Global heavy transport, lift and logistics specialist Mammoet has developed a new jacking and cradle system for XXL monopiles.
Mammoet’s latest engineering innovation allows for XXL monopiles to be stored and transported using existing support structures for the monopiles, reducing the need for upgrades to grillage and sand bunds and therefore reducing the associated costs for customers.
Its new jacking and cradle system adds 60cm of additional stroke over and above the standard SPMT systems. The system comprises two elements: jacking spacers that sit between SPMT modules to generate greater stroke, and 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, again saving on costs.
Each monopile saddle has a capacity of 1,000 tonnes and can handle monopiles up to 12m diameter. By using the system, Mammoet customers can maintain the existing methods of supporting and moving monopiles, even as they grow from 8m to 10m diameter, and beyond, reducing costs right through the fabrication, shipping and storage supply chains.
Monopiles are colossal cylindrical steel foundations that connect wind turbines to the seabed. According to Mammoet, they can weigh in excess of 3,000 tonnes and be over 120m long, and their growth shows no signs of stopping. As offshore wind turbines grow, their foundations are increasing in size, making transport and storage more difficult.
As developers build taller turbines, their foundations are getting larger in diameter and longer, placing them beyond the capabilities of existing handling equipment.
Additionally, 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.
READ MORE: Mammoet deploys PTC 210 DS ring crane, SPMTs for 114 2,200-tonne lifts.