double arrow

Complete and translate the following sentences. 1. It is difficult, sometimes, to tell difference between (висячие и вантовые мосты)

1. It is difficult, sometimes, to tell difference between (висячие и вантовые мосты). Suspension bridges may have (наклонные подвески) which resemble stay cables (fig. 10.3c). On the other hand, there are cable truss bridges, which look like suspension structures (fig. 10.3d). (Висячие вантовые фермы) with diagonal struts allow reducing the vertical (смещение).

2. An ordinary suspension bridge consists of one or more towers built above piers and a (неразрезная балка). Usually the girder is a truss or (балка коробчатого сечения), but if the spans are short, plate girders may be used. The ends of the cables are held in place by large (анкерные опоры) that are positioned at both ends of the suspension structure. Hanger cables or hanger ropes, suspended down from the main cables, are attached to the (основная балка) (fig. 10.3а).

3. Presently, suspension bridges are the most suitable structures for very long-span bridges. One of their basic (недостатки) is increased deformability. The of usage of prestressed suspension bridge with cable trusses may solve this problem.

4. Most cable-stayed bridges have powerful steel or reinforced concrete (балка жесткости). It resists a cable-stay (распор) (fig. 10.3b). Suspension bridges are constructed either with (анкерные опоры) or without. In case of anchor supports, they transmit the thrust to the foundations. The bridges of this type are (распорные) (fig. 10.3a). When suspension bridges have no anchor supports, the thrust is transmitted to the stiffening girder, and the bridges are (безраспорные) (fig. 10.3c).

5. (Динамические нагрузки) make a suspension structure highly vulnerable to aerodynamic forces and sensitive to vibration when the bridge spans are rather long. To reduce these effects, the cable is rigidly attached to the stiffening girder or an additional cable is secured.

6. (Возведение пилонов) is the most complicated building process in case of suspension and cable-stayed structures. The building material for towers is reinforced concrete for 300-500 m spans or steel for longer spans. The tower works simultaneously in (сжатие с изгибом). That is why its calculation requires high precision.

7. The thick wire cables carry the weight of the suspension bridge and traffic. The diameter of such cables may reach as much as 91 centimeters. They are made of steel wires twisted together. The main steel cables that pass over a saddle are extremely strong and (гибкий). The saddle allows the cables to slide when (подвижные нагрузки) pull them from one side of the bridge or the other one. The saddle also allows transferring the load from the cables to the tower rather smoothly.

8. The towers require massive (фундаменты), embedded deep into the river or sea bottom beneath the bridge. The abutments and the towers carry the cables that directly (поддерживать) the roadway by suspenders. In some cases, the roadway is laid on top of a truss to which the suspenders may be attached.

9. In other types of bridges the girders (опираться) on abutments and piers, but in suspension structures the girder is hanging and swaying under wind gusts. Nevertheless, the suspension bridges even with rather long spans are strong under usual traffic loads.

Сейчас читают про: