Complete and translate the following sentences.

1. The 9 m span made of (чугунная балка) failed under the train moving at the speed 65 km/h. It happened in Great Britain in 1883. The accident was caused by the (динамическая нагрузка) which the girder could not resist because of cast iron brittleness and a lot of (раковины) within it.

2. The worldwide known bridge (разрушение) took place on November 7^th, 1940 on the Tacoma River, in the USA. The (трехпролетный висячий мост) had been designed structurally safe for a wind pressure of 50 pounds per square foot. In spite of the fact, that the wind force being not very strong (40 mph), its (главный) 874 m span collapsed because of the amplification of the vertical and torsion vibrations created by resonance in a mild gale. Their combination produced (аэродинамическая неустойчивость).

3. One of the most vivid examples of negligence and carelessness causing bridge collapse was the construction of the Quebec Bridge in Canada. Its span made of (металлические фермы) was 548 m long. While being erected, the span fell into the water because of an engineering fault.

4. In 1875-several compressed elements of the bridge truss on the Kevda River in Russia lost their (устойчивость). The reason was in (выпучивание элементов при их сжатии) but this phenomenon had not been properly studied.

5. The Northern-Muya Tunnel collapse, at the BAM mainline, was caused by the (ось тоннеля) which went through the rock fault. It was a huge cone-shaped hollow of 600 m in diameter, filled with mud. The rock pressure broke down (временная крепь), and water and mud gushed into the tunnel.

6. To control (движение транспорта) in the regular and incident mode, the tunnel is equipped with modern signaling system.

Ask your teacher as many questions about ES failures as you can. Then working in pairs, practice the questions below and give the proper answers to them. Support your opinion by using vivid examples. Make up your own questions and help your partner to answer them if he/she is hesitant.

1. What factors may increase the risk of failures and collapses of R& M ES?

2. What disasters are most dangerous for Railway and Motorway ES?

3. What threatens bridges in the case of scours and harsh winter conditions?

4. What is the railway industry safety policy aimed at?

5. Do the railways conduct comprehensive bridge inspections?

6. What accidents are typical in tunnels?

7. What equipment can prevent the failure and collapse of R& M ES?

8. The Tacoma Bridge failed because of its extreme flexibility resulting from aerodynamic instability, didn’t it?

9. What stopped the construction of the Northern-Muya Tunnel?