Stable offshore foundations and structures with ballast

High-density MagnaDense aggregate provides weight for offshore constructions ensuring a stable foundation to withstand the motions of the sea.

Offshore foundations all over the world have been supplied with LKAB Minerals’ heavy MagnaDense to give them the right stability in seawaters. With a density of up to 5.1 t/m3 and the advantages as shown below in the picture of the Archimedes Principle, MagnaDense as either loose ballast or mixed into concrete will provide more weight and less volume.

Archimedes principle shows the advantage of heavy concrete used under water

Offshore structures that benefit from heavy aggregate

In instances where secure foundations are required MagnaDense is a valuable aggregate to provide weight and stability. Offshore platforms need to have considerable weight in order to withstand the motions of the sea and the stresses imposed on them.

Structures that can benefit from MagnaDense are:

  • Gravity Based Structures (GBS): MagnaDense enables platform legs and sub-sea bases to be built with more weight and with an enhanced ability to resist sea currents and to withstand ice bergs.
  • Gravity Based Wind Structures: it is preferred to make pre-cast foundations as light as possible so they are easier to handle and cheaper to transport. At their final position on sea these will be ballasted with the high density aggregate to increase the weight of the foundation.
  • SPARS: a spar is a floating platform used either for oil and gas storage or as a floating foundation for wind turbines. MagnaDense can be used in two different ways:
    • as a loose ballast pumped into place with a water slurry
    • in concrete as a stabilizer around the base of the SPAR.
  • Anchors for wave & tidal energy devices: to keep the wave power machinery in place, MagnaDense can be used as an aggregate in concrete or as loose ballast in the anchor, foundation or counterweight for the device.
  • Concrete mattresses: the large ’bed’ of concrete blocks held together in the shape of a mattress is used to keep pipelines at sea bottoms. The high density concrete blocks can be made with MagnaDense as a heavy aggregate.

MagnaDense is non-toxic and doesn’t react to sea water making it an ideal material for underwater usage. When used as loose ballast inside the construction, it is possible to recycle the MagnaDense as demonstrated with the decommissioning of a floating loading platform.

Summarizing the benefits of MagnaDense for underwater constructions are:

  • Potential cost reduction when ballasting at sea
  • Long underwater lifetime
  • Inert to seawater

View below video to easily understand the benefits of MagnaDense heavy aggregate for a large variety of offshore applications.

MagnaDense for offshore wind structures

The increasing number of offshore wind turbines around the world has shown an increasing need for heavy weight to ground the turbines over the past few years.

When constructed, the wind turbines require secure foundations that are unaffected by undersea currents and lifetime abrasion. By nature these foundations need to have a considerable weight in order to withstand the motions of the sea and the stresses imposed by the rotating blades.

For both gravity base wind structures or floating wind platforms MagnaDense ballast and filled concrete are utilised. MagnaDense is used when more density is required than would be achievable from conventional aggregates and concrete. Increasing the concrete density to 3.9t/m3  with MagnaDense can reduce the amount of concrete required whilst still offering stability and a long underwater lifetime.MagnaDense offers more weight and less volume.

World-wide supply to offshore structures

LKAB Minerals provides MagnaDense to many offshore projects all over the world that need high density concrete or heavy ballast. In addition to owned mines and stocks in the Northern part of Sweden, LKAB Minerals has several stock locations world-wide.

Contact your local sales person via the expert box in the top right corner and ask for the project brochure, datasheets or about the MagnaDense possibilities for your upcoming offshore project.

Application expert

Marina Hellsten
Sales Manager Magnetite

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