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Usually metal spans are erected from (типовые балки) or (типовые решетчатые фермы). The length of a standard girder is 55 m, and of a unified through truss it is between 33 and 132 m. Both structures may be (разрезные или неразрезные) ones. (Металлические балки) are lighter than those made out of reinforced concrete, and may be mounted by one or two (кран). When a girder is 55 m long, the builders cut it into four blocks to facilitate its delivery to the (строительная площадка). They may also build a temporary pier in the middle of the span. The cranes place the blocks on (временная опора и постоянная опора) where they (соединяться) by high strength bolts.
Standard trusses consist of separate elements: top and bottom chords, (раскосы, подвески, стойки, диагональные связи). A part of the span is mounted on temporary piers built under the (узлы фермы). Three or four segments are used as a (противовес) for further span erection. A (деррик-кран) moves along the mounted top chord using the cantilevering method. The truss joint elements are joined by (болты, фасонки, накладки) and other flat elements. Continuous metal girders are pushed towards the designed position with a (домкрат) like reinforced concrete beams.
The construction of a bridge superstructure above water is one of the erection methods. The superstructure blocks, delivered to the riverbank by special heavy trucks, are transhipped to the (баржа) with special equipment, and a barge carries the structures to the place.
Дата публикования: 2014-10-25; Прочитано: 694 | Нарушение авторского права страницы | Мы поможем в написании вашей работы!