Researchers from the KTH Royal Institute of Technology (KTH) in Stockholm, Sweden, are outfitting a number of the country’s aging bridges with sensors that permit earlier detection of wear and tear. The bridges, which could be considered the next object to join the Internet of Things, can even tweet their conditions throughout the course of the day. This enables engineers to gather important information regarding the effects of traffic, wind and temperature fluctuations on the bridges.
While bridge collapses are rare, the data transmitted by the sensors can assist engineers in being more proactive about detecting conditions that could lead to a collapse or other dangerous condition.
Raid Karoumi, the engineer behind the project and a professor in the division of Structural Engineering and Bridges at KTH, is quick to note that the internet-enabled sensors are not a substitute for visual inspections. But they can pick up deviations that could indicate impending changes in bridge conditions, improving safety, and even extending the life of the bridges.
For instance, an older bridge connecting Stockholm to Lidingö, a large island in the eastern part of Sweden’s archipelago, will be outfitted with sensors that can help determine if the bridge really does need to be replaced in 2020 as engineers projected. Based on the data gathered, the bridge could be permitted to stand another 10 years.
Sensors Deliver 400 Pieces of Information per Second
Perhaps best of all, the data collected—more than 400 pieces of information per second—can increase bridge safety while saving time and money. The sensors can detect cracks the human eye may not see, as well as identify the need for a visual inspection. Blocking a bridge to perform a visual inspection is not only costly, but also affects traffic patterns and increases congestion.
The technology is already in use on a bridge over the Svinesund Sound, connecting Sweden and Norway. Fitted with 72 sensors when it was built in 2005, the bridge has delivered 10 years’ worth of data about the bridge and its construction, which involves a single concrete arch.
The sensors provide valuable information regarding the bridge’s dimensions to help engineers determine whether the design is an effective model for future structures.
How It Works
Depending on the bridge, sensors operate either via cables or batteries. The cordless sensors are recharged with energy generated by the bridge's oscillations.
The technology opens the door to numerous other applications, from transmitting traffic information to reporting bridge oscillations when a train passes over.
The researchers at KTH continue to work on developing cloud connectivity, and even an artificial intelligence program for the sensor system. The goal is to enable engineers to improve the safety and longevity of future bridge designs—and maintain the safety of today’s bridges— through the data collected.