NUMERICAL ANALYSIS OF SUSPENDED LOAD MOTIONS OF LARGE DIAMETER PILES IN WAVES

Abstract

 In the construction of a monopile foundation for offshore wind power generation facilities, it is important to know how much the operation rate can be secured against the motion of the suspended load in order to calculate the process and costs, assuming that a large crane ship is used to set the monopile in the open sea. Therefore, analysis of the ship oscillations among waves was conducted with the suspended monopile to study the behavior of the suspended load. The analysis results showed that the suspended load moves significantly around the natural period of the hull and the load, and that the motion sometimes behaves like a double pendulum that the upper and lower ends of the suspended load move in opposite phases. It was also confirmed that the swing of the suspended load affects the sway of the ship via the boom motion. Furthermore, in the case where the monopile is half submerged in water, it was confirmed that the motion of the monopile is reduced compared to the case where that is in air, and it rotates with part of monopile as the fulcrum near the water surface.