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Licensing agreement with Obayashi Corporation Joint patent for part of the construction method

Construction Technology Certification No. 1005

Multiple nut bar construction method

Post-construction type high-strength shear reinforcement

Patent No. 6883982

Patent No. 6883983

Patent No. 6910793

Patent No.No. 7007089


  1. Good efficiency per drilling

  2. High workability and durability

  3. Can be constructed from the inside or one side of the Co structure

It is used for bridges with wall pressure of 400 mm or more, underground structures and tunnels.

AlreadyIn this method, holes are drilled from the inside of the walls, bottom slabs, and top slabs of existing underground structures, and high-strength shear reinforcing bars are inserted to increase structural seismic resistance.


groundSeismic reinforcement can be done in a short period of time and at low cost without improving the ground surrounding the lower structure.

MNB construction completed 2.JPG

material used

Multiple Nut Bar (MNB)

GermanyOur own mechanical anchor is a round nut made of S45C, which is made of the same metal as the hexagonal nut used for ordinary PC steel bars, so it has the same durability as a post-tension prestressed concrete anchor. there is.

SoBecause the PC steel bar "Multiple Nut Bar" with mechanical fixings is used as the shear reinforcing bar, it is stronger than the conventional shear reinforcing bar, reducing the number of drilling holes and shortening the construction cost and construction period. can.

Overview of reinforcement with multiple nut bars

MNB process and reinforcement image.jpg

underIn horizontal construction, the pre-grout method allows finishing immediately after insertion, and in upward construction, it is possible to use the formwork developed by our company in the post-grout method.

The water-cement ratio of the grout material that wraps the bar is 44% or less, so it has the same durability as existing structures.

Installation procedure for multiple nut bars

MNB work process 2.jpg
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