DAMS are inherently designed to store water.. DAMS are architectural marvel and lasting structure that survives Environment and water pressures. Deterioration of structure can be due to improper design, modification, natural degradation due to environmental effects, and due to man-made effects.
Like human, DAMS also age with time.
Unfortunately, DAMS have misshapen throughout history and the consequences on humans and the environment have been very large. One need to monitor and qualify following 5 important aspects :
Detecting the existence of the damage on the infrastructure.
Locating the damage / porosity.
Identifying the types of damage.
Quantifying the severity of the damage.
The impetus for Structural Health Monitoring (SHM) of national assets like DAMS is not only dictated by the considerations for transportation, safety, commercialize and economy of a region, but also by the implications to the nation's defense and preparedness; thus, necessitating REAL TIME Structural health Monitoring (SHM) to become an important constituent of any DAMS management system.
CONVENTIONAL NON-DESTRUCTIVE TECHNOLOGY
For SHM, there are many established NDT (Non-Destructive technology) procedures being practiced the world over. However, almost all these technologies employ contact-based sensors (Strain Gauges, Pressure Sensors, Load Cells, Ultrasonic Pulse Velocity Meters, Rebound Hammer, Piezo Electric Transducers, Fiber Bragg Grating?Or even Radar etc.) and have serious constraints in monitoring the entire spectrum of frequencies of vibrations, giving rise to uncertain and sometimes erroneous results during the structural audit. Independent Sensors are required to measure environmental indicators, Conditions & Vibrations and Sound. The data collected by sensors are either decentralized or proprietary. Sensors also have Complexity in Calibration. These conferences of sensors result in High Capital Cost & Maintenance overheads. Hence Real time Monitoring of DAMSs was not feasible.
A Paradigm shift is imperatively required to overcome the limitations of conventional systems. CATS introduce cutting edge technology wherein a single photonic system with an appropriate laser source is used for monitoring all parameters Condition and Vibration.
Against this backdrop, Photonics Monitoring is breakthrough in NDT procedures. The systems are novel and innovatively uses principles of laser back scattering in the environment of operation. CATS is only company providing single laser Sensor that can monitor and records various Movement, Force, Environment, Acceleration, Displacements, Velocity, Load impact, damage detection, Sound etc. It is one of its kind non-contact & non-imaging technique for remote monitoring. Accurate qualitative and quantitative data is collected in real time using a single laser source as a function of time and space.
Maintaining DAMS to prevent incidents is not easy, but can be made a lot simpler, safe and secured with a photonic monitoring system. VIDUR AND VEDA can monitor and analyze in real time the condition of a DAMS not only impacted by general wear and tear, load, but also due to weather including the water levels & pollution resulting to corrosion of reinforced steel in concrete due carbonisation. The key features of these technologies are : -
Nanometer resolution, with no frequency constraints.
One second display updates.
Sound is extracted from optical beam modulation data.
Guiding principles of Vidur & VEDA:- Vidur is non contacting probe that accurately measures maximum displacement, from the mean position Amplitude, Velocity & Acceleration in time and frequency domain.
Once the photonic system identifies the damage on DAMS, Drone with high resolution camera will be used to capture the details of damage. Photonic system will provide co-ordinates (Localisation) of Damage. The Drone will be directed to take capture live images of the damage. Thus, Photonic system will operate like brain to sense where the damage is or expected to be and Image processing will function as eyes recording the image of damage.
Inspecting entire submerged exterior of pier or abutments of DAMS is challenging. Commercial divers were assigned with tasks to inspect DAMS edifice. But this carried limitation related to low light, wreckage mapping etc. Visual Survey is now possible with so called under water drones or technically Remotely Operated Vehicles (ROV) to give an overall picture of integrity of the structure. The ROV can work against currents and hold its position facing the piers or other areas of interest.
The use of remote access techniques such as drones and ROVs will increase from general visual inspections to more in-depth techniques as technology improves and gets smaller.
These real time photonic monitoring systems will substitute Routine Inspection Module (Rim) & Detailed Inspection Module (Dim). Vibration and Condition monitoring of DAMS using Photonics enables the following crucial information related to structural integrity in real time, even under the impact of live loads (static and dynamic).
Accurately monitors vibration amplitude, velocity and acceleration in both time & frequency domains simultaneously, that elucidated to aesthetics, functionality, strength parameter, Balance service life and data analytics of DAMS. This results in structural integrity.
Photonic systems scan's the entire structure for occurrence of geometric deformation, multi-point displacement and sub millimeter deflection in real time with dynamic loading, up to 1000 data points per second.
Highly sensitive and accurate compared to any conventional technologies.
Patterns / Trends of strain and deflection on real time can be analyzed and historical data can be mapped and Geo-coded.
Detects Cracks and damage due to Water seepage, delamination & porosity, Corrosion etc.
Condition of Foundations & Check for Settlement at the bottom of Piers.
Monitoring of a pre-stressed reinforced concrete.
Controlling the structural efficiency during the phases of construction.
Allowing in the future, the periodical check of the structural performance under service loads.
Photonic systems also monitor, and records Counts, Type, Speed & Weight of Vehicle / Pedestrian thereby ascertaining impact on columns and beams. The system can record overloaded impermissible vehicle as well.
Acoustic Emission monitoring technique of pre-stressed and post-tensioned concrete DAMS.
DAMS health can be determined depending upon the age, traffic count, material of construction & Structural form. Thereby expected loss of service life, due to corrosion and expected balance service life of DAMS can be evaluated.
The sensitivity and accuracy of the monitored parameters are very high compared to conventional sensor measurements. The multifarious advantages of the systems include smaller time responses, higher accuracies, one system to measure a host of parameters in the time, frequency and spatial domains and the freedom from many known constraints associated with conventional sensors. Wireless network Systems (WSN)
All data from respective Units of Veda, Vidur and AUM are seamlessly transmitted through wireless network to Command and Control systems or designated cloud network. AI and Cognitive sensor based architectural system integrated with IOT is composed of :
Few Photonic sensors installed based on DAMS characteristics :-
Vibration and Deflection
Weather and Pollution
Load and impact of speed of Vehicle
Pressure on Walls
Recording of sound
Dynamic Big Data that stores DAMS condition data.
Cloud based server that calculates and analyzes data transmitted from the monitoring devices.
Once any parameter crossing threshold is earmarked by Photonic sensors with Geospatial information, Alarms signals can be set to inform the stakeholders of critical event. Individual can be assigned to gather visuals. Drone or ROV can be mobilized in case of inaccessible location. A Report on extent of Damage and need of maintenance, repairs or replacement will be advocated by Artificial intelligence platform. For ex. Determining whether there are deviations from the target load and thereby assess the maintenance requirements.