Dual prestressed beam and construction method thereof

Abstract

A double prestressed beam mainly comprises a prefabricated part and a cast-in-place part. Wherein the prefabricated part is manufactured in a factory and comprises profile steel, prestressed tendons, longitudinal bars, stirrups, shear bolts, H-shaped perforated steel plate connecting pieces and prefabricated concrete. In the manufacturing process, a vertical load is firstly applied to the profile steel to enable the profile steel to be bent and deformed to a certain degree, then prefabricated part concrete is poured and cured, when the concrete reaches certain strength, unloading is conducted, auxiliary profile steel is dismantled, and the profile steel on the lower portion contracts to apply first prestress to the concrete; however, deformation of the profile steel on the lower portion cannot be completely recovered due to constraint of the concrete, the profile steel still bends to a certain degree, at the moment, the prestressed tendons are tensioned to completely recover the deformation, and second prestress is applied to the concrete due to the action of the prestressed tendons. According to the method, the double prestressing force is applied to the concrete in sequence only by changing the construction process, and the cracking load and the durability in the use stage are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of buildings, in particular to a double prestressed beam and a construction method thereof. Background technique [0002] Some prefabricated steel concrete beams combine the good mechanical properties of steel concrete and the advantages of prefabricated assembly structures in construction. They have the characteristics of high mechanization, easy quality control, simple on-site procedures and time-saving construction. However, its anti-cracking performance is average. Some scholars combine prestressing technology with some prefabricated steel concrete, and apply prestressing to the prefabricated part during the prefabrication stage. However, the traditional prestressing construction method has extremely strict requirements on tension control stress. If the tensile stress is not properly controlled, it will cause tension cracking on the upper edge of the prefabricated beam and reverse arching of the beam. I...

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Problems solved by technology

[0003] In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a double prestressed beam and its construction method, which uses the H-shaped perforated steel plate connector to solve the problem that the prestress loss of the flexible connector is more serious. The rigidity can effectively restrain the concrete and reduce the loss of prestress; the H-shaped end flange increases the bearing area of ​​the concrete, which can effectively prevent the phenomenon of local crush damage of the prestressed concrete; the reinforced concrete tenon can effectively resist the longitudinal shear force, and has the function of preventing concrete from lifting, which is equivalent to the function of the big head part of the stud

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