ENVIRONMENTAL MONITORING SOLUTIONS

Applications

 

Dam Monitoring

Seismic instrumentation in dam monitoring

For a long time seismic instrumentation has been used in dams and other large civil infrastructures to study their responses to seismic actions. Due to recent developments in seismic instrumentation capabilities, the traditional "trigger-event" operating mode is now being upgraded towards continuous recording method for long-term study of the dams dynamic response to ambient/operational and seismic excitations.

 

This new approach represents a major breakthrough in terms of quantity and quality of the information that can be obtained from this type of system.

Continuous dynamic behavior monitoring

System features:
* automatic identification of the maximum acceleration at the dam body and foundation to characterize the dam response during earthquakes and under ambient/operational excitation;
* automatic identification of the main dam modal parameters every hour and comparison with modal parameters computed with a reference 3DFE dam model;

* automatic analysis of the time evolution of the main frequencies;
* development of a reliable 3DFE model of the system dam-foundation-reservoir to study the dam seismic response (the model calibration is performed using the modal parameters identified for several water levels and using the monitoring data collected during seismic events).

Automatic modal identification

One of the main features of this type of solution is the capability to automatically identify and compute the main dam modal parameters (natural frequencies, modal damping and mode shapes).


Comparison between computed and identified natural frequencies for different reservoir water levels and time changes of modal parameters proved to be a powerful tool for characterization of the structural health along the years, including:

* damage evolution induced by swelling;
* cracking due to earthquakes (comparison of the main modal parameters identified before and after a seismic event).

1st MODE

2nd MODE

3rd MODE

System benefits

* better knowledge of dam behavior
* increased operation safety
* early detection of structure pathologies allowing for timely mitigation/correction actions
* extension of expected structure's lifetime

Slow variation parameters

Beside the dynamic monitoring, several other parameters can be monitored in a dam, either as an individual manual reading sensor or as part of a fully automated data acquisition system.

 

STRUCTURAL MONITORING
Sensors for structural observation (rod extensometers, joint meters, piezometers, strain gauges, pendulum, etc...)
Automatic data acquisition systems for new or already existing instrumentation (including pendulum readout, Carlson type sensors, vibrating wire sensors, etc...)

 

HYDROMETRY
Staff gauges
Level and flow measurements


METEOROLOGY
Meteorological parameters