Case and interview
SenrigaN’s reliability and efficiency as seen in actual use
We had been waiting for efficient, reliable, non-destructive measurement technology
Eight-Japan Engineering Consultants, Inc. has a custom of actively adopting new technologies and it led the way in focusing on SenrigaN.
However, while many technologies are not suited to immediate adoption because they do not yet have sufficient performance history or verified results, for example, the company noted the results of demonstrative experiments with SenrigaN and case examples of measurements and kindly offered a place to actually use and evaluate it. Here, we are speaking to Terada from the Infrastructure Maintenance Management Department, the key figure who used SenrigaN.
Experiencing a measuring technology not influenced by conditions on the ground
› Why did you decide to try using SenrigaN?
Someone in another department had information on SenrigaN and I had vaguely heard about it from them, but the opportunity to actually learn about SenrigaN arose when I saw it being used on the site of a demonstrative experiment. The site was a pre-tensioned bridge over the sea, and it showed abnormalities, like plainly obvious concrete peeling and bubbling, as well as rust marks. The damage was considerable, and there were concerns that the tendons inside might have broken. Given this situation, it was necessary to investigate how the corrosion inside the beams was to find out the health of the bridge, and they decided to adopt SenrigaN, which does not require major preparations.
› What was your evaluation of SenrigaN after using it?
At this site, four people carried out the measurement, and of the 20 locations they measured, 4 were suspected of having ruptured. One of these locations in particular had severe bubbling and the concrete was peeling off, resulting in a condition as though it had been shaved, which allowed us to visually inspect the tendons inside, and we confirmed that they had ruptured. Thanks to think, I reached the conclusion as a member of the Infrastructure Maintenance Management Department that SenrigaN is accurate and reliable.
› What was your evaluation at your second site?
Compared to the first time, the weight and measuring time had both markedly improved, and because the second time coincided with the COVID-19 pandemic, the remote support structure was extremely helpful. The reduction in the measuring time in particular meant that we could measure more locations in one day, which increased the efficiency of the survey, I believe.
Because shaving was prohibited at the second site and the target was the pre-tensioned deck slabs, we were unable to use X-ray radiography, but on the other hand, I knew that SenrigaN was reliable from the first site, so it was good that we adopted it.
SenrigaN, an essential part of making accurate diagnoses as an infrastructure doctor
› How was it compared to other methods?
I believe that they can generally be divided broadly into two groups: shaving testing (destructive testing), and X-ray radiographic inspection (non-destructive testing). With a reinforced concrete structure, shaving testing would not have much effect, but prestressed concrete structures carry the risk of damaging or breaking the tendons while shaving. Moreover, shaving itself may be prohibited in some places.
In the case of X-rays, we need to take special considerations for safety, such as by having a specialist technician come, and conditions allowing measurement may not always be present, as in this site, where it would have been difficult to set up the necessary devices.
In the case of the second site especially, the local government had prohibited shaving under its management policy and we were not able to measure using X-ray radiographic inspection from under the beam, so if we had not had SenrigaN, the only testing we could have done was a visual inspection and the hammering vibration method. We also removed the pavement and investigated from above the beam, but because we were not able to see ruptures in the internal tendons easily, the manager would also have been in difficulty without SenrigaN.
› What is your process for adopting new technologies?
We have a meeting with the manager (customer) to talk about what kind of survey they want, using plans and other documents. In the case of the second site, SenrigaN was a new technology that the customer had never heard of, so we created a comparison chart (see below) to explain the differences between convention technologies and the results of the use at the first sight, which led to adopting it. In the case of SenrigaN and other little-known technologies, it is common to be unable to understand the measurement results from just looking at them, so the results report also needs to include an explanation of the technology and other information.
› What is necessary when adopting new technologies?
In the case of entirely unprecedented technologies, I think it is important to have firm results and performance showing that it is highly accurate and reliable, in particular. SenrigaN is a technology for detecting internal tendon ruptures, so reliability seems especially necessary because we are looking at a part that cannot be seen. Taking an extreme perspective, we do not know how accurate SenrigaN’s measurement results are, so cross-checking them with results from shaving in demonstrative experiments or the like (the SenrigaN website contains case examples showing performance with ruptures) and other evidence is extremely important.
› How would you like to use non-destructive testing in the future?
I’d love it if you could work a little harder on the price for SenrigaN, you know!
The real key, I think, is for SenrigaN, but also drones and robot technology, to be able to work more efficiently. However, this is based on a major assumption of reliability.
If that happens, we would be able to use the time for other work, so I would love to adopt them eagerly.
Internal testing in particular will become increasingly important in the future. I have heard that Konica Minolta is investigating technology to detect corrosion wastage, among other areas, so I have high expectations for that.
Further, we handle investigations of the components inside concrete, especially the salt concentration, with the destructive coring technique, which damages the structure, so I would appreciate it if you could handle something like this as well. I would be glad to cooperate wherever we can. I have high hopes for technical development capable of capturing internal abnormalities and safely measuring structure in efficient ways. In addition, I understand that concrete is the main target at present, but I would also like a testing technology to replace magnetic particle testing for steel bridges.