Indication №2 - by the superstructure material2.1. 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
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