Prise winners list

Development of simple, low-cost and high-accuracy nondestructive inspection device for concrete structure based on a new measurement principle

Oumu-town, Hokkaido
Nitto Construction Co.
Other award winners
Applied Research Inc., / Tomoaki Sakai
iTECS Technical Association, / Kunio Kyokudan
Tokai University, / Takumi Hayashi
Recommended by
Oumu cho

Kubo, Hajime  (58)

Our business would decline if we do nothing new, but Mr. Kubo did not wish to lay off his employees. He started a new different business that was closely related to his main business

The company developed "Concrete Tester (CTS)"that enabled a worker to assess the inner compressive strength and detect the surface deterioration and concrete delamination by lightly hitting the surface of concrete structure with a hammer. This very economical inspection device has much higher measurement accuracy than the conventional "test hammer (rebound hammer) method" and "hammering test method" and can record precise data. Since the inspection device correctly detects the dangerous points of concrete structure, workers can repair the damaged sections "very accurately". Inspection and repair work can be performed at low cost within a short time. In a situation where decrepitude buildings are a social problem, this inspection device will be used effectively for a nondestructive inspection. The company will put a new low-cost model in the market in May this year.


A tunnel accident prompted him to join a joint research group for nondestructive inspection

In June 1999, a concrete block fell from the ceiling of the Fukuoka tunnel in the Sanyo Shinkansen Line and hit a running train. Fortunately no serious accident was caused, but this accident gave a shock to our society because it destroyed the "myth of infallible safety of concrete". This accident prompted a man to develop a nondestructive tester that could measure the strength of concrete structure. The man who developed it is Mr. Kubo running a civil engineering and construction company in a small local town facing the Sea of Okhotsk. 
"I felt instinctively that this accident would occur again and become a social problem. A little later, I visited my university professor, Mr. Kyokudan, and asked him casually what he was researching at that time. He answered that he was conducting a joint research for nondestructive inspection for concrete, and I asked him then and there to let me join his team. Mr. Kubo made his decision promptly because there were the following reasons. "It was clear that the number of public works would decrease in the near future. However, I did not wish to lay off my workers when I considered the local economy. I was seriously looking for a new business to keep my employees."
However, if I started a new business without any concrete plan, I would not be able to make a success. I thought that I should start a new business, which I could start with a small capital, which was related to my main business, and for which I could use my technology. The subject of research by my university processor satisfied these conditions perfectly. 
Mr. Kyokudan and his teammates had been researching a method to detect the interior conditions of concrete by analyzing the waveform of vibration called "impact elastic wave" for about ten years. They completed a new inspection device soon, and the company started a new business for inspection of concrete structure by using the new device. The new device enabled an accurate nondestructive inspection, but had a few problems. The device was expensive and its data were difficult to analyze. He thought, "Isn't is possible to conduct inspection more economically and simply?"
In fact, there were already two relatively economical nondestructive inspection methods, namely "test hammer method" and "hammering test method". In the former method that detects the rebound hardness of concrete surface, the important measurement accuracy was not good and the complicated data correction was necessary. In the latter method, an experienced engineer hits the concrete surface with a hammer and makes judgment according the hitting sound. Therefore, this method does not provide an objective accuracy and data. 
Mr. Kubo and his teammates focused on development of a new inspection method that was different from those conventional technologies and completed a prototype in 2004. The next year, they put on sale high-accuracy nondestructive inspection device "CTS-02" that operated based on a new measurement principle.

The new inspection device measured the interior conditions of concrete accurately and simply at low cost and reduced the repair cost drastically

An acceleration meter is installed within the hammer-type inspection device. When it hits the measuring surface, it measures the acceleration, automatically analyzes its waveform and shows the interior condition of concrete. It detects the degree of deterioration and delamination as well as compressive strength of concrete. In addition, 15000 data can be recorded in a SD card.
"The researches conducted by public institutions also confirmed that the new inspection device had much higher accuracy and was much more economical than the test hammer method. This device can show a contour map of interior strength in color on a PC screen and enables workers to repair the defective section of concrete very accurately."
This inspection device is used by consulting companies, maintenance and repair companies and "public institutions" such as the Ministry of Land, Infrastructure, Transport and Tourism, the Ministry of Agriculture, Forestry and Fisheries and the Hokkaido government. This fact indicates the high credibility of this device. However, out of 240 sets that have been sold so far, 115 sets were sold to users in Hokkaido. "The sale of this device has just started and it will be sold widely in the nationwide market.
In addition to sales of the inspection device, this company operates a consulting business (inspection and diagnosis) with this device. Its branch office in Sapporo shifted its business from construction to consulting two years ago and turned business from red to black. The new business helped him to keep his employees, the company has developed and he says, "I will employ new university graduates this year for the first time." In the tough economic environment in Hokkaido, a civil engineering and construction company started a new business and made a success.
"We asked other companies to manufacture the parts for our device, but tired to purchase those "made in Hokkaido" as far as possible. Anyway I hope that Hokkaido will be prosperous. Even a small company such as us can manufacture a remarkable product that is used nationwide. There is no difference in technology between a big city and a local town. 
This product is used not only nationwide but also in Korea. It will not be a distant future when a technological product in Hokkaido will become a global brand.

Nitto Construction Co.

Mar. 1773
20 million yen
52 (as of Dec. 2009)
Brief information:
Started as a construction company for civil engineering, but the company entered the business of nondestructive inspection for concrete structure in expectation of drastic decrease in civil engineering work.

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A worker can see the interior conditions of concrete structure, which naked eyes cannot see, clearly at a glance.


A worker can perform measurement accurately by simply hitting the wall surface with the hammer. This convenience is one of the major features of this device.


The company produced a groundbreaking inspection device that may be used worldwide.