Overdick

Large diameter pile design and detailed pile driving assessment

OVERDICK is able to offer and perform complete state of the art pile driving assessments including geotechnical, structural and installation aspects.
A variety of sophisticated design and calculation tools enable our engineers to address challenges linked with (e.g.) large diameter monopiles, cyclic loading effects, fatigue assessment and pile handling.

Today’s large offshore wind turbines require adequate foundation types. Large diameter monopiles are offering a cost effective solution for the big wind turbines. The pile diameters are currently ranging up to approx. 8.5 m with comparable thin shell thicknesses and respective high D/t ratio. These designs require a far more detailed analysis approach compared to standard jacket foundation piles.

OVERDICK is able to design large diameter monopiles by covering all design aspects in house. Our geotechnical engineers are taking care of proper soil strength verification, cyclic degradation and evaluation of long term effects due to cyclic loadings. The structural department takes care of the global pile design, covering buckling verification and proper fatigue design, and the local design of cut outs, flange connection, lifting points and supports for internal components. Special focus is put on the fatigue strength of the pile attachments, which see high loadings during the pile driving operation. In these cases, OVERDICK is able to perform completely non-linear and explicit finite-element (FE) time domain analyses to assess the occurring loadings of the structural components. Advanced post-processing methods, e.g. rain-flow counting, are used to determine the final fatigue life times.
In addition, OVERDICK’s own welding engineers ensure adequate material, fabrication and welding method selection and may support the clients as well during construction phase on site.

OVERDICK has advanced experience and numerous reference projects for transport and installation planning of large monopiles. Method statements in conjunction with safe and handling efficiency optimized sea-fastening systems can be provided for all kind of installation concepts and assets.

Engineering capabilities:

• Geotechnical design
• Global structural ultimate limit state (ULS), service limit state (SLS), fatigue limit state (FLS), accidental limit state (ALS) design on basis of FE methods
• Detail structural design
• Stress concentration factor determination (e.g. with FE methods)
• Fatigue assessment on basis of frequency or time domain analyses
• Driving assessments using wave equation analysis; can be supplemented by detailed transient nonlinear FE
• Transport and installation planning
• Lifting point design
• Sea-fastening design
• Guiding tools and pile gates

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