Researchers invent new bridge sensors

BY STEPHANIE STEINBERG
Daily Staff Reporter
Published January 20, 2009

Bridge inspectors may soon be able to prevent bridges from collapsing thanks to a five-year research study conducted by the College of Engineering and the University of Michigan Transportation Research Institute.

The $19 million project funded by the National Institute of Standards and Technology and Technology Innovation Program will begin Feb. 1.

Assistant Engineering Prof. Jerome Lynch will lead the project, and work with 14 researchers from the College of Engineering who have developed bridge sensors that will monitor the condition of bridges. Lynch said the sensors can be used to detect if a bridge is damaged, cracking or corroding.

“Any sort of serious safety hazard to motors crossing the bridge, the sensors would be able to identify that,” Lynch said.

The system will also measure the effects of heavy loads on bridges — which is currently not assessed.

Four different types of sensors — including wireless sensors and sensors on vehicles and humans — will be used in concert as a single comprehensive system.

Lynch said the sensors will generate data about the bridges as cars drive over them. That data will then be relayed to an inspector on site or in an office nearby.

Victor Li, a professor of civil and environmental engineering also working on the project, has spent the last 15 years developing a new type of concrete that changes shape to support heavy loads.

“The concrete we created is a special type of concrete material which looks and feels like normal concrete until you put a lot of load on it, and it practically deforms like metal,” Li said. “If you bang it, it will turn into a curve shape just like a piece of metal will, and that’s not possible with normal concrete.”

In addition to the novel concrete, Chemical Engineering Prof. Nicholas Kotov invented a sensing skin made out of carbon nanotubes and polymers.

“Just like you would paint a bridge with a coat of paint, this would be a carbon nanotube composite that would be painted onto the surface of the bridge,” Lynch said.

The sensing skin can be designed to measure erosion and the behavior of a bridge under an applied load.

Tim Gordon, head of UMTRI’s engineering research division, said the state-of-the-art software will revolutionize the way bridges are inspected.

“At the moment, people tend to use inspections to inspect the bridge without being able to look at how it’s responding to heavy loads,” Gordon said.

The project’s organizers believe that it will not only improve bridge safety, but will also boost Ann Arbor’s economy, as Monarch Antenna Inc. and LFL Associates, two local technology companies invest in the project.

Monarch Antenna Inc. will provide the self-structuring antenna technology necessary for the sensors to communicate with each other wirelessly.

Tayfun Ozdemir, chief technology officer of Monarch Antenna, said the opportunity to participate in the project presented itself, and his company went for it.

“This project folds under the general field of wireless sensors, and it is a field that, as a company, we identify as a strong market to go after,” Ozdemir said. “It’s a really stimulating project for the local economy — not just for the University community.”

The Michigan Department of Transportation is giving the research team two bridges in Michigan to test the sensors on.

“The Department of Civil and Environmental Engineering is very excited about this new research award,” Nancy Love, professor and chair of civil and environmental engineering, said in an e-mail interview. “The project is very interdisciplinary, and it highlights the innovative contributions that the University of Michigan is making in infrastructure systems, which is an area of critical research need.”

Gordon, the head of UMTRI, said, “If it works out like we think, it could definitely lead to something that could be deployed nationally.”