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Ancient and modern bridges in this country have much in common. The Anji Bridge in Hebei Province was completed around the year 599, during the Sui Dynasty. It is the oldest surviving open spandrel stone arch bridge in the world. The width of the bridge deck is 10 m. The arch stones are about 1 m thick and 0.25 – 0.4 m wide so that the arched rings vary in width from 9.0 to 9.6 m. Thus, the external rings of the parallel longitudinal arches incline slightly inward, helping to resist collapse.

Between adjacent stones of each arch, two X-shaped iron anchors were placed, about a third of which survived until the mid-1950s, when major repair work was undertaken. It is worth noting that prior to this repair work the Anji Bridge was still open to truck traffic. However, some of the arched rings had collapsed several times during the long history of the bridge.

To consolidate the transverse junction between arched rings, 5 iron bars with capped heads were installed, as was an anchorage bar. A protective layer of facing stones was applied to the upper surface of the main arch. Additionally, 6 L- shaped stones, each 1.8 m long were fitted on each side of the bridge.

The abutments were built up using 5 layers of stone with total thickness of about 1.55 m and a width slightly greater than that of the arch. These stones rest directly on layers of natural coarse sand and are much lighter than normally found in ancient stone bridges.

Some original stones protecting the arches remain in use on side faces. Others in the middle field of the arch have been replaced by cover slabs made of reinforced concrete – with toothed connections. Cement mortar was also used, and additional layers of waterproof materials were applied.

After 1949, many open spandrel stone arch bridges were constructed in China, some with main span lengths of over 100 m, such as the Rainbow Bridge (1961) in Yunnan Province and the Jiuxigou Bridge (1971) in Sichuan Province, These were the longest open spandrel stone arch bridges in the world when they were built. Currently, the longest such span is found on the bridge completed in 1991 across Wuchao River in Hunan Province. This is an arch bridge with two ribs and a clear span of 120 m. Thus, the stone arch open spandrel bridge has continually developed in China throughout the course of history.

Timber cantilever bridges are found throughout China. Because timber beams cannot span long distances, and because of the difficulties in constructing piers in deep valleys and riverbeds in ancient times, the cantilever technique of bridge construction was developed.

According to literary sources, timber cantilever bridges were constructed in China as early as the 2nd century. A 5th century geographical survey “Annotations to River Couige Systems” records a timber cantilever beam bridge with span of more than 13 m in Gansu Province.

The Lu River Bridge in Hunan Province was an 8-span continuous cantilever bridge with stone piers and timber beams. The distance centre-to-centre be-

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tween the piers was about 21 m. The span between cantilever ends was about 10 m. This bridge was first constructed in the Southern Song Dynasty (1127-1279), and repaired and reconstructed many times subsequently.

One later repair used 3 long timber beams bound together and connected with iron nails. More than 10 such longitudinal beams were placed at every pier, each with a cantilever of about 1.3 m. On this base, a layer of longitudinal beams followed by another of transverse members were repeatedly piled up to a total of more than 20 layers. Finally, the beams over the cantilevers were erected and inclined timber struts were added later at the 4th layers of timber cantilevers.

Today, the longest continuous box beam bridge in China is the pre-stressed concrete LiUku Bridge over the Nir River in Yuiman Province, completed in 1990 with a maximum span of 154 m. The Second Qiantang River Bridge is a box beam highway bridge constructed parallel to a railway bridge and completed in 1992. Both bridges are continuous, with 18 spans of 45 + 65 +14 x 80 + 65 + 45 = 1340 m without internal expansion joints.

A bridge over the Whitewater River in Gansu Province was first mentioned in literature as early as the Western Jin Dynasty (266-316). At the, end of the 19th century, the Yinping Bridge was reconstructed as a timber cantilever beam bridge and remains in service today. The supports of this bridge are constructed of 10 gradually cantilevered layers of timber, the ends of which are raised to achieve a large angle, of elevation. These cantilevers not only reduce the span of the bridge, but also assume the function of inclined struts.

Cantilevering techniques, with ever larger angles of elevation formed by the overhangs of the piled layers, evolved into timber strut arch bridges using individual inclined struts. A typical example is the Gannan Bridge in Gansu Province, a type that serves as a precedent for modern strut-frame bridges.

Two methods for constructing chain suspension bridges are drawn from the Ming Dynasty book, written around 1600. Later in the 17th Century, the German C. C. Schraman painted the iron chain Yuringn Bridge and attributed it to the 1st century. The suspending chains were joined with the horizontal base chains, so it can be only considered a flexible suspension chain bridge without stiffening girders.

