Exercises:

Match English and Russian bridge terminology:

1. Bascule bridge	a) канава, ров
2. Cast iron railing	b) ледорез мостовой опоры
3. Conduit	c) низколегированная сталь
4. Ditch	d) бут
5. Low alloy steel	e) сосновая древесина
6. Pinewood	f) подземный водовод
7. Rough stone	g) чугунное ограждение
8. Starling	h) полная длина моста
9. Total bridge span	i) раскрывающийся мост

Complete and translate the following sentences:

1. In most cases, bridgeworks over the Moskva River are three-span structures (fig. 4.2a) because the river is rather narrow and an arch can bridge it with (средний пролет). (Боковые пролеты) are used as (путепроводы) since they are built over (автодороги) along the river.

2. The Krymsky Bridge is, without a doubt, a remarkable sight in Moscow, which is appealing to the eye. Its (основной несущий элемент) is the chain made of (низколегированная сталь) plates articulated with suspenders (fig. 4.2b). The parabola shaped chain looks majestic when illuminated during the evening hours.

3. (Совмещенный двухъярусный мост) over the Moskva River was built in Luzhniki in 1958 (fig. 4.2c). It was the only (мост с ездой посередине) in Moscow. The upper deck was used for motor vehicles and (пешеходы). Metro trains passed through the glassed lower (ярус) where they stop at the station. The total bridge span is nearly 2,650 ft with the central arch over the river of 650 ft and approaching spans. The central span of 5,000 ft was framed on the site and then shipped by two pontoons, lifted and placed on the piers. The length of the upper deck, including the (подмости) was 3,868 ft. It was the longest structure over Moskva River, but unfortunately, its (срок службы) lasted only about 30 years and the bridge had to be demolished.

Answer the following questions:

1. What building material was used for the first bridges in Moscow?

2. When was the first permanent bridge over the Moskva River constructed?

3. How many spans were there in the early Great Stone Bridge?

4. What famous bridges are known as the “splendid Moscow bridge ensemble”?

5. What are the principle characteristic features of the Moskvoretsky Bridge?

6. What bridge is the only suspension bridgework in Moscow?

Match the English and Russian bridge terms:

1. боковой пролет	а) Main load-bearing element
2. двухъярусный мост	b) Articulate
3. основной несущий элемент	c) Side span
4. подмости	d) Suspender
5. соединять шарнирно	e) Scaffold bridge
6. подвеска	f) Double-decked bridge

Unit 5

ST. PETERSBURG BRIDGES

Have you ever been to St. Petersburg? If so, try to complement the text with your own information.

Tsar Peter the Great restricted bridging his young capital in spite of the fact that the Neva River, being between 350 and 650 m wide, flows 13 km within the city limits. He wanted to speed up the development of his marine and merchant fleets. Nevertheless, there were some timber and floating bridges because the city, sprawling over the numerous islets of the Neva River Delta, was badly in need of them. The first floating bridge over the Neva was constructed in 1727. Like other early temporary bridges, it was made of rows of anchored barges tied together, which obstructed free shipping. As the water level in the river could considerably rise due to strong winds blowing in from the sea, the barges could be carried away or crushed by ice. A flourishing age of Russian bridge engineering began in 1762 with the establishment of the Bridge and Road Department. Soon more than three hundred bridges had been built across the many canals and river channels including timber, masonry, floating and cast iron structures, and St. Petersburg earned the reputation of one of the most beautiful cities in the world. The Hermitage, Winter and Prachechny bridges were reputed to be among the world’s finest examples of such structures.

At present, there are 360 bridges in the city and together with those in the suburbs, the figure will be 600. Each bridge has its own individual appearance but taken together they give the impression of one harmonious whole. Some, like the Liteiny Bridge are known for their wrought-iron bridge railings, others are graced with sculptural groups. The most attractive bridges are in the parks of Tsarskoye Selo, over the Fountanka River and the Griboedov Canal. Some of the bridges over the canals are so narrow that only two persons can walk abreast. The medieval-looking three-span bridges with massive stone towers were built in the 18^th century. Currently towers decorate only the Lomonosov and the Old-Kalinkin Bridges, the rest of them have been rebuilt and broadened. Some suspension bridges, built between 1820 and 1840, including the graceful Lion, Pochtamptsky and Bankovsky Bridges, have survived. The latter is a footbridge adorned with gilt winged lion-griffins. The supporting chains come out of the animals’ jaws making the bridge unique.

