Ramboll is the world leader within design of offshore foundations for wind turbines, having performed designs for more than 40 offshore wind farms. More than 65% of the world’s offshore wind turbines rise from foundations designed by Ramboll.
The designs are carried out by means of an advanced and state-of-the-art software design tool developed in-house. The software has been developed during the last 30 years and is continuously being updated and supplied with new features and models.
As one of the few designers worldwide, we perform load iteration with the turbine manufacturers in order to ensure the optimum design loads for the specific project and conditions.
Ramboll is experienced in designing according to the UK CDM regulations, and has had all projects certified by DNV, GL or SGS, and approved by the German BSH or the Prüfingenieur institution.
Covering all project phases
We perform conceptual or detailed design of all parts of the wind project including towers, foundations and the structures for transformer platforms. The design includes in-place analyses, spectral and time-domain dynamic analyses, fatigue analyses, and drivability of piles. An analysis of transportation and installation is also a natural part of Ramboll's competencies.
Our design of primary foundation structures includes:
- Extreme event analysis
- Scour development and possible protection system
- Natural frequency of the integrated structure
- Fatigue calculations
- Ship impact simulation
- Geotechnical design
- FEM analysis of details
Both steel and concrete foundations
We have experience from designing all types of turbine and substation platform foundations using both steel and concrete. By utilizing our decades of offshore oil and gas experience, our designs have proven to be both light and cost-effective while meeting all relevant standards and certification requirements.
Choosing the perfect foundation
We design within four main types of foundations; from the popular and cost-effective monopile to concrete gravity-base structures and steel jackets (open pdf brochure) and tripods. We are currently progressing detailed design of jacket structures for two European projects. Based on thorough analyses of water depths, soil conditions, turbine specifications including nacelle weight, revolving speeds and more, we select the most suitable foundation.
In our analyses we use 3D computations and the advanced Ramboll-developed ROSAP software, which allow us to not only design the structures in compliance with governing rules and standards, but also to optimise the structures saving the customers huge amounts in weight and cost.
Gravity-base foundations are typically selected for more rocky soil conditions, while the monopile is an excellent option for water depths of up to 35 metres in less rocky soil conditions. In deeper waters steel jackets piled to the sea bottom or fixed to the bottom using suction buckets is often the best option financially and technically, and it allows new installation opportunities. Again, as we design for varying conditions within a wind park, jacket structures may be individually customised, in many cases saving our customers considerably on steel weight and cost.
See also brochure on Foundation design.
Ramboll has designed offshore foundations for Repower, Siemens and Vestas turbines, which are currently in operation or being installed. In addition to this we have prepared studies involving several other turbine manufactures, who are not currently offering turbines for offshore applications.