抗拉强度范围内施加一个力，使钢筋弯曲成型) They are then used to prestress concrete, usually by pretensioning or posttensioning method(23). (它们预加应力于砼时，通常采用先张或后张法) Prestressed concrete has made it possible to develop buildings with unusual shapes,(预