As for chain bridges with stiffening girders no ancient examples survive. Since wood was the only material likely to have been used for stiffening girders, it is difficult to imagine timber girders with very large spans, although middle piers were apparently sometimes employed.

The largest modern suspension bridge in China is the Dazi Bridge in Tibet, with a main span of 500 m. The largest composite cable-stayed bridge of double tower form in China is the Nanpu Bridge in Shanghai, completed in 1991, with a main span of 423 m. At present, several cable-stayed bridges with a main span length of 400 m and more are being constructed in China. These projects include the composite cable-stayed Yangpu Bridge in Shanghai with a main span 602 m

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and other prestressed concrete cable-stayed bridges with main spans exceeding 400 m. All these bridges are for highway use.

III. Find 9 pairs of antonyms:

add; modern; repair; consolidate; develop; ancient; resist; demolish; assist; divide; suddenly; upper; heavy; bottom; light; confine; reduce; gradually

IV. Match the beginnings and the endings of the sentences and arrange them in the correct order according to the text.

1.Ancient and modern bridges in a) … a precedent for modern strut-

V. Read the text once again and complete the tables (but first copy the tables into your notebook).

The Anji Bridge

The LiUku Bridge

location

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year of construction

type

maximum span length

number of spans

total length

VI. Complete the following sentences by writing no more than three words for each answer:

1.Bridge building in China has a ________ history.

2.In middle of the 20th century ________________ bridges were constructed in China.

3.It was decided to develop the cantilever technique of bridge construction because of some problems connected with ___________________________.

4.Timber strut arch bridges appeared due to _____________________.

5.There were no ancient chain bridges with ______________________ in China.

6.Nowadays in China there are several _______________ and _____________

bridges.

Home Exercises

I.Memorize the words from Ex. I page 98.

II. Translate from English into Russian. Discuss the translation in your group.

1.Stones protect the arches.

2.He stones cherries.

3.This plant can’t be layered.

4.The abutments consist of 5 layers.

5.Don’t forget to wood.

6.Wood stiffened girders.

7.The road parallels the river.

8.This house is timbered.

9.Timber beams cannot span long distances.

10.He longed to be a chief engineer.

III. Get ready to tell a collective story about bridges in China using Ex. VI as a plan.

Text 26 

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I. Read the text and define the words in bold.

OUNASJOKI BRIDGE

One Finnish periodical gives some details on the Ounasjoki Bridge located on the highway № 4, at the border of the city of Rovaniemi, which is on the Arctic Circle. It crosses the river Ounas.

The structure is 4 span concrete box girder, prestressed both in longitudinal and transverse directions. Its overall length amounts to 254 m; the two central spans are each 70 m long. Abutments and piers are founded on bored piles.

The bridge was erected according to a cantilever method. The concrete deck was poured in 3.50 m with the aid of a trolley suspended from the cantilever. The choice of the method was influenced by the tight schedule due to climatic factors, giving very little time for the erection of the centering and pouring of concrete. The first end span, followed by a cantilever, 22.75 m long, was poured on forms supported by the scaffolding inside a protective cover. The outside temperatures at that time varied from –20˚ to – 30˚C.

After this stage concreting was continued by the cantilever method. As the length of the cantilever grew, it was suspended by means of cables on mast and by a temporary support until the next pier was reached. The same stages were repeated for each span; and when the opposite shore was reached the trolley was dismantled.

The cantilever method proved quite satisfactory for these arctic conditions. Special precautions were taken to protect concrete against frost such as heating concrete during laying, etc.

The bridge was constructed for the National Road of Public Roads and Waterways by A-Betoni Oy Company.

II. Translate into Russian.

Climatic factors; concrete deck; longitudinal directions; special precautions; central span; outside temperature; transverse direction; temporary support.

III. Read the figures and say how they are used in the text.

4 3.5

2 22.75

IV. Work in pairs. Ask and answer the questions.

1.What is overall length of the Ounasjoki Bridge?

2.According to what method was this bridge erected?

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3.Why was this method used?

4.When was the trolley dismantled?

V. Work in pairs. Correct your partner according to the model.

Model: The Ounasjoki Bridge is located on the highway № 2. - Oh, no.

You are wrong (Nothing of the kind! It’s not true. ). As far as I know, it is located on the highway № 4.

This bridge was erected according to a suspension method. Abutments and piers are founded on box piles.

