Due to the restrictions imposed by the BSH with regard to ram noise during the installation of offshore foundation structures, alternatives are being sought that do not require ram piles. One possibility is, for example, heavyweight concrete foundations, whose cavities can also be filled with sand if required, or foundation piles that are drilled or vibrated in. A heavyweight foundation made of steel has not been considered so far, although it is also possible to ballast with sand in a steel caisson. Together with a large lever arm, the necessary restoring moment against the wind and wave loads is activated.
Mr. P. Kelemen from Salzgitter has developed a foundation variant made of steel which acts as a heavyweight foundation. The aim of the design was to achieve a stable and fatigue-proof layout and dimensioning of the pipe sections and nodes of the K-tower offshore. The SKI Ingenieurges. mbH in Hanover was commissioned with this design.
The entire supporting structure is composed of two cylindrical tower sections and the K-Jacket, which is based on three caissons. Between the lowest tower section and the K-Jacket is the central tube node as an interface, with a pre-stressed ring flange connection serving to transmit power. Below the central tube node, the working platform is integrated into the foundation structure and thus used for load transfer. An adjustment is also integrated there in order to compensate for possible long-term misalignment of the K-jacket.