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)(3)

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。

4 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 th …… 此处隐藏：4799字，全部文档内容请下载后查看。喜欢就下载吧 ……