Monitoring the Construction of a Dam

Using Instrumentation to Monitor Structural Stability

CHESTERLAND, OH - March 31, 2011 - Many critical environmental elements and structural variables determine the long term strength and stability of a dam under construction. CAS DataLoggers was presented the challenge of determining the appropriate equipment to provide the construction engineers in a dam development project. Sensors including vibrating wire piezometers, joint meters, fill extensometers and strain gages were to be interfaced with a data logger as part of a long-term logging solution.

The project specifications demanded the use of a flexible, robust data logger to provide a large number of vibrating wire sensor inputs, compatibility with a SCADA system and the potential for future expansion. The compatibility of the dataTaker DT85G Data Logger with the sensor requirements and capacity of inputs available along with the proven track record in geotechnical applications made the solution evident. Two DT85G Data Loggers were each paired with three CEM20 modules which allowed for a total of 146 vibrating wire sensors to be intelligently distributed throughout the dam structure. If required, the system could be further expanded to connect up to 640 vibrating wire sensors.

Vibrating wire sensors have the ability to provide highly accurate measurements not affected by the electrical resistance of long lengths of cable. The sensors provided information about stress, fissuring, foundation deformation, uplift, displacement and seepage flow. A SCADA system was used to query the sensor data from the two dataTaker DT85G Data Loggers; capable of communicating by either ModBus RTU via RS-485 or ModBus TCP/IP via Ethernet.

The benefits of bundling the dataTaker solution with these sensors were many. It provided a cost effective data logger expandable to 320 channels able to accommodate 640 differential or 960 single-ended inputs. The DT85G Data Logger supports vibrating wire and other geotechnical sensors compatible with all major brands such as Slope Indicator, RST Instruments, Geokon, Soil Instruments, Roctest and AGI. The built-in web and FTP server allowed for remote access to logged data, configuration and diagnostics while the rugged design and construction provided reliable operation in the extremes of this geotechnical environment.

For more information on the DT85G Universal Intelligent Data Logger or any other CAS Data Logger product contact a Solution Analysts at (800) 956-4437 for recommendations specific to your application or visit

Contact Information:
CAS DataLoggers, Inc.
12628 Chillicothe Road
Chesterland, Ohio 44026
(440) 729-2570
(800) 956-4437

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