Ground Investigations Ireland Ltd (GII) is a leading ground investigation contractor based in Newcastle, Co. Dublin. The company offers a range of services to the civil, structural and environmental engineering industries across the country as director Fergal McNamara explains.
Specialising in geotechnical ground investigation and interpretation, GII provides an unrivalled service to consulting engineers, local authorities, port authority’s, public bodies and private clients throughout Ireland. It undertakes small, medium and large contracts on land and on water. This includes foundation studies for private developments, public projects such as schools and hospitals as well as large-scale investigation for infrastructure projects such as sewage, water and other utility schemes, roads and motorways, bridges, windfarms, ports and landfill sites. GII also sample, test and report on pyrite degradation and subsidence of buildings for individual house owners, local councils, builders, quarries and for legal purposes.
GII offers a range of site investigation methods, including trial pitting, cable percussion boring, rotary coring, dynamic probing and window sampling, and laboratory testing. They also have equipment available for limited access sites to gain important information for their clients. All investigation is carried out in accordance with Eurocode 7 Part 2: Ground Investigation and Testing (ISEN 1997 – 2:2007) and BS 5930: 1999 and A2:2010.
Engineering Geologist Fergal McNamara from Birr in Co. Offaly and Geotechnical Engineer James Lombard from Fermoy in Co. Cork teamed up in September 2005 to set up GII. The company has come through the recession to employ 38 staff comprising chartered engineers, geologists, drillers, assistant drillers and administration personnel.
“We’re one of only a handful of ground investigation contractors in Ireland,” Fergal explains.
“We offer a unique and comprehensive perspective on ground engineering and foundation works to our clients, and pride ourselves on our prompt, professional, cost-effective and friendly service. Our aim is to find the most cost-effective and safe build solution for our clients and provide them with all the necessary information for their proposed design, we also offer solutions or alternatives to poor ground conditions and carry out soil and rock slope inspections where necessary.
“We got off to a good start which was crucial to our survival during the downturn when we had just 12 staff on our books at one stage. It was tough going from the middle of 2008 until 2014 when the recovery started to happen but we had clients that appreciated our thorough approach and expertise in the field which kept us busy during this time. Since then, we’ve been very busy catering for the ground investigation needs of new and existing customers.”
Before building a structure, GII can conduct a site investigation to ascertain ground conditions and establish the depth, type and bearing capacity of the underlying soil and rock by using one of the above methods of investigation. The underlying soil and rock is looked at in situ and with samples taken from the site. When deemed necessary the soils are tested for classification, strength, contamination and chemical composition all of which affect the outcome of the design like the depth of the foundations, the disposal of materials and the type of concrete to be used. They will provide you with the factual information from the site investigation but their experienced engineers can evaluate all of this information from the site to the testing and recommend the best most cost effective solution for you.
The company has nine drill rigs in total, including five Dando cable percussion rigs and three Beretta rock coring rigs. It also operates two Tecopsa dynamic probe and window sampling machines, with some smaller equipment that can access limited access sites like the Geotool 3okg dynamic probe and window sampler.
As already stated, GII’s services include trial pitting, cable percussion boring, rotary coring, dynamic probing window sampling, laboratory testing and soil or rock slope inspections.
Trial pitting is carried out using a suitable tracked or wheeled excavator depending on the access limitations of the site to provide samples for testing and larger-scale visual inspection of subsoil conditions, one of our engineers are on site to log and sample the soil in situ.
Cable percussion boring is carried out using a Dando 2000 MK2 cable percussion rig. In situ testing includes standard penetration tests (SPTs); vane tests; permeability tests. Three types of sample can be taken with this rig disturbed samples; undisturbed (U100) samples and piston samples. Installations into the bored hole can give information on water or ground movement using either manually reading or automatic loggers.
GII have two 4.5 tonne T44 Berreta rigs and one 7.5 Tonne T47/S Berreta rig for rotary coring of rock, all of these rigs are capable of Geobore S which will obtain a continuous soil and underlying rock sample from the surface to the required depth. The coring is carried out with a diamond drill bit and the soil or rock material is recovered in a plastic liner, but the barrel is rotated into the ground under the weight of the drill-head. This method returns a core sample for subsequent logging to BS 5930 on which suitable laboratory testing is scheduled.
Dynamic probing and window sampling is carried out using a Tecopsa TEC10 with capacity for dynamic cone penetrometer testing and window sampling or the hand held Geotool 30kg. Providing information on the geotechnical properties of a soil, the dynamic probe test is a simple and inexpensive test that yields necessary information before considering a construction project and is useful for smaller building projects or for larger ones to correlate results.
Slope inspections are carried out by one of their experienced engineers. The engineer will examine all the points on the slope, take into consideration soil and rock type and determine if the slope is safe without any precautions or if stabilisation is needed, a report is then written to advise of the best course of action.
In addition, GII can provide laboratory testing of soil or rock samples, factual and interpretative reports to consulting engineers and the construction industry. The company also uses a very experienced team for sampling, testing and analysis of the problems associated with pyrite degradation and subsequent heave. The following testing is carried out by GII’s fully UKAS accredited partner laboratory in the UK – acid soluble sulphate; water soluble sulphate; total sulphur; petrographic examination; X-ray defraction scanning; scanning electron miscroscope.
GII works for a wide range of clients in the both the private and public sector, including Irish Water, Dublin Port, Shannon Foynes Port Company and ESB as well as large property developers like Cairn Homes and Ballymore Properties.
“We have carried out ground investigations for everything from a one-off house site in the countryside to the new National Children’s Hospital site at St. James’ Hospital in Dublin. Two of our biggest projects at present are for Shannon Foynes Port Company in Foynes, Co. Limerick and Irish Water, who are carrying out upgrade works to the Vartry Water Supply Scheme in Co. Wicklow,” Fergal concludes.
Ground Investigations Ireland Ltd
Telephone: +353 0(1) 601 5175 / 5176
Fax: +353 0(1) 601 5173
Email: [email protected]
Taken from Building Ireland Magazine, November 2017, Vol 3 No 10