Challenge
Ailes Marines required a DNV-compliant solution to support installation of the jacket foundations for 62 wind turbines at the Saint-Brieuc Offshore Wind Farm, offshore France. The system needed to provide a secure connection between the jacket foundations and installed pin piles during grouting, maintaining On Bottom Stability (OBS) while minimising the effects of Early Age Cycling (EAC).
The solution also needed to integrate with the jacket design and fabrication programme, operate effectively within challenging offshore conditions and be delivered within a demanding project schedule.
Solution
THREE60 developed its proprietary PileProp™ system, an innovative pile gripper solution using hydraulic cylinders to create a rigid connection between the jacket foundation and installed pin piles during grouting. Designed to meet DNV requirements for EAC and OBS, the system allowed each jacket to remain securely on station for up to seven days before grouting. This increased the available installation window and enabled installation vessels and supporting infrastructure to progress efficiently between locations.
The system could be operated either from the top of the jacket or remotely from a support vessel using line-of-sight wireless communication or 4G connectivity, providing additional operational flexibility. Working closely with Ailes Marines' Transport & Installation and Foundations teams, THREE60 designed, manufactured, installed and commissioned the system within a tight delivery programme. The design was standardised across the jacket foundations to create further efficiencies during manufacture and installation.
Result
PileProp™ was successfully deployed across the 62 jacket foundations during the 2022 and 2023 offshore installation campaigns. The system exceeded the original specification requirements, increased available installation windows and reduced the risk associated with early-age grout cycling, supporting efficient and reliable jacket installation.
By improving stability during the critical grouting phase and enabling greater flexibility in the offshore installation sequence, PileProp™ contributed to the successful delivery of the Saint-Brieuc Offshore Wind Farm and demonstrated an innovative approach to jacket foundation installation.
