Suspension bridges

The principle of a suspension bridge is simple. A suspension bridge has three essential parts: the towers, the anchorage and the cables. The roadway and the stiffening construction have local importance, but both may be wholly or partially destroyed without causing the collapse of the bridge. In all other types of bridge construction, the failure or buckling of a single truss will cause the collapse of the entire structure. So a suspension bridge is the safest type of construction.

The towers for suspension bridges have been built of wood, of stone and of steel, the last named representing the most modern development. The height of the towers depends upon the amount of sag adopted for the cables, which for maximum economy should be between one eighth and one twelfth of the span.

The anchorages have the function of securing the ends of the cables. Weight is therefore a prime thing, so the anchorages are generally built of masonry or concrete except in favoured location where it is possible to anchor the cables in natural rock.

The cables are the most important element of a suspension bridge, for these carry the roadway and give the structure its character. The construction of cables of large dimensions is simpler than it seems and less danger is involved than in the erection of most other types of bridges.

EXERCISES

I. Match the synonyms:

1. cause 1. total
2. collapse 2. make
3. entire 3. failure
4. anchor 4. seem
5. appear 5. secure

II. Pay attention to the translation of the underlined words:

Some - некоторый, несколько

Same - тот же самый, одинаковый

1. I should like to mention some famous suspension bridges which are well-known in the world, They are: the Brooklyn Bridge, the Golden Gate Bridge, the George Washington Bridge, the Tacoma Bridge. 2. A new project has been prepared for exactly the same load and conditions with the same span.

III. Translate the sentences into Russian, paying attention to the function of “should” and “would”:

1. A modern bridge demands greater skill from a designer for many things should be taken into consideration. 2. Everybody should acquire certain skill to work in caissons. 3. It was known that a temporary bridge would be built during the reconstruction of the bridge. 4. The designers required that the width of the bridge should be increased. 5. Had the bridge been rebuilt it would have met the modern traffic requirements.

IV. Translate the sentences, paying attention to the predicates:

1. A large group of designers was invited to the conference. 2. The report of the chief engineer about the new methods of construction was listened to with great interest. 3. The new ways of assembly the prefabricated parts were paid great attention to. 4. The causes of the bridge collapse were much spoken about.

V. Build up two sentences, using the following words:

Suspension bridge, main parts, consist of, superstructure, foundation has, any, substructure, deck, pier, cable, tower, following, anchorage.

VI. Translate from Russian into English:

1. Проезжая часть висячего моста должна быть достаточно жёсткой. 2. С эстетической точки зрения (artistically) вид висячего моста в основном определяется конструкцией пилонов. 3. Примерами знаменитых висячих мостов являются Бруклинский мост, мост «Золотые ворота», мост Джорджа Вашингтона, мост Такома. 4. Каждый из этих мостов имеет свою историю строительства. 5. Инженер-мостовик должен знать историю строительства висячих мостов.

VII. Complete the following sentences according to the text:

1. A suspension bridge has… 2. A suspension bridge is… 3. The towers of the suspension bridge were built of… 4. The height of the towers depends upon… 5. The amount of sag should be… 6. The cables are the most important elements of a suspension bridge for…

VIII. Give the definition to a suspension bridge.

IX. Read the following text without a dictionary:

THE GEORGE WASHINGTON BRIDGE

The George Washington Bridge was opened to traffic in the middle of the twentieth century. This bridge, at the time of building, was the longest bridge in the world. The George Washington Bridge is still considered one of the heaviest suspension bridges in the world, designed to carry the greatest loads.

Although construction problems in the building of the George Washington Bridge were sometimes unusual, better natural conditions for a large suspension bridge could scarcely be found. The ground on both sides of the river is high, and rock lies near the surface. This hard, basaltic rock also makes a natural anchorage for a suspension bridge.

X. Retell the text according to the following scheme:

1. The type of a bridge
2. The place of its construction
3. The construction period
4. The time for opening for traffic
5. Technical innovations
6. Distinctive features of the bridge

XI. Speak about great suspension bridges in the world.

VIII

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