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X. Copy the table and complete it comparing timber, stone and metal bridges.

XI. You are given a task to design a bridge over the Irtysh River. What bridge it will be (timber, masonry or metal)? Explain your choice.

Home Exercises

I.Memorize the words from Ex. I page 45.

II. What is the Russian for:

at present, is next to nothing, as compared to, such as, to pay due attention, as for

Use these word combinations in the sentences of your own.

III. Correct the statements. The first example is made for you.

1. The first cast iron bridge is being built now in Great Britain.

–No, it is not. The first cast iron bridge was built in Great Britain in 1779.

2. In the 20-th century bridges were erected using wrought iron.

–No, ……………………………………………………………………………

3.Steel is difficult to recondition as compared to other building materials.

– No, ……………………………………………………………………………

4.Metal superstructures are the best for short and medium spans.

–No, ……………………………………………………………………………

5. Metal bridges have more disadvantages than advantages.

–No, ……………………………………………………………………………

6. Welding is the most reliable method as compared to rivets and bolts.

–No, ……………………………………………………………………………

Text 11 

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Find the words you have read in the text below and translate the word combinations having these words. Use the words in the sentences of your own.

II. Work in pairs. Think of 2 or 3 questions using the words from Ex. I. Answer the questions of your partner.

III. Look at the title of the article. What do you think it is about? Say words you expect to find in the text.

IV. Read and check your guesses.

STEEL AND CONCRETE FOR HIGHWAY BRIDGES

The cost of bridges on motorways and other major roads can be cut significantly by a greater, and in some cases more efficient, use of steel instead of concrete in bridge construction, according to a report published recently by the Highway Directorate of the Department of the Environment. The report argues that it is possible to save up to 30% of the cost of many bridge decks by using steel for the main members. The British Steel Corporation and the British Constructional Steelwork Association were invited by the Ministry to participate in the study and retained an independent firm of consultants, C.J. Pell Prischmaun and partners, of 4 Manchester-Square, London W 1, to prepare new designs for bridges in consultation with Ministry. The study examined single and multi-span bridges, with spans ranging from 15 to 29 m, and the steel designs were based on the use of high tensile weathering steel (which does not require painting) to cut costs and eliminate maintenance. An alternative study was based on the use of nonweathering high tensile steel with a high-grade protection treatment system.

The Cement and Concrete Association has questioned the validity of the report and has said that the study attempts to draw comparisons between designs that are not comparable and that the steel designs prepared by the consultants do not comply with the Department’s own design criteria for bridges of this type. The Association also argues that the precast concrete beams examined in the study are less expensive than the compliers of the report assumed, whereas,

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since the time of the report, steel costs have risen some 10%. Another objection, says the Association, is that the steel designs are based on the use of weathering steel, which are not generally available.

V. Give Russian equivalents to the following word combinations: independent firm of consultants, single and multi-span bridges, high-grade protection treatment system, precast concrete beams.

VI. Find the definition of the following prepositions. Use the prepositions in the sentences of your own.

VII. Answer the questions to the text.

1.What is the way of cutting the cost of bridges on major roads?

2.What bridges were studied?

3.For what purpose was non-weathering high tensile steel with a high-grade protective treatment system used?

4.What has the Cement and Concrete Association questioned?

5.What are arguments of this Association?

VIII. Fill in the gaps without looking back at the text.

1.It is possible to save ... of many bridge decks by using steel for the main members.

2.The British Steel Corporation and the British Constructional Steelwork Association studied bridges with spans ranging....

3.The Cement and Concrete Association reported that weathering steel is not...

4.C.J. Pell Prischmaun and partners is...

IX. Give the summary of the text in 7 sentences.

Home Exercises

I.Memorize the words from Ex. I page 49.

II. Name the words, which these parts of speech were formed from: construction, significantly, recently, constructional, independent, consultation, treatment, comparison, comparable, precast, generally, available.

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combinations having these words. Use the words in the sentences of your own.

II. Work in pairs. Think of 2 or 3 questions using the words from Ex. I. Answer the questions of your partner.

III. Do you know the difference between the suspension and cable-stayed structures? Read the text and find the answer to this question.

SUSPENSION AND CABLE-STAYED BRIDGES

Suspension and cable-stayed bridges are often confused. The matter is that they have very much in common: stiffening girders or trusses, anchor supports and hangers. And besides their main carrying element is a flexible stayed cable.

The difference between these two bridge types is determined by the two following indications:

1.A suspension bridge has a curvilinear steel rope called a cable or a chain.

2.A cable-stayed bridge steel ropes are rectilinear. They are called cable stays.

The next indication is that suspension bridges usually have a continuous steel rope from the first tower top to the second one.

The Hamber Bridge in Great Britain is claimed as world record for a suspension structure because of its 1410 m span length. The cable-stayed bridge across the Freiser River in Canada has a 465 m span, which is the longest one for this sort of structures all over the world.

