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Penta-Ocean Construction Co., Ltd.

21 General Contractors and PLT will begin demonstration tests in FY 3/23
on a joint R&D project called “Bar Arrangement Inspection System”
for recognizing 3D layout of reinforcing bars

Tokyo, Japan – Mar. 29, 2022 – In September 2020, 21 General Contractors (hereinafter "The Kyoken 21companies" *1) and Prime Life Technologies Corporation (hereinafter "PLT") signed a joint research and development agreement to develop a "Bar Arrangement Inspection System", which recognizes the three-dimensional arrangement of rebar. This system uses a dedicated camera to three-dimensionally capture and recognize the number, diameter, spacing, and arrangement of rebars in the inspection area. The Kyoken 21 companies and PLT will conduct demonstration tests at construction sites in FY 3/23 with the aim of reducing inspection time by 60%, with a full-scale operation starting in FY 3/24 in their sight.


■Joint development scheme for continuous improvement

The unique feature of the development structure is that it is a joint development scheme between The Kyoken 21 companies, which are also the service users, and PLT, which is the service operator. By grasping the issues and differences in inspection methods used by The Kyoken companies 21 during the bar arrangement inspection, and reflecting them in the development requirements, we will be able to build a highly accurate service tailored to various construction sites. In addition, we plan to utilize the joint development scheme after the start of operation, to make continuous improvements based on feedback from each construction site, leading to a service that is easy for other construction companies to implement.


■Joint development integrating individual R&D activities

The development is currently underway by combining the "Rebar recognition technology using artificial intelligence (AI)" developed by The Kyoken 21 companies, and "Systems, camera devices, and application technology for inspecting rebar arrangement", developed by PLT in collaboration with Panasonic Corporation.

■Background of Research and Development (R&D)

A common issue in the construction industry is the future shortage of skilled engineers due to their imminent retirement and a decrease in the number of young engineers joining the industry. On the other hand, with the demand for stricter quality control, it takes longer to train field technicians who are qualified for advanced quality control. In addition, the Ministry of Land, Infrastructure, Transport, and Tourism has set a goal of improving productivity at construction sites by 20% by FY 3/26 through the use of ICT. The Kyoken 21 companies and PLT share a solid commitment to solving these issues using digital tools, which was the grounds for developing the “Bar Arrangement Inspection System."

■Outline of Bar Arrangement Inspection System

The main feature of the inspection system is the recognition of three-dimensional rebar arrangement. The outline of the target specifications of the bar arrangement inspection system in the demonstration test is shown below.




  • The ability to register and create data for bar arrangement inspection from structural design drawings

  • The ability to measure bar arrangement (number of bars, diameter, spacing, and arrangement) based on
    images taken using a dedicated camera

  • The ability to automatically cross-check with registered design data and measurement results (the range of automatic cross-checking should be expanded gradually)

  • The ability to output the cross-sectional shape of the bar arrangement

  • The ability to upload inspection results to a cloud server and share with relevant parties

  • The ability to output inspection records as inspection forms

  • The ability to trace back any modification made







■Future development plans

  • FY 3/23: Demonstration tests at construction sites of The 21 Kyoken companies
  • FY 3/24: PLT to launch the full-scale "Reinforcement Arrangement Inspection Service" for The 21 Kyoken companies
  • Within the same year, the scope will be expanded to include general contractors other than The 21 Kyoken companies (plan)


The 21 Kyoken companies (in Japanese alphabetical order)


Asunaro Aoki Construction Co.,Ltd.,  Asanuma Corporation,
Hazama Ando Corporation,  Okumura Corporation,
Kitano Construction Corporation Kumagai Gumi Co., Ltd.,
Penta-Ocean Construction Co., Ltd.,  Sato Kogyo Co., Ltd.,
Daisue Construction Co., Ltd.,  Takamatsu Construction Co., Ltd.,
Tekken Corporation,  Tokyu Construction Co., Ltd.,
Toda Corporation,  Tobishima Corporation,  Nishimatsu Construction Co., Ltd.,
JDC Corporation,  Haseko Corporation,  P.S. Mitsubishi Construction Co., Ltd.,
MATSUMURA-GUMI Corporation, MURAMOTO Corporation, Yahagi Construction Co., Ltd.



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