Please Avoid Tilting

Abstract

Everything rests on the pile. Over half the planned offshore wind farms are to have monopile foundations, while over 40% will have multiple piles. The RAVE project Application-Oriented Design and Monitoring Model for Offshore Foundation Constructions investigated foundations, carried out model trials and equipped a wind turbine in Alpha Ventus with sensors. The more wind that pressed onto the turbines, the more load was experienced by its pile in the seabed. The pore water pressure – the tension in water-filled pores in the seabed – can influence the load-bearing behaviour there. After an extreme storm the foundation is most vulnerable when greater pore water pressure loosens the seabed. After a while it hardens again. Larger pile diameters ensure better stress distribution. The task remains to consider real impact scenarios for the foundation, which experiences constantly changing load directions and time sequences, from the brief peak to the long-term impact.