Pi-shaped cross section prefabricated capping beam adopting internal prestressed steel bar and prefabricated method thereof

Abstract

The invention discloses a prefabricated UHPC capping beam structure with a pi-shaped cross section and a prefabricated method thereof. The capping beam comprises a top plate and two web plates, wherein a part of the web plates covering between two upright post piers is a thickened section, and parts of the web plates outside two sides of the two upright post piers are a gradual change section andan equal thickness section; the lengths of the gradual change section and the equal thickness section on the web plates are the same, the equal thickness section is close to an end of the web plates,the gradual change section is between the thickened section and the equal thickness section; the thickness of the gradual change section is linearly gradual, and the thicknesses of both ends are matched with the thickened section and the equal thickness section respectively; and a plurality of top plate prestressed steel bars and a plurality of web plate prestressed steel bars are respectively arranged inside the top plate and inside the two webs plates. During a prefabrication, vibrating and compacting are carried out by an attached vibrator, a prefabrication element is cured by adopting steam, and finally, the top plate prestressed steel bars and the web plate prestressed steel bars are stretched in a symmetrical stretching mode at two ends. The prefabricated UHPC capping beam structurewith the pi-shaped cross section and the prefabricated method thereof further reduce an overall weight of the capping beam and are expected to reduce weight by more than 55% relative to a solid capping beam.

Description

technical field [0001] The invention relates to the technical field of cover beam construction, in particular to a π-shaped cross-section prefabricated cover beam using prestressed tendons in the body and a prefabricated method thereof. Background technique [0002] The wide application of ultra-high-performance concrete materials, referred to as UHPC (Ultra-High Performance Concrete), makes it possible to reduce the weight of components with large volume and load such as cap beams. [0003] In the prior art, there are certain defects in the prefabricated cover beam structure using UHPC materials. For example, the invention patent publication with the publication number CN106869012A discloses a prefabricated thin-walled cover beam using an internal prestressing system. This technical document In the technology disclosed in , by designing the cover beam as a hollow thin-walled structure with a "mouth" shaped section, although the overall weight of the cover beam is effectivel...

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Problems solved by technology

[0004] However, in practical application, according to the technology disclosed in the above-mentioned technical documents, in the process of manufacturing the cover beam, there is a problem that the processing workload of the inner mold is large, and the inner mold cannot be reused, and the structural weight is still relatively large (compared to the solid cover beam. The weight loss rate is about 35% to 40%)

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