Electricity Supply Board
NVM Limited are currently contracted to monitor inclination and movement by the ESB and ESBi on all hydro dams on Ireland’s East Coast and Munster Regions – (Hydro Dams located at Ardnacrusha, The river Lee Dams in Cork, Leinster's Goldenfalls, Lexlip and Pollaphuca Reservoirs).
The process involves Inclinometer casing placed inside the dam wall and using a pre–configured measurement probe, readings are taken to show signs of movement or failure in the concrete dam walls
Irish Rail Dart Underground
From July 2009 to March 2010, NVM Ltd engineers recorded and logged baseline noise and vibration measurements at over 80 noted sensitive locations throughout Dublin City including (Christchurch Catherdral, Dublin Castle, The Gaiety Theatre and St Stephen’s Green).
This data was to provide the existing noise and vibration levels at residential and commercial properties, for the completion of the project Environmental Impact Assessment Statement for the new DART UNDERGROUND PROJECT.
These details were then passed on to Irish Rail and Arup Consulting Engineers to provide backup data for the comprehensive oral hearings and An Bord Pleanála planning meetings required prior to the project commencement.
M3 Motorway Project Clonee to Kells
Since May 2007 NVM Ltd have been providing the monitoring equipment and data acquisition of environmental noise, dust and traffic and structural vibration monitoring levels along the construction route of the M3 Motorway Project.
This is an ongoing project which entrails attended meetings with residential committees, NRA officials and local historical groups, regarding on going monitoring at sensitive residential receptors, and ongoing unattended long term monitoring points at historical sites, such as (Hill of Tara, Rathlugh Monument).
Our technical staffs have also installed vibrating wire piezometers on motorway embankments during motorway development over poor ground to monitor water levels and movement during fill and load testing.
NVM Ltd conducts the maintance, recalibration and repair of all monitoring equipment on site, while also providing weekly reports and updates on monitoring levels to SIAC FERROVIAL JV and NRA project supervisors.
Mater Hospital New Campus Project
NVM Ltd currently provides full environmental monitoring services to John Sisk & Sons Limited Building Contractors on the Mater Hospital New Campus Building.
Having previously provided monitoring services to PJ Hegarty and Company during the site enabling project, NVM were selected to provide continued monitoring on site for the duration of the construction project.
Our services include –
- The attendance of an on site independent monitoring supervisor,
- ongoing data collection,
- daily and weekly monitoring of inclinometers movement,
- pneumatic and stand pipe piezometer measurements,
- environmental and occupational noise measurements within the adjacent hospitals and nurse education buildings,
- structural vibration measurements and environmental dust measurements
- water sampling and air quality monitoring
- monthly site dust monitoring using the Bergerhoff method
Trinity College Dublin
In July 2009 NVM Ltd (National Vibration Monitoring Ireland) were
contacted by Trinity College Dublin to provide geo-technical instrumentation
on a vacuum consolidation field trial.
Through their agency and close affiliation with Geosense Instrumentation UK,
NVM were able to supply the instrumentation and provide backup to our client
by way of installation support and data aquisition on the project.
This project is currently being monitored by Trinity College and NVM technical staff in an
effort to provide results to the NRA for future road projects
The following is an update on how this FIRST OF ITS KIND PROJECT is currently performing.
The article was taken from the June edition of Construction and Property News Magazine. on Piling and Ground Stablization.
" Trinity College Dublin is currently testing an innovative technique, known as vacuum consolidation, to improve peat ground conditions, as part of the National Roads Authority Fellowship initiative.
Vacuum consolidation is a ground improvement method use to accelerate ground settlements and increase the shear strength of soft soils using the atmospheric pressure as a temporary surcharge. The surface of the ground is covered by a geomembrane and the air pressure beneath this sheet is reduced using a vacuum pump. Prefabricated vertical drains are used to accelerate the flow of water from the peat. This technique has not been used before in this country.
The TCD/NRA Vacuum Consolidation field trial is being carried at on Bord Na Móna grounds on the Ballydermot bog, Co. Offaly. The field trial comprises a heavily instrumented 10x10m area where 98 vertical drains were drivendown to a depth of 2.65m from the surface. To investigate the effect of the spacing of the drains in the ground improvement two subareas were built, one with 0.85m spacing and a second with 1.20m spacing. The test required to measure settlement, positive and negative pore water pressure, barometric pressure, temperature, water table and rainfall.
The instrumentation for this test section was supplied by National Vibration Monitoring Ireland Limited/Geosense who also contributed valuable technical assistance. The system includes 6 push-in Vibrating Wire Settlement Cells, 10 push-in Vibrating Wire Piezometers (calibrated for both positive and negative pressure) and a surface barometer/thermometer. The system described was complemented with 26 surface settlement plates to monitor surface settlement, 17 stand pipes to monitor water table and a rain gauge.
Due to the difference in spacing of the two subareas, each of them required independent monitoring of settlement and pore pressure. This was achieved by pushing in 3 settlement cells and 4 piezometers at the centre of each subarea, at different depths. One of the remaining piezometers was located at the inner edge of the site to investigate the boarder effect, while the other was placed outside to observe if the vacuum pressure has any effect outside of the studied area. The surface barometer/thermometer and one of the settlement cells are connected to data loggers taking hourly readings, allowing constant monitoring of the test.
The field trial has been running continuously for over 5 months, through the winter and spring of 2009 and 2010. The information gathered from the instrumentation system has allowed Trinity College to understand the behaviour of the peat ground subjected vacuum pressures and the effect of the different spacing of the drains."
Testimonial from Juan Pablo Osorio Salas BEng,MEng
When talking about the input that NVM / Geosense had in providing assistance to the project…
”On top of reliable, accurate and easy to use instruments, I have always found somebody willing to help me every step of the way from the system design, to the installation and monitoring, with a friendly attitude whether over the phone or on site, even in the worst winter we have seen in 40 years”.
Juan Pablo Osorio Salas BEng,MEng
Geotechnical Research Group
Department of Civil Structural & Environmental Engineering
Trinity College Dublin