Tuesday, August 21, 2007

Sensing danger

States apply sensors to bridge conditions
The Interstate 35 eight-lane bridge in Minneapolis that collapsed earlier this month had been showing signs of fatigue for several years, although the bridge did routinely pass safety checks. After the collapse, inspectors admitted that there are limits to today’s safety inspection techniques.

Now the research and development community is looking into the idea of embedding sensors within the bridges themselves. Such sensor units would not act as last-minute alarms but would let inspectors know how the material is holding up after years of use.

With funding from the Maryland State Highway Administration, the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., has developed a small, low-cost sensing package, called a Wireless Embedded Sensor Platform, that could be used with new bridges.

When multiple units are embedded within a bridge, the WESP can monitor the state of the structure. At a cost of less than $10 for each unit, such platforms could one day prevent disasters such as the one in Minneapolis.

ASCE Report Infrastructure Report Card 2005

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