Offshore Wind farm Concept Design 

CONFIDENTIAL CLIENT

K2 engaged Empire Engineering to perform the concept design of gravity base and jacket foundations for 10m and 40m water depths offshore Japan. 

The site is located within the near shore area of the Aomori Prefecture. Due to the rock seabed conditions at the site, the client wished to consider both Gravity Base and Jacket foundations. The client was also investigating two WTG options for the sitea MHI Vesta V117 4.0MW and Siemens Gamesa SWT-8.0-167, both in 10m and 40m water depths. Therefore, 8 concept designs were required.  

Empire initially designed the Gravity Base solution as a hybrid concrete structure design combining the features of a ballasted gravity base structure and a floating caisson to achieve the following principle characteristics: 

  • Complete construction of the foundation within a dry dock
  • Self-stable during tow out to site 
  • Self-stable during ballasting 
  • Low cost of construction 
  • Maximised repeatability and standardisation 
  • Suitable for exposure to extreme hydrodynamic loading. 

The Jacket concept design consisted of 3 and 4 leg solutions for the MHI Vesta and Siemens Gamesa WTGs respectively with drilled and grouted piles. The structures are designed to be towed to site on a standard offshore barge and lowered onto preinstalled piles and grouted into place.  

Analysis_Image
GBF 3D Print EE
Jacket 3D Print EE

All designs were checked for ULS conditions and optimized for weight and standardization. The jacket designs were also checked for FLS conditions. 

Key project summary

Client
www.k2management.com/

Key services
Concept design, Jacket Design, Gravity Base Design

Lead Engineer
Dr Alan Marson

Wind farm
Confidential

Key results

Result 1

An efficient set of 8 concept designs were delivered covering multiple wind turbine designs, water depths and foundation types.

Result 2

Designs were optimized for fabrication, transportation and installation.

Result 3

Designs were delivered suitable for costing at the early stage of the project.