As a monopile ( [ mɒnəʊ paɪl ]; composed of the Greek word Mónos for " alone", " only ", " one " and the English word pile for "thorn " ) is a form of foundation for offshore structures is referred to in the building industry. Mainly used come Monopiles the construction of offshore wind turbines in shallow waters.
An establishment with a monopile is, as its name implies, consists of a single, round steel pile which is driven by a construction vessel or a jack-up rig from the ocean floor, looking out the upper end of the water surface. The slimness and simplicity of design is advantageous on the one hand, since the production and transport of a foundation element can be very cost effective and space-saving. In addition, the interference with the seabed is limited to a very small area, which reduces the preparatory work to a minimum. A possibly more necessary scour protection from bulk stones is easy to produce. On the other hand, the slenderness limits the maximum possible length. Therefore Monopiles come up to a water depth of around 20 m used, with the development of larger monopile continues advancing.
Need to ensure a secure anchoring embed at least half its length into the ground, so that tubes be used with over 40 m length of the pile in the rule. May be present along the entire length no major obstacles in the stone floor, which restricts the use on sandy, rocky soils not. The diameter of the monopile range of several meters. 2003 version for technical reasons the maximum diameter was still at 5 m, 2013 piles have been able to be successfully rammed with a diameter of 6 m, which expands the application on areas with up to 30 m water depth. The actual installation of the monopile take just only about two hours.
To reduce disturbance of marine animals by Rammgeräusche in the water, bubble curtain are used that break the sound generated in the pipes and reduce the noise.
Another way to introduce the foundation piles is the ingress. For this purpose, a special flushing procedure for the installation of offshore foundations ( SIOF ) was developed.
One possibility for the stabilization of the monopile in deep waters is the lateral bracing with steel cables or chains. The construction, however, loses the advantage of rapid construction and represents an invisible obstacle for shipping