About thirty St. Petersburg bridges are world-famous structures put under state protection. The Anichkov Bridge over the Fountanka River (fig. 5.1), being part of our national heritage, is one of them. In 1715, the Admiralty engineer battalion under the command of M. Anichkov built a wooden three-span drawbridge about six metres wide. It was constructed on a pile foundation. In 1841, the old structure was replaced with an arch masonry bridge, as wide as Nevsky Prospect was, with four towers on the corners, decorated with sculptures by Pavel Klodt. The sculptural group represents a youth thrown to the ground, then rising on his knee while trying to tame a rearing horse. At last, the untamed energy of the animal comes under control, as the youth becomes steady on his legs, and finally the horse obeys the youth’s will.

Not very far off, there is the Egyptian Bridge decorated with four sphinxes. Heavy chains, spanning the towers, support its 54-metre span. In winter of 1905 the bridge, which was 80 years old, collapsed. A cavalry squadron crossing the Fountanka River caused the disaster. The natural occurrence of bridge vibrations and the impact of the horses’ hooves were in accord and resulted in a resonance condition powerful enough to bring the whole structure down. Moreover, metal bridge elements lost their strength under frost. This destructive condition is called metal cold brittleness. Fifty years later, the bridge was rebuilt.

Exercises:

Remember the meaning of the following words and word combinations:

An anchor, a row of barges, numerous islets, flourishing bridge age, frequency of impact, natural frequency, iron cold brittleness, a gulf.

Answer the following questions:

1. Why did Peter the Great restrict bridge building in St. Petersburg?

2. When did the flourishing bridge age start?

3. What old bridges in the central part of the city can you name?

4. What famous bridges were built over the Fountanka River?

5. Do you know why the Egyptian Bridge collapsed?

Read the text and ask each other questions to test your knowledge.

Many bridges dominate St. Petersburg’s riverfront and their number is still growing, largely due to the city’s proximity to the sea. The very planning of the city was determined by its position at the mouth of the Neva River, which provides easy access to the Gulf of Finland, with its two arms. One of them was spanned in 1850 by remarkable engineering work, now named after Lieutenant Schmidt, (fig. 5.1), a hero of the 1905 revolution. Engineer S. Kerbedz and architect K. Brulov designed it. This is the oldest permanent bridge and the last one before the Neva flows into the gulf. At the beginning of the 20^th century, it appeared to be too narrow for traffic and impassable for navigation. In 1938, the bridge had to be dismantled and replaced with a wide seven-span structure designed by Professor G. Peredery. The total bridge span is 331 m, and its modern movable span let ocean vessels of 50-60 m in height sail up the Neva River. It was the first time that engineers had pioneered electric welding instead of riveting for such heavy metal structures.

The Liteiny Bridge was designed by engineer A. Struve and architect Ts. Cavos and spans the Neva River (fig. 5.1). Constructed in 1879 it was the first bridge to be installed with electrical lighting along its total length of 408 m. The old structure could not meet modern traffic demands, and its steel arches corroded. The reconstruction preserved its original form because steel girders were placed on the reconstructed piers in 1967. Its bascule leaf holds the world record for its dimensions and weight of 3,225 tons, which can be lifted by powerful hydraulic devices within two minutes. The bridge has never been renamed and boasts highly artistic wrought iron railings adorned with Russian State Emblems.

One of the famous Neva bridges was built on the eve of the 100^th Anniversary of St. Petersburg’s foundation. The celebration was marked by the international competition for the best bridge design. The idea of a cantilever arch structure put forth by French engineers prevailed, and the Trinity Bridge was built nearby the Summer Garden in 1903. The Neva River is very wide at this place so the bridge with its gentle metal arches is rather long. Its total bridge span is 582 m and the bascule span allows for free shipping. The next competition was announced for the Palace Bridge construction close to St. Basil Pointer (fig. 5.1). The expert commission adopted a five-span structure with sculptural decoration in classical style, but the First World War cancelled that plan and the bridge designed by A. Pshenitsky was completed in strict monumental style in 1916. Its total length is 250 m, and the 57 m steel bascule span, directed towards the pale sky during the “white nights”, looks very romantic. It is part of St. Petersburg’s architecture.

It was no easy task to connect the soft riverbanks of the Neva River. However, innovative building technology provided suitable solutions. The Volodarsky Bridge (fig. 5.1) was designed by Professor G. Peredery and architect A. Nickolsky, and opened to traffic in 1936. Steel tubes filled with concrete were used as arch reinforcement and can resist great compression. The reinforced elements look as if they are entirely made of metal, and the concrete river piers are faced with granite. The bascule span mechanisms were installed inside the piers. The length of each of the two river spans, supported by slope arches, is 101 m. The arches have no wind bracing and the wind force is transmitted to suspenders and the bridge floor. The bascule, double-leaf middle span is made of metal. One of the characteristic features of the bridge piers is the absence of cutwaters.

