土木工程专业英语上册_翻译苏小卒_同济大学(考试手机专业版) (1)(DOC)

本课程介绍

在学习普通英语（包括常用词汇和语法结构）的基础上，接合前几个学期已经掌握的关于土木工程的专业知识，本课程节选了《土木工程专业英语》上册中的内容，涉及建筑材料、材料力学、结构力学、钢筋混凝土结构、钢结构、测量、土力学、招投标、建筑施工等九个方面的专业英语知识，从而使大家对土木工程领域内的专业词汇以及科技类文献中的常用句型有个初步的、基本的学习和了解，为以后查阅专业文献和参与国际交流打好基础。

第三单元

The principal construction materials of earlier times were wood and masonry-brick, stone, or tile, and similar materials. The courses or layers（砖层）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（雅典的帕台农神庙）, for example, have holes drilled（钻孔）in them for iron bars that have now rusted away（锈蚀殆尽）. The Romans also used a natural cement called pozzolana, made from volcanic ash, that became as hard as stone under water.

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。

Both steel and cement, the two most important construction materials of modern times, were introduced（推广）in the nineteenth century. Steel, basically an alloy of iron （铁合金）and a small amount of carbon, had been made up to that time（到那个时候）by a laborious（繁复的）process that restricted it to such special uses as sword blades（刀刃）. After the invention of the Bessemer process （贝塞麦炼钢法）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 (适当的) of tension, a force which, as we have seen, tends to （往往）pull 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（连续的应力变化）.

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。

Modern cement, called Portland cement, was invented in 1824. It is a mixture of limestone（石灰石）and clay, which is heated and then ground into a powder（磨成粉末）. It is mixed at or near the construction site （施工现场）with sand, aggregate (small stones, crushed rock, or gravel), and water to make concrete. Different proportions of the ingredients （配料）produce concrete with different strength and weight. Concrete is very versatile; it can be poured, pumped, or even

sprayed into （喷射成）all kinds of shapes. And whereas steel has great tensile strength, concrete has great strength under compression. Thus, the two substances complement each other（互补）.

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。

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（在…情况下）both compression and tension are factors（主要因素）. Steel rods（钢筋）are embedded in（埋入）concrete to make reinforced concrete in concrete beams or structures where tension will develop （出现）. Concrete and steel also form such a strong bond - the force that unites（粘合）them - that the steel cannot slip（滑移）with the concrete. Still（还有）another advantage is that steel does not rust in concrete. Acid（酸）corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid.

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。

The adoption of structural steel and reinforced concrete caused major changes in traditional construction practices（施工作业）. 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（防火地面）. Both these changes served to（有利于）reduce the cost of construction. It also became possible to erect（建造）buildings with greater heights and longer spans.

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。

Since the weight of modern structures is carried（承受）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（承重墙）. Today, however, curtain walls are often made of lightweight materials such as glass, aluminum, or plastic, in various combinations.

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。

Another advance in steel construction（结构）is the method of fastening together（连在一起）the beams. For many years the standard method was riveting. A rivet is a bolt with a head that looks like a blunt screw（圆头螺丝钉）without threads（螺纹）. It is heated, placed in holes through the pieces of steel（钢构件）, and a second head is formed at the other end by hammering（锤击）it to hold it in place（固定就位）. Riveting has now largely been replaced by welding, the joining together of pieces of steel by melting（熔化）a steel material between them under high heat.

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。

Prestressed concrete is an improved form of reinforcement（加强方法）. Steel rods are bent into the shapes to give them the necessary degree of tensile strength. They are then used to prestress （对..预加应力）concrete, usually by one of two different methods. The first is to leave channels in a concrete beam that correspond to（相应于）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（模板）that corresponds to the shape of the finished structure（成品结构）, 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（非常理想）material.

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。

Prestressed concrete has made it possible to develop（建造）buildings with unusual shapes, like some of the modern sports arenas, with large space unbroken by any obstructing supports（阻碍的支撑物）. The uses for this relatively new structural method are constantly being developed（不断地扩大）.

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。

The current tendency is to develop（采用）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.

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。

Lightweight concretes, another example, are now rapidly developing（发展）throughout the world. They are used for their thermal insulation(绝热性). The three types are illustrated below（举例说明如下）: (a) Concretes made with lightweight aggregates; (b) Aerated concretes (US gas concretes) foamed（起泡）by whisking（搅拌）or by some chemical process during casting; (c) No-fines concretes.

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。

All three types are used for their insulating properties（绝热性）, mainly in housing, where they give high（非常）comfort in cold climates and a low cost of cooling（降温成本）in hot climates. In housing, the relative weakness of lightweight concrete walls is unimportant, but it matters（有重大关系）in roof slabs, floor slabs and beams.

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。

In some locations, some lightweight aggregates cost little more than（几乎等于）the best dense （致密）aggregates and a large number of （大量）floor slabs have therefore been built of lightweight aggregate concrete purely for its weight saving, with no thought of（没考虑）its insulation value.

在某些地区，一些轻质骨料的费用几乎等于最致密的骨料，因此大量的楼面板采用轻骨料混凝土制作纯粹是节约重量，而没考虑它的绝热价值。

The lightweight aggregate reduces the floor dead load（恒载）by about 20 per cent resulting in （导致）considerable savings in the floor（楼盖结构）steel in every floor and the roof, as well as in the column steel and (less) in the foundations. One London contractor（承包商）prefers to use lightweight aggregate because it gives him the same weight reduction in the floor slab as the use of hollow tiles, with simpler organization and therefore higher speed and profit. The insulation value of the lightweight aggregate is only important in the roof insulation, which is greatly improved（改进）.

轻质骨料使楼面的恒载减少了约20%，因而大量的节约了每层楼面以及屋面的楼盖结构中的钢材和柱子与基础中（较少）的钢材使用量。一位伦敦的承包商宁愿使用轻质骨料，因为这使楼面板上减少的重量与用空心砖相同，且组织更简单，因而速度和利润更高。轻质骨料的绝热价值只在屋面绝热时显得重要，它已被大大地改进了。

作业练习

通过两篇Reading Materials 的学习，进一步了解建筑材料中最常用的混凝土材料的一些特点、种类和性能等，从而更多地掌握一些专业词汇和句法。

教学目标

了解构件（主要为梁）的设计过程

了解单轴应力与多轴应力对失效理论的影响

熟悉材料力学中涉及的专业词汇

熟悉科技类文献常用句型

熟悉in general、usually、frequently的不同含义与be referred to as、be known as、that is、be defined as、in other words 等的用法

Introduction 介绍

Mechanics of Materials deals with（研究）the response of various bodies, usually called members （构件）, to applied forces（施加力）. In Mechanics of Engineering Materials the members have shapes that either exist in actual structures or are being considered for their suitability（根据其需要）as parts of proposed（拟建的）engineering structures. The materials in the members have properties that are characteristic of commonly used（常用的）engineering materials such as steel, aluminum, concrete, and wood.

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。

As you can see already from the variety of materials, forces, and shapes mentioned, Mechanics of Engineering Materials is of interest to（对..有价值）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（足以）ensure that it can carry its loads safely and without excessive distortion. In general（通常）, then, we are interested in both the safe load that a member can carry and the associated（相关的）deformation. Engineering design would be a simple process if the designer could take into consideration（考虑）the loads and the mechanical properties of the materials, manipulate（利用）an equation, and arrive at（得到）suitable dimensions.

Design is seldom that simple. Usually（通常）, on the basis of（根据）experience, the designer selects a trial（试算）member and then does an analysis to see if that member meets the specified requirements. Frequently（常常）, it does not and then a new trial member is selected and the analysis repeated. This design cycle（设计周期）continues until a satisfactory solution is obtained. The number of cycles（循环次数）required to find an acceptable design diminishes as the designer gains experience.

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。

Design of Axially Loaded Members 轴向力构件的设计

To give you some insight into （使..有一些了解）the design cycle, an extremely simple member will be dealt with first. That member is a prismatic bar with a force, P, acting along its longitudinal axis in the direction（纵轴向）such that it tends to elongate the bar. Such a force is referred to as（称为）an axial tensile load（轴向拉力）, and we can readily imagine it trying to（努力..）pull the fibers apart and to cause failure on a transverse plane（横向平面）. It is safe to assume that all fibers of the bar, in regions remote from（远离）the point of application of the load, are being pulled apart with the same load intensity（荷载强度）. With this assumption, the load intensity or stress is uniform on a transverse plane and is given by

when P is in（以..为单位）Newtons and A is in square metres, stress, ,is in Newtons per square metre (N/m2), which is by definition（根据定义）Pascals (Pa).

为了使你对设计周期有一些了解，首先研究一个非常简单的构件。构件是个棱形的杆件，其上沿着它的纵轴向作用一个力P，这样往往使杆件在该方向上伸长。这样的力称为轴向拉力，我们能容易地想象它在努力地将纤维拉开，导致横向平面的破坏。安全地假定杆件的所有纤维在远离荷载施加点的区域以相同的荷载强度被拉开。在此假定下，荷载强度或应力在横向平面上是均匀的，为

当P的单位为牛顿、A的单位为平方米时，应力σ的单位为牛顿每平方米（N/m2），根据定义为帕斯卡（Pa）。

For a given axial load and given dimensions, the stress can be calculated from (4-1) and compared with（与..相比）the stress that can be safely carried by the material. The safe stress, known as（称为）the design stress or allowable stress（许用应力）, is determined by tests performed on material made to（按照）the same specifications as the part being considered. A safety factor（安全系数）,

frequently imposed by a legally established code（法规）, is applied to the strength, as determined by tests, to give the allowable stress. The allowable stress, a , is given by

where f is the stress at which the material fails (failure to be defined later) and n is the safety factor.

对已知的轴向力和（构件）尺寸，可根据公式（4-1）计算出应力，并与材料能安全承受的应力作比较。安全应力，称为设计应力或许用应力，它是通过对材料的试验来确定的，该（试验）材料按照与所考虑（验算）的杆件相同的规范制作。根据法规规定，通常对试验所确定的强度考虑安全系数后得到许用应力。许用应力 a 为

这里， f 为材料失效（失效在下文有定义）时的应力，而n为安全系数。

Before approving（核准）trial dimensions, the designer makes certain（确信）that the design is safe by determining that the inequality（不等式）

is satisfied. The inequality is usually more convenient in the form

不等式常常以更合适的形式出现，即

在核准试算的尺寸之前，设计者通过确定不等式成立而确信设计的安全，即

It might at first（起先）seem that the designer would always dimension（选定..的尺寸）the cross section（横截面）so that the stress would exactly equal the allowable stress. However, it may be very costly to produce parts that have nonstandard sizes, so it is usually more economical to waste some material by selecting the next（接近的）larger standard size above that required by the allowable stress. Departure from（背离）standard sizes is justified（合理的）in cases where the penalty（不利后果）for excess weight is very severe, as in aircraft（航天器）or space-ship（宇宙飞船）design.

