Bridge Monitoring

ODOT utilizes MeasureTek to lengthen life of the historical Conde McCullough Bridge over Coos Bay

Problem Statement:

Oregon, with all of its water and waterways, has over 2700 bridges.  The Oregon Department of Transportation (ODOT) employs a staff of 50 people to design and maintain these bridges.  One of the most common causes of bridge failure and deterioration is corrosion of the supporting metal by galvanic action, or corrosion.  The metal in the bridge acts as the anode in the galvanic process, and corrosion ensues.  By placing a different material, to act as a sacrificial anode so the bridge metal is then the cathode, this allows the temporary material to breakdown rather than the supporting bridge structure.  With a large bridge structure, the presence of the alternate material is not enough to cause a potential difference and sufficient current flow.  Therefore,  a DC power source  is added to provide sufficient current flow.  Instrumentation is needed to monitor this DC power source, provide control of power to the sacrificial anode array (graphite and silver), and monitor the array voltages for performance. 

Solution Description:
MeasureTek provided a system that was housed in four cabinets, each with a Campbell Scientific data logger, two multiplexers, a communication modem, and an internal temperature sensor; as well as one local temperature, humidity and dew point monitoring station.  The base cabinet contained a Verizon cellular internet modem to permit remote access to the system data, communication between cabinets was with RS485 communication.  All stations were equipped with a AC Power, which was also monitored by the datalogger.

Control is provided for the DC source such that power supplies operate only if the internal cabinet doesn't get too hot; once shut down, they are not enabled until a second user input target temperature is reached.

Result:
The system data is continually providing control, transferring and storing data, with internet accessible data.  The system was installed in January, 2012.

For more information on this or other applications, please contact MeasureTek at (541) 924-8988 or visit our website at www.measuretek.com.