The total length of St. Petersburg’s bridges is more than eleven kilometers, and the Alexander Nevsky Bridge is the longest and widest amongst them. Its overall length is more than 900 m including approaches, and the width is 35 m. The bridge was put into operation in 1965, and represents a typical engineering structure from the second half of the last century, looking strict and in harmony with its surroundings. The Big Okhta Bridge is of a through type. It was designed by engineer G. Krivoshein and opened to traffic in 1911. Its total bridge span is 355 m. N. Belelyubsky and G. Krivoshein designed the Finlandsky Railway Bridge. That through bridge was put into operation nearly a century ago, in 1911.

Exercises:

What can you say about the Neva River bridges?

1. How many bridges in St. Petersburg can you name?

2. Are all the Neva River bridges open at night?

3. Which bridge is the longest structure over the Neva River?

4. Have all the Neva River bridges been reconstructed?

Complete and translate the following sentences using the Word list below.

1. (Арочные пролетные строения) are the best structures for (судоходство) on rivers with low banks. Besides, they decorate the splendid (городской архитектурный ансамбль) in St. Petersburg.

2. The characteristic feature of all the Neva River bridges is a (разводное пролетное строение) to clear a channel for ocean going vessels.

3. Some of the movable spans are (однокрылые или двукрылые раскрывающиеся пролетные строения), and some are called (поворотный пролет). They pivot horizontally by (барабан вращения). In St. Petersburg there are no (вертикально-подъемные пролетные строения) as they are inferior to the (раскрывающиеся мосты) from an architectural point of view.

4. The Volodarsky Bridge superstructure is made of (арочные фермы). Thin (подвески) between arches and (проезжая часть) are made of (железобетон). Currently the concrete (выщелачиваться). This results in (трещины) and the (арматура) suffers from corrosion.

The Word list

1. арматура	a) Reinforced steel
2. вертикально-подъемный пролет	b) Vertical-lift span
3. двукрылый раскрывающийся пролет	c) Double leaf bascule span
4. однокрылый раскрывающийся пролет	d) Single leaf bascule span
5. поворотный пролет	e) Swing span
6. проезжая часть	f) Bridge roadway
7. разводное пролетное строение	g) Bascule span
8. трещина	h) Crack, flaw

Unit 6

TIMBER AND MASONRY BRIDGES

Read the text about different building materials. Compare them and say which one is more suitable for permanent or temporary structures.

Early bridges were made of timber and stone because those building materials could be easily found anywhere (fig. 6.1, 6.2.). Materials were free and abundant, and there were low labour costs, since slaves, soldiers, or natives did the work. The Romans built many wooden structures, but their reputation rests on masonry bridges. Roman bridges are famous for using the circular arch form, which allowed for much longer spans and provided more permanence than wood. Stone is strong in compression but weak in tension. Its primary application has been in arches, piers, and abutments. Besides, stone is durable, weatherproof and resistant to freezing and thawing. The most suitable rock for this purpose is granite, basalt, dolomite and the widespread and rather cheap sandstone or limestone. The bridge builders also used artificial stone, i.e. concrete made from a mixture of water, sand, gravel, and a binder, such as cement. Concrete is strong in compression and weak in tension.

The Romans used cement for piers in rivers. They developed a cofferdam, a temporary enclosure made from wooden piles driven into the riverbed to make a sheath, often sealed with clay. Concrete was poured into the water within the ring of piles. Although most surviving Roman bridges were built on rock, the Pont Sant’Angelo Bridge, the finest surviving bridge in Rome, stands on cofferdam foundations, built in the Tiber River 1,800 years ago. It consists of seven stone arches and five main spans about 18 m each, supported on piers seven meters high. Mounted on the parapets are statues of Saint Peter and Paul and ten statues of angels.

Concrete with steel bars embedded in it is called reinforced concrete. The steel carries all the tension; the concrete protects the steel from corrosion and fire. Reinforced concrete has become an economical substitute for stone. In addition to its price and load-carrying advantages, reinforced concrete can be molded into a variety of shapes, allowing for much creative expression.

