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Dam Monitoring   Dam Monitoring:
Since the dynamic behaviour of dams under severe earthquake motion is not known satisfactorily, data from strong motion instruments can form the basis for a more reliable seismic assessment of the existing and future dams.  After data is processed it can assess and compare dam behaviour against seismic design criteria applicable to dam operations. Dam’s provide essential benefits, including drinking water, power generation, flood protection, irrigation, and recreation.    

Seismic Systems and GeoSIG offer dam monitoring system instrumentation in an effort to record seismic motions, reservoir effects, and other ambient dynamic activity to continuously monitor dam structural safety within the context of a safe operating dam environment.  Seismic Systems has provided dam monitoring solutions to several dams in California and GeoSIG has maintained a strong presence around the world in the form of dam monitoring.


High Rise Buildings   High Rise Buildings:
Recording the response of buildings during strong earthquake shaking is a key element in improving seismic design.  Recorded data is valuable to assist post earthquake structural evaluation and form an important complement to data from regular networks.  Lessons learned from post earthquake data are reviewed to improve the success in future events.

In various cities and counties in the United States, high rise buildings are required to have (3) working Accelerographs  in the building.  The instruments shall be located in the basement, midportion, and near the top of each building.   Maintenance and service of the instruments shall be provided by the owner of the building, subject to the approval of the building official.  Data produced by the instruments shall be made available to the building official on request.   Maintenance and service of the instruments need to be provided annually by an approved testing agency.  Seismic  Systems provides, installs and services accelerograph equipment in high rise buildings across the United States.  We can arrange qualified installation, maintenance, and training anywhere in the United States.


Strong Motion Networks  

Strong Motion Networks:
Any country as large as the USA faces difficult choices within its earthquake monitoring strategy. Striking the right balance between the possibility of a large earthquake in a remote area causing little disruption and a smaller earthquake in a densely populated causing massive damage has to be a risk very carefully managed.

A current area of significant risk has been identified as surrounding the San Francisco East Bay and the Hayward fault areas. The USGS is trying to achieve a denser and more uniform seismograph spacing in the Bay Area to provide better measurements of ground motion during earthquakes. To do this, the NetQuakes instruments are deployed that communicate their data to the USGS via the Internet. These instruments connect to an existing local network using WiFi and use existing Broadband connections to transmit data after an earthquake.

On 6 Jun 2009 a 3.1 earthquake rattled the East Bay but there were no immediate reports of injury or damage. Scientists then probed the Lucas Valley for earthquake clues as the one almost certain thing around the East Bay area is that something bigger now appears to be looming. On 25 Jun 2009 the USGS described the Hayward fault as "a tectonic time bomb, due anytime for another magnitude 6.8 to 7.0 earthquake and that the coming Hayward fault earthquake will probably kill hundreds of people and cause damage worth perhaps $100 billion". This locality has therefore been identified as an area where the precise seismic risk of earthquake is not yet fully understood.

New instrumentation has been sought to monitor this emerging situation and included finding suitable locations within built up areas to accept and install earthquake monitoring systems. The NetQuakes seismographs specification requires access the Internet via a wireless router connected to an existing Broadband Internet connection. The seismograph then transmits data to the USGS only after earthquakes above the magnitude of around 3, but will not consume any significant bandwidth and should require only minimal maintenance.

While enhancing the Strong Motion Network coverage in this seismically high-risk area, the measurements improve also the ability to make rapid post-earthquake assessments of expected damage and contribute to the continuing development of engineering standards for construction projects. They may well also shape future requirements within other urban areas over a longer time period.

Link to official NetQuakes project website


Structural Health Monitoring   Structural Health Monitoring SHM:

Our Solutions for Structural Health Monitoring

• GMS-18 Netquakes Recorder
• CR-5P Seismic, Earthquake and Structural Multichannel Recording System


What is Structural Health Monitoring?
Structural Health Monitoring (or SHM) is an innovative method of monitoring structural safety, integrity and performance without otherwise affecting the structure itself. SHM utilises several types of sensors – embedded in, or attached to – a structure to detect the presence, location, severity and consequence of damage.

Why Structural Health Monitoring?
Let’s consider some existing structures such as buildings, bridges, tunnels, high-rise constructions, historical monuments and railways.
Unsatisfactory inspection can lead to problems that only become apparent when structures are in critical need of repair. The strength and serviceability of the structure can be considerably – even terminally – reduced by natural or human-made events, earthquakes, increased levels of use and design changes.

The result is that repair costs become comparable with replacement costs. The emerging use of SHM that we are witnessing is a result of the increasing need for the monitoring of innovative designs and materials as well as a better management of existing structures. This is further enhanced by the ongoing development and sophistication of sensors, data acquisition systems, wireless and internet technologies and other advances in technology.

In the past we have seen catastrophic structural failures such as the famous collapse of the Tacoma Bridge in 1940, (Tacoma, WA, USA); the collapse of the Historical Archive of the City of Cologne, (Germany), in 2009, or the tragic 1995 Sampoong Department Store collapse in Seoul, (South Korea). Events such as these drastically show how vulnerable infrastructure can be if exposed to conditions like wind (Tacoma), ground deformation (Cologne) or overload (Seoul). These very factors that eventually lead to failure can be measured with Geosig instruments, as well as their force, severity and effect on the structure. This not only reduces risks and costs, but also avoids disaster through early damage detection and therefore saves lives as well as the structure.

• What are the advantages of Structural Health Monitoring?
The ideal SHM system provides you with on-demand information about your structure's integrity and serviceability, as well as warnings concerning any damage detected. Therefore SHM significantly reduces repair costs through early damage detection, making the monitored structure safer and increasing the cost efficiency of its maintenance.

Structural Monitoring can significantly reduce insurance premiums for those operating - or in charge of - the safety of infrastructure such as bridges, railways or tunnels.

Other advantages of SHM include:
• increased understanding of in-situ structural behaviour
• assurance of structural strength and serviceability
• decreased down-time for inspection and repair
• development of rational maintenance/management strategies and
• an increased effectiveness in allocation of scarce resources.

Additionally SHM enables and encourages the reliable use of new and innovative materials and designs in both architecture and engineering.

Methodology & Technology

• How does Structural Health Monitoring work?

Each structure is unique, therefore the monitoring system that must be applied is also singular. In close cooperation with the contractor, GeoSIG delivers tailor-made SHM systems for each project. Trigger levels for issuing warning signals (when previously defined values are exceeded) will be set according to its particular properties and capabilities, with reference to design, resistance, durability and stability.

Various types of sensors are attached to - or embedded in - the structure itself. These devices collect raw data (accelerations, deformation/strain, temperature, moisture levels, acoustic emission, and loads among others) and transfer it to a Data Acquisition System (DAS). From the DAS, the data is collected and sampled. It is then transmitted to an offsite location for automatic, intelligent processing. This level of remote monitoring eliminates the need for site visits. The goal is to remove mundane data, noise, thermal, or other unwanted effects before storage, and to make data interpretation easier, faster and more accurate. Diagnostics convert abstract data signals into useful information about the structural response and condition.

This detailed physical data analysis can be then used to enable rational, knowledge-based engineering decisions.

In essence, SHM’s variety of measurement techniques and data interpretation create “intelligent structures” that are safer, long-lasting, more secure, and cheaper to operate, maintain and insure.
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