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II. Answer the questions:

1. What do cantilever bridges consist of?

2. How are the two cantilevers joined together?

3. What are the two sections of each cantilever?

4. How are the free ends joined together?

5. What does a center span consist of?

6. What are cantilever bridges made of?

7. Why are suspension bridges considered to be the most impressive type of bridges?

8. What is the length of the main span?

9. Where are suspension bridges built?

10. How many cables does a suspension bridge have?

LANGUAGE FOCUS

III. Match the meanings of these terms with their definition:

suspension bridge, anchor arm, cable, cantilever bridge, suspender, anchorage

1. A bridge made of two cantilevers whose projecting ends meet but do not support each other.

2. A bridge that has its roadway hung on cables and chains between towers.

3. A part of a cantilever bridge between the shore and the pier.

4. A place to anchore.

5. A strong thick rope, now usually made of wires twisted together.

6. A thing that suspends

IV. Translate:

A refinement of the beam, called a cantilever, is used to construct bridges with even longer spans. In simple cantilever bridges, such as those that are found in many parts of Asia, the structure rests on crisscrossed log foundations with narrow bases that flare outward as they rise to support the roadway. A modern cantilever bridge may use only two intermediate piers set a short distance from either bank. The main support members of a suspension bridge are parallel cables composed of thousands of individual strands of wire. These run, supported by each tower and curving at the middle, the entire length of the bridge and are anchored on either end.

V Insert the words from the list:

cables, roadway, diagonal, railroad, tower,

cantilevered, load, beam-bridge, outward,

self-supporting, suspended span, scaffolding, rigidity, trains

1. Cantilever bridges are a more complex version of a design. In a cantilever design, a … is built on each side of the obstacle to be crossed and the bridge is built … or … from each tower. The towers support the entire … of the cantilevered arms. The arms are spaced so that a small: can be inserted between them. Cantilever bridges are … during construction. They are used in situations in which the use of … or other temporary supports would be difficult.

2. Suspension bridges consist of two large or main … that are hung from towers. The … is suspended from smaller vertical cables that hang down from the main cables. In some cases … cables run from the towers to the roadway and add … to the structure. Suspension design is rarely used for … bridges, because … are heavier and can travel faster than highway traffic.

VI. Make the precis of the text

Text 5. CABLE-STAYED BRIDGES

Cable-stayed bridges resemble suspension bridges. Both have roadways that hang from cables, and both have towers. In a cable-stayed bridge, however, the cables that support the roadway are connected directly to the towers.

A cable-stayed bridge may be used if its foundation can support only one tower. Most cable-stayed bridges have three spans, but some have one tower and two spans. The most efficient cable-stayed bridges have a main span about 700 feet (210 meters) long.

The cables of a cable-stayed bridge may be linked from the roadway to the towers in several ways. The cables may extend from various points on the roadway to the tops of the towers, forming a radiating pattern. The cables form a fan pattern, also called a harp pattern, if they are connected from a variety of points on the roadway to several points on the towers. It the cables are attached from one point on the roadway to various points on the towers, they form a star pattern.

Moveable bridges

Moveable bridges have a roadway that is moved entirely or partially to provide enough clearance for large ships to pass. There are three types of moveable bridges, bascule bridges, vertical lift bridges, and swing bridges. A bascule bridge tilts upward to open. Some bascule bridges open at one end, and others the middle. A vertical lift bridge has a roadway that extends between two towers. The roadway rises between the towers, and ships pass underneath. A swing bridge is mounted on a central pier. The bridge swings sideways to enable ships to pass.

Bascule bridge

Vertical lift bridge

COMPREHENSION CHECK

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