Indication № 7 – by the service life.
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English in Bridge Engineering. Unit 1. Bridges Classification.
Vocabulary. mention - упоминать in a wide sense - в широком смысле provide a crossing over - обеспечить возможность пересечения be classified - классифицироваться function - функция reinforced concrete - железобетон сable-stayed - вантовый include - включать flexible - гнущийся rigid - негнущийся service life - срок службы
It has already been mentioned that bridges in a wide sense of this term mean constructional works comprising a superstructure and a substructure. In a narrow sense this term means a structure built to provide a crossing over a river.
In technical literature bridges are classified according to their indications as follows:
Indication №1—by the main road function. 1. Railway bridges. 2. Motorway bridges. 3. Foot-bridges (Pedestrian bridges). 4. City bridges. 5. Pipe lines. 6. Metro-bridges. 7. Combined systems or road-cum-rail bridges (carrying various means of transport).
Indication №2 - by the superstructure material. 2.1. Timber bridges (wooden bridges). 2.2. Stone bridges (masonry bridges). 2.3. Reinforced concrete bridges. 2.4. Metal bridges. 2.5. Steel reinforced concrete bridges (composite bridges). 2.6. Suspension bridges. 2.7. Cable-stayed bridges.
The suspension and cable-stayed bridges include the structures with the flexible stayed ropes as the main carrying element. Curvilinear ropes are used for suspension bridges and rectilinear ropes are used for cable-stayed structures. The ropes are made of metal wire strands and that is why suspension and cable-stayed structures can be regarded as variants of metal bridges.
Indication № 3 – by a structural model. 1. Beam bridges. (Spans of rectangular shape rest on supports). 2. Arch bridges. (A curvilinear structure produces a horizontal thrust through skewbacks to the supports). 3. Frame-type bridges. (Spans and supports are all indivisible rigid structure). 4. Cantilever bridges. (These structures include cantilever arms, i.e. elements built out of their supports). 5. Combined systems. (They consist of several simple structures – beam + arch). Indication № 4 – by the position of the bridge floor. 1. Deck bridges. 2. Through bridges. 3. Half-through bridges.
Indication № 5 – by the overall bridge length. 1. Short bridges (up to 25 m long). 2. Medium bridges (from 25 to 100 m long). 3. Long bridges (more than 100 m long).
Indication № 6 – by the number of spans. 1. Single-span bridges. 2. Double-span bridges. 3. Three-span bridges. 4. Multi-span bridges.
Indication № 7 – by the service life. 1. Permanent bridges. (Service life is 80-100 years.) 2. Temporary bridges. (Service life is about 10-15 years.) 3. Short-term bridges. (They are built for the period from two – three days to one year.)
In addition to the mentioned bridge types there are drawbridges (movable bridges), floating (raft) bridges and the ferrying.
Answer the questions: 1) How bridges are classified in technical literature? 2) What are the advantages and disadvantages of beam bridges? 3) What are the advantages and disadvantages of truss bridges? 4) What are the advantages and disadvantages of cable-stayed bridges? 5) What materials are most commonly used and why?
Exercises: 1) Find the equivalents: трубопровод совмещенный мост (для автомобильного и ж/д транспорта) железобетонный вантовый мост балочный мост рамный мост балочно-консольный мост
комбинированный мост с ездой посередине мост с ездой понизу сквозная ферма с ездой понизу разводной; подъемный мост
2) Match the opposite adjectives: long, temporary, pedestrian, single-span, vertical, flexible
1. short bridge ≠
2. multi-span bridge ≠
3. permanent bridge ≠
4. motorway bridge ≠
5. horizontal thrust ≠
6. rigid structure ≠
3) Complete the sentences:
1. The term «bridge» means …
2. According to their function bridges are classified into …
3. According to the superstructure material bridges are classified into …
4. A suspension bridge consists of …
5. Service life of temporary bridges is …
6. Combined systems consist of …
7. I know different types of bridges, for example …
4) Change the sentences from Active into Passive Voice:
1. We consider bridge building to be a science.
2. We believe many bridges to have been constructed 2000 years ago.
3. Nature has given to man the idea of bridge.
4. We know the Romans to have brought arch bridge construction to its high degree of perfection.
References: http://www.shortspansteelbridges.org/Gallery/Images.aspx
Unit 2. Bridge or Tunnel.
