Foundations for wind turbines. Strong winds, necessary for efficient operation of wind farms, require carrying extreme overturning forces onto the ground. Technical requirements related to efficient operation of wind turbines significantly restrain foundation solutions in terms of dislocations (settlements and rotations). The inevitable increase of height and capacity of wind turbines leads to a systematic grow of these moments and limitations on dislocations. Therefore, traditional direct foundations are designed to have increasingly larger dimensions, irrespective of soil conditions. Nowadays we have already exceeded the height and capacity limits that allow for efficient application of direct foundations. Design and cost analyses show that in case of large wind farms, direct foundations are cost-effective only if high bearing sand soil is present in the foundation bed. Otherwise, piled foundations are recommended and technically and economically justified. The advantages of deep foundation on precast reinforced concrete piles are as follows:
• shorter time of piled foundation installation – 1-2 days;
• instant assessment of compression and tension capacities of driven piles (no need to wait for setting of concrete);
• significant savings of material for piles and pile caps,
• significant lowering of foundation dimensions;
• lower costs of foundation (e.g. decrease in 21.4m diameter foundation plate to 16m diameter pile cap of piled foundation enables to lower the total cost of foundation to 20%);
• higher safety of construction (piled foundation is less sensitive to faulty performance during the construction phase).
Drilled piles/piles formed in the ground similarly applied usually have worse technical parameters: longer time of execution and lower capacity/stiffness parameters, limitated application of load tests, etc. In case of smaller wind turbines and bearing soils, direct foundation still remains a more efficient solution. With thin layers of low bearing soil a underlying stratum of bearing soil, direct foundation in improved soil is recommended. For soil improvement, we offer columns formed with the Deep Soil Mixing (DSM) method. Basing on our rich experience, both in execution and design of foundations for hundreds of wind turbines, we provide our Clients with optimal design solutions as well as cost-effective and technically efficient execution.
Tests and measurements. Within the performed geotechnical works we also offer all kinds of test and measurements, including:
• soil investigation;
• static and/or dynamic load tests;
• assessment of pile capacities based on sets and dynamic formulas;
• distribution of forces in piles;
• soil pressure measurements under pile caps/direct foundation;
• pile integrity/quality tests;
• monitoring of impact of piling work on the environment (vibrations, noise, soil dislocation).
Design Office. We also offer design support of experienced designers from our Design Office, who provide professionally prepared calculations and detailed, technical and as-build design documentations. Scope of our services is always customized to the real needs of our Client.
We invite you for cooperation.