起先似乎设计者总是在选定横截面的尺寸，以使应力恰好等于许用应力。但是，生产非标准尺寸部件的成本可能很高，因此，通常人们会选择比按许用应力要求的尺寸大一些的标准尺寸部件，这样尽管浪费了一些材料，但总体上更经济。但不选择标准尺寸的做法在诸如航天器和宇宙飞船的设计中证明是合理的，因为多余重量产生的不利后果是很严重的。Design of Beams 梁的设计

Up to this point（至此）we have looked at（考虑）the beam problem as a problem in analysis; that is（即）, for a given set of loads, span, and cross section we have been calculating the stress. The more commonly encountered problem is to select a standard section, or design a member, for a given span and loads without exceeding a certain allowable stress. Under some conditions the allowable stress may be dependent upon the dimensions and shape of the cross section, in which case the selection of the member becomes more difficult. For the present（暂时）we will take the allowable stress as though（似乎）it depends only on the strength of the material and the safety factor.

至此，我们已经考虑了梁的问题而进行了（问题）分析，即对给定的一组荷载、跨度和横截面，我们已经计算了应力。更常遇到的问题是在不超过某个许用应力下对一个给定的跨度和荷载选择一个（构件的）标准截面，或设计一个构件。在某些条件下，许用应力可能依赖于横截面的尺寸和形状，这种情况下的构件选择会变得比较困难。暂时我们将采用许用应力法，似乎它只取决于材料的强度和安全系数。

A trial member will be acceptable（合格）when the stress is equal to, or less than, the allowable stress, that is, if

For design purposes this inequality is more useful in the form

In the usual design process the maximum bending moment is taken from（取自于）the bending moment diagram（弯矩图）and the allowable stress is determined (quite frequently in accordance

with（根据）the rules of some legally constituted code) from standard strength tests in combination with（与..结合）a safety factor. The right-hand side of (4-6) is then known, and it remains（仍然是）to select or design a member that will satisfy the inequality. When a standard section is to be used, the tables（表格）could be searched until a member is found such that the combination of I and c satisfies (4-6). This takes more time than is really necessary, since the tables also provide the value of I/c for each member under the heading（标题）S, the section modulus（截面模量）.

当试算构件的应力等于或小于许用应力时，也就是说，如果

在通常的设计过程中，最大的弯距从弯距图上取得，而许用应力通过标准强度试验并考虑安全系数后确定（往往是根据一些法规的规则）。这样，已知式（4-6）右手边的值，则仍然是选择或设计构件以满足该不等式。当使用标准截面时可以查找表格，直至找到的构件其I和c值的组合能满足式（4-6）。这样花费的时间比实际需要的多，因为表格中在截面模量S的标题下也提供了每一个构件的I/c的值。

试算构件即为合格。根据设计的需要，（上述）不等式以下列形式出现更有用，即

That is, the section modulus is defined as（定义为）

To select a member, the S column（列）is consulted（查阅）and any member that satisfies (4-8) could be used. The members with very high values of S will obviously be understressed（应力不足的）and wasteful of material. The best design, if there are no other constraints, will be that which satisfies (4-8) with the minimum amount of material.

With tabulated values of S available it is much more convenient to use (4-6) in the form

The smallest acceptable S does not necessarily coincide with（符合）the most economical member. To select the lightest and most economical standard section, the listed values of mass should be examined to find the lightest member with an acceptable S. The problem becomes much more complex if built-up（组合）member is being designed because its cost will depend upon the combined costs of web plate, angles and cover plates as well as fabrication（装配）costs so that the lightest member is not necessarily the most economical.

截面模量定义为

为选择构件而查阅S这一列，则任何满足式（4-8）的构件都可采用。显而易见，对S值很高的构件，其应力是不足的，并浪费了材料。如果没有其他的限制，最好的设计将是以最少的材料满足式（4-8）。能接受的最小的S值不必是最经济的构件。为了选择最轻和最经济的标准截面，应检查列出的质量值，以找到能接受的S值下的最轻构件。如果在设计一个组合构件时，则问题变得复杂得多，因为它的费用将依赖于腹板、角钢和盖板的费用以及装配的费用，因此，最轻的构件未必是最经济的构件。

根据表格中得到的值S，将式（4-6）以下列形式使用要方便得多，即

Deflections Due to Bending 弯曲挠度

The main purpose of this chapter（本节）was to develop（提出）the flexure（屈曲）formulas, and to provide some experience in applying them. Statically indeterminate（超静定）cases were encountered and some insight（认识）gained as to（就..）the difficulty and importance of this category of problem.

本节的主要目的是提出屈曲公式，并在运用公式时提供一些经验。当遇到超静定的情况时，就此类问题的难点和重点获得一些认识。

Superposition（叠加法）was presented（提出）as the preferred（优先的）method for solving certain problems. However, becoming familiar with（熟悉）superposition was more important than finding solutions to the problems（问题的答案）because superposition has application in many areas of stress analysis and will be used frequently in our future studies.

为解决某些问题，叠加法作为优先的方法被提出。但是，熟悉叠加法远比找到问题的答案重要，因为叠加法已经用于应力分析的很多领域，而且，在我们今后的研究中还会经常使用。

Moment-area（弯距图面积法）was found to be a convenient method for solving various problems. It is a method that becomes quite complicated and requires further development（展开）when more advanced structures are encountered. At the present stage it is sufficient for you to be acquainted with（了解）the fundamentals（基本原理）of the method. Deflection of long-radius （长半径）curved beams was introduced（引入）to illustrate the power of the principles underlying（构成..的基础）the moment-area method and so that you would appreciate（知道）the differences between straight and curved beams.

为解决不同的问题，发现弯距图面积法是一种很便利的方法。但当遇到更先进的结构时，此法会变得非常复杂，需要进一步地展开。对你来说在目前阶段了解此法的基本原理已经足够了。引入长半径曲梁的挠度来举例说明构成弯距图面积法基础的原理的功效，使你能知道直梁与曲梁之间的区别。

This chapter afforded an opportunity to become familiar with singularity functions （奇异函数）, and you have seen that certain problems can be greatly simplified by their use. It must be appreciated（意识到）that merely an introduction to the topic has been given; there is much more to learned by those who have a special interest. To illustrate a serious limitation（缺陷）at our present stage, we can express distributed loads （分布荷载）that are variable and are intermittent, but we cannot write a load function for concentrated loads. If we had taken the next step and dealt with the concentrated load, we would have encountered the source of the expression（表达式）“singularity function”, but having regard for（考虑）the scope of this book we have stopped short of（达不到）that step.

本节使你熟悉了奇异函数，并发现通过利用它们能大大地简化某些问题。但必须意识到仅仅是介绍了题目，对那些有特殊兴趣的人还有很多要学。我们可以表示变化的、间断的分布荷载，但不能写出集中荷载的荷载函数，说明了在我们目前阶段（该函数）还存在着严重的缺陷。如果我们进入下一步去研究集中荷载，便会遇到奇异函数表达式的来源，但是考虑到本书的范围，我们不再进入那一步。

Failure Theories 失效理论

In the design of a member subjected to a uniaxial（单轴的）load, the stress was compared with the stress to cause failure in test specimens（试件）that had also been subjected to uniaxial load. This is the simplest of all design problems; the method is quite adequate（合适的）, since the nature（性能）of the loads and the stresses in the test and in the part being designed are identical. However, we soon encounter cases where the member being designed is not so simple and the stresses are not uniaxial; consider, for example, the stresses in the web of a beam or in a pressure vessel（压力容器）. In these cases we know that the stress is two-dimensional（两向的）or biaxial and it may, in other cases, be three-dimensional, or triaxial.

For a structure having biaxial or triaxial stresses, how should we check the safety of the design? The most obvious way would be to conduct tests（进行）in which specimens are stressed（受力）to failure in the same multiaxial（多轴的）manner as in the structure; the allowable multiaxial stress then be determined by the application of an adequate safety factor. However, this would require a group of tests for every new set of multiaxial stresses that occurred in design. Such tests are difficult to perform, and the cost of performing them in the required numbers would be prohibitive. Consequently, we need a theory by which the results of the standard uniaxial test can

be used to predict（预测）the failure of a part made of the same material when the stresses are multiaxial. In other words（换句话说）, we need a failure theory.

在设计承受轴向力的构件时，将其应力与导致同样承受轴向力的试验样本（试件）失效的应力相比。这是所有设计问题中最简单的；该法是非常合适的，因为试验和设计中的荷载和应力性质是完全相同的。但是，不久我们便会遇到正在设计的构件不是那么简单，其应力也不是单轴向的；例如，考虑梁的腹板应力或压力容器中的应力。在这些情况下，我们知道其应力是两向的或两轴的，而在其他情况下可能是三向或三轴的。对一个有着两轴或三轴应力的结构，我们应该如何检查它的设计安全性？最显然的办法是进行试验，即试件以与结构相同的多轴受力方式失效；然后运用适当的安全系数确定许用的多轴应力。但是，对设计中出现的每组新的多轴应力都将需要一组试验。这样的试验很难进行，而且以需要的数量进行试验的费用也是禁止的。因此，我们需要一个理论，根据它可以通过利用标准单轴试验的结果来预测同样材料制作的构件在承受多轴应力时的失效。换句话说，我们需要一个失效理论。To illustrate the need for a failure theory, let us consider a cylindrical pressure vessel. To avoid unnecessary complications, we will consider that all welds（焊缝）are 100% efficient and that the walls（容器壁）are thin. Under internal pressure the main stresses（主应力）are circumferential and longitudinal, and it was implied（认为）in an earlier case that only the circumferential stress, because it is larger than the longitudinal stress, needs to be considered in judging the adequacy of the design. In this approach we tacitly（默认）assumed that the maximum stress could be treated as （看作为）a uniaxial stress and that it alone determined the safety of the design. The longitudinal stress was not considered although it may, without our knowledge（在我们的知识之外）, have had an influence on strength. It happens that our approach in this case is acceptable, but, in a biaxial state of stress, the second stress is not always inconsequential（不重要）and an understanding of failure theory is necessary in order to avoid making some serious errors.

为了举例说明需要一个失效理论，让我们考虑一个圆柱形的压力容器。为避免不必要的复杂，我们认为焊缝完全有效，容器壁是薄的。在内部压力下，主应力是环向和纵向的，由于环向应力比纵向应力大，因此，在一个较早的例子中认为只有环向应力需要在判断设计的适用性时加以考虑。在这个方法中，我们默认地假定最大的应力（即环向应力）可看作为单轴应力，并由它单独地确定设计的安全性。尽管在我们的知识以外，纵向应力可能会对强度有影响，但不被考虑。正巧，在这种情况下我们的方法能被接受，但是，在两轴应力状态下，第二种应力不总是不重要的，为了避免造成一些严重的错误，对失效理论的理解是必要的。Unfortunately, as we will discover, no single theory（单一理论）will be found to apply in all cases; for example, theories that are satisfactory for ductile materials are not acceptable for brittle materials. We will also find that one of the best theories is too complex for everyday use and that most designers prefer（更喜欢）a simpler theory that introduces（产生）a small but safeside（安全的）error.