Vocabulary. obstacle — препятствие water space — водный массив by means of — с помощью connect — соединять rapid increase — быстрый рост land-based — наземный trade and commerce — торговля cross over — пересекать bear in mind — иметь в виду sea current — морское течение vessel — судно seabed — морское дно provide — обеспечивать sufficient — достаточный require — требовать embankment- насыпь depend (on) — зависеть put into operation — запускать high-speed — высокоскоростной severe — суровый The vast water areas all over the world represent the world obstacles for people’s communication. A man has been striving to subdue water spaces by means of the main road connecting continents, islands, etc. because the economy becomes globolised.
The English Channel separating Great Britain and Europe the Straits of Gibraltar between Europe and Africa, the Bosporus between Europe and Asia, the Bering Strait connecting the Eurasian and American continents, Japanese-islands might offer the missing link for rapid increase land-based transportation to promote improved trade and commerce to facilitate greater economic integration.
Builders always have the choice between bridging and tunneling in crossing over or under a large waterway. Each sort of a structure offers its advantages and shortcomings. One should bear in mind the influence of strong sea currents, great water depth, and large capacity vessels with great boundary dimensions (the under clearance of the bridges must be about 65 m high not to prevent shipping), complicated geological seabed structure. Seabed silt is a rather soft foundation for supports footing. In addition these regions are seismically dangerous and constructional works must provide sufficient strength against seismic waves.
The advantages of the bridge crossing may be the following:
1. Low cost of construction in comparison with a tunnel structure though sometimes it may be quite the opposite.
2. Bridges require lower maintenance costs because tunnels call outlays for water discharging, ventilation, illumination, etc. The longer subaquatic structure is, the heavier outlays are required.
The advantages of the tunnel are:
1. Free shipping is very important under intensive navigation. Tunnels are much safer as compared to the bridge crossing because bridge supports must be calculated for the berthing impact. Being deep beneath the water surface, tunnels do not interfere with navigation. In addition, weather conditions cannot influence the traffic.
2. The architectural view of the tunnel is more attractive because there is no need for high approach embankments.
The final decision for choosing a bridge or a tunnel depends on many factors and not only on technical ones. In some cases bridges are much more preferable. In 1974 the bridge across the Bosporus was erected. In 1985 the bridge crossings connected some Japan islands.
The strait separating Denmark and Europe was also spanned by a bridge.
But the choice fell on a tunnel underneath the English Channel. In 1994 the railway tunnel from Great Britain to France was put into operation. It provides a high-speed rail link with shuttle trains reducing the travel time between the two countries to three-and-a-half hours. Needless to say that the cost of this tunnel is enormous. Another group of Japanese-islands were also connected by the tunnels in 1987. The problem «a bridge or a tunnel» is being discussed for the type of structures in the nearest future in Italy and across the Straits of Gibraltar and the Bering Strait. The choice falls on a bridge crossing in Europe and on a tunnel for the severe northern conditions.
Answer the questions: 1. What are the advantages of tunnels? 2. What are the disadvantages of tunnels? 3. What are the advantages of bridges? 4. What are the disadvantages of bridges?
Exercises: 1) Find the equivalents:
world obstacles; sea currents; boundary dimensions; seabed silt; maintenance costs; bridge supports; weather conditions; railway tunnel; travel time
2) Choose the best variant:
1. There always was a choice between bridging and tunneling in … over or under a large waterway. a) crossing b) crippling c) cruising
2. Bridges require lower maintenance … than tunnels. a) corrosion b) corrugations c) costs
3. Tunnels are much … as compared to the bridge crossing. a) saving b) saver c) safer
4. Weather conditions cannot influence the … through tunnels. a) traffic b) transfer c) transit
5. The cost of the tunnel under the English … is enormous. a) Cheddar b) Channel c) Canal
3) Find the opposites to the words:
gathering _____________
slow _________________
drawback_____________
allow_________________
bound (adj.) ___________
lessening _____________
small________________
shallow _____________
4) Are the sentences True or False? Correct the wrong ones:
1. ______ The Straits of Gibraltar separates Europe from Africa.
2. ______ The under clearance of the bridges must be over 60 m high not to prevent shipping.
3. ______ For the first time the Bosporus was bridged in 1973.
4. ______ Tunnels require lower maintenance costs.
5. ______ Vessels can navigate much easier if there are no bridges.
6. ______ The Bosporus bridge managed to withstand the wind blows up to 162 km per hour.
References: http://www.bris.ac.uk/civilengineering/bridges/Pages.html
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