The concrete deck was poured with the aid of a temporary support. The bridge was under construction in summer time.

All the spans were erected in a different manner.

VI. Fill in the diagram and describe the way of Ounasjoki Bridge construction.

OUNASJOKI BRIDGE

concrete deck _________

first end span pouring

___________ by cantilever method

suspension by ____________

trolley dismantling

Home Exercises

I.Form the nouns from the verbs and use them in your own sentences.

To protect; to erect; to repeat; to heat; to construct; to suspend.

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II. Change the following sentences according to the model.

Model: It is necessary to examine the accuracy of these results.

1.The progress of the work depends on how efficient the organization is (efficiency).

2.The type of pump used will vary according to how much liquid is being pumped (amount).

3.It is necessary to test how much concrete will be consumed (quantity).

4.It is doubtful how accurate the results are (accuracy).

5.It is not clear whether these calculations are correct (accuracy).

Text 27 

I. Look through the text and cross out the items which do not fit in the content.

Bridge location. Bridge construction. Bridge structure. Way of traffic passing.

Replacing the structure. Decision to replace the structure.

II. Read the text and check your answers.

A UNIQUE TRANSPORTER HIGHWAY BRIDGE

The city of Duluth, Minnesota, which is situated at the head of Lake Superior, owns and operates a most unique type of highway bridge. The highway connecting Duluth with a strip of land behind which the harbour is located is crossed by the harbour entrance through which a large number of boats passes during the period of the year when the lake is open to navigation.

At the time that the bridge was constructed the highway traffic was relatively small and a type of structure was desired so that the shipping would be interfered with as little as possible. Such a requirement was found to be met by the transporter type of structure, this type of bridge consisting of an overhead frame of steelwork upon which a carriage moves back and forth.

Shipping is therefore free to pass at all times without it being necessary to open the bridge as would be the case if a movable span structure had been used. Highway traffic consisting of foot passengers or vehicles is loaded on the carriage on one side of the Channel and carriages propelled by electric motors moves to the other side and the vehicles unloaded.

For a number of years this bridge has served very satisfactorily but recently

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the highway traffic has increased so much that vehicles are delayed and have to wait in line for their turn to be carried across. So the city has deemed it necessary to replace this structure with one of the ordinary type of movable spans so that vehicles traffic will be served with less inconvenience. This transporter type of bridge is used rather extensively in Europe but the structure in Duluth holds the distinction of being the only one of its kind serving highway traffic in the United States.

III. What notion is described?

-an area of water protected from the open sea by land or walls, in which ships can shelter;

-a large vehicle used for carrying heavy objects;

-to change position;

-a time when each member of a group must or may do something;

-movement of ships over water

IV. Complete the sentences.

1.A unique type of highway bridge is situated …

2.The transporter type of structure was chosen because…

3.Passengers and vehicles were carried by…

4.Because of highway traffic increase…

5.This transporter type of bridge is the only in…

V. Match the town and the bridge situated in it. Can you describe each of

Text 28 

I. Match the Russian and the English equivalents. Use the English words in the sentences of your own.

повторение

место

полый

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II. Read the text and express the main idea.

BRIDGING THE CHANNEL

The type of the bridge proposed for the Channel crossing with accommodation for road and rail traffic would consist of a long series of standard repetition spans of about 740 feet, each on concrete supporting piers and with such longer spans, at intervals, as may be required for navigation of larger craft. Some 800.000 tons of structural steel would be necessary for the superstructure of such a bridge.

The construction of a bridge of such a size and type presents problems and opportunities quite different from those encountered in normal structures. Its construction requires the fullest adoption of mass production methods at all stages of work.

The principle construction hazard of a Channel bridge lies in the prevailing weather conditions. These invite a scheme with the highest possible degree of preassembly on shore and the minimum of work on the actual site of the bridge.

The concrete piers on which the bridge spans would rest must be prefabricated on shore in large hollow sections, launched and floated to their permanent sites where they can be sunk into position with the aid of equipment on mobile working platforms.

III. Complete the sentences using the text.

1.The bridge for the Channel would consist of…

2.For the superstructure of such a bridge it would be necessary…

3.The construction of the bridge requires…

4.The concrete piers must be…

IV. Answer the questions.

1.What is the type of the bridge proposed for the Channel?

2.For what purpose do we need long spans?

3.For what part of the bridge would some 800.000 tons of structural steel be necessary?

4.What methods are necessary for the construction of this bridge?

5.Where must the concrete piers be prefabricated?

Home Exercises

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