Figure 49 Monopile upending tool, courtesy of Houlder.
Function
Foundation handling equipment is used to manoeuvre the foundations into position before driving them into the sea bed.
What it costs*
The crane, upending frame, pile gripper, pile guiding positioning frame and monopile plug are part of the contractor’s equipment. Lifting tools, are usually rented.
Who supplies them
Suppliers include Houlder, IHC IQIP and Temporary Works Design.
Key facts
Monopiles are transported in the horizontal position.
A lifting tool grips a flange at the top of the monopile, to which the crane hook is secured.
The base of the monopile is gripped by an upending frame while the monopile is raised into the vertical position.
The crane then lifts the monopile and moves into position for piling. A pile guiding and positioning frame is used to position the monopile accurately and ensure verticality. The pile must be installed within 0.25° of vertical.
If a floating vessel is used for piling, a motion-compensated pile guiding and positioning frame may be used.
If the monopile is floated out to site, a monopile plug is used to maintain buoyancy and provide a towing point.
Jackets are transported in the vertical position if a heavy-lift vessel with deck space is used. If the jacket is to be installed in relatively benign conditions, a sheer leg crane vessel may transport a single jacket to site from port.
Equipment may be designed and built for a specific project or installed more or less permanently on the vessel with the flexibility to be used for a range of different projects.
Equipment may be owned or rented by the installation contractor.
What’s in it
- Crane
- Lifting tool
- Upending frame
- Pile gripper
- Pile guiding and positioning frame
- Monopile plug