Study on Spudcan Soil-Structure Interaction of a Wind Turbine Installation Vessel

Abstract

A site-specific assessment should be performed before a wind turbine installation vessel (WTIV) operates at a given location. In the present study, structural assessments of a WTIV were performed in the southwest sea of South Korea. Spudcan penetration behavior was calculated, and a load path under the horizontal environmental load was predicted using International Organization for Standardization (ISO) 19905-1. The complex stress and strain state of the soil under the spudcan commonly is simplified, as a boundary condition, to a value of soil stiffness. These boundary conditions include pinned footings, fixed footings, and a foundation model based on the ISO. Soil-structure interaction effects can be considered when the boundary conditions are set as springs with a corresponding yield surface. From the present structural analysis results, a reduction in the stresses of the members at the leg-hull connection could be found. Yield first occurred in the leeward spudcan, after which the moment in the spudcan decreased. Also, penetration depth and soil capacity were found to have had significant impacts on the structural analysis results.