ABSTRACT
In the North Sea and the Baltic Sea in Europe a vast number of offshore wind farms are being planned and several have already been installed in recent years. Monopiles have been proven the economic foundation solution for offshore wind energy towers at most locations. The paper gives a state-of-the-art review on the design of such piles under both monotonic and cyclic loading, including the results of recent research. The p-y method is usually applied to predict the behavior of laterally loaded piles. The existing calculation approaches for piles in sand and clay are discussed, showing that for monopiles with a small length-to-diameter ratio new p-y formulations are desirable. Recently developed new p-y formulations are presented and discussed. The behavior of monopiles under cyclic loading is also addressed, focusing on the accumulation of permanent pile deformations with increasing load cycle numbers.
