Outline

The first of its kind in the world! “Partial High-Strength Rebar" that combines two types of strength in one rebar.
Achieves hinge relocation and improves building efficiency.

Double Stark is a deformed steel bar for reinforced concrete, manufactured in accordance with JIS G 3112, in which the strength of a portion of the steel bar is increased by high-frequency heat treatment.
This product consists of a normal-strength area (base material section) that conforms to the specifications of the original rebar, a high-strength area, and a transition area whose properties gradually change. By installing a normal-strength area and a high-strength area in one rebar at arbitrary locations, it is possible to realize hinge relocation of beams, thereby reducing damage at the column-beam joint.
This product also won the 2018 Cho-Monozukuri Component Award.

Benefits

(1) Lower environmental impact

The amount of rebar used can be reduced by about 30% compared to the conventional method, which is expected to result in effective use of resources and reduce carbon dioxide emissions generated in the production process.

(2) Greater comfort through more available living space

Failure at the base of the beam is inhibited, which may allow for openings at the base.
It may be possible to use the high-strength area of partial high-strength rebar in a column-beam connection as high-strength rebar, thus reducing the cross-section of the beam.

(3) Improved workability

Overcrowded reinforcement and double reinforcement can be eliminated, and the number of joints and fixtures can be lowered by reducing the number of rebars.

Type and specifications

The high-strength area has been certified as MSRB-0106 by the Minister in accordance with Article 37-2 of the Building Standards Act.
Obtained GBRC Performance Certificate No. 20-17 (construction method using partially reinforced high-strength steel double-stark in reinforced concrete beams).

Mechanical Properties

Steel grade and given name

Production plant

Manufacturing Process

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