很不幸，正如我们将发现的，没有找到一个单一的理论能运用于所有的状况，例如，满足延性材料的理论，脆性材料不能接受。我们也将发现每天在使用一个最好的理论太复杂了，多数设计者更喜欢用一个会产生小而安全的错误但较简单的理论。

In developing（提出）the various failure theories, we cannot avoid three-dimensional effects, but we will treat（讨论）only those cases in which one of the stresses is zero, thus avoiding complications that would tend to obscure（使..模糊不清）the important part of the theories. This is not a serious limitation, since in engineering practice（工程实践）most problems are reduced to （简化为）the biaxial stress state for design. When shear stresses（剪应力）occur along with（与..一起）normal stresses（正应力）, the principal stresses（主应力）are determined. Thus, for practical

（实用的）purposes, we need to consider failure in a material subjected to two nonzero（非零）normal stresses while the third normal stress is zero. For ease in（为了便于..）designating （称呼）those principal stresses we will use numerical subscripts（数字下标）; 1 and 2 b e ing the nonzero stresses and 3 being zero.

在提出不同的失效理论时，我们不能避免三向的影响，但我们将只讨论其中某一个应力为零的情况，因而避免了复杂性，因它往往使理论的重要部分模糊不清。这不是个严重的缺陷，因为在工程实践中，多数问题在设计时被简化为两轴应力状态。当剪应力与正应力一起存在时，主应力便被确定。这样，为了实用的目的，我们需要考虑承受两个非零正应力而第三个正应力为零的材料的失效。为了便于称呼那些主应力，我们采用数字下标： 1和 2作为非零应力，而 3为零。

We cannot discuss failure theory until we have defined failure. We might take the obvious definition that a material has failed when it has broken into（分为）two or more parts. However, it has already been pointed out that in most applications a member would be unserviceable（不再适用）due to excessive distortion long before（早在）it actually ruptured（断裂）. Consequently, we will relate failure to yielding and consider that a material has failed when it will no longer return to（恢复）its original（最初的）shape upon（一旦）release of the loads. In a simple tensile test （拉伸试验）we would then say that a ductile material has failed when the material begins to yield. Then for uniaxial stress, failure occurs when the stress reaches the yield stress, y , in either tension or compression.

在我们定义了失效后才能对其进行讨论。我们可能会下一个明显的定义，即当材料分成两部分或更多时失效。但是，在多数应用中已经被指出，一个构件早在它实际断裂之前由于过分的变形而不再适用。因此，我们将失效与屈服联系起来，并认为一旦荷载解除而材料不再恢复到其最初的形状时即为失效。在一个简单的拉伸试验中，我们可以说当延性材料开始屈服时即已失效。对单轴应力而言，当应力达到屈服应力 y（不管拉或压）时即为失效。Brittle materials fail by a different mechanism and will be discussed after the theories for ductile materials have been presented（介绍）.

脆性材料由于不同的机理而失效，这将在介绍延性材料的理论之后进行讨论。作业练习

通过一篇Reading Material 的学习，进一步了解材料力学的发展史、安全系数的求解、纯弯梁的应变分析、超静定梁的分析等。

Unit 5 第五单元

Structural Analysis 结构分析

教学目标

了解结构分析的假定和几种方法

了解结构分析中运用的几个定理

熟悉结构力学中的专业词汇

熟悉科技类文献中的常用句型

熟悉as a consequence、as a result、for these reasons、therefore 以及as a consequence of、as a

result of 的含义；state 的不同用法；relate to、relate….to、be related to 的区别；be equal to、be equated to、equal 的用法；with respect to、regarding、considering、as to 的用法

A structure consists of（由..组成）a series of connected parts used to support loads. Notable（显著的）examples include buildings, bridges, towers, tanks, and dams. The process（过程）of creating any of these structures requires planning（规划）, analysis, design, and construction（施工）. Structural analysis consists of （包括）a variety of mathematical procedures（数学程序）for determining such quantities as the member forces and various structural displacements（位移）as a structure responds to its loads. Estimating realistic loads for the structure considering（根据）its use and location is often a part of structural analysis.

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。

Only two assumptions are made regarding（关于）the materials used in the structures of this chapter. First, the material has a linear stress-strain relationship（线性的应力-应变关系）. Second, there is no difference in the material behavior when stressed in tension vis-a-vis（与..相比）compression. The frames and trusses studied are plane structural systems（平面结构体系）. It will be assumed that there is adequate bracing perpendicular to（垂直于）the plane so that no member will fail due to an elastic instability（弹性失稳）. The very important consideration regarding such instability will be left for the specific（具体的）design course.

All structures are assumed to undergo only small deformations as they are loaded. As a consequence（因此）we assume no change in the position or direction of a force as a result of （由于）structural deflections（变位）. 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（一次一个）may be added algebraically（几何相加）to determine the struct ure’s response when both system(s) are applied simultaneously.

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。

In the real sense（真正意义上）an exact analysis of a structure can never be carried out since estimates always have to be made of the loadings and the strength of the materials composing（构成）the structure. Furthermore, points of application（作用点）for the loadings must also be estimated. It is important, therefore, that the structural engineers develop（形成）the ability to model（模拟）or idealize（使..理想化）a structure so that he or she can perform a practical force analysis of the members.

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。

Structural members are joined together in various ways depending on the intent（意图）of the designer. The two types of joints most often specified（规定的）are the pin connection and the fixed joint（节点）. A pin-connected joint allows some freedom for slight（轻微）rotation, whereas the fixed joint allows no relative rotation between the connected members. In reality, however, all connections exhibit（显现）some stiffness toward joint rotations, owing to friction（摩擦）and material behavior. When selecting a particular model for each support（支座）or joint, the engineer must be aware of how the assumptions will affect the actual performance（运行）of the member and whether the assumptions are reasonable for the structural design. In reality, all structural supports actually exert（产生）distributed surface loads（面荷载）on their contacting members. The resultants（合力）of these load distributions are often idealized as the concentrated forces（集中力）and moments, since the surface area （表面积）over which the distributed load acts is considerably smaller than the total surface area of the connecting members. The ability to reduce an actual structure to（将..简化为）an idealized form can only be gained by experience. In engineering practice, if it becomes doubtful（不明确）as to how to model a structure or transfer the loads to the members, it is best to consider several idealized structures and loadings and then design the actual structure so that it can resist（抵抗）the loadings in all the idealized models.

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。这些荷载分布的合力常常理想化为集中力和弯矩，因为分布荷载作用的表面面积比相连的构件的总的表面面积小很多。将一个实际的结构简化成一种理想的形式的能力只有通过经验才能获得。在工程实践中，如果就怎样模拟一个结构或将荷载传递给构件变得难以确定时，最好考虑几个理想的结构和荷载，然后设计实际的结构，使它在所有理想的模型中都能抵抗荷载。

It may be recalled（回想）from statics that a structure or one of its members is in equilibrium（处于平衡）when it maintains a balance of force and moment. When all the forces in a structure can be determined strictly from these equations, the structure is referred to as statically determinate（静定的）. Structures having more unknown forces than available equilibrium equations（平衡方程）are called statically indeterminate. As a general rule, a structure can be identified as（确定）being either statically determinate or statically indeterminate by drawing free-body diagrams（隔离体图）of all its members, or selective parts of its members, and then comparing the total number of unknown reactive force and moment components（分量）with the total number of available equilibrium equations.

从静力学可以回想起当一个结构或它的一个构件维持力和弯矩的平衡时即处于平衡状态。当一个结构中所有的力能严格地根据这些方程式来确定，该结构称为静定的。如果结构上未知的力比能得到的平衡方程多时称为超静定结构。作为一般的规律，一个结构可以通过画出所有构件或经选择的部分构件的隔离体图，然后比较未知的反力和弯矩的分量总数目与可用的平衡方程总数目是否相等来确定其是静定结构还是超静定结构。

In particular, if a structure is statically indeterminate, the additional equations（附加方程）needed to solve for（求解）the unknown reactions（反力）are obtained by relating the applied loads and reactions to the displacement or slope（转角）at different points on the structure. These equations, which are referred to as compatibility equations（相容性方程或协调方程）, must be equal in

number to the degree of indeterminacy（不确定次数）of the structure. Compatibility equations involve（涉及）the geometric and physical properties of the structure.

特别地，如果一个结构是超静定的，可以通过建立作用力和反力与结构不同点上的位移或转角的关系来得到用以求解未知反力所需的附加方程。这些称为相容性方程的方程式在数量上必须等于结构的不确定次数。相容性方程涉及结构的几何和物理性能。There are two fundamental methods of analysis for trusses: the method of joints and the method of sections. Both start with（从..着手）a free-body diagram of the truss as a whole（基本上）, from which the equilibrium equations are written and solved for the support reactions（支座反力）.

有两种分析桁架的基本方法：节点法和截面法。两种方法基本上都从桁架的隔离体图着手，根据它可以写出平衡方程并求解支座反力。

The method of joints: After the support reactions have been found, a joint is selected that has no more than（不超过）two members connecting for which the axial forces are unknown. The free-body diagram of that joint is drawn, the forces are summed（合计）in two directions, and each sum is equated to（等于）zero. When drawing the free-body diagram, it is a good idea to assume that the unknown forces are tensions and to show（表示）them so on the free-body diagram by their exerting a pull on（对..施加拉力）the joint. When this is assumed, the resulting sign（符号）of the unknowns when evaluated（计算）will match（符合）the conventional（习惯的）+ for tension and –for compression. Once a joint has been analyzed, its members become knowns, and adjacent joints（相邻节点）, which might have had three or more unknowns, can then be solved since some of these unknowns have become knowns. This process（过程）continues from joint to joint, each time selecting a joint whose number of unknown members does not exceed 2.

节点法：求出支座反力后，选择一个节点其上连接着轴向力未知的构件不超过两根。画出节点的隔离体图，将力在两个方向上进行合计，每个方向（力）的合计等于零。当画出隔离体图时，有个好主意是假定未知力是拉力，并在隔离体图上通过对该节点施加一个拉力来表示。这样假定后，未知力计算结果的符号将与习惯的正为拉力负为压力相符。一旦一个节点已经被分析，其上的构件成为已知构件，相邻的节点可能曾经有三个或更多的未知力，但因为其中的一些已经成为已知，因此也能求出。这个过程从一个节点到另一个节点连续进行，每次选择的节点其上未知构件（力）的数量不超过两根。

Almost all truss systems are configured（装配）so that analysis using the method of joints must begin at one end and proceed（继续）joint by joint toward the other end. If it is necessary to evaluate the forces carried by a member located（位于）some distance from the ends, the method of joints requires the calculation of the forces in many members before the desired one is reached. The method of sections provides a means（方法）for a direct calculation in these cases. After the support reactions have been calculated the truss is cut through（切开）(analytically分析上) so that one part of the truss is completely severed from the rest. When this is done, no more than three unknown members should be cut. If possible（如果可能）the cut（切口）should pass through the member or members whose internal forces are to be found. A free-body diagram of the part of the truss on one side of（在..一边）this section is drawn, and the internal forces are found through the equilibrium equations. Since the system of forces（力系）on the free-body diagram is a plane non-concurrent（非共点）force system, three equilibrium equations may be written and solved for the three unknowns.

