CRL sort out excessive movement in concrete bases

Aikengall windfarm sits in the hills above Dunbar just south of Edinburgh. CRL became involved in this project when issues were discovered with the stability of the turbine towers and after further investigations it became apparent that a programme of remedial work would need to be carried out to stabilise the towers

CRL in Scotland had developed a repair solution for this type of turbine where the steel embedment of the tower had started to exhibit signs of excessive movement in the concrete base. This solution involved deep injection works that allowed the failed load bearing areas of the concrete to be flushed clean and reinstated with ductile epoxy resin.

The principal reason for this problem occurring is the failure to install an adequate seal between the tower and the concrete base. This seal is essential to prevent water entering the annulus between the steel tower and the concrete base. On completion of the stabilisation works, CRL installed a high-quality spray applied waterproofing system to prevent future water ingress in this area.

This process was carried out in a planned maintenance programme over a five-year period which, with careful planning, minimised the turbine downtime and the subsequent loss of generation.

The first five turbines that were repaired had bespoke monitoring equipment installed in the basement of the towers to record the relative movement between to tower and the concrete base. This was continuously recorded for several years after completion of the works and no movements were recorded that fell outside the original design parameters for this type of turbine.

CRL have continued to work closely with the windfarm owner, Community Windpower, and have been involved in the extension of this windfarm via our grouting framework with Siemens Gamesa and have provided repair support and advice on several other windfarms that CWP own and operate.

CRL have now further developed this solution and have completed successful stabilisation repairs to over sixty turbines of this type.

Works carried out include;

    • Hydrodemolition to expose reinforcement,
    • Core drilling to create injection ports,
    • Resin injection to stabilise turbines,
    • Waterproofing to prevent future water ingress, and
    • Install remote movement monitoring.

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