Construction technology for stretching notch by cast-in-situ prestress box beam

Abstract

The invention discloses a construction technology for stretching a notch by a cast-in-situ prestress box beam, comprising four steps: the first step: arranging a notch die plate, positioning and fixing an anchorage by utilizing the notch die plate so as to control the inclination angle of anchorage installation and the position of the anchorage centerline, thereby improving installation accuracy;the second step: reserving a tensioning apparatus suspension hole, a secondary casting hole and an air vent to solve the problem of the construction difficulties such as recovery of intercepted steelbars of the notch, prestress stretching, secondary casting and the like; the third step: stretching prestress; and the fourth step: plugging the notch; adopting the method that a grouting material ispoured from the secondary casting hole reserved on the top part of the lower notch to replace the conventional method that inclined die casting is adopted and redundant concrete is eliminated after die removing, thereby solving the problems of the compactness and strength of the secondary casting and the tight connection between the secondary casting and an original structure, therefore, the method is simpler and easier, and the casting quality can be guaranteed more easily.

Description

technical field [0001] The invention relates to a bridge construction technology, in particular to a construction technology of a cast-in-place prestressed box girder tensioning slot. Background technique [0002] With the rapid development of science and technology, municipal bridges and other structures have become more beautiful in shape, but at the same time, some small problems in engineering construction continue to appear, and the construction of the lower notch of cast-in-place prestressed box girder is one of many problems. [0003] 1. In some projects, due to the improper support method of the notch formwork (the formwork set up to form the tension notch) (for example, the manual attached figure 1 : Directly fix the anchors on the steel skeleton of the transverse beam, and then use foam to make the anchors into the shape of tension notches; or fix the anchors on the simple formwork without reinforcement skeleton. These conditions are prone to deformation during co...

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Problems solved by technology

), resulting in deviations in the installation of anchors, leaving hidden dangers to the quality of the project;

[0004] 2. In order to facilitate the support of the notch formwork at the notch of some projects, some steel bars of the transverse beam are cut off, and no structural steel bars are reserved in the later stage, resulting in planting or digging out bars afterwards, which not only wastes a lot of manpower , material resources, and the construction period is affected, the quality of steel connection cannot be guaranteed;

[0005] 3. The construction method of notch plugging in some projects is improper (for example: inclined mold method: as attached to the manual figure 2 ; Mortar filling method: Use high-grade mortar to fill the notch in stages until it is straight with the surrounding box girder concrete

To sum up, the construction of the lower slot of the fish-belly box girder has high technical and quality requirements, and has certain technical and construction difficulties

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