几乎所有的桁架体系是装配的，因此采用节点法进行的分析必须从一个端点开始，并一个节点连着一个节点地朝另一个端点继续进行。如果有必要计算位于端部一定距离的构件上的力，节点法需要在到达这根要求（计算）的构件之前计算很多构件中的力。在这些情况下截

面法提供了一个直接计算的方法。当求出支座反力后，桁架（在分析上）被切开，从而一部分桁架同其余部分完全分离。当这样切开时，应该切出不超过三个构件的力是未知的。如果可能，切口应穿过将要求解内力的构件。画出在截面一边的桁架部分的隔离体图，并通过平衡方程式求解内力。由于隔离体图上的力系是平面非共点的，因而可以写出三个平衡方程式并求出三个未知力。

Influence lines（影响线）have important application for（应用）the design of structures that resist large live loads（活荷载）. An influence line represents（代表）the variation of either the reaction, shear, moment, or deflection at a specific （特定的）point in a member as concentrated force moves over the member. Once this line is constructed（作图）, one can tell at a glance（一眼便知）where a live load should be placed on the structure so that it creates（引起）the greatest influence at the specified point. Furthermore, the magnitude（大小）of the associated （相关的）reaction, shear, moment, or deflection at the point can then be calculated from the ordinates（纵坐标）of the influence-line diagram.

For these reasons（因此）, influence lines play an important part in the design of bridges, industrial crane rails（吊车轨道）, conveyors, and other structures where loads move across their span（全长）. Although the procedure（步骤）for constructing an influence line is rather basic（基本的）, one should clearly be aware of the difference between constructing an influence line and constructing a shear or moment diagram. Influence lines represent the effect of a moving load only at a specified point on a member, whereas shear and moment diagrams represent the effect of fixed loads at all points along the axis of the member.

影响线在设计抵抗大量活荷载的结构时有着重要的应用。一根影响线代表着当集中力在构件上移动时构件上一个特定点的反力、剪力、弯矩或挠度的变化。一旦画出这根线，任何人一眼便知活荷载应该置于结构的哪个位置才能对这个特定的点引起最大的影响。而且，这点上相关的反力、剪力、弯矩或挠度可从影响线图的纵坐标上计算出来。因此，影响线在桥梁、工业吊车轨道、输送机和其它有荷载在整个结构长度上移动的结构设计中扮演着重要的角色。虽然画出一条影响线的步骤是相当基本的，但任何人应该清楚地意识到画一条影响线与画一条剪力或弯矩图的区别。影响线只代表着移动荷载对构件上特定点的影响，而剪力和弯矩图代表固定荷载对沿着构件轴线的所有点的影响。

Deflections of structures can occur from various sources（原因）, such as loads, temperature, fabrication errors, or settlement. In design, deflections must be limited in order to prevent cracking of attached（附属的）brittle materials such as concrete or plaster (石膏) . Furthermore, a structure must not vibrate or deflect（变位）severely in order to “appear”safe for its occupants（居住者）. More important, though（然而）, deflections at specified points in a structure must be computed if one is to analyze statically indeterminate structures. We often determine the elastic deflections of a structure using both geometrical and energy methods. Also, the methods of double integration（双重积分）are used. The geometrical methods include the moment-area theorems（弯矩图面积定理）and the conjugate-beam method（共轭梁法）, and the energy methods to be considered are based on virtual work（虚功）and Castigliano’s theorem（卡氏最小功定理）. Each of these methods has particular advantages or disadvantages.

结构的挠度可以因不同的原因而发生，如荷载、温度、制造错误或沉降。设计中，挠度必须加以限制以阻止附属的脆性材料如混凝土或石膏的开裂。而且，为了向居住者显示安全性，结构不能严重地振动或变位。而更重要的是如果有人要分析超静定结构，必须计算出结构中规定点的挠度。我们通常采用几何法和能量法来确定结构的弹性挠度。也采用双重积分法。几何法包括弯矩图面积定理和共轭梁法，而考虑的能量法是基于虚功定理和卡式最小功定

理。每一种方法都有其特别的优缺点。

We can determine the equation of the elastic curve by integration of equation d2v / dx2 = M / EI. Solution of this equation requires two successive（连续的）integrations to obtain the deflection v of the elastic curve. For each integration, it is necessary to introduce（引入）a “constant of integration”（积分常数）, and then solve for the constants to obtain a unique solution（唯一解）for a particular（特定的）problem. It should be realized that the method of double integration is suitable only for elastic deflections（变位）such tha t the beam’s slope is ver y small. Furthermore, the method considers only deflections due to bending.

我们可以通过对方程d2v / dx2 = M / EI的积分来确定弹性曲线的方程。该方程的求解需要两个连续的积分，以获得弹性曲线的挠度v。对每次积分，有必要引入积分常数，求出该常数以获得一个特定问题的唯一解。应该了解到双重积分法只适合于弹性变位，因而梁的转角是非常小的。而且，该法只考虑了由于弯曲引起的挠度。

The initial ideas（最初的概念）for the two moment-area theorems were developed（提出）by Otto Mohr and later stated formally（正式确定）by Charles E. Greene in 1872. These theorems provide a semi-graphical （半图解）technique for determining the slope of the elastic curve and its deflection due to bending. They are particularly advantageous（有利）when used to solve problems involving beams especially those subjected to a series of concentrated loadings or having segments（段）with different moment of inertia（惯性矩）. Theorem 1: The change in slope（转角变化）between any two points on the elastic curve equals the area of the M / EI diagram between these two points. Theorem 2: The deviation（偏差）of the tangent（正切）at point B on the elastic curve with respect to（相对于）the tangent at point A equals the “moment”of the M / EI diagram between the two points A and B computed about point A (the point on the elastic curve), where（这里）the deviation tA/B is to be determined.

最初的关于两个弯矩图面积定理的概念是由Otto Mohr提出，后来由Charles E. Greene在1872年正式加以确定。这些定理为确定弹性曲线由于弯曲引起的转角和挠度提供了半图解的方法。当用以解决包括梁在内的问题，特别是那些承受一组集中加载的梁或有着不同惯性矩的梁段时，它们（指弯矩图面积定理）是特别得有利。定理1：弹性曲线上任何两点之间转角的变化等于这两点之间的M / EI图的面积。定理2：弹性曲线上B点的正切相对于A 点的正切的偏差等于点A与点B之间的M / EI图对A点（该点在弹性曲线上）的矩，这里偏差tA/B将被确定。

The conjugate-beam method was first presented（提出）by Otto Mohr in 1860. Essentially（本质上）, it requires the same amount of computation（计算量）as the moment-area theorems to determine a beam’s slope or deflection; however, this method relies only on the principles of statics and hence its application will be more familiar（常见）. The basis for the method comes from（来自于）the similarity（相似性）between both dV/dx = - and d2M/dx2 = - , which relate a beam’s internal shear and moment to its applied loading, and d /dx = M/EI and d2y/dx2 = M/EI, which relate the slope and deflection of its elastic curve to the internal moment.

共轭梁法首先在1860年由Otto Mohr提出。本质上说，它与弯矩图面积定理一样在确定梁的转角或挠度上需要相同的计算量；但是这种方法只依赖于静力学的原理，因此，它的应用更常见。该法的基础来自于dV/dx=- 和d2M/dx2=- 之间的相似性，它将梁的内部剪力和弯矩与它施加的荷载联系起来，而d /dx = M/EI和d2y/dx2 = M/EI将弹性曲线的转角和挠度与内部弯矩联系起来。

Note that the shear V compares with（与..对应）the slope , the moment M compares with the displacement y and the intensity of the external load compares with the area under the M/EI

diagram. To make use of this comparison we will consider a beam having the same length as the real beam, but refer red to here as the “conjugate beam”.

注意剪力V与转角 相对应，弯矩M与位移y相对应，而外力的强度 与M/EI图下的面积相对应。为了利用这些对应，我们将考虑一根与实际梁一样长的梁。但是这里称为共轭梁。

In general, though（然而）, remember that if the real support allows a slope, the conjugate support must develop（产生）a shear; and if the real support allows a displacement, the conjugate support must develop a moment, note that the conjugate beam is “loaded”with the M/EI diagram, in order to conform to（与..一致）the load on the real beam. We can therefore state（陈述）two theorems related to the conjugate beam, namely（即）, Theorem 1: The slope at a point in the real beam is equal to the shear at the corresponding point（相应点）in conjugate beam. Theorem 2: The displacement of a point in the real beam is equal to the moment at the corresponding point in the conjugate beam.

然而通常要记住如果实际的支座允许一个转角，共轭的支座必须产生一个剪力；如果实际的支座允许一个位移，共轭的支座必须产生一个弯矩，注意共轭梁用M/EI图来加荷，以便与实际梁上的荷载一致。因此，我们可以陈述与共轭梁相关的两种定理，即，定理1：实际梁上某一点的转角等于共轭梁上相应点的剪力。定理2：实际梁上某一点的位移等于共轭梁上相应点的弯矩。

For more complicated loadings or for structures such as trusses and frame, it is suggested（建议）that energy methods be used for the computation. All energy methods are based on the conservation of energy principle（能量守恒原则）, which states（规定）that the work（功）done by all the external forces acting on a structure, Ue, is transformed into（转化为）internal work or strain energy（应变能）UI, which is developed（形成）when the structure deforms（变形）.

对于较复杂的荷载或结构如桁架和框架，建议应该采用能量法来计算。所有的能量法是基于能量守恒原则，它规定了作用在结构上的所有外力作的功Ue转化成内部功或结构变形时形成的应变能UI 。

The principle of virtual work was developed by John Bernoulli in 1717 and is sometimes referred to as the unit-load method（单位荷载法）. It provides a general means（一般方法）of obtaining the displacement and slope at a point on a structure, be it（无论是）a beam, frame, or truss. Before developing the principle of virtual work, it is necessary to make some general statements（一般规定）regarding the principle of work and energy.

虚功原理在1717年由John Bernoulli提出，有时称为单位荷载法。它提供了获得结构上某一点的位移和转角的一般的方法，不管该结构是梁、框架还是桁架。在提出虚功原理之前，关于功和能量的原理有必要作些一般规定。

If we take（取）a deformable（可变形）structure of any shape or size and apply a series of external loads P to it, it will cause internal loads u at points throughout the structure. It is necessary that the external and internal loads be related by the equation of equilibrium. As a consequence of（通过）these loadings, external displacement will occur at the P loads and internal displacement will occur at each point of internal load u.

如果我们取一个任何形状或尺寸的可变形结构，并对它施加一组外力P，它将导致整个结构上的点产生内力u。有必要通过平衡方程将内外力联系起来。通过这些荷载，外部的位移 发生在荷载P作用处，而内部位移 发生在内力u所处的每个点。

In general, these displacements do not have to be elastic, and they may not be related to（与..有关）the loads; however, the external and internal displacements must be related by the compatibility of

the displacements. In other words, if the external displacements are known, the corresponding internal displacements are uniquely defined（唯一确定）. In general, then, the principle of work and energy states（表述）:

P = u （5-1）

Work of External Loads = Work of Internal Loads

一般来说，这些位移不必是弹性的，它们可能与荷载无关。但是外部位移与内部位移必须通过位移协调联系起来。换句话说，如果已知外部位移，则相应的内部位移可惟一的确定。通常，功和能量原理表述为

P = u （5-1）

外力功=内力功

Based on this concept, we will now develop（提出）the principle of virtual work so that it can be used to determine the displacement of a point on a structure. To do this, we will consider the structure (or body) to be of arbitrary（任意）shape as shown in Fig. 5-1-(b). Suppose it is necessary to determine the displacement of poi n t A on the body caused by the “real loads” P1, P2, and P3. It is to be understood that these loads cause no movement of the supports; in general, however, they can strain(使..产生应变) the material beyond the elastic limit.

