PORTLAND, Ore. Monitoring the structural integrity of New York state bridges could become a model for wireless sensor networks nationwide.
Researchers at Clarkson University will make New York the first state with a 24/7 wireless bridge monitoring system. The state will spend up to $500,000 to deploy the first wireless sensor network for monitoring bridge stress.
"We measure the vibrational response of the bridge to any kind of loading: ambient traffic, environmental or a full-load test where we know the load's weight and can measure if the bridge is responding as it should be," said engineering professor Kerop Janoyan at Clarkson University (Potsdam, N.Y.).
|Using three, two-axis accelerometers, a six degrees-of-freedom sensor installed on bridges can measure shock and vibration in any direction.|
The project is being funded by the New York State Energy and Research Development Authority. Clarkson University has also begun working with TransTech Systems Inc. (Schenectady, N.Y.) to craft a commercial version of Janoyan's group's wireless bridge monitoring system.
The wireless sensor nodes use accelerometers and strain gauges as well as more exotic sensors from ultra sound to eddy currents, depending on specific monitoring problems. Wireless nodes, which are battery powered, are polled by a master single-board computer that aggregates sensor data and determines whether to alert inspectors.
"All of the weak points, especially inside a bridge's load columns, can have sensors installed to assess their health," said Janoyan. "If you install the sensors during new construction, then the cost is trivial compared to the cost of the massive steel and concrete beams and columns."
Janoyan's team has installed instruments on several New York bridges, including one under construction.
A test bridge between Canton and Potsdam, N.Y., has 40 channels of sensors with data logged in real-time from the wireless sensors at a basestation. By the end of 2007, Janoyan plans to have a wireless sensor network permanently installed on a New York state bridge.