Connected bridges: these engineers who want to make bridges talk

Have you ever passed under a bridge, contemplating its structure, and wondering what these stones could say if they could speak? This is the objective of the “Connected Bridges” program, headed by CEREMA, the French reference organization in the design and maintenance of engineering structures: listening and observing to better understand the condition of bridges, but also when and how to best maintain them.

Bridges in a state of emergency

The events in Genoa and Mirepoix have triggered this sudden awareness. In 2018, a portion of the Morandi motorway viaduct collapsed. In the aftermath of this impressive event, a Senate commission revealed a ticking time bomb: in small local authorities, a large number of bridges are not inspected or simply not recorded. As an echo to this alarm signal, the bridge of Mirepoix-sur-Tarn collapsed when a heavy truck passed over it a few months later.

The stakes are high: there are between 200,000 and 250,000 bridges in France that need to be regularly monitored and maintained. Although the majority of these bridges do not pose any particular problem, it is still a pharaonic task for some local authorities which, beyond the necessary skills, sometimes have difficulty managing a fleet of infrastructures with limited means.

This is why the idea of connecting bridges is slowly gaining ground to allow a more organized, optimized and less costly management of an aging heritage through the monitoring of pathologies but also through a better understanding of their life:

• Monitoring of certain pathologies at a distance
• Understanding of the actual traffic or the impact of certain events, such as the passage of exceptional convoys.

In cities, the concept is becoming popular in the wake of the Smart Cities.

Connected bridges: a response to these challenges

However, these monitoring systems suffer from a number of teething problems, such as the fact that they do not last long enough to be installed on a permanent basis, or the difficulties in aggregating and interpreting this mass of data. Moreover, local authorities have little experience with existing solutions.

This is why the State, as part of the France Relance plan, has released 4 million euros to help 17 projects mature under the watchful eye of CEREMA, whose expertise in this field will guarantee the value of these new systems!

But a new player could well change the deal: Mon-it, a young French company with Italian origins (NTSG), claims a solution that seems to sweep away the main difficulties of competitors. With more than 7 years of experience, this robust, passive solution, with sensors devoid of electronics and low energy consumption, offers a complete measurement system. By design, it is capable of lasting at least 35 years!

Above all, the company has built up end-to-end know-how that enables it to offer complete support: from the architecture of the solution and assistance with installation to secure storage and interpretation of results, with a model certified by the CNR, the Italian equivalent of our CNRS.

Today, NTSG is involved in many different projects ranging from the generalized monitoring of bridges and tunnels of the Italian highway network to the new Lyon-Turin tunnel.

These monitoring systems for connected bridges will not flourish on all of the more than 200,000 existing bridges and tunnels, but it is certain that they will play a major role in the digital transition of our infrastructure management, making it more reliable, more transparent, more fluid and thus probably less costly. With technology that is difficult to master from start to finish, there is no doubt that the experience of our transalpine friends will be invaluable! Our team is ready to support you in understanding these sensor technologies!

About the author,

Maxence, Consultant in the Chemistry, Materials and Mobility Alcimed’s team in France