Raheenleagh Wind Farm

Gavin and Doherty Geosolutions Ltd (GDG) was appointed by ESBi to provide geotechnical advice on the design of the foundation for Wind Turbine T11 at Raheenleagh Windfarm in Co Wicklow and to carry out the detailed design of the driven pile solution required for the foundation of the turbine.

The foundation design for T11 is a compression pile base adapted from the gravity base foundation which will be employed for the remaining 10 wind turbines, which are founded on bedrock.

The footing shape was octagonal with an inscribed circle of 20 m diameter and a footing depth of 3.7 m. As T11 is founded on up to 12m of stiff gravelly clay rather than bedrock, the proposed gravity base foundation was not considered adequate to resist the large overturning moments expected.

Scope of Work:

An optioneering exercise was undertaken by GDG in order to select the preferred foundation choice for this location. Both tension and compression piled bases were considered. The compression pile base was further developed by  completing the design for the ULS, SLS and FLS conditions. An iterative process was undertaken to select the representative soil-structure stiffness for design. The design included cyclic loading checks and settlements on the piles. The output included detailed engineering drawings of the foundations and steel reinforcement drawings for the piled elements.