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Yu’s Method Uses Radar to Inspect Roads and Bridges

Data Will Help Detect Structural Damage

Tzu-Yang Yu

By Edwin L. Aguirre

On July 10, 2006, a 3-ton concrete ceiling panel in Boston’s Interstate 90 connector tunnel fell on a car heading to Logan Airport, killing a passenger and injuring the driver. After the collapse, a section of the tunnel was closed for nearly a year. This Big Dig tragedy illustrates the need for regular monitoring and inspection of the country’s highway and bridge infrastructure to prevent further loss of life and property.

Asst. Prof. Tzu-Yang Yu of the Structural Engineering Research Group in the Department of Civil and Environmental Engineering has developed a new method that can help. His non-contact, non-destructive technique uses radar signals to conduct in-depth inspections of buildings, bridges, roadways, tunnels and dams for any structural defect or damage to the concrete or rebar.

“The practical application of this technique will be a portable, handheld device to collect radar measurements from the surface of the structure at a distance of about 20 to 50 meters,” says Yu. “In my planned inspection configuration, only one inspector is needed to operate this device. He or she can launch the electromagnetic waves away from the structure, without stopping traffic on the highway or getting into trouble when inspecting bridge piers or foundations across rivers or valleys.”

The data collected will help government planners and engineers make any necessary maintenance, repairs or overhauls to the structure.

Yu recently published a book about his method entitled “Damage Detection of GFRP-Concrete Systems Using Electromagnetic Waves: Theory and Experiment,” which is available at

“In my book, I describe the general background of the problem, followed by a theoretical treatment on the mathematical basis of the technique,” he says. “I’m using this book in teaching my graduate course in civil engineering.”

In 2007 Yu applied for a patent for his radar-inspection method with the U.S. Patent and Trademark Office, which published his application on Sept. 3 this year.   
Yu is also co-principal investigator, along with researchers from Northeastern University, the University of Vermont and State Agricultural College, and Witten Technologies Inc., in the VOTERS (Versatile Onboard Traffic Embedded Roaming Sensors) project. This involves conducting mobile surface and subsurface inspections of roadways and decks using an automated, real-time “drive-by” monitoring system installed on ordinary vehicles.

The VOTERS project runs from 2009 to 2014, and is funded by National Institute of Standards and Technology’s Technology Innovation Program. UMass Lowell received a total grant of $868,000 for the study.

For more information about Yu’s work, visit his website at

The cover of Prof. Yu's new book.