Session: New & Innovative FOW Design

Paper Number: 165295

165295 - Structural Integrity of a Reinforced Concrete Semi-Submersible Platform for a 15 MW Floating Offshore Wind Turbine 

Abstract: 

There is a growing trend in the use of higher-power Offshore Wind Turbines (OWT), installed at significant distances from the coast and in deep waters, aiming to increase clean energy production and reduce costs. These floating structures, usually made of steel, are subjected to significant loads due to wind, waves, and their own weight. However, due to the high costs of construction, transportation, maintenance, and service life, reinforced concrete is being studied as a viable alternative for this type of structure. This study presents a new reinforced concrete semi-submersible platform designed to support a 15 MW wind turbine. The proposed platform offers several advantages over existing designs. Its hexagonal base supports the central part of the structure and significantly reduces vertical movements due to its larger projected area in the horizontal plane, thereby increasing damping in the vertical direction. Additionally, this configuration simplifies construction and minimizes stress concentrations at the pontoon connections. Moreover, the robust hexagonal base shifts the center of gravity downward toward the keel, resulting in a high metacentric height and, consequently, superior hydrostatic stability in both operational and transport conditions. Further mitigation of vertical motion can be achieved by incorporating and optimizing heave plates or bilge keels into the structure. After the hydrostatic analysis, a structural analysis was conducted, considering the DLCs under operational and extreme conditions. This analysis was performed using finite element software, allowed the evaluation of the platform's structural behavior based on the distribution of stresses and displacements, following the failure criteria for reinforced concrete. Finally, a cost analysis of the materials confirmed that the proposed platform is highly economical compared to equivalent steel structures.

Presenting Author: John H. