Part III supplementary reading

ПРИМЕР ДЛЯ ПЕРЕВОДА СВЯЗНОГО ТЕКСТА

1) Прочитайте текст, не прибегая к словарю. Builder's Machinery and Equipment

Considerable development has taken place in recent years in builder's plant and equipment. Such mechanical aids in builder's work as lifting appliances, concrete mixers, and excavating machinery are widely used in modern building construction practice. But building machinery and equipment is such a wide-ranging subject that it is possible only, when dealing with it in the present article, to give just a general review of some civil engineering plant.

Steel Scaffolding

No item of builder's equipment has gained popularity so rapidly as tubular scaffolding and its many advantages over the pole scaffold make it clear why it has almost entirely replaced the latter. Correctly used, it is more rapidly erected, more convenient for internal work, and takes up far less valuable space when stored.

Concrete Mixers

There exist two principal types of concrete mixers: revol­ving drum type and continuous mix type, the former being in far more general use. Ranging in size from miniature affairs to gigantic batching plants capable of producing several hundreds of cubic yards in a working day, most mixers are described in terms of their input of dry material and their output of mixed concrete per batch. The revolving-drum type of mixing plant is available in various sizes, the most popular models being the 7/5, 10/7 and 14/10. Mixers of greater outputs are referred to in terms of the output of mixed con­crete per batch, e. g. half-yard mixer, two-yard mixer etc.

On any large contract a central mixing plant is usually erected which is a big enterprise in itself. To provide a continuous flow of concrete mix there is, at the central mixing plant, a stockpile system containing coarse aggregates of different sizes and fine aggregates from minus # 4 to plus # 100.

Lifting Equipment

The sole purpose of lifting tackle, whatever its nature,is to enable men to lift heavier loads more rapidly than is possible by their unaided efforts. Such lifting appliances as pulley blocks, platform hoists, cableways, and cranes play a very important part in all civil engineering operations, the particular circumstances of the work determining the best type of equipment and tackle to be used. However, it would be no exaggeration to say that the crane is the most important single item to be found on any site, whether large or small.

Road-Making Machinery

Much of the devices and plant used for the construction of roads, aircraft runways and similar work is of the same type as that used for general civil engineering construction, yet there are certain specialized machines peculiarly suitable for road construction such as different types of graders and scrapers and the dozer family.

Excavating Machinery

Excavators are now recognized as an essential part of the equipment for use upon the construction of large buildings and housing estates. Building operations, of course, embody varying classes of work, and while the economy and efficien­cy of mechanical methods are well known, such economies would not result in many cases if it were necessary to apply a single purpose machine separately to each of the various duties. The best application obviously is an all-purpose unit that can be converted to suit each class of work. In designing excavating machinery, the engineers try to make one attach­ment serve as many purposes as possible, so that the changing of the type of equipment to suit the particular work can be done without the expense of providing additional attachments.

The universal type excavators are quickly convertible for different uses. They have in fact "101 uses", and upon large building and construction jobs they need never be idle while the builder has work in hand.

Wheel excavators are sometimes used for digging trenches. Intended for stripping operations these machines may be very powerful; for example, the wheel drive motor of a recently put into operation wheel excavator is 250 hp @ 220 v or 500 hp @440 v.