Steel bar and joint of steel bar

Abstract

The invention provides a steel bar capable of suppressing the interference of reinforcing steel bars. The steel bar (1) is used as the main reinforcement of steel bar concrete and the diameter of the end of the steel bar is expanded compared with the diameter of the steel bar body (2). The outer periphery of the steel bar is formed with the thread portion (3) of a male screw (4). The thread number of the male screw (4) is 6-9. The ratio (d3/d1) of the small-diameter of the male screw (4) to the diameter of the steel bar body (2) is 1.05-1.50. The corner (5) at the edge of the thread portion (3) with the steel bar body (2) is preferably formed to be round. In addition, a round corner is formed by the die forging of the thread portion (3) formed by the diameter expanding of the end of the steel bar compared with the steel bar body (2). The diameter of the round corner is preferably to be 1-3 times of that of the pitch of the male screw (4).

Description

technical field [0001] The present invention relates to a steel bar and a steel bar joint used as main bars (main iron bars) of reinforced concrete. Background technique [0002] In reinforced concrete, in order to make the steel bar of the limited standard length as the main bar become a continuous bar on site, a bar joint is used. As a steel bar joint, it is generally a lap joint or a pressurized gas welded joint that makes the steel bar coincide with a specified length; the lap joint makes the structure of the steel bar configuration complicated due to the overlap, and the quality of the pressurized gas welded joint is determined by the technology of the crimping worker. Such a disadvantage. [0003] Therefore, as a special joint, a joint in which cement slurry is injected into the sleeve together with the reinforcement has been developed. This special joint for injecting grout is preferable in terms of simplification of the reinforcement structure and put into practica...

AI Technical Summary

Problems solved by technology

[0006] However, in conventional threaded joints, since a threaded portion having an enlarged diameter compared with the steel bar body is formed at the end of the steel bar, if the axial length and / or diameter of the threaded portion are large, the There is a possibility that the connecting tool that the threaded part is screwed may interfere with reinforcements other than the main reinforcements arranged around the reinforcements.

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