土木工程毕业汉英翻译
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1.土木工程土木工程是工程的最多样化的分支机构之一。
土木工程师计划、设计、施工，和维护大量的结构和公共、商业和工业使用的设施。
这些结构包括住宅，办公室和工厂大厦；公路、铁路、机场、隧道、桥梁、港口、渠道和管道。
在其他大多数的国家它们还包括运输系统许多其他设施，以及将为我们的生活带来便利的和维护我们的健康污水及废物处理系统。
直到大约1750年，人们才开始使用“土木工程师”这一术语。
约翰.斯密顿在英格兰普利茅斯附近，建造了著名的埃迪斯通灯塔的建造师，开始自称为“土木工程师"来将自己与当时的军事工程师区分开。
然而，土木工程这个职业却像文明一样古老。
古埃及人用最简单的机械原理和装置建造了许多至今仍矗立的庙宇和金字塔，包括吉萨大金字塔和在卡纳克的Amon-Ra的寺庙。
这个大金字塔，481英尺（146.6 米）高，由2250000个石块组成，石块的平均重量超过1.5吨（1.4 吨）。
建造如此的纪念性建筑使用了大量的人力。
埃及人也作了一些重达1000吨(900吨)的石头的大块切割的方尖塔。
硬青铜的切削刀具在其中使用到了。
为了从采石场向尼罗河运输石材埃及人建造了长堤和道路。
由埃及人竖设的大块石头通过使用拉杆、斜平面、滚子和雪橇来移动。
2.建筑材料早期主要的建筑材料是木材和砌体，如砖、石、瓦以及类似的材料。
砖层之间通过砂浆、沥青（一种焦油状的物质）或其他一些粘合剂粘合在一起。
希腊人和罗马人有时用铁条或夹子来加固他们的房屋。
例如，雅典的帕台农神庙柱子中曾钻孔以便加入铁条，如今都已锈蚀殆尽。
罗马人也用称作白榴火山灰的天然水泥，它用火山灰制作，在水中会变得与石头一样坚硬。
作为现代两种最重要的建筑材料，钢材与水泥在十九世纪得到了推广。
直到那个时候，钢材才通过繁复的过程制造出来，基本上是铁合金，并含有少量的碳，因而被限制在一些特殊的用途如刀刃。
在1856年发明了贝塞麦炼钢法后，钢材才得以大量低价获得。
钢材巨大的优势即是它的抗拉强度，也就是当它在适当的拉力下不会失去强度，正如我们所看到的，该力往往能够将很多材料拉开。
新的合金进一步提高了钢材的强度，并消除了一些缺点，如疲劳，即在连续的应力变化下导致强度减弱的趋势。
现代水泥发明于1824年，称为波特兰水泥。
它是石灰石和粘土的混合物，加热后磨成粉末。
在或靠近施工现场，将水泥与砂、骨料（小石头、压碎的岩石或砾石）、水混合而制成混凝土。
不同比例的配料会制造出不同强度和重量的混凝土。
混凝土的用途很多，可以浇筑、泵送甚至喷射成各种形状。
混凝土具有很大的抗压强度，而钢材具有很大的抗拉强度。
这样，两种材料可以互补。
它们也以另外一种方式互补：它们几乎有相同的收缩率和膨胀率。
因此，它们在拉、压为主要因素时能共同工作。
在出现拉力的混凝土梁或结构中，将钢筋埋入混凝土而成钢筋混凝土。
混凝土与钢筋形成如此强大的结合力——这个力将它们粘合在一起——以致于钢筋在混凝土中不会滑移。
还有另一个优势是钢筋在混凝土中不会锈蚀。
酸能腐蚀钢筋，而混凝土会发生碱性的化学反应，与酸相反。
结构钢与钢筋混凝土的采用使传统的施工作业发生了明显的变化。
对多层建筑，再也没必要采用厚的石墙或砖墙，且施工防火地面变为容易得多。
这些变化有利于降低建筑的成本。
它也使建造高度更高和跨度更大的建筑物成为可能。
由于现代结构的重量由钢或混凝土框架承受，墙体不再支承建筑物。
它们成为幕墙，将日晒风吹雨打阻挡在外，而让光线进入。
在较早的钢或混凝土框架建筑中，幕墙一般由砌体构成；它们具有承重墙的结实外观。
但是今天，幕墙通常由轻质材料组成，如玻璃、铝或塑料，并形成不同的组合。
钢结构中的另一个进步是梁的连接方式。
在很多年里，连接的标准方式是铆接。
铆钉是个有头的螺栓，看上去象个没有螺纹的圆头螺丝钉。
铆钉加热后穿过钢构件之间的孔洞，并通过锤击另一端而形成第二个铆钉头，从而将其固定就位。
如今铆接已大量地被焊接所替代，钢构件间的连接通过在高热下熔化它们之间的钢材料（即焊条）进行。
预应力混凝土是加强法的改进形式。
将钢筋弯成一定的形状以使它们具有必要的抗拉强度，然后用该钢筋对混凝土施加预应力，通常可采用两种不同方法中的任何一种。
第一种方法是在混凝土梁中按钢筋的形状留下孔道，当钢筋穿过孔道后，通过在孔道内灌注薄砂浆（一种稀薄的砂浆或粘合剂）将钢筋与混凝土粘结在一起。
另一种（更常用的）方法是将预应力钢筋置于按成品结构的形状设置的模板的较低部位，然后将混凝土倒入（模板）而包围着钢筋。
预应力混凝土使用了较少的钢筋和混凝土，由于它是如此的经济，因此是一种非常理想的材料。
预应力混凝土使建造独特形状的建筑物成为可能，象一些现代的运动场，它具有不受任何支撑物阻挡视线的大空间。
这种较新的结构方法的使用正在不断地被扩大。
目前的趋势是采用较轻的材料。
例如，铝的重量比钢轻得多，但具有很多相同的性能。
铝材梁已经用于桥梁建筑和一些建筑的框架。
另一个例子是轻质混凝土，如今已在全世界快速地发展，因它们的绝热性而被采用，其三种类型举例说明如下：(a)轻质骨料制成的混凝土；(b)通过浇筑时搅拌或一些化学方法起泡而成的加气混凝土（US加气混凝土）；(c)无细骨料混凝土。
这三种类型的混凝土都是由于它们的绝热性而被使用，主要用于房屋，使其在寒冷的气候中非常舒服，在炎热的气候中降温的成本不高。
在房屋中，墙采用较薄弱的轻质混凝土不重要，但是屋面板、楼面板和梁（采用轻质混凝土）则有重大关系。
3.材料力学材料力学用以研究不同物体（通常称为构件）对施加力的响应。
在工程材料力学中，构件的形状可以是实际结构中存在的，也可以根据其需要而进行考虑（设计），作为拟建工程结构的部件。
构件中材料的性能即是常用的工程材料如钢材、铝材、混凝土和木材的特性。
正如你已经从提到的各种各样的材料、力和形状所看到的，工程材料力学对所有的工程领域都有价值。
工程师利用材料力学的原理来确定是否该材料的性能和构件尺寸足以保证它能安全地承受荷载且没有过多的变形。
通常，我们关心的是构件能承受的安全荷载及其相应的变形。
如果设计者能通过考虑荷载和材料的力学性能，并利用公式得到合适的构件尺寸，那么工程设计将是一个简单的过程。
然而设计很少那么简单。
通常，根据经验，设计者选择一个试算构件，然后进行分析，看它是否满足规定的要求。
它常常不会满足要求，则再选择一个新的试算构件，再进行分析。
这样的设计不断重复，直至得到一个满意的结果。
当设计师拥有一定的经验后，为得到一个可接受的设计所需要的循环次数会减少。
4.结构分析结构由一系列相连的用以支撑荷载的构件组成。
显著的例子包括建筑、桥梁、塔、水箱和大坝等。
建造这些结构中的任何一个的过程需要规划、分析、设计和建造。
结构分析包括各种各样的数学程序以确定诸如当一个结构对荷载有响应时构件的力和不同结构位移的大小。
根据结构的使用和位置来估计它的实际荷载经常是结构分析的一部分。
关于本章结构中所用的材料只作了两点假设。
首先，材料具有线性的应力应变关系。
其次，材料的性能在受拉和受压时没有区别。
研究的框架和桁架是平面结构体系。
假定垂直于平面的方向有足够的支撑，因而构件不会因为弹性失稳而失效。
一个非常重要的关于这种失稳的考虑留待具体的设计过程关于本章结构中所用的材料只作了两点假设。
首先，材料具有线性的应力应变关系。
其次，材料的性能在受拉和受压时没有区别。
研究的框架和桁架是平面结构体系。
假定垂直于平面的方向有足够的支撑，因而构件不会因为弹性失稳而失效。
一个非常重要的关于这种失稳的考虑留待具体的设计过程。
假定所有的结构在它们加荷时只经历小的变形。
因此，我们假定当结构变位时荷载的位置与方向不变。
最后，因为假定了线弹性材料和小位移，叠加原理将适用于所有的情况。
这样当两种不同的力系同时施加时，可以由不同的力系一次施加一个引起的位移或内力几何相加来确定结构的响应。
真正意义上对一个结构准确的分析是永远也不可能进行的，因为总是不得不估计荷载和构成结构的材料的强度。
而且，必须估计荷载的作用点。
因此，结构工程师有能力模拟一个结构或使其理想化很重要，这样，他或她能对构件进行实际的力的分析。
结构构件根据设计者的意图采用不同的方式连在一起。
最常规定的两种节点是铰接节点和固定节点。
铰接节点允许有一些轻微的转动自由，而固定节点不允许相连的构件有相对的转动。
但是，事实上由于摩擦和材料的特性使所有的连接对节点的转动显现出一些刚度。
当为每一个支座或节点选择一个特定的模型时，工程师必须知道该假设将如何影响构件的实际运行，以及该假设是否对结构的设计是合理的。
实际上，所有的结构支座在它们接触的构件上产生分布的面荷载。