基于这个概念，现在我们将提出虚功原理，以便用以确定结构上某一点的位移。为此，我们考虑图5-1-(b)显示的具有任意形状的结构或物体。假定有必要确定由实际荷载P1、P2 和P3 引起的A点的位移。可以被理解为这些荷载不引起支座的移动；但是一般而言，它们能使材料的应变超过弹性极限。

Since no external load acts on the body at A and in the direction of , the displacement can be determined by first placing on the body a “virtual” load such that this force P’ acts in the same direction as , Fig.5-1-(a). For convenience（方便起见）, which will be apparent（显而易见）later, we will choose P’to have a “unit”magnitude（单位值）, that is P’= 1. The term “virtual”is used to describe the load, since it is imaginary（想象的）and does not actually exist as part of the real loading. The unit load (P’) does, however, create an internal virtual load u in a representative（典型的）element or fiber of the body, as shown in Fig.5-1-(a).

由于没有外力作用在物体的A点以及 的方向上，则位移 可以通过在物体上先设置一个虚力，即如图5-1-(a)中作用一个与方向 相同的力P’来确定。为了方便起见（后面会显而易见），我们选择P’有一个单位值，即P’=1。用术语“虚”来描述荷载，因为它是想象的，非实际存在的真实荷载的部分。但是，单位荷载P’在物体的典型单元或纤维中产生了一个内部虚力u，如图5-1-(a)所示。

Here it is required that P’and u be related by the equation of equilibrium. As a result of（通过）these loadings, the body and the element will each undergo a virtual displacement due to the load P’, although we will not be concerned with（关心）its magnitude. Once the virtual loadings are applied and then the body is subjected to the real loads P1, P2, and P3, Fig.5-1-(b), point A is displaced an amount , causing the element to deform dL.

这里要求P’和u通过平衡方程联系起来。通过这些（虚）荷载，物体和单元各自由于荷载P’而经历一个虚位移，尽管我们不会关心它的数值。一旦施加虚荷载，然后物体承受图5-1-(b)中的实际荷载P1、P2和P3，则点A产生位移值 ，导致单元发生变形dL。

As a result（因此）, the external virtual forc e P’ and internal virtual load u “ride along” by（乘上） and dL, respectively（分别地）, and therefore perform external virtual work of 1 on the body and internal virtual work of u dL on the element. Realizing that the external virtual work is equal to the internal virtual work done on all the elements of the body, we can write the virtual

work equation as

1 = u dL （5-2）

因此，外部虚力P’和内部虚力u分别与 和dL“乘在一起”，因此在物体上形成外部虚功，在单元上形成内部虚功。了解到外部虚功等于对物体所有单元作的内部虚功，我们可以

写出虚功方程

1 = u dL （5-2）

Where P’=1=external virtual unit load acting in the

direction of

u = internal virtual load acting on the element in

the direction of dL

= external displacement caused by the real loads

dL = internal deformation of the element caused

by the real loads

By choosing P’ = 1, it can be seen that the solution for follows directly, since = u dL .

这里，P’等于1，也等于作用在 方向上的外部虚单位力；

u等于以dL方向作用在单元上的内部虚力；

等于真实荷载引起的外部位移；

dL等于真实荷载引起的单元的内部变形。

可以看到通过选择P’=1能直接得到解，因为 = u dL 。

In a similar manner, if the rotational displacement（转动位移）or slope（转角）of the tangent at

a point on a structure is to be determined, a virtual couple moment（力偶矩）M’having a “unit”magnitude is applied at the point. As a consequence（因此）, this couple moment cause a virtual load in one of the element of the body. Assuming that the real loads deform（使..变形）the element

at amount dL, the rotation can b e found from the virtual-work equation 1 = u dL . This method for applying the principle of virtual work is often referred to as the method of virtual forces（虚力法）, since a virtual force is applied resulting in the calculation of a real displacement. The equation of virtual work in this case represents a compatibility requirement for the structure.

以相似的方法，如果要确定结构上某一点切线的转动位移或转角，可在该点上

施加一个虚的单位力偶矩M’。因此，力偶矩在物体的某一单元中形成一个虚力。假定实际

的力使单元的变形值为dL，则转角 可从虚功方程1 = u dL中得到。运用虚功

原理的方法通常称为虚力法，因为施加虚力能计算出实际的位移。在这种情况下虚功方程代

表着对结构的协调要求。

Although not important here, realize（意识）that we can also apply the principle of virtual work as

a method of virtual displacements（虚位移）. In this case virtual displacements are imposed on（强

加于）the structure, while the structure is subjected to real loadings. This method can be used to determine a force on or in a structure, so that the equation of virtual work is then expressed as an equilibrium requirement.

了解到我们也能运用虚功原理形成虚位移法，尽管在这儿不太重要。这种情况下，虚位

移强加于结构，而结构承受实际的荷载。该法能用以确定结构上或结构中的力，因此虚功方

程表示为平衡要求。

In 1879 Alberto Castigliano, an Italian railroad engineer, published a book in which he outline（概述）a method for determining the deflection or slope at a point in a structure, be it a truss, beam, or frame. This method, which is referred to as Castigliano’s second theorem（卡氏第二定理）, or the method of least work（最小功法）, applies only to structures that have constant temperature（恒

温）, unyielding（不易弯曲）supports, and linear elastic material response.

1879年Alberto Castigliano，一个意大利的铁路工程师，出版了一本书，书中他概述了确定结构（无论是桁架、梁或框架）中某一点的挠度或转角的方法。这种称为卡氏第二定理或最小功法的方法仅应用于具有恒温、支座不易弯曲和材料线弹性响应的结构中。

If the displacement of a point is to be determined, the theorem states（表明）that it is equal to the first partial derivative（一阶偏导数）of the strain energy in the structure with respect to （关于）a force acting at a point and in the direction of displacement. In a similar manner, the slope at a point in a structure is equal to the first partial derivative of the strain energy in the structure with respect to a couple moment acting at the point and in the direction of rotation.

如果要确定某一点的位移，该定理表明位移等于结构中的应变能对于作用在该点并沿该位移方向的力的一阶偏导数。以相似的方式，结构上某一点的转角等于结构中的应变能对于作用在该点并沿该转角方向的力偶的一阶偏导数。

The derivation（推导）of the theorem requires that only conservative forces（保守力）be considered for the analysis. These forces do work that is independent of（与..无关）the path and therefore create no energy loss（能量损失）. Since forces causing a linear elastic response are conservative, the theorem is restricted to linear elastic behavior of the material. This is unlike the method of virtual force, which applies to both elastic and inelastic behavior.

定理的推导要求分析时只考虑保守力。这些力作功与路径无关，因此不造成能量的损失。由于引起线弹性响应的力是保守的，因此该定理（在运用时）被限制在材料的线弹性状态。它不象虚力法可以运用于弹性和非弹性状态。

When analyzing any indeterminate structure, it is necessary to satisfy equilibrium, compatibility, and force-displacement requirements for the structure. Equilibrium is satisfied when the reactive forces hold the structure at rest（保持结构静止）, and compatibility is satisfied when the various segments（部分）of the structure fit together（配合在一起）without intentional（故意的）breaks or overlaps（断裂或重叠）. The force displacement requirements depend upon the way the material responds, which in this chapter we have assumed linear-elastic response. In general there are two different ways to satisfy these requirements when analyzing a statically indeterminate structure: the force or flexibility method（柔度法）, and the stiffness or displacement method.

当分析任何不确定的结构时，有必要满足结构的平衡、协调和力-位移要求。当反力保持结构的静止时满足平衡（要求），当结构中不同的部分配合在一起而没有故意地断开或重叠时满足协调（要求）。力-位移要求依赖于材料响应的途径，在本篇我们已经假定为线弹性响应。当分析一个超静定结构时，一般有两种不同的方法来满足这些要求：力法或柔度法以及刚度法或位移法。

The force method was originally（最初地）developed by James Clerk Maxwell in 1864 and later refined（提炼）by Otto Mohr and Heinrich Muller-Breslau. This method was one of the first available（最早采用）for the analysis of statically indeterminate structures. As suggested（提示）by the name, the force method consists of writing equations that satisfy the compatibility and force-displacement requirements for the structure and involve（涉及）redundant forces（冗余力）as the unknowns. The coefficients（系数）of these unknowns are called flexibility coefficients. Since compatibility forms（形成）the basis for this method, it has sometimes been referred to as the compatibility method or the method of consistent displacements（位移协调法）. The redundant forces are determined by satisfying the equilibrium requirements for the structure. The fundamental principles（基本原理）involved in （涉及）applying this method are easy to understand and develop（阐述）.

力法最初由James Clerk Maxwell 在1864提出，后由Otto Mohr和Heinrich Muller-Breslau 加以提炼。该法是最早可采用的分析超静定结构的方法之一。正如其名称所提示的，力法包括写出满足结构协调要求和力-位移要求的方程以及涉及未知冗余力的方程。这些未知力的系数称为柔度系数。由于协调性形成了这个方法的基础，它有时被称为协调法或位移协调法。通过满足结构的平衡要求来确定冗余力。涉及该法运用的基本原理是很容易理解和阐述的。When Marxwell developed the force method of analysis, he also published（发表）a theorem that relates（使..互相关联）the flexibility coefficients of any two points on an elastic structure –be it a truss, a beam, or a frame. This theorem is referred to as the theorem of reciprocal displacements（位移互等定理）and may be stated as follows（陈述如下）: The displacement of a point B on a structure due to a unit load acting at point A is equal to the displacement of point A when the unit load is acting at point B, that is fBA = fAB. The theorem also applies for reciprocal rotations（转角互等）. Furthermore, using a unit force and unit couple moment, applied at separate （分开的）points on the structure, we may also state: The rotation in radians（以弧度为单位）at point B on a structure due to a unit load acting at point A is equal to the displacement at point A when a unit couple moment is acting at point B.

当Marxwell提出力法分析时，他也发表了使弹性结构上任意两点的柔度系数相关的定理-无论是桁架、梁或框架。该定理称为位移互等定理，可以陈述如下：由作用在结构上A点的单位力引起B点的位移等于当单位力作用在B点时引起的A点的位移，即fBA = fAB。该定理也适用于转角互等。而且，将单位力和单位力偶矩施加在结构上不同的点，我们也可以陈述为：由作用在结构上A点的单位力引起B点的转角（单位为弧度）等于当单位力偶矩作用在B点时引起的A点的位移。

The displacement / stiffness method of analysis is based on first writing force-displacement relations（关系式）for the members and then satisfying the equilibrium requirements for the structure. In this case the unknowns（未知量）in the equations are displacements and their coefficients are called stiffness coefficients. Once the displacements are obtained, the forces are determined from the compatibility and force-displacement equations.

