UMTRI to Participate in Bridge Monitoring Grant

Posted 01/15/2009
Researchers at the University of Michigan, including several UMTRI staff members, are leading a $19-million project to better monitor the health of bridges. Over the next five years, they will create the ultimate system for monitoring bridge infrastructure, and install and test it on several bridges.

The bridge monitoring system is envisioned to include several different types of surface and penetrating sensors to detect cracks, corrosion, and other signs of weakness. The system would also measure the effects of heavy trucks on bridges, which is not currently possible. Through enhanced antennas and the Internet, the system would wirelessly relay the information it gathers to an inspector on-site or to a decision maker in an office miles away.

The bridge monitoring system would place data-gathering devices on bridges and trucks, and use a wireless network to transfer the information gathered to both inspectors on-site at the bridge and decision makers at remote office locations.

Funded in large part by the National Institute of Standards and Technology (NIST)'s Technology Innovation Program (TIP), the project involves fourteen researchers from the University of Michigan (UM) College of Engineering and UMTRI, as well as engineers from five private firms in New York, California, and Michigan. The remaining funding comes from cost-sharing among the entities involved and the Michigan Department of Transportation (MDOT). MDOT is providing unfettered access to state bridges to serve as high-visibility test sites for showcasing the technology.

"This project will accelerate the field of structural health monitoring and ultimately improve the safety of the nation's aging bridges and other infrastructures," says Jerome Lynch, principal investigator on the project and assistant professor in the UM Department of Civil and Environmental Engineering. "We want to develop new technologies to create a two-way conduit of information between the bridge official and the bridge. We are excited to collaborate on these transformative technologies with partners like MDOT who could use them immediately to improve bridge inspection processes."

Four types of sensors will contribute to gathering data. Victor Li, E. Benjamin Wylie Collegiate Professor of civil and environmental engineering, has developed a high-performance, fiber-reinforced, bendable concrete that’s more durable than traditional concrete and also conducts electricity. Researchers would measure changes in conductivity, which would signal weaknesses in the bridge. On test bridges, the deck would be replaced with this concrete.

Lynch and a colleague are developing a carbon nanotube-based sensing "skin" that would be glued or painted on to bridge "hot spots" to detect cracks and corrosion invisible to the human eye. The skin's perimeter is lined with electrodes that run a current over the skin to read what's happening underneath based on changes in the electrical resistance.

Low-power, low-cost wireless nodes could look for classical damage responses like strain and changes in vibration. These nodes would harvest energy from vibrations on the bridge or even radio waves in the air. These nodes are being developed by Dennis Sylvester, an associate professor in the UM Department of Electrical Engineering and Computer Science, and Khalil Najafi, Schlumberger Professor of Engineering, Arthur F. Thurnau Professor, and chair of the U-M Electrical and Computer Engineering Division.

Sensors will also be housed in the vehicles that travel on the bridge. UMTRI researchers will outfit a test vehicle to measure the bridge's reaction to the strain the vehicle imposes, which is not currently known. Understanding how vehicles, especially trucks, affect bridges is a critical piece of information that could help predict the structure's lifetime. This effort is led by Tim Gordon, research professor and head of UMTRI's Engineering Research Division. Other UMTRI team members include senior research associate Steven Karamihas, research scientist Ralph Robinson, and business development manager Todd Anuskiewicz.

Today, bridge inspectors rely mostly on their eyes to determine if a structure is sound. "Our work will add to what is currently done, not replace it," Gordon said. "The infrastructure problem and the feasibility of new monitoring strategies are emerging at the same time. We believe we have ways of testing the performance of bridges as integrated structures, not just by inspecting their components."

Other parts of the system will organize data into meaningful displays and communicate it from the sensors to the inspector. Vineet Kamat, assistant professor in UM's Department of Civil and Environmental Engineering, will lead the human-infrastructure interaction effort.

"The technologies from this project could prove very beneficial to the citizens of Michigan in the longer lasting, smarter, safer, and ultimately more sustainable roadways," says MDOT Director Kirk Steudle. "Recognizing that our nation's infrastructure is the backbone of our economy, this type of innovative research is critical to the future of Michigan and the United States. MDOT is pleased to partner with the University of Michigan on this important engineering project."

Lynch says if this set-up were installed on all bridges, researchers could then make statistical comparisons among bridges. This would help them determine if, for example, all suspension bridges developed certain dangerous signs of wear after a certain age.

Additional UM researchers include associate professor Mingyan Liu, professor Amir Mortazawi, associate professor Michael Flynn, and professor Atul Prakash from the Department of Electrical Engineering and Computer Science, and professor Amit Ghosh from the Department of Materials Science and Engineering. Engineering firm partners are Weidlinger Associates (New York), SC Solutions (California), LFL Associates (Ann Arbor), Monarch Antenna (Ann Arbor), and Prospect Solutions (New York).

The University has taken steps to protect the intellectual property relating to this project thus far, and plans to find commercialization partners in order to bring the technology to market.