Incorporating new perspectives to build the future of social infrastructure

Highways that stretch through the heart of the city. Subways that run like a mesh. Bridges that we cross on our daily walks. The bridges and tunnels that we pass through on a daily basis are indispensable to our lives, supporting large numbers of people and vehicles. In recent years, however, maintenance and management of bridges and tunnels has become a major issue, as aging bridges and tunnels have resulted in collapsed walls. Professor Hidehiko Sekiya of the School of Architecture and Urban Design is conducting research on monitoring structures such as bridges and tunnels in order to make society safer and more secure.

Steel materials used in infrastructure structures are subjected to repetitive forces that cause damage, which then propagates. These “fatigue cracks” eventually lead to major failure, and the structures themselves are severely damaged. In addition to human casualties, the subsequent restoration work takes an enormous amount of time, resulting in significant economic losses. To prevent such accidents, daily maintenance inspections are indispensable, but conventional visual inspections are subject to the possibility of oversight, in addition to the recent shortage of manpower. To solve this problem, Professor Sekiya has developed a system that can automatically perform maintenance and inspections in real time using microscopic machines called MEMS. By simply attaching the developed system to bridges and shielded tunnels, the system can evaluate the condition of the structures based on vibrations caused by cars and trains, and even if an earthquake were to occur, the system can instantly check the condition of the infrastructure structures.

Professor Sekiya’s research is wide-ranging and includes studies on making construction sites more efficient. You may have seen a construction site in the city with one person holding up a measuring tape and another person looking through it with a machine. The machine is called a level surveyor, and it measures the height of the building or structure to check that it is properly built according to the plan. The equipment is evolving, but the principle has remained unchanged for a long time. Our research is to see if we can automate this process.”
Level surveying must be done early in the morning and even in bad weather, and it is often hard work at some sites. In addition, the lack of manpower and rising labor costs are also becoming an issue. Professor Sekiya’s research is replacing the surveying work with sensors. In an experiment conducted on a PC bridge (prestressed concrete bridge) under construction, it was confirmed that the results analyzed from the data acquired by the sensors were almost identical to the data obtained by conventional level surveying. Furthermore, research on measurement methods utilizing GNSS, a positioning system using multiple satellites, is underway, which is expected to further improve the efficiency of construction management.
Research is also being conducted on “digital twins,” in which real-world structures are reproduced on a computer for simulation and data analysis. Rather than simply reproducing a model, a highly accurate model is created based on data obtained from the actual structure. It will be possible to predict what will happen to this structure 50 or 100 years from now. We will be able to say, ‘This part of the bridge should be reinforced,’ or ‘This part of the road should be repaired first.’”
Research with the private sector is also active. For example, one such research project involves embedding sensors in road pavement to acquire a variety of data. In addition to detecting the movement of vehicles and people and measuring the health of the pavement, they are also working on data that can be used for automatic driving in the future. “All of this research, including bridges, tunnels, and roads, is being conducted with the idea of how best to build the infrastructure of the future.”

Professor Sekiya says that the greatest motivation for continuing his research is the realization that it has been implemented in society and has contributed to the enrichment of people’s lives. “I think it is important to make the results of our research known to as many people as possible through publications and other means, and then to implement the results in society.”
He also emphasizes the importance of conducting demonstration tests on actually constructed structures. “In many cases, it is difficult to reproduce actual phenomena as they are in simulations because of the various assumptions involved and the difficulty of modeling. Bridges and tunnels cannot be mass-produced; each one is an original. The data obtained will vary depending on the temperature and humidity, so it is important to actually measure, not just simulate.”

In central Tokyo, many people, cars, and trains come and go every day, and with this traffic comes the aging of structures. We asked him about research that can only be conducted in Tokyo. “Tokyo has a diverse range of issues, and there are experts in many different fields. I think we need to share our challenges and work together to solve them.”
What kind of society does Professor Sekiya hope to realize through his research? “With today’s technology, it is difficult to say that this infrastructure is absolutely safe. However, we can improve safety through further research. I hope that through research, we can develop technologies that will enable us to construct attractive structures even with a smaller population, so that people can lead richer lives than before.”

Infrastructure such as bridges, tunnels, and roads are an indispensable part of our daily lives. They play a major role by supporting daily commuting, logistics, and transportation. However, as time passes, they have become increasingly decrepit, and issues such as difficulties in inspection and maintenance management due to lack of manpower have become more pronounced. Facing this reality head-on, Professor Sekiya is taking on the challenge of realizing monitoring and efficient construction management of structures using the latest technology. Professor Sekiya’s goal is not only to improve safety, but also to build a sustainable and attractive infrastructure of the future through technological innovation. This is not only to protect structures, but also to build a bridge to the future that will enrich people’s lives.