位移法或刚度法的分析是基于最初写出的构件的力-位移关系式，并且要满足结构的平衡要求。在这种情况下，方程式中的未知量是位移，而它们的系数称为刚度系数。一旦求得位移，就可从协调方程和力-位移方程中确定力。

Early in the 20th century slope deflection（转角位移法）was the most popular（流行的）method in use for analyzing statically indeterminate frames. It was developed by Professor G.A. Maney and began its reign of popularity（开始盛行）almost immediately after its publication（发表）in 1915. Fifteen years later the moment distribution method（弯矩分配法）was introduced and there began a period of spirited professional competition （激烈的专业竞争）over the merits（优势）of the two methods, with moment distribution eventually emerging as the “winner”, primarily because of its speed and simplicity. But the competition has not ended. Today, although moment distribution continues as（依然作为）the more popular method, there remain many contemporary （同时代的）engineers who prefer slope deflection.

早在20世纪，转角位移法是用以分析超静定框架最流行的方法。它由G.A. Maney教授提出，并在1915年发表后几乎迅速开始盛行。15年后弯矩分配法被采用，并在一段时期内开始了对两种方法的优势展开的激烈的专业竞争，弯矩分配法最终以胜者出现，主要是由于它的速度和简单。但是竞争没有结束。今天，尽管弯矩分配法依然作为较流行的方法，仍有很多同时代的工程师较喜欢用转角位移法。

They contend（辩解）that in performing a slope deflection analysis the engineer can acquire a

《土木工程专业英语》段兵延第二版全书文章翻译精编版

第一课 土木工程学土木工程学作为最老的工程技术学科，是指规划，设计，施工及对建筑环境的管理。此处的环境包括建筑符合科学规范的所有结构，从灌溉和排水系统到火箭发射设施。 土木工程师建造道路，桥梁，管道，大坝，海港，发电厂，给排水系统，医院，学校，公共交通和其他现代社会和大量人口集中地区的基础公共设施。他们也建造私有设施，比如飞机场，铁路，管线，摩天大楼，以及其他设计用作工业，商业和住宅途径的大型结构。此外，土木工程师还规划设计及建造完整的城市和乡镇，并且最近一直在规划设计容纳设施齐全的社区的空间平台。 土木一词来源于拉丁文词“公民”。在1782年，英国人John Smeaton为了把他的非军事工程工作区别于当时占优势地位的军事工程师的工作而采用的名词。自从那时起，土木工程学被用于提及从事公共设施建设的工程师，尽管其包含的领域更为广阔。 领域。因为包含范围太广，土木工程学又被细分为大量的技术专业。不同类型的工程需要多种不同土木工程专业技术。一个项目开始的时候，土木工程师要对场地进行测绘，定位有用的布置，如地下水水位，下水道，和电力线。岩土工程专家则进行土力学试验以确定土壤能否承受工程荷载。环境工程专家研究工程对当地的影响，包括对空气和地下水的可能污染，对当地动植物生活的影响，以及如何让工程设计满足政府针对环境保护的需要。交通工程专家确定必需的不同种类设施以减轻由整个工程造成的对当地公路和其他交通网络的负担。同时，结构工程专家利用初步数据对工程作详细规划，设计和说明。从项目开始到结束，对这些土木工程专家的工作进行监督和调配的则是施工管理专家。根据其他专家所提供的信息，施工管理专家计算材料和人工的数量和花费，所有工作的进度表，订购工作所需要的材料和设备，雇佣承包商和分包商，还要做些额外的监督工作以确保工程能按时按质完成。 贯穿任何给定项目，土木工程师都需要大量使用计算机。计算机用于设计工程中使用的多数元件（即计算机辅助设计，或者CAD）并对其进行管理。计算机成为了现代土木工程师的必备品，因为它使得工程师能有效地掌控所需的大量数据从而确定建造一项工程的最佳方法。 结构工程学。在这一专业领域，土木工程师规划设计各种类型的结构，包括桥梁，大坝，发电厂，设备支撑，海面上的特殊结构，美国太空计划，发射塔，庞大的天文和无线电望远镜，以及许多其他种类的项目。结构工程师应用计算机确定一个结构必须承受的力：自重，风荷载和飓风荷载，建筑材料温度变化引起的胀缩，以及地震荷载。他们也需确定不同种材料如钢筋，混凝土，塑料，石头，沥青，砖，铝或其他建筑材料等的复合作用。 水利工程学。土木工程师在这一领域主要处理水的物理控制方面的种种问题。他们的项目用于帮助预防洪水灾害，提供城市用水和灌溉用水，管理控制河流和水流物，维护河滩及其他滨水设施。此外，他们设计和维护海港，运河与水闸，建造大型水利大坝与小型坝，以及各种类型的围堰，帮助设计海上结构并且确定结构的位置对航行影响。 岩土工程学。专业于这个领域的土木工程师对支撑结构并影响结构行为的土壤和岩石的特性进行分析。他们计算建筑和其他结构由于自重压力可能引起的沉降，并采取措施使之减少到最小。他们也需计算并确定如何加强斜坡和填充物的稳定性以及如何保护结构免受地震和地下水的影响。 环境工程学。在这一工程学分支中，土木工程师设计，建造并监视系统以提供安全的饮用水，同时预防和控制地表和地下水资源供给的污染。他们也设计，建造并监视工程以控制甚至消除对土地和空气的污染。他们建造供水和废水处理厂，设计空气净化器和其他设备以最小化甚至消除由工业加工、焚化及其他产烟生产活动引起的空气污染。他们也采用建造特殊倾倒地点或使用有毒有害物中和剂的措施来控制有毒有害废弃物。此外，工程师还对垃圾掩埋进行设计和管理以预防其对周围环境造成污染。

土木工程专业英语全部

Lesson 1 Compression Members New Words 1. achieve achievement 2. eccentricity center, 中心; ec centric 偏心的；ec centricity 偏心，偏心距 3. inevitable evitable 可避免的avoidable; in evitable 不可避免的unavoidable 4. truss 桁架triangular truss, roof truss, truss bridge 5. bracing brace 支柱，支撑；bracing, 支撑，撑杆 6. slender 细长，苗条；stout; slenderness 7. buckle 压曲，屈曲；buckling load 8. stocky stout 9. convincingly convince, convincing, convincingly 10. stub 树桩，短而粗的东西；stub column 短柱 11. curvature 曲率；curve, curvature 12. detractor detract draw or take away; divert; belittle，贬低，诽谤； 13. convince 14. argument dispute, debate, quarrel, reason, 论据（理由） 15. crookedness crook 钩状物，v弯曲，crooked 弯曲的 16. provision 规定，条款 Phrases and Expressions 1. compression member 2. bending moment shear force, axial force 3. call upon (on) 要求，请求，需要 4. critical buckling load 临界屈曲荷载critical 关键的，临界的 5. cross-sectional area 6. radius of gyration 回转半径gyration 7. slenderness ratio 长细比 8. tangent modulus 切线模量 9. stub column 短柱 10. trial-and-error approach 试算法 11. empirical formula 经验公式empirical 经验的 12. residual stress 残余应力residual 13. hot-rolled shape 热轧型钢hot-rolled bar 14. lower bound 下限upper bound 上限 16. effective length 计算长度 Definition （定义） Compression members are those structural elements that are subjected only to axial compressive forces: that is, the loads are applied along a longitudinal axis through the centroid of the member cross section, and

人教版新目标英语课文翻译七年级上全一册

预习单元1—3 Starter Unit 1 Section A 1a 早上好，海伦！嗨，鲍勃！早上好，艾丽斯！喂，弗兰克！喂，埃里克！早上好，戴尔！ Section B 1 下午好，戴尔！嗨，辛蒂！你好吗？我很好，多谢。你好吗？我很好。 Self Check 1 嗨喂上午下午晚上好的好谢谢好的4 年龄手他床Just for Fun 晚上好！ Starter Unit 2 Section A 1b 这用英语怎么说？一张地图。一个橙子。Section B 1a 用英语说这是什么？一把钥匙。请拼一下。Self Check 3夹克衫艾丽斯地图钥匙橙子戴尔海伦格雷斯辛蒂鲍勃钢笔弗兰克被子埃里克尺子 4 名字能他腿美好的牛奶去狗 Starter Unit 3 Section A 1a 这是什么？它是字母V。它是什么颜色的？它是红色的。这是什么？它是字母Z。它是黑白相间的。Section B 1b 这把钥匙是黄色的。这把尺子是蓝色的。这支钢笔是红色的。Self Check 它是绿色的。 字母意思（铅笔芯）硬黑激光唱片英国广播公司停车（美国）全国篮球协会千克小号/中号/大号不明飞行物中央电视台联合国 一单元 Section A 1a 我是吉娜。见到你真高兴。 Grammer Foucs你的名字是什么？我的名字是詹妮。我是詹妮。他的名字是什么？他的名字是托尼。她的名字是什么？她的名字是吉娜。 Section B 1c 你的电话号码是什么，李欣？是281-6926。3b 她的电话号码是什么？她的姓氏是什么？她的名字是什么？ Self Check 1 我她是身份证什么我的喂你的他的她的名姓电话号码 Just for Fun你的名是什么？ZIG。你的姓是什么？ZAG。 二单元 Section A 1a 那是你的双肩背包吗？不，不是。它是他的双肩背包。这是你的铅笔吗？是的，它是。它是我的铅笔。这是你的尺子吗？不，不是。它是她的尺子。 铅笔钢笔书橡皮擦尺子铅笔盒书包卷笔刀词典 2b 请原谅，索尼亚。这是你的铅笔吗？是的，谢谢。那是我的橡皮。简，这是你的尺子吗？不，不是。它是她的尺子。好的，这是我的书。这是你的铅笔盒，简。Section B 1a 棒球手表电子游戏机身份证钥匙笔记本戒指钢笔 1b 这是什么？一块手表。你怎样拼写它？…… 3a 这是你的手表吗？给艾伦打电话495—3539。艾伦，失物招领箱中的电子游戏是你的吗？尼克招领：笔记本这是你的笔记本吗？请给玛丽打电话。电话#235—0285。寻物：我的学生证。我的名字是托尼。请打电话685—6034 3b 失物招领一串钥匙。请给大卫打电话529—6403 Self Check Just for Fun嘘！什么？用英语说这是什么？一块手表。你怎样拼写它？它（那个） 三单元 Section A 1a那是我的两个兄弟。并且那是我姐妹。母亲父亲父母兄弟祖母祖父朋友祖父母姐妹 1c 这是他的姐妹。这些是他的兄弟们。 2c 这是吉姆吗？，不，他不是。他是戴夫。 Grammer Foucs 这是你姐妹吗？不，不是的。这是我的朋友。这些是我的朋友们。那是你的兄弟吗？是的，他是。那个是我的兄弟。那些是我的兄弟们。 3a那是安娜，那是保罗。她是你的姐妹吗？是的，她是。他是你的兄弟吗？不，他不是。他是我的朋友。 4她是你阿姨吗？是的，她是。 Section B 2c 这些是我的父母。这是我的祖父。这是我的朋友,林方。亲爱的玛丽：谢谢你的全家福照片。这是我的全家福照片。你的朋友艾玛这是我的弟弟，托尼。这是我的妹妹，莫娜。这些是我的父母。 Self Check 1 这那这些那些妈妈爸爸父母姐妹兄弟（外）祖母朋友叔叔（舅舅）（外）祖父婶婶（舅妈）堂（表）兄弟（姐妹）（外）祖父她他 Just for Fun那是你的妹妹吗？不，不是。那是我表妹。那是你的妹妹吗？不，不是。那是我的姑姑。谁是你妹妹？这是我的妹妹。 四单元 Section A 1a桌子床梳妆台书柜沙发椅子双肩背包书钥匙棒球抽屉植物我的双肩背包在哪儿?在桌子下面。我的书在哪儿?在沙发上。我的棒球在哪儿?它在双肩背包里。1c 双肩背包在哪儿？在桌子下面。 2c 棒球在沙发上吗？不。不在。他在椅子下面。Grammar Focus棒球在哪儿？在双肩背包里。我的电子游戏机在哪儿？在床下。你的书在哪儿？他们在椅子上。他的钥匙在哪儿？在梳妆台上。她的钥匙在哪儿？在桌上。3a书包在哪儿？我不知道。它在梳妆台上吗？不，它不在。我的书在哪儿？我不知道。它们在床上吗？不，他们不在。 4 双肩背包在哪儿？它在桌子底下吗？不，它不在。它在桌子上。 Section B 1a 数学书闹钟激光唱片电子游戏机录像带帽子笔记本在哪儿？在床上。 3a 亲爱的飞飞：请把这些东西带给你的姐姐：她的帽子、手表、笔记本、钥匙和身份证。帽子在梳妆台上。手表在