1.Civil engineeringCivil engineering is one of the most diverse branches of engineering. The civil engineer plans, designs, constructs, and maintains a large variety of structures and facilities for public, commercial and industrial use. These structures include residential, office, and factory buildings; highways, railways, airports, tunnels, bridges, harbors, channels, and pipelines. They also include many other facilities that are a part of the transportation systems of most countries, as well as sewage and waste disposal systems that add to our convenience and safeguard our health.The term “civil engineer”did not come into use until about 1750, when John Smeaton, the builder of famous Eddystone lighthouse near Plymouth, England, is said to have begun calling himself a “civil engineer” to distinguish himself from the military engineers of his time. However, the profession is as old as civilization.In ancient Egypt the simplest mechanical principles and devices were used to construct many temples and pyramids that are still standing, including the great pyramid at Giza and the temple of Amon-Ra at Karnak. The great pyramid, 481 feet(146.6 meters)high, is made of 2.25 million stone blocks having an average weight of more than 1.5tons (1.4 metric tons). Great numbers of men were used in the construction of such monuments. The Egyptians also made obelisks by cutting huge blocks of stone, some weighing as much as 1000 tons (900 metric tons). Cutting tools of hard bronze were used.The Egyptians built causeways and roads for transporting stone from the quarries to the Nile. The large blocks of stone that were erected by the Egyptians were moved by using levers, inclined planes, rollers, and sledges.2.Construction materialsThe principal construction materials of earlier times were wood and masonry-brick, stone, or tile, and similar materials. The courses or layers were bound together with mortar or bitumen, a tarlike substance, or some other binding agent. The Greeks and Romans sometimes used iron rods or clamps to strengthen their building. The columns of the Parthenon in Athens, for example, have holes drilled in them for iron bars that have now rusted away. The Romans also used a natural cement called pozzolana, made from volcanic ash, that became as hard as stone under water.Both steel and cement, the two most important construction materials of modern times, were introduced in the nineteenth century. 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 After the invention of the Bessemer process in 1856, steel was available in large quantities at low prices. The enormous advantage of steel is its tensile strength; that is, it does not lose its strength when it is under a calculated degree of tension, a force which, as we have seen, tends to ull apart many materials. New alloys have further increased the strength of steel and eliminated some of its problems, such as fatigue, which is a tendency for it to weaken as a result of continual changes in stress.Modern cement, called Portland cement, was invented in 1824. It is a mixture of limestone and clay, which is heated and then ground into a powder. It is mixed at or near the construction site with sand, aggregate (small stones, crushed rock, or gravel), and water to make concrete. Different proportions of the ingredients produce concrete with different strength and weight. Concrete is very versatile; it can be poured, pumped, or even sprayed into all kinds of shapes. And whereas steel has great tensile strength, concrete has great strength under compression. Thus, thetwo substances complement each other.They also complement each other in another way: they have almost the same rate of contraction and expansion. They therefore can work together in situations where both compression and tension are factors. Steel rods are embedded in concrete to make reinforced concrete in concrete beams or structures where tension will develop. Concrete and steel also form such a strong bond - the force that unites them - that the steel cannot slip with the concrete. Still another advantage is that steel does not rust in concrete. Acid corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid.The