Construction method of 55-m moving framework cast-in-situ super-span continuous box girder

Abstract

The invention discloses a construction method of a 55-m moving framework cast-in-situ super-span continuous box girder and belongs to the technical field of moving framework casting. According to themethod, a counter-force system which is capable of transferring a part of a box girder load to a former span cantilever section is set up, the deflection and the bending moment of a main moving framework girder in bearing the load of a super-span box girder can be reduced, and then the bending moment and the deflection of the main girder of a 55-m moving framework are within safe ranges when a 60-m span box girder is cast in situ. According to the construction method, the construction cost can be remarkably lowered, and the construction rhythm can be accelerated.

Description

technical field [0001] The invention relates to the technical field of mobile formwork pouring, in particular to a construction method for cast-in-situ super-span continuous box girders with a 55m mobile formwork. Background technique [0002] The mobile formwork cast-in-place equal-section prestressed concrete box girder is an advanced construction method for bridges in the world. There is no need to install formwork supports under the bridge during construction. It has the advantages of simple construction procedures, short construction periods, and continuous construction. The traffic and navigation requirements under the bridge have been widely used at home and abroad. [0003] When moving the formwork cast-in-place box girder, in addition to bearing its own weight, it mainly bears the load of the cast-in-place box girder. When facing a super-span box girder (the span of the box girder is greater than the applicable span of the mobile formwork), the mobile formwork The ...

AI Technical Summary

Problems solved by technology

At present, the main method is to increase the steel consumption of the main girder of the mobile formwork and strengthen the rigidity of the main beam, so that the mobile formwork can adapt to the load of the long-span box girder. However, in this way, the steel consumption of the mobile formwork is doubled. Take the 62.5m mobile formwork of the bridge as an example, the main girder weighs 550t, and the total weight of the whole set of equipment is about 1400t. When the MSS construction promotion span reaches 80m, the steel consumption is as high as 2400t, and the installation, disassembly and transportation of steel components of the mobile formwork are significantly improved. difficulty

[0004] At the same time, in the specific construction, the spans of different holes of multi-span long bridges are often not consistent. For example, the span of the largest hole of the bridge is 60m, while the span of the remaining holes is about 55m. Cast-in-place girders double the amount of steel used, significantly increasing the implementation cost; and if the box girder is cast-in-place with a 55m mobile formwork, the bending moment and The deformation and deflection are doubled, which is prone to instability and has serious safety hazards

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