Masonry bridges offer the following advantages: long-lasting performance (only wars and earthquakes can destroy them); the aesthetic merits of masonry bridges adorn many urban landscapes; greater ability to resist overloads; considerable reduction of maintenance costs. Possible disadvantages of masonry bridges are: greater dead weight as stone density is between 2 and 2.7 t/m³; only the arch structure is allowed (it produces the horizontal force – the thrust, which requires powerful foundations and solid ground to rest on (fig. 6.1); construction of masonry bridges requires a lot of manual labour.

Wood is relatively weak in both compression and tension, but it has usually been widely available and is inexpensive. It has been used effectively for small footbridges. Nevertheless, in the 18^th century, designs with timber reached new span length, and Swiss builders used trusses with spans of 58 m over the Rhine River. Engineers now incorporate laminated wooden beams and arches into some modern bridges. Timber bridges usually serve as short-term structures lasting 10-15 years (fig. 6.2). Timber piles and cribs are often used for bridge foundations. The best types of wood used for spans and piers are pine, spruce, fir, and other softwoods such as larch or cedar. This sound wood is easily treated and does not decay. Expensive wood species such as oak, hornbeam and beech are applied only to the most important elements – the caps and dowels. To increase its waterproof capability timber is impregnated with antiseptics. It extends the service life up to 25-30 years. Plywood spans are widely used because they are more durable, rigid and lighter than those made of logs and squared beams.

Exercises:

Try to guess the meaning of the following word combinations:

Frost-resistant building material; corrosion-resistant metal; rot-resistant timber; fire-resistant covering; water-resistant concrete; wind-resistant structure; torsion resistant bridge element.

Match the Terms.

1. возгорание	a) Sheath
2. гниение древесины	b) Build up
3. диагональный раскос	c) Post
4. монтаж	d) Shrinkage of wood
5. наклонная свая	e) Joint
6. обшивка	f) Batter pile, raking pile
7. прогон	g) Wet rot
8. составная деревянная балка	h) Stringer, baulk
9. стойка	i) Ignition
10. узел	j) Joggle beam
11. усушка древесины	k) Gang framework of bridge
12. пакетное пролетное строение	l) Inclined brace

Think of answers to these questions. Give a reason to support what you say.

1. What sorts of natural stones can be used for bridgeworks?

2. Why is the arch span so widely spread in masonry bridgework?

3. What is a cofferdam?

4. What tree species are most suitable for bridge structures?

5. Can concrete make bridge architecture considerably different?

6. Why are the maintenance costs of masonry structures less than other bridges?

7. Why does the service life of timber bridges last about 15-30 years?

8. Can plywood resist heavy live loads?

9. Which bridge components can be made of wood?

Translate the following sentences into English:

1. Достоинства деревянных мостов: минимальные строительная стоимость, вес элементов и срок строительства; достаточно высокая прочность древесины по отношению к собственному весу.

2. Недостатки деревянных мостов: малый срок эксплуатации; сложности пропуска льда из-за небольших пролетов (3-5 метров); гниение; трещины от усушки древесины; возможность возгорания моста.

3. Фундаменты мостов представляют собой вертикально и наклонно забитые сваи, т.е. бревна.

4. Конструкция опор состоит из стоек и диагональных раскосов, соединенных между собой в узлах. Элементы опор состоят из бревен или брусьев.

5. Пролетные строения деревянных мостов представляют собой бревна или брусья, которые называются прогонами. Для данных типов пролетных строений величина пролета составит от 3 до 6 м.

6. Большие пролеты перекрываются составными пакетными пролетными строениями, в которых отдельные бревна или брусья объединены в единую конструкцию при помощи шпонок и болтов.

7. Самые большие пролеты деревянных мостов в 15-30 м перекрываются пролетными строениями в виде клееных фанерных конструкций или деревянных форм. Иногда используются деревянные арки.

Express your ideas about the building qualities of stone and wood.

Unit 7

REINFORCED CONCRETE BRIDGES

Read the text and learn the terminology using the list of words.

Concrete, being an artificial stone possesses the same good qualities as natural stones. It is strong in compression and weak in tension, therefore it has been substituted for natural stone in arch bridges because the arch is strong in compression. The greater strength of concrete permits slender sections with elegant lines and at the same time provides strength equal to that of masonry structures of far greater mass. Concrete is fire resistant and therefore it has become one of the most common building materials all over the world. The strength of concrete is measured in kg/cm² of force, needed to crush a sample of a given age or hardness, but concrete’s strength is affected by environmental factors, especially temperature and moisture. It would be reasonable to add that the cost of natural stone is at least double that of precast concrete.

