Freyssinet and the Plougastel bridge, Brittany, France

 

After Robert Maillart, Eugene Freyssinet (1879-1962) was the second great name in early 20th-century concrete bridge building. A graduate of the Ecole des Ponts et Cbaussees, he began his career in 1907 as a junior engineer at Moulins in south central France. The local highway department was preparing to replace three old sus­pension bridges over the River Allier. Freyssi­net offered to build all three for the price of the one — to his own reinforced-concrete bridge designs. His offer was accepted, and he was given sole responsibility for the work.

During the construction Freyssinet carried out tests, in which he linked the bases of an arch with steel bars under tension to observe its pattern of movement. As a result, he was the first to discover concrete "creep" — the slow compaction which continues to take place after solidification.

The huge structure of three 180m (592ft) seg­mental arch spans across the Elorn estuary near the town of Plougastel in Brittany, which Freyssinet completed in 1930 after five years' work, broke all records for bridges in reinforced concrete. His structure was of monumental clarity and simplicity: enormous, hollow, concrete-box arches rose to a height of 27.5m (90ft) at their centres, where they were 4.5m (14ft 8in) deep and 9.5m (31ft) wide. It was the first time that Freyssinet had employed a concrete-box structure, and he put the three spans on their places by building a huge wooden arch which was supported at each end on a floating concrete barge and tied for stability. Then he used it successively as formwork for each concrete arch. The twin trussed deck was then built on vertical elements of reinforced concrete.

The Plougastel Bridge's greatest importance lay in Freyssinet's investigation of concrete creep, which led to his realization of the technology of prestressing.

VIII. What do the following numbers in the text refer to:

1879-1962, 1907, 592ft, 1930, 27.5m, 4.5m, 9.5m.

IX. Complete the sentences with the words from the box:

Reinforced concrete creep prestressing structure formwork     spans

1. To construct cheaper bridges Eugene Freyssinet suggested to use ________.

2. Technology of ________appeared after investigation of concrete creep.

3. Eugene Freyssinet discovered concrete ______after solidification.

4. To support concrete arches ________were used.

5. Concrete arch ________were the examples of monumental clarity and simplicity.

6. It was the first time when Freyssinet had employed a concrete-box ________.

 

X. Fill in the chart using the information from the text. Make a short presentation of the bridge according to the plan:

The date of the Plougastel bridge completion./The type of the bridge./The material used./The number of spans./The length of spans. /The height of the arches. /The depth of arches in the centre./The width of arches in the centre.

 

UNIT 7.  EXAMPLES OF SOME MODERN LARGE CABLE-STAYED BRIDGES

I. Match the words on the left and their Russian equivalents on the right.

1. cast in-situ concrete                          a) опоры

2. equilibrium                                  b) пейзаж

3. cable stay                                             c) точность

4. scene                                            d) равновесие

5. precision                                      e) монолитный бетон

6. pillars                                          f) долина

7. valley                                           g) ванта

 

II. Read and translate the attributive groups.

Southern France cable-stayed multi-spanned bridge; the 12^th world highest bridge deck; the 2006 International Association for Bridge and Structural Engineering Outstanding Structure Award; steel reinforced concrete construction; cable-stayed bridge traditional building method; 343.0 metres cast-in-situ concrete mast; economically efficient cable-stayed bridge design; French engineering genius, structure precision computer calculations; structure computer calculation accuracy; A75 motorway route, cable stays anchorage zone, span cross-section shape.

 

III. Match the parts of the bridge and their definitions.

1) cable                              a) part of the bridge the cars drive on

2) deck                               b) the distance from one pier of the bridge to the other

3) pier                                c) a bridge whose deck is directly supported from pylons by straight cables

4) pylon                             d) a thick, strong, metal rope

5) span                              e) a tall, strong column which holds a bridge up

6) cable-stayed bridge        f) a tall tower that holds heavy wires

 

IV. Add the words in the box.

Adjective Noun

high   _____

long   _____

________   depth

wide   ______

V. Complete the sentences with the correct word in brackets.

1. The ______ of the road is 6 m. (wide/width).

2. The river is 230 km _______ (long/length).

3. The sea has a ________of 330 m (deep/depth).

4. These pylons are over 80 m _______(high/height).

5. These oil wells are more than 700 m _______(deep/depth).

6. The total ______of the road is about 120 km. (long/length)

7. The tunnel is 15 km_______ (wide/width).

8. The______of the bridge is 130 m (high/height).

 

VI. Read and translate the text.