Case Studies Archive

Steel Cased Bottom Driven Piles, Avonmouth

client: Bluedot Construction

technique: Steel Cased Bottom Driven Piles

contract value:

As part of a new build commercial steel frame development, our repeat business Client Bluedot Constriction appointed us to install 49nr 220mm diameter steel cased bottom driven piles.

In soft soils conditions such as those which can be expected in Avonmouth, and along the Severn Estuary more generally, the use of our 9.0t mini drop hammer rigs can help to significantly reduce site set up costs. With low noise & vibration, and minimal follow on pile cropping requirements, this is a useful system for a range of projects.

Dynamic Compaction, Heathrow

client: Readie Construction

technique: Dynamic Compaction

contract value: £390,000.00

In 2015 GeMech were appointed by Principal Contractor Readie Construction to carry out Dynamic Compaction of a highly variable – both in terms of its nature and thickness – Made Ground deposit, to facilitate the use of ground bearing foundations and internal ground bearing slabs for a large commercial development South of Heathrow.

Work on the Southern boundary was successfully completed within 15.0m of the Network Rail boundary, without any excess vibration or disruption to the running lines.

Validation testing included plate load testing, zone load testing using 1.5m square test plates, and seismic geophysical testing using the Continuous Surface Wave (CSW) method.

Vibro Stone Columns, Worcester

client: RM Contractors

technique: Vibro Stone Columns

contract value:

As part of a new build residential housing development, our Client RM Contractors appointed us to install over 1600 stone columns, and associated validation testing. The use of vibro stone columns for housing developments results in a programme and cost-efficient substructure solution.

Dynamic Compaction, Momentum, Rainham

client: Readie Construction

technique: Dynamic Compaction

contract value: £938,955.90

GeMech were contracted by principal contractor Readie Construction to carry out ground improvement using the Dynamic Compaction method, to perimeter roads and yard slabs for a new commercial unit development on the Northern bank of the River Thames in Rainham.

The ground conditions comprised of up to 10.0m of Made Ground (Silty Sandy Gravel), over Alluvial Clay & Gravel, with Chalk bedrock at depth.

GeMech were employed to carry out dynamic compaction sufficient to ensure that maximum long-term settlement in the Made Ground was controlled to within 25mm, under an applied bearing pressure of 20kPa at surface level.

The site was bounded to the North by an operational landfill site, with vibration limits of 50mm/s PPV imposed at the site boundary to avoid potential for damage to the landfill slurry containment wall.

34,430sq.m of Dynamic Compaction work was completed over a 68 working day period, at an average rate of 500sq.m per day, using up to a maximum of 2 rigs.

Dynamic Compaction, Chichester

client: Ikon Construction

technique: Dynamic Compaction

contract value: £320,000.00

Across two visits during 2015 & 2017, GeMech completed dynamic compaction to building foundations and ground bearing slabs for lightly load commercial units, built over a backfilled Gravel Pit which had more recently been used as a concrete production site.

The ground conditions comprised up to 8.5 of Made Ground (Sandy Gravelly Silt), over residual Gravel and London Clay.
During the second phase of the project, dynamic compaction work was required within 4.0m of the phase 1 boundary. Vibration monitoring was undertaken, and continuous surveillance was put in place to ensure there was no detrimental impact on the occupied neighbouring buildings.

The compaction points on the second phase of this project were filled during construction using site won crushed concrete, alongside a small quantity of imported recycled aggregates, resulting in a low cost, low emboded carbon solution.

Ebbw Fawr – Core Drilling

client: Galliford Try

technique: CFA & Core Drilling

contract value: £215,000.00

GeMech Foundations once again provided a solution for a difficult project in Ebbw Vale. The towns historic steel industry had left plenty of obstructions, making development difficult for many parts of the site. Galliford Try approached GeMech to carry out piling works through an old basement slab as part of a classroom extension. With the old slab left in-situ, GeMech cored through the basement past 6.0m of made ground, dealing with 25mm thick rebar and a slab varying in thickness, but up to 1.5m thick in multiple areas. Once coring operations had been completed, 30nr. 450mm diameter CFA piles were installed to depths up to 14.5m by our Comacchio CH450.

GeMech’s ability to provide this bespoke solution saved a costly exercise in removing the basement slab in its entirety, and once completed allowed quick follow-on construction of the pile caps and other foundations

Close up of our driven piling machine and equipment

Driven Precast Concrete Piling, Weston-Super-Mare

client: Hat Roofing Ltd

technique: Driven Precast Concrete Piling

contract value: £40,000.00

The recent adaption to our Vermeer HL2500 allowed GeMech to provide a driven precast concrete pile solution on this site in Weston-Super-Mare, allowing cost savings for the client. 250mm square precast concrete piles were driven to 16.0m depth in to Mercia Mudstone bedrock.

Fairwater Campus, Cardiff

client: ISG Ltd

technique: CFA Bearing Piles

contract value: £515,000.00

Installation of multiple diameter CFA piles using 2 GeMech rigs. Programme was key on this project and weekly meetings with the client were required to update them on sequence and progress.