Plain concrete does not easily resist wind, earthquakes, vibrations and other forces and is therefore unsuitable in many structures. At the beginning of the 19^th century concrete was reinforced with metal bars (fig. 7.1). The idea was to transfer the tensile stress from concrete to the reinforcement (fig. 7.1b). Concrete that has been hardened onto imbedded metal (usually steel) is called reinforced concrete. The reinforcing steel, which may take the form of rods, bars or mesh, contributes to tensile strength. At present reinforced concrete is suited to short and medium bridge spans (up to 40-60 m). Nevertheless, having sufficient strength and permanency it is also rather competitive with metal for longer spans which remain in service for hundred of years. Reinforced concrete spans are of a great variety because of their ability to work in compression and tension as well as in flexure. The durability and appearance of a bridge depend on the concrete strength.

Concrete is used for the large-scale manufacturing of simple beams, continuous girders, cantilever-beam systems, arches, frames and combined systems (arch and beam or arch and truss), etc. The builders use monolithic or cast in situ reinforced concrete, precast concrete, prestressed concrete and other concrete grades. Prestressed concrete is an important variation of reinforced concrete. Prefabricated reinforced concrete is manufactured at ready-mix-plants and the bridge members are mounted in situ from ready-made segments and blocks. High-strength concrete is made by reinforcement (fig. 7.1c, 8) and prestressed with jacks (fig. 7.1c, 9).

When reducing the structure’s weight, coarse aggregate such as crushed rock, pebbles and gravel is substituted with slag and claydite. This results in light concrete. All aggregate materials must be clean and free from soft particles or vegetable matter, because even small quantities of organic soil compounds result in chemical reactions that seriously affect the strength of the concrete. The mixture must have just enough water to ensure that spaces between the aggregate are filled, and that the concrete is liquid enough to be poured and spread effectively.

Bridges made of reinforced concrete offer the following advantages:

1. Substantial saving of steel, which is a scarce building material.

2. Substantial reduction of maintenance costs as compared with metal bridges.

3. Greater rigidity as compared with metal bridges.

4. Long-term service life (80-100 years).

5. Various high-level architectural forms.

The disadvantages of reinforced concrete bridges may be enumerated as:

1. Great dead weight.

2. Great labour and Production time increases for bridge elements.

3. The development of hairline cracks inducing reinforcement deterioration.

4. Hidden hollow spaces, which are difficult to remedy.

5. Problems with concrete placement under low temperature.

Exercises

Discuss the following questions:

1. What is the difference between concrete and reinforced concrete?

2. What is the best length for reinforced concrete spans and why?

3. What design model is most preferable for reinforced concrete bridges?

Complete and translate the following sentences using the Word list given below:

1. The length record for the truss span of 63 m was set up in the Novosibirsk region (fig. 7.2a). The design was proposed at The Novosibirsk Institute of Railway Engineering. Professor K. Yackobson, who held the Chair of Bridge Engineering, headed the group of designers. (Элементы фермы) were made of (предварительно напряженный железобетон). The most difficult thing was to make (узлы) where (раскосы) (1) were attached. The main idea of that span was a very (жесткая балка) (2) which acted as a (нижний пояс фермы).

2. Another innovation in masonry construction is the use of (преднапряженный бетон). Either pretensioning or post tensioning processes achieves it. In pretensioning, the length of steel wire, (канаты) or ropes are laid in the empty mold and then pulled and anchored. After the concrete has been poured and allowed to set, the (анкеры) are released and, as the steel seeks to return to its original length compresses the concrete.

3. Working (арматура) in slab structures is inside a slab itself. It is parallel to the beam centre line. A part of the reinforcement in ribbed beams is also parallel to the bearing member axis (fig. 7.1). Another part of the reinforcement is in the middle of the beam. It is placed in the (нижний пояс). At the span sides the reinforcement ends are bent up (fig. 7.1).

4. In most cases bridge spans are built according to a standard design with beams made of (обычный или предварительно напряженный железобетон). These beams can represent [плитная конструкция (fig. 7.2b) и ребристая конструкция (fig. 7.2c)]. Slab structures are used for spans from 6 to 12 m long, and ribbed structures are suitable for spans between 9 and 42 m long. (Несущий элемент) of slab structures is a slab (3), and in ribbed structures the bearing element is a [стенка с верхним (5) и нижним (6) поясами].

