5.10 Translate the text into English

Единственным неразводным мостом (fixed bridge) через Неву стал Большой Обуховский мост, который является важной составляющей (component) Петербургской кольцевой автодороги (loop motoroad) (fig. 5.1; 5.2h). Это вантовый мост – один из самых длинных мостов России. Фактически (actually), это два одинаковых (identical) моста с противоположным направлением движения. Полная длина мостового перехода составляет 2824 м, включая судоходный пролет (the span over the shipping channel) в 382 метра и съезды (approach ramp) с моста. Подмостовой габарит равен 30 метрам. Благодаря своим размерам эта массивная конструкция входит (to be among) в сотню самых крупных вантовых мостов мира.

Открытие его первой очереди (the first half of the bridge) состоялось 15 декабря 2004 года с участием президента РФ В.В. Путина. 19 октября 2007 года был торжественно открыт (to hold an inauguration) мост-близнец (twin bridge) — вторая очередь моста. С января 2008 мост был полностью сдан в эксплуатацию с односторонним двухполосным (two-lane) движением на каждом пролете.

Мост построен в достаточно сложном для навигации участке Невы, однако (however) с широко расставленными (widely arranged) по берегам Невы пилонами высотой 126 м и высоким пролетом, мост совершенно незаметен (non-unobtrutive) для плывущих по реке судов.

Unit 6 timber and masonry bridges

6.1 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 were easily available from anywhere (fig. 6.1 – 6.4). Wood and rock were handy and abundant, and, besides, there were low labour costs since unskilled natives, slaves or soldiers did the work.

Many wooden and masonry bridges were built by the Romans. Using the circular arch form for masonry structures, they built much longer spans and provided more durability in comparison with wood. As stone is strong in compression, 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 bridges is granite, basalt, dolomite as well as the widespread and rather cheap sandstone or limestone.

Figure 6.1 Masonry Bridge (каменный мост)

Figure 6.2 Timber Bridge (деревянный мост):

1 – Pile (свая); 2 – Stringer (прогон); 3 – Cap (насадка); 4 Post (стойка);

5 – Diagonal Braces (диагональные схватки); 6 – Log (бревно);

7 – Squared Beam (брус).

The bridge builders also used artificial stone, i.e. concrete made from a mixture of water, sand, gravel, and a binder, such as cement. It is strong in compression and rather weak in tension like natural rock. Bridge builders use concrete with embedded steel bars, called reinforced concrete, molding it into a variety of shapes and expressing their creative ideas by this artificial stone. The structures made of reinforced concrete are safe and durable because steel bars carry all the tension and concrete protects steel bars from corrosion and fire. Reinforced concrete has become an economical substitute for natural stone.

The Romans already knew cement and used it for constructing piers in rivers. They developed special technologies to pour concrete into the water within a ring of wooden piles driven into the riverbed. The Romans often sealed the ring with clay; therefore, they invented a cofferdam. Many Roman bridges have survived because they stand on cofferdam foundations, like for instance, the Pont Sant’Angelo Bridge, the finest surviving bridge in Rome, built across the Tiber River over 1,800 years ago. The bridge has seven stone arches and five main spans about 18 m each, supported on seven-meter piers. In the Middle Ages the bridge parapets were decorated with the statues of Saints Peter and Paul and ten statues of angels (fig.6.1a).

a – the Pont Sant’Angelo Bridge in Rome, Italy	b – The Pont du Gard Aqueduct Bridge, France

Figure 6.3 Masonry Bridges

Masonry bridges offer the following advantages: long-lasting performance (only wars and earthquakes can destroy them); the aesthetic merits of masonry bridges blend well with many different urban landscapes; larger ability to resist overloads; considerable reduction of maintenance costs. Possible disadvantages of masonry bridges are: higher dead weight as stone density is between 2 and 2.7 t/m³; only the arch structure is allowed, and it requires solid ground and powerful foundations to rest on (fig. 6.1; 6.2); 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 inexpensive. It suits well for small footbridges. Engineers now incorporate laminated wooden beams and arches into some modern bridges (fig. 3.1a; 6.4).

a – Railway timber bridge	b – Covered timber bridge

Figure 6.4 Timber Bridges

Timber bridges usually serve as short-term structures lasting only for 10-15 years. Bridge foundations are often made of timber piles and cribs (fig. 6.1). The best types of softwood used for spans and piers are pine, spruce, fir, larch and cedar. This well structured wood is good for woodworking and does not rapidly decay. The most important elements – the caps and dowels are made of most expensive wood species such as oak, hornbeam and beech. To increase its water resistant capability, builders impregnate timber 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

6.2 Find the Russian equivalents for the following English terms

Artificial stone, basalt, cedar, circular arch, clay, dolomite, freezing, laminated wooden beam, limestone, manual labour, oak, plywood, to pour concrete, sandstone, seal, solid ground, softwood, squared beams, steel bars, stone density, thawing, wood species, waterproof, weatherproof

6.3 Try to guess the meaning of the following word combinations

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

6.4. Find the English equivalents to the following Russian terms

Бук, граб, ель, железобетон, качественная древесина, лиственница, насадка сваи, обработка древесины, пихта, пропитывать древесину, ряж, свая, шпонка.

6.5 Match the Terms

1. вентиляция, просушивание	a) Cofferdam
2. влажность	b) Build up, mounting
3. возгорание	c) Vertical post
4. волокна	d) Shrinkage of wood
5. гниение древесины	e) Connection, junction, joint
6. диагональный раскос	f) Batter pile, raking pile
7. зазор	g) Decay, rot
8. кессон	h) Pad
9. монтаж	i) Ignition
10. наклонная свая	j) Joint gap
11. пакетное пролетное строение	k) Packed chord
12. прогон	l) Brace, diagonal rod
13. прокладка	m) Airing
14. расположение вдоль одной линии	n) Joggle beam
15. соединительный выступ; шпунт	o) Alignment
16. составная деревянная балка на шпонках	p) Joggle
17. стойка	q) Humidity
18. узел	r) Grain, fiber
19. усушка древесины	s) Stringer, baulk