Comprehension check

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I. Decide whether the following statements are true or false according to the text:

1. The primary materials used for bridges have been iron and concrete.

2. Prestressed concrete is made of sand, gravel and cement.

3. Though wood is weak in compression and tension it has been widely used because it is cheap.

4. As stone is strong in tension and weak in compression it has been used in arches and piers.

5. Cast iron was first used during the industrial revolution.

6. Steel is stronger, superior to any iron in both tension and compression.

7. Concrete is strong in tension and weak in compression.

8. As steel carries all the tension, reinforcement allows to use less concrete.

9. The holes for tendons are curved inside.

II. Answer the questions

1. What materials are used for bridges?

2. What are modern bridges built with?

3. Why was wood widely used in the construction of bridges?

4. When was iron first used?

5. What is the difference between cast iron and wrought iron?

6. What is concrete?

7. What is reinforced concrete?

8. What does post-tensioned prestressing involve?

9 What puts the beams into tension?

10 What makes bridges lighter and less expensive?

LANGUAGE FOCUS

III. Match the meaning of the terms with their definition.

Wood, concrete, stone, iron, steel

1 The hard, compact mineral material of which rocks are made up.

2 The hard, fibrous substance beneath the bark of trees and shrubs.

3 An alloy of iron and carbon.

4 A mixture of cement, sand, gravel and water that hardens as it dries.

5 The commonest and most useful metal, from which tools and machinery are made.

IV. Insert the words and translate the sentences.

Ductility, strength, steel, dactile, form, yield, cast iron, difference, tension, spans

Amongst bridge materials … has the highest and most favourable strength. It is therefore suitable for the most daring bridges with the longest … A special merit of steel is its … due to which it deforms considerably before it breaks, because it begins to … above a certain stress level. For bridges high … steel is often preferred. The higher the strength the smaller the proportional … between the yield strength and the tensile strength. This means that high strength steels are not as … as those with normal strength. For building purposes, steel is fabricated in the … of plates by means of rolling when red hot for bearings and some other items … is used for members under … only, like ropes or cables there are special steels