Mammoet has developed a jacking and cradle system capable of handling the world’s largest monopile foundations for offshore wind farms.
The system comprises two elements: jacking spacers that sit between SPMT modules to generate greater stroke, as well as hydraulic, foldable saddles that cradle the monopile so it can be supported at higher points, to prevent excessive ovalisation.
Each jacking spacer has a capacity of 430 tonnes split across two towers – with multiple units in use per transport configuration. The system slots between SPMT modules, so transport configurations maintain the same minimum ride height. This enables grillages and sand bunds to remain as low as possible.
Each monopile saddle has a capacity of 1,000 tonnes and can handle monopiles up to 12 m in diameter.
These features, Mammoet explained, means the system can handle the growing size of the structures.
The engineered transport provider added: “Also, when an XXL monopile is lifted, its self-weight causes big deformations. This means that monopiles need to be raised higher than their supports to be loaded or unloaded. Mammoet’s new jacking and cradle system adds 60 cm of additional stroke over and above the standard SPMT systems. This allows customers to continue using existing support structures as monopiles grow.”
By using the system, Mammoet said customers can maintain the existing methods of supporting and moving monopiles, even as they grow from 8 m to 10 m diameter, and beyond. “This reduces whole-project costs right through the fabrication, shipping and storage supply chains,” the company explained.
