Infrastructure protectionSmart infrastructure sensors are powered by the pavement, bridges they monitor
As states look to improve its infrastructure — roads and bridges — researchers think they may have one solution. They are creating smart infrastructure sensors that are powered by the pavement and bridges they are designed to monitor. These small sensors will self-diagnose damage and mechanical failure in pavements and bridges.
Self-powered, wireless sensors to monitor bridges and roadways // Source: msu.edu
As the state of Michigan looks to improve its infrastructure — roads and bridges — a team of Michigan State University researchers think they may have one solution.
Nizar Lajnef, an assistant professor of civil and environment engineering, and Shantanu Chakrabartty, an associate professor of electrical and computer engineering, are creating smart infrastructure sensors that are powered by the pavement and bridges they are designed to monitor.
“We are working on sensors that extract their power from the vibration and strain of their environment,” Lajnef said. “There is no external source of power — no batteries. They are completely self-powered.”
An MSU release reports that prototype work began as part of Lajnef’s doctoral research in 2008 at MSU. It has evolved into a national project with the U.S. Department of Transportation that has already generated one patent, three patent applications, and three USDOT grants totaling $1.7 million, including $1.4 million of new funding.
The goal: To create very small sensors that can self-diagnose damage and mechanical failure in pavements and bridges.
“Battery-powered sensors last only two to three years, max,” Lajnef told Engineering News-Record. Moreover, it takes at least five years for a road and 10 to 12 years for most highways to show cracking, he adds. Because sensors are embedded in asphalt, however, batteries are not easily changed. The other option is to wire every sensor to a power source, a process that is too time consuming and expensive. “It’s so hard to install classic, wired, straight-gate sensors that they’ve never been used in a real project,” says Lajnef.
“This passive system harvests its energy from the infrastructure that becomes its host,” Lajnef said. “We have completely removed batteries and all interface electronics from the process. It’s different from any of the current systems being used today.”
The sensor prototype uses less than 800 nanowatts of power, which is significantly less than in today’s existing technology. Data is collected wirelessly using handheld readers that scan the structure. Lajnef said part of the research will evaluate whether smart phones can be used for the collection of data.
Prototypes are currently being tested at the U.S. Federal Highway Administration’s Turner Fairbanks Highway Research Facility, near Washington, D.C. The objective is to monitor infrastructure degradation, which is critical for maintenance and safety.
The researchers are using the data to predict how a bridge or highway ages and when it needs replacement. “You can detect damage under the road before it surfaces,”Lajnef told ENR.
Now, DOTs must visually monitor the aging of infrastructure for cracks. Lajnef says this retroactive method is more costly than predicting aging before it happens. “If you have the info that foretells cracking, you can anticipate it in terms of scheduling construction,” says Lajnef.
“Additional information on bridges and pavements would save a lot of money, which we hope our zero-maintenance sensors will do,” he added.
In addition, the researchers also are developing new methods to understand the data that are being generated by the sensors.
