Construction device and construction method of self-adaptive post-tensioning prefabricated box girder

Abstract

The invention discloses a construction device and a construction method for a prefabricated box girder by an adaptive post-tensioning method. The construction device comprises a fixed pedestal and two adjustable pedestals respectively arranged at both ends of the fixed pedestal. The adjustable pedestal comprises a pedestal foundation and an upper hinged pedestal. , the lower hinged pedestal, the pedestal translation track and the pedestal translation track, the pedestal translation track is set on the base of the pedestal, the lower hinged pedestal is movably set on the pedestal translation track, the upper hinged pedestal and the lower hinged pedestal are hinged through a hinge shaft, and the upper A locking component is also arranged between the hinged base and the lower hinged base to limit the relative rotation of the two, the base of the base is abutted against the fixed base, and the top surface of the upper hinged base is flat. Construction methods include pedestal installation, upper hinged pedestal positioning, formwork installation, concrete pouring, formwork removal and tensioning. The invention can ensure that the bottom of the beam is always in the state of surface contact and load before and after tensioning, and effectively solves the problems of stress concentration and cracking of the beam end concrete during the tensioning process.

Description

technical field [0001] The invention relates to the construction of expressway post-tensioned prestressed concrete prefabricated box girders, in particular to a construction method for adjustable pedestals and self-adaptive post-tensioned prefabricated box girders. Background technique [0002] Expressway post-tensioned prestressed box girder 300 has a small cross-section and low stiffness. Such as figure 1 As shown, after the beam body is stretched and arched, the bottom wall at the mid-span of the beam body gradually breaks away from the fixed pedestal 200, and the self-weight of the beam body is gradually transformed from the bottom wall to the end edges of the beam body, that is, the beam body ends are supported by the surface converted to point supports ( figure 1 middle P), the distance between the two ends of the beam body becomes shorter, and the beam body tends to be compressed, the friction at the bottom of the fixed pedestal constrains the compression of the bea...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide a method that ensures that the bottom of the beam is always in a state of surface contact and load before and after tensioning, and effectively solves the problems of stress concentration and cracking of the concrete at the beam end during the tensioning process. Construction method of adjusting platform base and self-adaptive post-tensioning prefabricated box girder

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