Bridging the safety gap

If you’ve ever idled in bumper-to-bumper traffic on a bridge, wondering just how much weight the structure could withstand, chances are that Northeastern’s Ming Wang could tell you. His monitoring system might even be in place on that very structure.

An internationally recognized expert in monitoring the structural health of bridges, tunnels, and other infrastructure, Wang has garnered funding from sources including the National Science Foundation, Federal Highway Administration, and National Institute of Standards and Technology (NIST). The newly hired professor of civil and environmental engineering has invented and holds patents on several sensors and systems used worldwide.

Wang is leading a team of researchers and joint-venture partners in the development of sensors to detect abnormalities in highways and bridge decks, a five-year, $9 million project funded by NIST’s Technology Innovation Program. Fourteen Northeastern undergraduate and graduate students from disciplines including mechanical, electrical and computer engineering, as well as computer science, will participate.

From his sensor technology laboratory on campus, Wang also remotely monitors some of the world’s largest bridges, gauging the stress, strain, vibration, and movement they withstand in commuter traffic and weather conditions.

Minute-by-minute real-time readings of the Hangzhou Bay Bridge, a cable-stayed bridge in China, show how the structure’s 1,600-foot center span, tower and supports react to the weight of cars and trucks, and to the impact of severe weather, such as typhoons. In Hong Kong, the world’s second longest cable-stayed span, the 4,300-foot Stonecutters Bridge, is outfitted exclusively with Wang’s sensors, which monitored cable stress during construction and since the bridge opened in April 2009.

Wang’s focus on developing infrastructure-monitoring technology took hold in 1995, when he was asked to consult on the retrofitting of the Yi Sun-Sin Bridge in South Korea, which had shown evidence of decay and excessive vibration.

“I played a major role in the decision to retrofit that bridge, and also helped to develop a monitoring system for the Chungmu Bridge in Korea,” he says. “It was while I was working on these projects that I discovered there was a real need for civil engineers like myself to develop sensors that could warn people when a bridge was nearing critical stress levels.”

Wang, who also played a significant role in monitoring and retrofitting the Kishwaukee Bridge in Rockford, Ill., plans to turn his attention to bridges and structures in New England.

“It’s an exciting place to study and maintain,” he says. “New England has some of the oldest bridges, and states don’t have funding to build all new ones. Therefore, it’s important to maintain what we have.”

Wang holds a doctorate in structural dynamics and random vibration from the University of New Mexico.