adoption of structural steel and reinforced concrete caused major changes in traditional construction practices. It was no longer necessary to use thick walls of stone or brick for multistory buildings, and it became much simpler to build fire-resistant floors. Both these changes served to reduce the cost of construction. It also became possible to erect buildings with greater heights and longer spans.Since the weight of modern structures is carried by the steel or concrete frame, the walls do not support the building. They have become curtain walls, which keep out the weather and let in light. In the earlier steel or concrete frame building, the curtain walls were generally made of masonry; they had the solid look of bearing walls. Today, however, curtain walls are often made of lightweight materials such as glass, aluminum, or plastic, in various combinations.Another advance in steel construction is the method of fastening together the beams. For many years the standard method was riveting. A rivet is a bolt with a head that looks like a blunt screw without threads. It is heated, placed in holes through the pieces of steel, and a second head is formed at the other end by hammering it to hold it in place. Riveting has now largely been replaced by welding, the joining together of pieces of steel by melting a steel material between them under high heat.Prestressed concrete is an improved form of reinforcement. Steel rods are bent into the shapes to give them the necessary degree of tensile strength. They are then used to prestress concrete, usually by one of two different methods. The first is to leave channels in a concrete beam that correspond to the shapes of the steel rods. When the rods are run through the channels, they are then bonded to the concrete by filling the channels with grout, a thin mortar or binding agent. In the other (and more common) method, the prestressed steel rods are placed in the lower part of a form that corresponds to the shape of the finished structure, and the concrete is poured around them. Prestressed concrete uses less steel and less concrete. Because it is so economical, it is a highly desirable material.Prestressed concrete has made it possible to develop buildings with unusual shapes, like some of the modern sports arenas, with large space unbroken by any obstructing supports. The uses for this relatively new structural method are constantly being developed.The current tendency is to develop lighter materials, aluminum, for example, weighs much less than steel but has many of the same properties. Aluminum beams have already been used for bridge construction and for the framework of a few buildings.Lightweight concretes, another example, are now rapidly developing throughout the world. They are used for their thermal insulation. The three types are illustrated below: (a) Concretes made with lightweight aggregates; (b) Aerated concretes (US gas concretes) foamed by whisking or by some chemical process during casting; (c) No-fines concretes.All three types are used for their insulating properties, mainly in housing, where they give highcomfort in cold climates and a low cost of cooling in hot climates. In housing, the relative weakness of lightweight concrete walls is unimportant, but it matters in roof slabs, floor slabs and beams.3.Mechanics of MaterialsMechanics of Materials deals with the response of various bodies, usually called members, to applied forces. In Mechanics of Engineering Materials the members have shapes that either exist in actual structures or are being considered for their suitability as parts of proposed engineering structures. The materials in the members have properties that are characteristic of commonly used engineering materials such as steel, aluminum, concrete, and wood.As you can see already from the variety of materials, forces, and shapes mentioned, Mechanics of Engineering Materials is of interest to all