2020-04-07
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Long-span bridge-building, the 20th century long-span bridge-building, suspension bridge construction principle, suspension bridge construction completion, modern suspension bridge building techniques; road traffic, road traffic problem, growing road traffic problem, growing road traffic problem solution; eyebar chain, eyebar chain span, self-anchoring eyebar chain.
IV. Read and tell about the peculiarities of the George Washington bridge.
THE GEORGE WASHINGTON BRIDGE, NEW YORK, USA
It was a long time dream of the Swiss engineer Othmar Amman to build bridge across the Hudson River.
The George Washington Bridge construction began in 1927. It was opened for traffic in 1931 and became the new example of suspension bridge construction art. It had side spans of only 186m (610ft) each when those on the Brooklyn had been substantially longer at 283m (930ft). The four suspension cables contained between them 107,000 miles (172,000km) of wire.
The George Washington Bridge presented its builders with a comparatively easy task. The west bank anchorage was ideal, driven direct into hard rock, although the east bank required the excavation of a huge cavern, which was then filled with mass concrete in order to create a firm anchorage. For the towers, there was no need for difficult caisson-sinking, as there had been on the Brooklyn Bridge. The George Washington's east tower could be constructed on dry land, although the piers for the west tower still had to be founded well below water level. For this, two huge sheet steel cofferdams were used, driven to a maximum depth of 26m (85ft) and then pumped out so that construction could be made in the dry.
Originally, it was intended that the bridge would have two decks, with eight lanes of roadway above and an urban rapid-transit rail line below, but during construction the latter was abandoned. Amman calculated that the length of his bridge and its mass, 56,000 tons of steel in total, were enough for him to rely on the 3m (10ft) thick plate-girder deck for sufficient stiffness. He was right; his bridge proved stable for the next 30 years. The second deck that had originally been designed was added in 1962 to meet the requirements of increasing road traffic.
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THE GEORGE WASHINGTON BRIDGE FACTS
Suspended span 1O67m/3,500ft; depth of stiffening truss 8.8m/29ft; height of towers 183m/600ft; width of deck 36.3m/119ft; original depth to span ratio 1:350; depth to span ratio 1:90 with stiffening truss.
VII. Fill in the box using information from the text.
| George Washington | Brooklyn | |
| The date of construction | 1865-1867 | |
| Engineers who constructed the bridges | John A. Roebling, Washington Roebling | |
| The length of the suspension spans | 322 m (1,057 ft) | |
| The type of tower construction | Caisson-sinking | |
| The type of traffic passing on the bridge | Road traffic |
VIII. Make a short presentation about one of the suspension bridges in the world. As a hint you can describe the Camden bridge using the following plan.
1. The name of the bridge The Camden Bridge
2. The place of construction Philadelphia
3. The date of construction 1926
4. The name of the constructor American cable company
5. The type of construction suspension
6. The longest span length 564 m (1,850 ft)
7. The type of traffic Road and railway
8. The material used for construction Steel
UNIT 5. THE PROGRESS IN SUSPENSION BRIDGE BUILDING
I. Match the words with Russian equivalents.
1. collapse a) шторм
2. gale b) стренга, прядь
3. hazard c) предел
4. pressure d) анкерное крепление
5. margin e) вред, опасность
6. strand f) провод
7. anchorage g) давление
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8. wire h) катастрофа
II. Match the words on the left to the synonyms on the right.
1. collapse a) rival
2. link b) problem
3. hazard c) limit
4. challenge d) connection
5. margin e) danger
6. competitor f) peculiarity
7. feature g) accident
III. Translate the following attributive groups.
Suspension bridge collapse, suspension bridge collapse reason, suspension bridge collapse reason investigation; girder design, plate girder design, tremendous plate girder design; pier foundation, concrete pier foundation, massive concrete pier foundation, massive concrete pier foundation design; safety margin, bridge safety margin, bridge strands safety margin, bridge strands safety margin calculation.
IV. Make sentences. Write the words in the correct order.
1. 270 /has/ metres/ The /sea /of/ depth /a – The sea has the depth of 270 metres.
2. deep/ is /metres/ 25/ river /The - __________________________________
3. is/ metres/ 330/ span /long/ The - _________________________________
4. a /160 /The /height /metres/ of/ have/ pylons -________________________
5. the/ 22 /kilometers/ length /The /road /of/ is - ________________________
6. width /has/ 8/ deck /The /metres /of /a - __________________________ ______________________________
V. Make Active sentences Passive. Use the model:
Engineers thoroughly learnt the lessons of suspension bridge collapse. The lessons of suspension bridge collapse were thoroughly learnt by engineers.
1. Authorities appointed famous engineers to design the new bridge.
2. Thick ice-drifts blocked the Mackinac Straight in winter.
3. The designer ensured a special span structure for aerodynamic stability.
4. The builders anchored the foundation in rock 60 m below water level.
5. Strong winds hit the bridge sides every winter.
VI. Read and translate the text.
