Connected bridges share their condition - #stillhere Thursday, 17 November 2016

Researchers from the KTH Royal Institute of Technology in Sweden are rigging up the country’s bridges with multiple sensors that allow early detection of wear and tear. The bridges can even tweet throughout the course of a day.

Professor Raid Karoumi, from the KTH Division of Structural Engineering and Bridges, said that while the internet connections aren’t a substitute for visual inspections, they do provide valuable information about how bridges are impacted by traffic, wind and temperature fluctuations.

“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,” he said.

The information from the sensors could also extend the life of bridges. Karoumi gives the example of an old bridge connecting Stockholm to the island of Lidingö, which is slated to be replaced in 2020. However, detailed information from the sensors about the bridge's state may allow it to stand for another 10 years.

He says the real-time data (up to 400 pieces of information per second) provides clues to what causes wear and tear, even detecting cracks that aren’t even visible to the naked eye.

“Of course you drive still out and look,” Karoumi adds. “But this technology will help to determine when and where an inspection is required, and it will also provide valuable information to those who perform the inspections. It is costly to block traffic so it is good if the inspections are made when necessary.”

The information can also be used to refine future designs. He says a specially-designed bridge, supported by a single concrete arch, that connects Sweden and Norway was fitted with 72 sensors when it was completed in 2005. The researchers now have 10 years’ worth of data.

“For newly constructed bridges, we want to check how they behave,” Karoumi says. “You want to confirm that the calculation models used for dimensioning are correct,” he said.

“We dimension our bridges for 120 years of life and we want to use the measurements as a kind of footprint that we can compare them with later."

[Professor Raid Karoumi with some of the bridges of Stockholm. Photo: Håkan Lindgren/KTH]

Transport/Infrastructure will be a major topic of discussion at the Australian Engineering Conference 2016 in Brisbane on November 23-25.