TEXBASE – The “lightweight“ Gravity Foundation

New cooperative project in Germany for a new offshore foundation design

In the beginning of July a cooperative of the Bremen based Maritime Offshore Group GmbH, the steel construction company conferdo GmbH & Co. KG, the Technical University of Middle Hessen and the Franzius-Institute for Hydraulic and Coastal Engineering at the Hannover University began a development project for a new offshore foundation. The design is based on the HEXABASE foundation of the Maritime Offshore Group and ThyssenKrupp Mannex and is planned as a gravity foundation, which will be on one hand simple to transport and otherwise will stand securely on the seafloor with an 8  MW wind turbine on top.

Instead of planning a massive and voluminous gravity foundation as the existing designs, the cooperative takes a completely new approach. The major components of the existing HEXABASE will be combined with new supporting feet arrangements, which also will be equipped with ballast tanks containing several thousand tons of sand.

The ballast tanks walls will be made of a very resistible textile layer that will separate and held back the sand from the filled in mixture from the water. This will make small ballast tanks possible. The foundation will rest on six plate-shaped elements, which will be made of very resistible fabric covered frames. This feature will enable the adaption to very different soil conditions without any environmental harmful preparation of the seafloor. From the HEXABASE the modular design that has been optimized for an economical serial production by partitioning the making of components by several suppliers will be taken over to the new design.

The Technical University of Middle Hessen is responsible for the structural design. The Maritime Offshore Group will design the ballast tanks and the supporting feet elements. The steel constructor Conferdo will plan the production process and after-sales support. The Franzius-Institute will analyse the effects of the foundation on the seafloor like scouring in theoretical studies and tank tests in Hannover.

The project will be finished in mid of 2017. The new product will be offered and manufactured by the ThyssenKrupp Mannex GmbH like the HEXABASE today would wide exclusively.

The new design offers feature like the economic serial producibility and the environmental friendly time saving installation, which are significant advantages to competitive products like the XXL-Monopiles. As planned for the HEXABASE, the TEXBASE-foundation will be completely protected by new extremely resistible anti-corrosion coating made by BASF Coatings GmbH.

The TEXBASE-project is sponsored by the Central innovation program (ZIM) of the German Federal Ministry for the Economy.

Bremen

October 2015

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