Author: seismic

Wind Turbines are one of the cleanest and most attractive options for renewable energy. Evolution in this sector has lead to larger support structures and rotor blades. Furthermore, the turbines are exposed to environmental conditions that are not always favorable, aging of the supports, or even worse to defects in the construction process.
The purpose of monitoring this turbine is to investigate cracking damage which was spotted on the support base, which is made of reinforced concrete, to estimate the progressions of the crack and the stability of the wind tower.
The monitoring system is composed of:
– 1 Poseidon Light (legacy product now ATLAS)
– 1 Trixial accelerometer true FBA 0.5g
– 1 Poseidon (legacy product now TRITON)
– 1 4G router

Structures are subjected to progressive deterioration due to various external factors such as aging, stress, environmental condition, accidents and to internal factors such as the lack of quality controls or defects in the construction process.
The health of structures is of primary interest because it represents a potentially high risk for life and property.
The Structural Health Monitoring of the two Hospitals is part of the OSS Lunitek monitoring systems which started in 1996 with winning a contract with Civil Defence.
The wired SHM system of the Sulmona Hospital was installed in the 2009 and it’s running 24/7. The system of the Foligno Hospital covers one area of the building and it comprises of a wireless Poseidon system (our legacy product, now called TRITON). This solution saves on installation costs and it is not invasive, as cable deployment in an operational hospital it is not easy!
In the case of strong earthquake and loss of mains power, the system is backed up by batteries and keeps on recording.

Through the Italian national network of the Seismic Observatory of Structures (Osservatorio sismico delle strutture – OSS), the Department of Civil Protection (DPC) monitors the oscillations caused by earthquakes in 160 constructions of public property.

The OSS allows the damage to be estimated, occurred to the monitored structures because of an earthquake. Through the OSS, structures that are of strategic importance for the seismic emergency management can be kept under control. Moreover, original data can be supplied to the technical-scientific community, that allow to improve the understanding of the response of structures to earthquake. Finally, such data contribute a useful background for updating the technical regulations for constructions in seismic zones.

In 1996 Lunitek won a contract with Civil Defence and since then we supplied systems for 96 buildings and more than 1000 true force balance accelerometers.

Our share of the OSS (Seismic Observatory of Structure) network is now about 70% as can be seen in Figure 1.

Furthermore, every year, a maintenance contract guarantees that the systems are running correctly and we guarantee to repair malfunctioning systems in less than 3 days.

The OSS Lunitek monitoring systems are mostly wired systems, but we also have buildings running with wireless systems.

The main concern with nuclear power plants and earthquakes is the structural integrity of the plant and the temperature of the reactor core. If the temperature goes into an uncontrolled state, the reactor will overheat and melt down with conceivable consequences.
Seismic monitoring is the primary measure used to avoid and mitigate potentially dangerous situations which could be caused by an earthquake. PGA (Peak Ground Acceleration) provides an idea of the real entity of a tremor. Magnitude alone does not affect PGA since the latter depends also on the depth of the earthquake.
When PGA exceeds a preset threshold, the seismic monitoring system alerts the central control center forcing a shutdown.
Our systems have been in use at the nuclear power plant of Caorso since 2002 with our previous company name and, as of 2015 the new Lunitek models are also being used in Trino Vercellese.
Even if both Caorso and Trino are no longer active nuclear plants, they need seismic monitoring because radioactive fuels are still present and need the utmost attention.

One of the most interesting application of SENTINEL is the project of structural health monitoring of the University Mariano Galvez in Guatemala.
The university is located in zone 2 of Guatemala City.
The specifications of the request was for 4 buildings. The professors from University are working to retrofit the structures with seismic isolator and have wanted to set up a monitoring system for those buildings. In particular they asked to evaluate the impact of the seismic isolator retrofit on buildings, calculating the natural frequencies before and after.
The Structural Health Monitoring solution is composed of:
– 40 Sentinel Accelerographs ± 2g
– 7 Triton A160 ± 2g
– 1 SHM software Lunitek Asclepius

Dams represent a high-risk potential for downstream life and property.
Dams and large water reservoirs are often constructed in valleys which are usually areas with high seismicity in fact they exist because active erosion is taking place. Furthermore, the reservoirs themselves can trigger seismic events due to the fact that the weight of the water produces a change in the stress levels of the rock under the reservoirs and the pore pressure decreases its effective strength. Aging and structural changes must to be taken into account too.
For these reasons dams should be monitored with high performance seismic instrumentation and monitoring systems to provide information on the health status of the structure and send alerts in the case of potential issues.

Lunitek has supplied and installed systems for monitoring dams in Italy under the commission and control of the Italian Civil Defence.
FOTO: diga Fiastra, diga Fiastra4, diga liscione1

The monitoring system of Fiastra Dam consist of the following elements:
– 3 Poseidon Lights (datalogger legacy version, now ATLAS)
– 3 Biaxial true force balance accelerometers LTFB160
– 1 Triaxial true force balance accelerometer LTFB160
– 3 Power supply units
– 1 Router for the remote communication with central server in Rome
– 2 WiFi repeaters to extend the WiFi coverage signal.

In 2020, through our dealer NEOTEK we were selected by the Institute of Engineering Seis-mology and Earthquake Engineering (ITSAK) to provide a telemetry Structural Health Monitor-ing system monitoring the dynamic response of the central building of the University of Mac-edonia, Thessaloniki.
Four autonomous TRITON triaxial accelerographs were installed, one free-field, one in the basement, one on the 2nd floor and one on the roof of the building. The instruments are con-nected to a local network (LAN) and are remotely accessible from the Control Center of ITSAK. Data is continuously streaming to the Control Center but is also stored in the accelerographs. Common time is provided by individual GNSS aerials.
The Web Interface Jupiter processes the data and provides continuous monitoring of the waveforms in real time.

Through Lunitek TRITON accelerographs, the BMKG Institute carried out the microtremor data analysis which aims to reduce the risk of building damage and casualties due to the earthquake. The analysis was conducted by measuring microtremor and processing the data. In this way the safety of the buildings can be known in the event of an earthquake.

Lunitek supplied TRITON accelerographs for new stations and TBM tunnel interstations of the Athens Metro extension line. They were used to monitor the construction phases and conduct an accurate analysis of the TBM parameters.

Line 2, with its 27 km, will revolutionize mobility in Lima, which currently only has one line for rail transport. It represents a very strategic and challenging infrastructure project for the city.

In compliance with local regulation E.030 “Diseño Sismo-Resistente” and Geophysical Institute of Peru (IGP), Lunitek’s local dealer installed a seismic station with TRITON-M90-T to evaluate the structural response to strong earthquakes.