fields of engineering. The engineer uses the principles of Mechanics of Materials to determine if the material properties and the dimensions of a member are adequate to ensure that it can carry its loads safely and without excessive distortion. In general, then, we are interested in both the safe load that a member can carry and the associated deformation. Engineering design would be a simple process if the designer could take into consideration the loads and the mechanical properties of the materials, manipulate an equation, and arrive at suitable dimensions.Design is seldom that simple. Usually, on the basis of experience, the designer selects a trial member and then does an analysis to see if that member meets the specified requirements. Frequently, it does not and then a new trial member is selected and the analysis repeated. This design cycle continues until a satisfactory solution is obtained. The number of cycles required to find an acceptable design diminishes as the designer gains experience.4.Structural AnalysisA structure consists of a series of connected parts used to support loads. Notable examples include buildings, bridges, towers, tanks, and dams. The process of creating any of these structures requires planning, analysis, design, and construction. Structural analysis consists of a variety of mathematical procedures for determining such quantities as the member forces and various structural displacements as a structure responds to its loads. Estimating realistic loads for the structure considering its use and location is often a part of structural analysis.Only two assumptions are made regarding the materials used in the structures of this chapter. First, the material has a linear stress-strain relationship Second, there is no difference in the material behavior when stressed in tension vis-a-vis compression. The frames and trusses studied are plane structural systems. It will be assumed that there is adequate bracing perpendicular to the plane so that no member will fail due to an elastic instability. The very important consideration regarding such instability will be left for the specific design course.All structures are assumed to undergo only small deformations as they are loaded. As a consequence we assume no change in the position or direction of a force as a result of structural deflections. Finally, since linear elastic materials and small displacement are assumed, the principle of superposition will apply in all cases. Thus the displacements or internal forces that arise from two different forces systems applied one at a time may be added algebraically to determine the structure’s response when both system(s) are applied simultaneously.In the real sense an exact analysis of a structure can never be carried out since estimatesalways have to be made of the loadings and the strength of the materials composing the structure. Furthermore, points of application for the loadings must also be estimated. It is important, therefore, that the structural engineers develop the ability to model or idealize a structure so that he or she can perform a practical force analysis of the members.Structural members are joined together in various ways depending on the intent of the designer. The two types of joints most often specified are the pin connection and the fixed joint. A pin-connected joint allows some freedom for slight rotation, whereas the fixed joint allows no relative rotation between the connected members. In reality, however, all connections exhibit some stiffness toward joint rotations, owing to friction and material behavior. When selecting a particular model for each support or joint, the engineer must be aware of how the assumptions will affect the actual performance of the member and whether the assumptions are reasonable for the structural design. In reality, all structural supports actually exert distributed surface loads on their contacting members.。
