The main geotechnical challenge offshore is handling the large cyclical loads on structures and foundations from waves and wind. The growth of the offshore wind market over the last two decades has provided NGI with the opportunity to provide support to developers, contractors and consultants from Europe, the US and Asia in challenging environments.
Today, NGI is one of the leading suppliers to the offshore wind industry, covering activities from the earliest concept and final evaluation stage through FEED and detailed design to installation and operation. Our experience in foundation design covers all foundation and anchor concepts: monopiles, suction caissons/buckets, piled jackets, gravity base structures, and anchors for floating wind.
Our capabilities include a large suite of design tools from calibrated analytical solutions to complex 3D finite element analysis soil-structure interaction models, allowing our projects to benefit from optimal solutions.
The installation of circular skirts using negative pore pressure (suction) led to the development of suction bucket foundations as an alternative to piles, and later to suction anchors used to secure floating platforms. The video above explains this concept.
Research and development
The challenges and NGI's research in offshore foundation engineering are currently concerned With:
- software development - for example calculation of the holding capacity of skirt foundations/suction anchors, soil structure interaction
- model testing and behaviour of pipelines and flexible pipes in soft clay
- decommissioning and relocation of offshore installations
- geotechnical aspects of offshore wind farms
- new challenges from greater sea depths with softer sediments
Together with our clients, NGI develops and improves foundation concepts in challenging conditions, which can be validated through NGI's instrumentation and monitoring services. NGI's leading role in the advancement of offshore geotechnics is evidenced by our active work in numerous committees covering the development and update of international standards and regulation.