E-Found®, Housing Development, Kelty
George Wimpey Housing Development, Kelty, Fife
Client: George Wimpey East of Scotland Ltd.
Contract Management: CON-FORM Contracting Ltd.
Engineers: McGregor & McMahon
CON-FORM was appointed by George Wimpey to carry out specialist ground engineering works to a former quarry site.
The site had previously been an open cast coal mine which had subsequently been back filled. The area under construction comprised both parts of the open cast area and the undisturbed natural ground. The original design had proposed piled foundations for the houses in the open cast mine footprint, with shallow depth foundations in the areas of virgin ground and deeper foundations, such as concrete trench fill, in the areas of fill.
CON-FORM proposed a two tier strategy to overcome the geotechnical issues encountered on site. The fill areas to be engineered using bulk fill modification of the site won materials to enhance the soil's shear strength and bearing capacity to enable the use of standard foundations, and in the areas of cut over the open cast mine area, its E-Found® alternative foundation solution.
This required the excavation, re-engineering and replacement of 3 metres of the original fill area.
The material was re-engineered in 300mm layers, using lime stabilisation with standard compaction applied on each layer. Rolling Dynamic Compaction (RDC) was then applied every 1.2 metres of lift to tie the fill layers together and minimise potential differential settlement, with 40mm of additional vertical displacement typically achieved per RDC layer.
The re-engineered ground was capable of supporting traditional strip footings and either met or exceeded the design bearing capacity of 75kPa.
Key Benefits of the CON-FORM Solution
- Reduction of imported materials.
- Simplified construction methodologies employed, e.g. strip footing construction on re-engineered material ILO piled foundations and suspended floor slabs.
- No requirement for the design, construction and removal of a piling mat.
- Geotechnical issues fixed on a permanent basis.
- E-Found® system accepted under the NHBC Buildmark warranty scheme.
- Earlier access to areas of the site.
- Adoption of E-Found® foundation solution delivered savings in the region of £300,000 versus the proposed original design.