The basic advantages of the suspension and cable-stayed bridges are as follows:

1.They provide the possibility to construct very long spans from 500 to 1500 meters.

2.High efficiency of these structures is due to the fact that the weight of one square meter of such spans is considerably less in comparison with other bridge systems.

3.Suspension and cable-stayed bridges offer more aesthetic merits. No doubt these structures are most attractive.

The disadvantages of the suspension and cable-stayed bridges are as follows:

1.Low vertical stiffness, i.e. the structure greatly flexes under the live load.

2.Low horizontal stiffness, i.e. considerable shift due to the wind force in the horizontal plane.

3.High sensibility to the dynamic and aerodynamic loads.

High efficiency of the suspension and cable-stayed bridges is due to the following factors:

1.The builders use the high strength wire with rated resistance 10000 MPa.

2.The chains and cable stays work only in tension, which is much easier than to

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work in compression. Working in compression the bridge elements may loose their stability.

3.There is no slacking in cables and cable stays, so the tension concentration is reduced to the minimum value.

4.Hangers and cable stays work as piers supporting a stiffening girder at many points.

5.The stiffening girder is free from working for its dead weight, which is transmitted, to the cable and the towers. This girder behavior becomes possible due to the special erection technique.

To make a stiffening girder lighter the designers employ the force regulation in cable stays. This results in most acceptable force distribution in bridge elements beforehand.

IV. Guess the meaning of the words.

A hanger, a steel rope, vertical stiffness, horizontal stiffness, high strength wire, a designer, a square meter, resistance.

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ing. The process is repeated until the deck sections meet in the middle, where they are connected. The ends are anchored at the abutments.

Fig. 5

Fig. 6

IX. Tell your group mates everything you know about suspension and ca- ble-stayed bridges.

Home Exercises

I.Memorize the words from Ex. I page 52.

II. Copy and complete the table.

Text 13 

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II. Scan the text for about 10 minutes. For questions 1 – 3, choose the answer (A, B, C, D) you think fits best according to the text.

1.The ordinary supports are made of A steel.

B timber. C concrete. D limestone.

2.Footings are subdivided into

A monolithic and precast footings.

B large and small footings.

C cable and hinged footings.

D shallow and deep footings.

3. Builders make additional grouting bed

A to strengthen the surrounding ground in the water. B to exhaust the water.

C to place the falsework.

D to avoid the shrinkage cracks.

III. Now read the text carefully and check your answers.

SUPPORTS AND FOOTINGS CONSTRUCTION TECHNOLOGY

In most cases bridge supports are made of concrete and reinforced concrete. Steel supports are employed for over bridge and trestle bridges but not so fre-

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quently.

The ordinary supports made of concrete may be subdivided into three groups according to the construction technology:

1.Monolithic supports. The concrete is placed against the falsework in situ. The falsework determines the supports shape and dimensions.

2.Precast supports. The supports are mounted of the prefabricated concrete blocks.

3.Combined supports (precast with cast-in-place concrete supports). This sort of supports is practiced on a large scale and represents the structures assembled from the precast concrete blocks and monolithic concrete placed in situ.

Technological process of the support footing erection may be rather various and depends on a support structure. This process may be influenced by the geological conditions, ground firmness, type and dimensions of the supports, loads from the spans and supports.

First, footings are subdivided into two large groups: shallow footings, deep footings.

Shallow footings are usually designed as monolithic ones on the natural bed. This is one of the simplest and rather cheap technologies but it can be employed only for firm grounds. The construction of such footing begins from the pit working. If a pit is excavated rather deep in a dry place for the abutments and over bridge supports as well as viaduct and trestle bridge supports, the builders employ a sheet piling. The same is done if a pit is excavated on a riverbed.

A sheet piling is made of metal bars driven to the calculated depth into the ground by a pile driver. Then several pumps exhaust the water from the sheet piling and after that the builders erect a falsework and install a reinforcement. Then they place concrete against the falsework and ram it in place. As a rule, the reinforcement does not work in tension but resists to the shrinkage cracks appearing during concrete setting.

The most difficult work is to place the concrete for pier footings erected on the riverbed. The matter is that despite the pumps working some water enters the pit. That is why the builders make additional grouting bed to strengthen the surrounding ground in the water. And then they place the footing itself.

IV. Guess the noun which goes with the adjectives. Make up one sentence using all these 5 nouns.

1)timber, concrete, steel _ _ _ _ _ _

2)monolithic, precast, combined _ _ _ _ _ _ _ _

3)reinforced, prefabricated, precast _ _ _ _ _ _ _ _

4)difficult, interesting, home _ _ _ _

5)deep, coal, refuse _ _ _

V. What notions are described below? How are they reflected in the text?

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