Forthbank Wind Energy Development - Partnerships for Renewables

Forthbank Wind Energy Development
4.8 Civil Works
Wind Turbine Foundations
4.8.1 Foundation construction design will be finalised at the detailed design engineering stage.
However, a typical foundation design for the candidate turbine is shown in Figure 4.6. Prior to
construction, detailed intrusive ground investigations, will be undertaken at each turbine
location and, depending on the information derived from these investigations, modifications
could be made to the foundation designs.
4.8.2 The wind turbines are likely to be installed on reinforced concrete foundations, established on
suitable load bearing strata (following excavation) or on deep piled foundations depending on
ground conditions. The proposed type of foundation for the three turbines located on the
landfill area will require a reinforced concrete slab, pile cap and deep piled foundations. The
piles will be required to penetrate through the waste mass and the superficial deposits and be
socketed into the underlying rock. The reinforced concrete foundations measure typically up to
20m in diameter and have a depth of approximately 1.5m. A working area around the concrete
foundations will be restored following construction of the foundation and the tower.
4.8.3 It is assumed that the construction of the turbine foundations will require the excavation of
subsoil to a suitable bearing strata and landfill material prior to installation of deep piles and
pile cap of a suitable form that will maintain adequate containment of leachate within the
landfill. Clay is expected to be present beneath the landfill material. Turbine founding in the
north-eastern part of the site will be located (micro-sited) to avoid the two disused adits in the
area.
4.8.4 Excavated material from Turbine 1 (if appropriate) will be reused for access track construction.
Construction of Crane Pads
4.8.5 Each wind turbine requires an area of hard standing to be built adjacent to the turbine
foundation. This provides a stable base on which to lay down turbine components ready for
assembly and erection, and to site the two cranes necessary to lift the tower sections, nacelle
and rotor into place. The crane hard standing will be left in place following construction in
order to allow for the use of similar plant should major components need replacing during the
operation of the proposed wind energy development. These could also be utilised during decommissioning
at the end of the proposed wind energy developments life. The total area of
hard standing at each turbine location, including the turbine foundations and the crane pad will
be approximately 1240m 2 (maximum 20m width x 62m length). Approximately a third of this
area will be dressed back with topsoil and landscaped into the surrounding area upon
completion of turbine erection.
4.8.6 A typical crane hard standing is illustrates in Figure 4.7.
November 2010 Chapter 4 Page 7
Copyright Partnerships for Renewables Development Co. Ltd 2010 ©