土木工程专业英语正文课文翻译

第一课土木工程学 土木工程学作为最老的工程技术学科，是指规划，设计，施工及对建筑环境的管理。此处的环境包括建筑符合科学规范的所有结构，从灌溉和排水系统到火箭发射设施。 土木工程师建造道路，桥梁，管道，大坝，海港，发电厂，给排水系统，医院，学校，公共交通和其他现代社会和大量人口集中地区的基础公共设施。他们也建造私有设施，比如飞机场，铁路，管线，摩天大楼，以及其他设计用作工业，商业和住宅途径的大型结构。此外，土木工程师还规划设计及建造完整的城市和乡镇，并且最近一直在规划设计容纳设施齐全的社区的空间平台。 土木一词来源于拉丁文词“公民”。在1782年，英国人John Smeaton为了把他的非军事工程工作区别于当时占优势地位的军事工程师的工作而采用的名词。自从那时起，土木工程学被用于提及从事公共设施建设的工程师，尽管其包含的领域更为广阔。 领域。因为包含范围太广，土木工程学又被细分为大量的技术专业。不同类型的工程需要多种不同土木工程专业技术。一个项目开始的时候，土木工程师要对场地进行测绘，定位有用的布置，如地下水水位，下水道，和电力线。岩土工程专家则进行土力学试验以确定土壤能否承受工程荷载。环境工程专家研究工程对当地的影响，包括对空气和地下水的可能污染，对当地动植物生活的影响，以及如何让工程设计满足政府针对环境保护的需要。交通工程专家确定必需的不同种类设施以减轻由整个工程造成的对当地公路和其他交通网络的负担。同时，结构工程专家利用初步数据对工程作详细规划，设计和说明。从项目开始到结束，对这些土木工程专家的工作进行监督和调配的则是施工管理专家。根据其他专家所提供的信息，施工管理专家计算材料和人工的数量和花费，所有工作的进度表，订购工作所需要的材料和设备，雇佣承包商和分包商，还要做些额外的监督工作以确保工程能按时按质完成。 贯穿任何给定项目，土木工程师都需要大量使用计算机。计算机用于设计工程中使用的多数元件（即计算机辅助设计，或者CAD）并对其进行管理。计算机成为了现代土木工程师的必备品，因为它使得工程师能有效地掌控所需的大量数据从而确定建造一项工程的最佳方法。 结构工程学。在这一专业领域，土木工程师规划设计各种类型的结构，包括桥梁，大坝，发电厂，设备支撑，海面上的特殊结构，美国太空计划，发射塔，庞大的天文和无线电望远镜，以及许多其他种类的项目。结构工程师应用计算机确定一个结构必须承受的力：自重，风荷载和飓风荷载，建筑材料温度变化引起的胀缩，以及地震荷载。他们也需确定不同种材料如钢筋，混凝土，塑料，石头，沥青，砖，铝或其他建筑材料等的复合作用。 水利工程学。土木工程师在这一领域主要处理水的物理控制方面的种种问题。他们的项目用于帮助预防洪水灾害，提供城市用水和灌溉用水，管理控制河流和水流物，维护河滩及其他滨水设施。此外，他们设计和维护海港，运河与水闸，建造大型水利大坝与小型坝，以及各种类型的围堰，帮助设计海上结构并且确定结构的位置对航行影响。 岩土工程学。专业于这个领域的土木工程师对支撑结构并影响结构行为的土壤和岩石的特性进行分析。他们计算建筑和其他结构由于自重压力可能引起的沉降，并采取措施使之减少到最小。他们也需计算并确定如何加强斜坡和填充物的稳定性以及如何保护结构免受地震和地下水的影响。 环境工程学。在这一工程学分支中，土木工程师设计，建造并监视系统以提供安全的饮用水，同时预防和控制地表和地下水资源供给的污染。他们也设计，建造并监视工程以控制甚至消除对土地和空气的污染。

土木工程专业英语词汇(整理版)

第一部分必须掌握，第二部分尽量掌握 第一部分： 1 Finite Element Method 有限单元法 2 专业英语Specialty English 3 水利工程Hydraulic Engineering 4 土木工程Civil Engineering 5 地下工程Underground Engineering 6 岩土工程Geotechnical Engineering 7 道路工程Road (Highway) Engineering 8 桥梁工程Bridge Engineering 9 隧道工程Tunnel Engineering 10 工程力学Engineering Mechanics 11 交通工程Traffic Engineering 12 港口工程Port Engineering 13 安全性safety 17木结构timber structure 18 砌体结构masonry structure 19 混凝土结构concrete structure 20 钢结构steelstructure 21 钢-混凝土复合结构steel and concrete composite structure 22 素混凝土plain concrete 23 钢筋混凝土reinforced concrete 24 钢筋rebar 25 预应力混凝土pre-stressed concrete 26 静定结构statically determinate structure 27 超静定结构statically indeterminate structure 28 桁架结构truss structure 29 空间网架结构spatial grid structure 30 近海工程offshore engineering 31 静力学statics 32运动学kinematics 33 动力学dynamics 34 简支梁simply supported beam 35 固定支座fixed bearing 36弹性力学elasticity 37 塑性力学plasticity 38 弹塑性力学elaso-plasticity 39 断裂力学fracture Mechanics 40 土力学soil mechanics 41 水力学hydraulics 42 流体力学fluid mechanics 43 固体力学solid mechanics 44 集中力concentrated force 45 压力pressure 46 静水压力hydrostatic pressure 47 均布压力uniform pressure 48 体力body force 49 重力gravity 50 线荷载line load 51 弯矩bending moment 52 torque 扭矩53 应力stress 54 应变stain 55 正应力normal stress 56 剪应力shearing stress 57 主应力principal stress 58 变形deformation 59 内力internal force 60 偏移量挠度deflection 61 settlement 沉降 62 屈曲失稳buckle 63 轴力axial force 64 允许应力allowable stress 65 疲劳分析fatigue analysis 66 梁beam 67 壳shell 68 板plate 69 桥bridge 70 桩pile 71 主动土压力active earth pressure 72 被动土压力passive earth pressure 73 承载力load-bearing capacity 74 水位water Height 75 位移displacement 76 结构力学structural mechanics 77 材料力学material mechanics 78 经纬仪altometer 79 水准仪level 80 学科discipline 81 子学科sub-discipline 82 期刊journal ,periodical 83文献literature 84 ISSN International Standard Serial Number 国际标准刊号 85 ISBN International Standard Book Number 国际标准书号 86 卷volume 87 期number 88 专着monograph 89 会议论文集Proceeding 90 学位论文thesis, dissertation 91 专利patent 92 档案档案室archive 93 国际学术会议conference 94 导师advisor 95 学位论文答辩defense of thesis 96 博士研究生doctorate student 97 研究生postgraduate 98 EI Engineering Index 工程索引 99 SCI Science Citation Index 科学引文索引 100ISTP Index to Science and Technology Proceedings 科学技术会议论文集索引 101 题目title 102 摘要abstract 103 全文full-text 104 参考文献reference 105 联络单位、所属单位affiliation 106 主题词Subject 107 关键字keyword 108 ASCE American Society of Civil Engineers 美国土木工程师协会 109 FHWA Federal Highway Administration 联邦公路总署

七年级下册英语翻译

Unit1 SectionA 1 1-1a 部分翻译 What can these people do?Match the activities with the people． 这些人会做什么？将活动与人物配对。 ____ 唱歌/ ____ 游泳 ____ ____ 跳舞/ ____ 画 ____ chess ____ 下国际象棋 English ____ 说英语 the guitar ____ 弹吉他 原文—I want to join the art culb． 我想参加美术社团。 —Can you draw? —Yes，I can． 你会画画吗？是的，我会。 —Can you swim? —No,I can't. 你会游泳吗？不，我不会。 —I want to join the music club． 我想参加音乐社团。 —Oh，can you sing? 哦，你会唱歌吗？—Yes，I can．是的，我会。 1-1b 部分翻译 Listen and number the conversations[1-3]．听录音，为对话编号[1-3]． A: Can you swim? 你会游泳吗？ B：No，I can't．不，我不会。 A:I want to join the art club. 我想参加美术社团。 B: Can you draw? 你会画画吗？ A: Yes,I can．是的，我会。 A:I want to join the music club我想参加音乐社团。 B：Oh, can you sing? 哦，你会唱歌吗？ A: Yes,I can．是的，我会。 1-1c 部分翻译Practice the conversations above with your partner. Then make your own conversations. 与你的同伴练习上面的对话。然后编你自己的对 话。 1——2a 部分翻译 Listen to these versations and circle the clubs you hear．听这两段对话，圈出你听到 的社团。 a．English club 英语社团 b．art club 美术社团 c．music club 音乐社团 d．chess club 国际象棋社团 e．swimming 游泳社团 原文—What club do you want to join? 你想 参加什么社团？ —I wantto join the chess club．我想参加 国际象棋社团。 2—2b 部分翻译 Listen again. Complete the sentences. 再昕一遍录音，完成下面的句子。 1．Lisa wants to join the ____ club，but she can't play____． 莉萨想参加____社团，但她不会下____。 2．Bob wants to join the ____ club．He likes to speak ____. 鲍勃想参加____社团。他喜欢说____。 3．Mary likes music．She can ____ and ____．Bob likes music，too．They want join the ____club． 玛丽喜欢音乐。她会____和____。鲍勃也喜欢音 乐。他们想参加____社团。 3—2c 部分翻译 Look at 2b and talk about what the people can do and the clubs they want to join. 看2b并谈论人们能做什么以及他们想参加的社 团。 原文 —What club does Lisa want to join? 莉萨想 参加什么社团？ —She wants to join the... 她想参加…… 4—2d 部分翻译 Role-play the conversation． 分角色表演对话。 Jane: Hi，Bob．What club do you want to join? 简：你好，鲍勃。你想参加什么社团？ Bob：I want to join a sports club． 鲍勃：我想参加体育运动社团。 Jane: Great !What sports can you play? 简：太好了！你会什么运动？ Bob: Soccer. 鲍勃：足球。 Jane: So you can join the soccer club． 简：这么说你可以参加足球社团。 Bob：What about you? You're very good at telling stories. You can join the story telling club． 鲍勃：你呢？你很擅长讲故事。你可以参加讲故 事社团。 Jane：Sounds good．But I like to draw，too． 简：听起来不错。但我也喜欢画画。 Bob: Then join two clubs，the story telling club and the art club! 鲍勃：那就参加两个社团，讲故事社团和美术社 团！ Jane: OK，let's join now! 简：好的，我们现在去参加吧! 1—3a 部分翻译 Write questions and answers with the words

