POTSDAM - Clarkson University researchers will set up a wireless sensor network on a state bridge this fall to measure vibration and strain in real-time and test what could become an early detection system for bridge failures.
Last fall, Clarkson researchers outfitted a bridge in St. Lawrence County with the system, which has 40 channels of sensors that send wireless data to a base station, and it tested successfully, said Kerop Janoyan, an associate professor of civil and environmental engineering at the northern New York school.
“It's hard to say any system will preclude all failures - those events will still happen. But this system would give warning to deterioration and worsening situations,” Janoyan said.
“It is like a central nervous system so you have feedback continuously on the structural health of the bridge,” said Janoyan, who is working with nearly $600,000 in grants from the New York State Energy Research and Development Authority, Federal Highway Administration and state Department of Transportation.
Since the collapse of the Interstate 35 bridge in Minneapolis earlier this month, research and development of improved bridge monitoring technology has taken on a renewed vigor.
Some electronic bridge monitoring systems are already in use in Pennsylvania, Ohio and Utah. Meanwhile, dozens of universities, private companies and government agencies are in various stages of research and testing, developing a variety of systems ranging from the simple to the sophisticated.
One bridge monitoring technology would use “nanotube paint” that can turn any surface into a sensor patch that can reveal microscopic faults in two dimensions.
At Los Alamos National Laboratory in New Mexico, scientists are using electronic sensors and an inspection system in an unmanned helicopter to detect electrical charges emitted by stress on material.
Most bridge inspections are conducted now just as they were decades ago - visually, with binoculars to look for cracks and a hammer to test the trusses for hollow spots, said Janoyan.
While they remain necessary, visual inspections are susceptible to error and subjectivity, he said.
A 2001 Federal Highway Administration study underscored the shortcomings of such inspections. In that study, 49 inspectors from 25 states were asked to examine bridges previously checked.
They missed 96 percent of emerging cracks. In some instances, one team of inspectors passed a bridge that was failed by another team.
But Janoyan said any bridge monitoring system should be a supplement to continued visual inspection.
In the past, rigging bridges with wired sensors was expensive, cumbersome and time consuming, Janoyan said. Without the problems of running cables and wires, more sensors can be used - and a bridge doesn't have to be closed to traffic to be outfitted with the sensors, which are typically secured with adhesive.
The cost per sensor is substantially cheaper than wired technology, he said.
Janoyan will test his system on a longer, multispan bridge sometime this fall. The location has not yet been finalized, he said. The system will be tested on a second state bridge in the spring, he said.
Orrin MacMurray is president and CEO of C&S Companies, the design engineers for bridge rehabilitation on Routes 81 and 690 in Syracuse. He said bridge monitors are not a bad concept, but he believes it would be difficult to equip all the different types of bridges.
Bridges are made of many different materials and they deteriorate in different ways. For example, he said, how would the device measure water erosion, which was the cause of the 1987 Thruway bridge collapse? What if the steel beams are about to fail? What if the concrete is old?
“On the surface, it sounds like something that's a good idea and a good concept,” MacMurray said. “It's when you get into the details that it becomes difficult.”
“It's hard to say any system will preclude all failures - those events will still happen. But this system would give warning to deterioration and worsening situations,” Janoyan said.
“It is like a central nervous system so you have feedback continuously on the structural health of the bridge,” said Janoyan, who is working with nearly $600,000 in grants from the New York State Energy Research and Development Authority, Federal Highway Administration and state Department of Transportation.
Since the collapse of the Interstate 35 bridge in Minneapolis earlier this month, research and development of improved bridge monitoring technology has taken on a renewed vigor.
Some electronic bridge monitoring systems are already in use in Pennsylvania, Ohio and Utah. Meanwhile, dozens of universities, private companies and government agencies are in various stages of research and testing, developing a variety of systems ranging from the simple to the sophisticated.
One bridge monitoring technology would use “nanotube paint” that can turn any surface into a sensor patch that can reveal microscopic faults in two dimensions.
At Los Alamos National Laboratory in New Mexico, scientists are using electronic sensors and an inspection system in an unmanned helicopter to detect electrical charges emitted by stress on material.
Most bridge inspections are conducted now just as they were decades ago - visually, with binoculars to look for cracks and a hammer to test the trusses for hollow spots, said Janoyan.
While they remain necessary, visual inspections are susceptible to error and subjectivity, he said.
A 2001 Federal Highway Administration study underscored the shortcomings of such inspections. In that study, 49 inspectors from 25 states were asked to examine bridges previously checked.
They missed 96 percent of emerging cracks. In some instances, one team of inspectors passed a bridge that was failed by another team.
But Janoyan said any bridge monitoring system should be a supplement to continued visual inspection.
In the past, rigging bridges with wired sensors was expensive, cumbersome and time consuming, Janoyan said. Without the problems of running cables and wires, more sensors can be used - and a bridge doesn't have to be closed to traffic to be outfitted with the sensors, which are typically secured with adhesive.
The cost per sensor is substantially cheaper than wired technology, he said.
Janoyan will test his system on a longer, multispan bridge sometime this fall. The location has not yet been finalized, he said. The system will be tested on a second state bridge in the spring, he said.
Orrin MacMurray is president and CEO of C&S Companies, the design engineers for bridge rehabilitation on Routes 81 and 690 in Syracuse. He said bridge monitors are not a bad concept, but he believes it would be difficult to equip all the different types of bridges.
Bridges are made of many different materials and they deteriorate in different ways. For example, he said, how would the device measure water erosion, which was the cause of the 1987 Thruway bridge collapse? What if the steel beams are about to fail? What if the concrete is old?
“On the surface, it sounds like something that's a good idea and a good concept,” MacMurray said. “It's when you get into the details that it becomes difficult.”
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