Case Studies > Design: Equipment & Technology

Pile Restraint Arms for Rampion Wind Farm

Houlder has installed a second pair of Pile Restraint Arms for the Rampion Offshore Wind project. The 256t arms ensure foundation piles are kept vertical as they are hammered into the seabed. Leased to Rampion Offshore Wind, they will operate on the Swire Blue Ocean Pacific Orca installation vessel.

The pile restraint arms provide the horizontal restraint required to resist environmental forces acting on the large foundation piles during installation.  They complement a set already installed and operating on the MPI Offshore Discovery jack up vessel. These currently successfully handle piles of up to 850t in weight, 80m length and 7m diameter 

As well as designing the 22m x 8m arms, Houlder has redesigned the vessel attachment and is providing a new grillage support structure.  The grillage support structure is to be placed on the main deck at the aft end of the Pacific Orca vessel and is designed to require no underdeck strengthening and intervention. Further, this design enables fast mobilisation and demobilisation of the equipment as a large proportion of assembly and testing is performed on the quayside prior to vessel arrival.

James A. Russell, Marine Equipment Director commented “The fact we have pile handling equipment on both the MPI Discovery and Pacific Orca during the construction of the Rampion Offshore Wind Farm is testament to the knowledge and experience of our engineers. They know moving large heavy foundations safely and cost effectively requires ingenious thinking, rigorous analysis and well thought through planning. By working in partnership with Rampion Offshore Wind and their contractors, we continue to improve our solutions and look forward to solving future challenges as wind farms move further offshore and into deeper waters.”

Houlder managed a full installation and commissioning service for the pile restraint arms as part of Rampion Offshore Wind’s equipment lease agreement. The arms are now in operation of the UK’s  Sussex coast. The Rampion development is due to be completed in 2018.