Tests which put the load of 37 London buses on wind turbine piles have been completed, with the results being used to develop new design methods for offshore wind farms.
Dong Energy and ESG tested 28 piles in Cowden, England and in Dunkirk, France, where conditions are similar to those of the bed of the North Sea. Initial results show that less steel could be used in the pile foundation, saving money.
During the tests, each of the 28 piles were pulled sideways until failure.
Dong Energy lead geotechnical engineer and Pisa Project technical manager Alastair Muir Wood said: “We’re very pleased with the test results, which confirm that traditional design methods in these soils are very conservative. The results indicate that in these site conditions there may be opportunities for savings identified by reducing the quantity of steel in the foundation. In other words, there’s a savings potential that will contribute to reducing the cost of electricity.”
The joint industry project known as Pisa undertook the testing and it was done to assess new design methods being developed by Pisa, with the academic working group led by Oxford University.
Source: Dong Energy
ESG project director Steve Turner, who undertook the tests, said: “The Pisa project has provided some of the most challenging testing we’ve ever undertaken. With the largest test, we were simultaneously monitoring more than 250 different precision instruments, while applying a load greater than the weight of 37 London double decker busses.”
Dong Energy research and development project manager Jesper Skov Gretlund added: “The Pisa Project is a great example of inter-industry collaboration to solve a common problem. If the thickness or length of the steel piles can be reduced by even a small fraction, the saving in cost is quite considerable since smaller construction vessels can be used and larger turbines constructed. The next challenge is to analyse all of the data collected in order to refine our methods and apply these findings to our foundation designs.”
The full results of the tests will be published early next year.