Questions to the text:

1. What are earth-digging machines designated for?

2. What types may excavators be?

3. Where are single-bucket excavators indispensable?

4. What operations does the working cycle include?

5. Are single-bucket excavators divided into building, quarry, slipping, tunnel types according to their purpose?

6. How many changeable attachments may single-bucket excavators be fitted with?

7. Single-bucket excavators are self-propelled, aren’t they?

8. Where are they mounted on?

9. What are the main components of single-bucket excavators?

10. Are multi-bucket excavators used for digging trenches?

11. What kind of work are they used for?

12. Are buckets secured to either endless chain or large wheels diameter wheel?

13. How are multi-bucket excavators classified?

Road construction

Roads are built of different materials. Here are some of them. Road metal is a mass of stones, broken up for use in making or mending roads.

Concrete is a mixtures of cement, gravel, sand and water which becomes hard when dry.

Tar and asphalt are mixtures of complex organic components. The foundation of rock or stone upon which a road is built is its road-bed.

Every road has its surface which may be smooth or rough. Sometimes a road is covered with flat stones to make a pavement.

Pavement is the covering of a road or a street made of flat blocks of wood, stone or asphalt. Now pavement is often a paved path for foot-passengers at the side of a road. In the USA it is called a sidewalk. That part of a road that is especially used by wheeled traffic is called a carriage way.

When a road is damaged it must be repaired. People employed to keep roads in repair are called roadmen or road-menders.

Vocabulary:

1. road metal – щебенка

2. concrete (n) – бетон

3. tar (n) – деготь,гудрон

4. compound (n) – соединение

5. road-bed – грунтовое основание, земляное полотно

6. surface (n) – поверхность, покрытие

7. smooth (adj) – ровный, гладкий

8. rough (adj) – грубый, неровный

9. flat (adj) – плоский

10. path (n) – путь

11. foot-passenger – пешеход

12. sidewalk (n) – тротуар

13. wheel (n) – колесо

14. carriage-way – проезжая часть дороги

15. roadmen – дорожные мастера

16. damage (v) – разрушать, повреждать

17. mend (v) – ремонтировать

18. repair (v) – ремонтировать

19. pave (v)– мостить

20. pavement (n) – мостовая, покрытие

21. cover with (v) – покрывать

Questions to the text:

1. What materials are roads built of?

2. What do we call road metal?

3. What is concrete?

4. What do we call a road-bed?

5. Give a synonym of the world “surface”.

6. Give a synonym of the word “Sidewalk”.

7. What kind of surface may a road have?

8. What is a road surface made of?

9. What is a carriageway?

10. Give a synonym of the word “carriageway”?

11. What does the word “to repair” mean?

12. Who repair roads?

Types of bridges

Bridges are classified into cantilever bridges, arch bridges, girder bridges and suspension bridges. There are also bridges of mixed type.

A cantilever bridge is the earliest and the simplest type of bridge. The span of this bridge isn’t usually long. An arched bridge consists of an arch, a deck, columns and abutments. Arches require abutments to resist the push that results from their tendency to spread when they are loaded. The suspension type of bridge is a modern development. A suspension bridge is the safest structure known to bridge engineers. It is most economical in comparison with other types. No falsework is needed, it is easily constructed, using materials that are easily transported. A suspension bridge consists of the following parts: the towers, the anchorages, the cables and the stiffening truss. The main carrying member is the cable. The towers are built of stone or steel. The anchorages are generally built of masonry or concrete. The suspension cables are made of steel wires.