土木工程专业英语课文原文及对照翻译

土木工程专业英语课文原 文及对照翻译 Newly compiled on November 23, 2020

Civil Engineering Civil engineering, the oldest of the engineering specialties, is the planning, design, construction, and management of the built environment. This environment includes all structures built according to scientific principles, from irrigation and drainage systems to rocket-launching facilities. 土木工程学作为最老的工程技术学科，是指规划，设计，施工及对建筑环境的管理。此处的环境包括建筑符合科学规范的所有结构，从灌溉和排水系统到火箭发射设施。 Civil engineers build roads, bridges, tunnels, dams, harbors, power plants, water and sewage systems, hospitals, schools, mass transit, and other public facilities essential to modern society and large population concentrations. They also build privately owned facilities such as airports, railroads, pipelines, skyscrapers, and other large structures designed for industrial, commercial, or residential use. In addition, civil engineers plan, design, and build complete cities and towns, and more recently have been planning and designing space platforms to house self-contained communities. 土木工程师建造道路，桥梁，管道，大坝，海港，发电厂，给排水系统，医院，学校，公共交通和其他现代社会和大量人口集中地区的基础公共设施。他们也建造私有设施，比如飞机场，铁路，管线，摩天大楼，以及其他设计用作工业，商业和住宅途径的大型结构。此外，土木工程师还规划设计及建造完整的城市和乡镇，并且最近一直在规划设计容纳设施齐全的社区的空间平台。 The word civil derives from the Latin for citizen. In 1782, Englishman John Smeaton used the term to differentiate his nonmilitary engineering work from that of the military engineers who predominated at the time. Since then, the term civil engineering has often been used to refer to engineers who build public facilities, although the field is much broader 土木一词来源于拉丁文词“公民”。在1782年，英国人John Smeaton为了把他的非军事工程工作区别于当时占优势地位的军事工程师的工作而采用的名词。自从那时起，土木工程学被用于提及从事公共设施建设的工程师，尽管其包含的领域更为广阔。 Scope. Because it is so broad, civil engineering is subdivided into a number of technical specialties. Depending on the type of project, the skills of many kinds of civil engineer specialists may be needed. When a project begins, the site is surveyed and mapped by civil engineers who locate utility placement—water, sewer, and power lines. Geotechnical specialists perform soil experiments to determine if the earth can bear the weight of the project. Environmental specialists study the project’s impact on the local area: the potential for air and

土木工程专业英语

non-destructive test 非破损检验 non-load—bearingwall 非承重墙 non—uniform cross—section beam 变截面粱 non—uniformly distributed strain coefficient of longitudinal tensile reinforcement 纵向受拉钢筋应变不均匀系数 normal concrete 普通混凝土 normal section 正截面 notch and tooth joint 齿连接 number of sampling 抽样数量 O obligue section 斜截面 oblique—angle fillet weld 斜角角焊缝 one—way reinforced(or prestressed)concrete slab “单向板” open web roof truss 空腹屋架， ordinary concrete 普通混凝土(28) ordinary steel bar 普通钢筋(29) orthogonal fillet weld 直角角焊缝(61) outstanding width of flange 翼缘板外伸宽度(57) outstanding width of stiffener 加劲肋外伸宽度(57) over-all stability reduction coefficient of steel beam·钢梁整体稳定系数(58) overlap 焊瘤(62) overturning or slip resistance analysis 抗倾覆、滑移验算(10) P padding plate 垫板(52) partial penetrated butt weld 不焊透对接焊缝(61) partition 非承重墙(7) penetrated butt weld 透焊对接焊缝(60) percentage of reinforcement 配筋率(34) perforated brick 多孔砖(43) pilastered wall 带壁柱墙(42) pit·凹坑(62) pith 髓心(?o) plain concrete structure 素混凝土结构(24) plane hypothesis 平截面假定(32) plane structure 平面结构(11) plane trussed lattice grids 平面桁架系网架(5) plank 板材(65) plastic adaption coefficient of cross—section 截面塑性发展系数(58) plastic design of steel structure 钢结构塑性设计(56) plastic hinge·塑性铰(13) plastlcity coefficient of reinforced concrete member in tensile zone 受拉区混凝土塑性影响系数

(完整)七年级英语下册全课文翻译--小4号字

Unit1 2d： Jane: 你好，鲍勃，你想加入什么俱乐部？ Bob:我想加入运动俱乐部。 Jane:棒极了!你会玩什么运动？ Bob:足球. Jane:这么说你可以加入足球俱乐部。 Bob:那么你呢？你非常善长讲故事.你可以加入讲故事俱乐部。 Jane:听起来不错。但我也喜欢画画。 Bob:那就加入两个俱乐部，讲故事俱乐部和美术俱乐部! Jane:好的，让我们现在去加入吧！ Section B 2a： 1.你好，我是Peter，我喜欢打篮球。我会说英语，我也会踢足球。 2.你好，我是Ma Huan，我会打乒乓球和下国际象棋。我喜欢与人们交谈和做游戏。 3.我的名字是Alan。我在学校音乐俱乐部。我会弹吉他和钢琴。我也会唱歌和跳舞。 2b: (A)我们老人之家需要帮助。在七月份你有空吗？你善于与老人相处吗？你会与他们说话做游戏吗？他们会给你讲故事，你们可以交 朋友。它既有趣又好玩！请在今天拨打电话698-7729与我们联系。 (C)放学后你忙吗？不忙？你会说英语吗？是吗？那么，我们需要 你帮助说英语的学生做运动。这事轻松的，容易的！请来学生运动中 心吧。拨打电话293-7742联系Mr.Brown. (B)你会弹钢琴或者拉小提琴吗？在周末你有时间吗？学校需要帮助教音乐。它不难！拨打电话555-3721联系https://www.wendangku.net/doc/f04118754.html,ler. Unit2 2d： Interviewer :Scott有一份有趣的工作。他在一家广播电台工作。Scott，你的广播节目在几点？Scott:从晚上十二点到早上六点。 Interviewer :你通常几点起床？ Scott:晚上八点半。然后我九点吃早饭。Interviewer :那是个有趣的早饭的时间。 Scott:是的。之后，我通常在十点二十左右锻炼。Interviewer :你什么时候去上班？ Scott:在十一点，所以我工作从不迟到。 2b：你好，我是Tony，我不喜欢早起床。在早上，我八点起床。然后，我在八点三十去上学。我没有许多时间吃早饭，因此，我通常吃的非常快。午饭我通常吃汉堡。放学后，我有时打半小时篮球。当我到家的时候，我总是先做作业。在晚上，我要么看电视，要么玩电脑游戏。在十点三十，我刷牙，然后上床睡觉。 Mary是我的妹妹。她通常在六点半起床。然后她总是洗淋浴，吃丰盛的早饭。然后，她在八点三十去上学。在十二点，她吃许多水果和蔬菜作为午饭。午饭后，她有时打排球。她总是在晚饭后吃冰激凌。她知道那对她不好，但冰激凌尝起来好极了！在晚上，她做家庭作业，通常还要游泳或者散步。在九点三十，她上床睡觉。 Unit3 section A 2e: Lisa:嗨，Jane.这是你的自行车吗？ Jane:是的，我每天骑它去上学。你是怎样到学校的？ Lisa:我通常乘公共汽车。 Jane:从你家到学校有多远？ Lisa:我不确定...... 大约有10千米？乘公共汽车大约需要20分钟。你到学校花费多长时间？ Jane:骑自行车大约需要15分钟。那是很好的锻炼。Lisa:是的。哦，祝你在学校度过快乐的一天。Jane:你也是。 Section B： 2b：过河去学校 你是怎样到学校的？你步行还是骑自行车？你乘公共汽车还是乘火车去？对于许多学生来说，到达学校是容易的。但是对于在中国的一个小村庄里的学生来说，是困难的。在他们的学校和村庄之间有一条很大的河。那儿没有桥，对于小船来说，这条河流太湍急不能摆渡。因此这些学生乘索道过河去学校。 一个11岁的男孩，亮亮，每个上学日都过河。但是他不害怕。“我爱和我的同学们玩耍。我爱我的老师。他对我来说，就像父亲一样。” 这些学生和村民中的许多人从没有离开过这个村庄。有一座桥是他们的梦想。他们的梦想能实现吗？ 3a： 嗨，远方的人， 你好吗？谢谢你的上一封电子邮件。你想知道我怎样到学校，对吗？奥，我通常在大约8点离开家，步行去公共汽车站。校车通常在大约8:15来。学校离我家大约20千米。乘公共汽车到那儿大约花费40分钟。乘公共汽车从来不枯燥，因为我总是

土木工程专业英语修正版

Take the road of sustainable development civil engineering Abstract: Civil Engineering is the oldest in human history "technical science" as a system of industrial activity, the essence of civil engineering production process, is a technical process Civil engineering is the construction of various facilities in science and technology, collectively, both refer to the construction of the object, that is built on the ground, underground, water facilities, a variety of projects, but also refers to the application of materials, equipment and carried out survey and design , construction, maintenance, repair and other technology. As an important basis for discipline, civil engineering has its important attributes: a comprehensive, social, practical, technical and economic and artistic unity. With the progress of human society and development, civil engineering has already evolved into large-scale comprehensive subject, and has many branches, such as: construction, railroad engineering, road engineering, bridge engineering, specialty engineering structures, water supply and drainage projects, port engineering, hydraulic engineering, environmental engineering and other disciplines. There are six professional civil engineering: architecture, urban planning, civil engineering, built environment and equipment engineering, water supply and drainage works and road and bridge projects. Civil engineering is a form of human activity. Human beings pursued it to change the natural environment for their own benefit. Buildings, transportations, facilities, infrastructures are all included in civil engineering. The development of civil engineering has a long history. Our seniors had left a lot of great constructions to us. For example, Zhao Zhou Bridge is the representative of our Chinese civil engineering masterpieces. It has a history of more than 1300 years and is still service at present. Civil engineering has been so rapid development of the period. A lot of new bridges have been constructed, and many greater plans are under discussion. China is a large county. And she is still well developing. However, civil engineers will be facing more complex problems. We should pay attention to the growing population and a lot of deteriorating infrastructures. We should prepare for the possibility of natural disasters. To meet grow needs in the