The Svinesund Bridge connecting Sweden with Norway

Bridges in IoT era can tweet about their state

Image credit: Gunnar Egset/Wikimedia Commons

Swedish construction engineers are embracing the Internet of Things by fitting sensors into bridges, making the infrastructure not only self-monitoring but also able to tweet about its condition.

The researchers from KTH Royal Institute of Technology say that by evaluating data from dozens of sensors placed at the most strained parts of the bridges, they would be able to tailor maintenance in order not only to avoid accidents, but also to extend a bridge’s designed lifetime by up to a decade.

“Just as a doctor places a stethoscope and heart rate sensors on your chest, we put our sensors where we want to monitor the condition of the bridge,” explained structural engineering professor Raid Karoumi, who leads the research.

The technology, Karoumi said, is not designed to replace inspections carried out by human professionals. However, by detecting the slightest changes, the sensors would indicate when actually an inspection is required.

“It is costly to block traffic so it is good if the inspections are made when necessary,” the engineer said.

The sensors are delivering up to 400 pieces of information per second – all in real time. In the amount of data, analysts can uncover indications of issues long before they develop into full-blown problems. For example, they can detect cracks that are yet invisible to the naked eye.

The technology can be used to tailor repairs of old bridges but also to fine-tune maintenance of new ones.

The idea is for the sensors to harvest energy from the vibrations of the bridge.

“There are various types of energy collection systems,” said Karoumi. “Radio waves can be converted to energy, which we’re testing on the Lidingö bridge in collaboration with Uppsala University.”

The researchers recently processed ten years’ worth of data from the Svinesund bridge, which connects Sweden to Norway. The bridge, completed in 2005, was fitted with 72 sensors during construction.

One of the bridges involved in the experiments was even enabled to send real time data about its status into an online app – sort of tweeting about its condition. However, the project was stopped due to security concerns.

Researchers from the US University of New Hampshire are exploring a similar idea. They recently fitted the Memorial Bridge, connecting New Hampshire to Main, with sensors that monitor not only the bridge’s structural stability, but also the traffic travelling across the bridge and environmental conditions such as concentrations of pollutants in the air.

The Living Bridge, as the engineers call it, is fitted with 40 sensors that enable the structure to self-diagnose problems and report them to the researchers.

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