Manufacturing method for prestress small box girder

Abstract

The invention discloses a manufacturing method for a prestress small box girder. The prestress small box girder is divided into an open groove section located in the middle and anchoring sections located at the two ends, the manufacturing method comprises the following steps that 1, the open groove section is poured, open grooves used for arranging prestress ribs are reserved in a web plate of the open groove section, and two tensioning holes used for tensioning the prestress ribs are preset at intervals for a certain distance at the bottoms of the open grooves; 2, the prestress ribs penetrate through the open grooves reserved in the open groove section, the prestress ribs after penetrating are fixedly connected with steel bar cages of the anchoring sections at the two ends of the prestress small box girder, and the anchoring sections located at the two ends of the prestress small box girder are poured; 3, after the anchoring sections are poured and solidified, the prestress ribs aretensioned downwards by tensioning equipment through two transverse tensioning holes in the bottoms of the open grooves, and the tension value and the elongation value of the prestressed ribs are checked to meet the requirement; and 4, the open grooves in the open groove section are poured, then the third pouring is finished, the tensioning equipment is disassembled after the open grooves are solidified, and then the manufacturing of the whole prestress small box girder is completed. According to the manufacturing method for the prestress small box girder, the grouting in the prestressed tension of the small box girder is denser, and meanwhile, the utilization rate of the prestress ribs is improved.

Description

technical field [0001] The invention relates to the field of bridge construction, and relates to a method for manufacturing a small box girder, in particular to a method for manufacturing a prestressed small box girder. Background technique [0002] Prefabricated continuous small box girders are widely used in small and medium-span bridges in my country because of their simple structure, convenient construction, low cost, and time-saving construction. In this type of prefabricated beams, prestressed tendons are an essential component. The relatively mature tensioning methods in prestressed construction at this stage are post-tensioning and pre-tensioning. According to whether the prestressed tendon is in contact with concrete, it can be divided into bonded prestressed concrete and unbonded prestressed concrete. In the prefabrication of continuous small box girders, the post-tensioning method is adopted for the prestressed tendons, and the bonded form is bonded. But adopt ...

AI Technical Summary

Problems solved by technology

But adopt the post-tensioning method, the following problems will occur with the existing construction technology: (1) the tension force at the end of the prestressed tendon is relatively large, while the tension force at the mid-span is often small; (2) after the prestressed tendon is stretched , there is a situation that the channel grouting is not dense, which affects the quality of the beam

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