Tensioning method for prestressing tendons adjacent to existing line box girders

Abstract

The invention discloses a method for tensioning prestressing tendons adjacent to existing line box girders. The method comprises the steps of 1, installing a tensioning lifting device; 2, pouring and maintaining the box girder; 3, penetrating and fixing the prestressing tendons; 4, moving and installing a center hole jack; 5, fixing the center hole jack; 6, tensioning the prestressing tendons; and 7, tensioning the next prestressing tendon. The tension lifting device is arranged on the hanging basket main truss, so that the tension lifting device can move along with the hanging basket, repeated installation of the tension lifting device is avoided, meanwhile, use of large machines can be reduced, and construction procedures are simplified; the cross-core jack is moved by adopting the tensioning lifting device, traditional construction is replaced, the construction cost is reduced, and the construction period is shortened; and material transfer and machine tool transfer are prevented from being limited on the premise of being adjacent to the existing line, and the construction difficulty is reduced.

Description

technical field [0001] The invention belongs to the technical field of box girder construction, in particular to a method for stretching prestressed beams of a box girder adjacent to an existing line. Background technique [0002] At present, the conventional prestressed tendon threading methods are divided into the first threading method and the latter threading method. Among them, the beam-through method is usually used in ordinary prestressed structures, and its construction difficulty is relatively low; while the beam-through method is often used in large-span prestressed structural systems, its construction is more difficult, and with the span of components As the number increases, the difficulty of construction will also increase accordingly. The so-called post-stretching method refers to the method of pre-fabricating the prestressed tunnel and pouring concrete, and then carrying out the method of prestressed tendon penetration. When the traditional post-stretching b...

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Problems solved by technology

When the traditional post-stretching beam method is used to stretch the prestressed beam, it relies on manpower or machinery to directly stretch the prestressed beam. In a large-span prestressed structural system, manual or traditional machinery greatly increases the construction cost. , the construction period is also long; and in the area adjacent to the existing line to build a box girder, due to the safety distance limit, large lifting equipment such as tower cranes cannot be used. ergonomics

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