Word list

1. верхний пояс фермы	a) Top chord of truss
2. изгиб	b) Flexure
3. нижний пояс фермы	c) Bottom chord of truss
4. обычный бетон	d) Ordinary concrete
5. плита	e) Slab
6. преднапряженный бетон	f) Stressed concrete
7. пустоты	g) Hollow spaces
8. растягивающее усилие	h) Tension
9. ребристая конструкция	i) Ribbed structure
10. сборный бетон	j) Precast concrete
11. сжатие	k) Compression
12. стенка балки	l) Beam web, girder web

Here are the answers to some questions about reinforced concrete bridges. Make up the questions.

1. The first concrete bridge with 16 m span was erected in France in 1875.

2. The earliest Russian reinforced concrete beam bridge was built by the design of Professor N. Belelyubsky in 1893.

3. The following bridges are acclaimed as world records for concrete structures:

• the longest spans among beam systems are 76 m in the R.S.A.

• the longest spans among continuous beam systems are 105 m in Japan

• the longest spans among trussed girders are 63 m in Russia

• the longest spans among arch bridges are 22 m in the Ukraine

Unit 8

METAL BRIDGES

Think of different building materials and answer the following questions.

1. When do we use the term “metal bridges”?

2. What advantages does steel offer in comparison to timber or reinforced concrete?

3. What is low alloy steel?

4. What joining methods for metal elements do you know?

Read the text and check your answers. How much did you guess correctly?

Metal bridges may be constructed of cast iron, iron, steel and aluminum alloys. Cast iron is an alloy of iron that contains carbon, along with varying amounts of silicon and manganese. Cast iron is hard and brittle owing to its high carbon content and therefore is inferior for most purposes to wrought iron. Wrought iron is soft and ductile. Cast iron is strong in compression but weak in tension. Wrought iron, on the other hand, is as strong in compression as cast iron, but it also has much greater tensile strength. The Iron Bridge, spanning the River Severn near Coalbrookdale in Great Britain, is generally considered the first cast iron structure.

In the 19^th century, bridges were erected using wrought iron. Then cast iron and wrought iron were succeeded by high-strength steel. It is stronger and superior to iron in both tension and compression. Due to its rigidity and durability steel is simply the best building material. It is easily treated compared to other building materials. Low alloy steel offers superior quality owing to the fact that it contains such rare elements as nickel, chromium, manganese, etc. Currently stainless steel grades are widely used in both space and building industries. Such steel does not need any painting because of the oxide film on its surface.

Metal superstructures which are suited to medium and long spans, and made a good showing for the length between 50 and 1,500 m, varying the bridge appearance with continuous and discontinuous beams (fig. 8.1a), frames, arches, trusses (fig. 8.1b and d) cantilever structures, combined systems, etc. The length of the structures ranges within 150 m for discontinuous beams and within 500 m for cantilever-beam spans.

Frame span length is within 100 m limits. Trusses are employed for spans of 200 m in length, and in the case of 300 m, arch spans are built.

Metal bridges offer the following advantages: high-strength building material; great permissible span length; durability; large-scale production of bridge construction elements; convenience at erection, maintenance and overhaul.

The disadvantages of metal bridges include considerable steel consumption, corrodibility, high dynamic sensitivity, and great maintenance costs (in case of painting).

Metal elements used in construction can be jointed by welding (fig. 8.2a and b) rivets (fig. 8.2b and c) or bolts (fig. 8.2c). Welding is the greatest cost saving method but is not as reliable as riveting or bolting. Rivets are not widely used because driving them is rather complicated, and bolts are commonly used (fig. 8.2).

Exercises:

What are the English equivalents for the following Russian terms?

Алюминий, чугун, железо, низколегированная сталь, нержавеющая сталь, коррозия металла, окислы металла, металлические конструкции, соединение металлических элементов.

Say whether these statements are true:

1. The span length for metal bridges is: a) 10-50 m b) 50-100 m c) 50-1500 m.

2. The principal advantage of metal spans is: a) reconstruction convenience

b) reinforced concrete savings c) bridging long spans.

3. The most reliable method of joining metal elements is/using: a) welding b) rivets c) bolts.

4. Standard truss length is: a) 42 m b) 77 m c) 100 m.

5. Oxide film is applied to: a) low alloy steel b) stainless steel c) aluminum.

Match the Russian and English terms:

1) внешняя нагрузка	a) Steel grade
2) крупносерийное производство	b) Wrought iron
3) низколегированная сталь	c) Truss web
4) марка стали	d) Rib
5) ребро жесткости	e) Low alloy steel
6) решетка фермы	f) External load
7) сварочное железо	g) Large-scale production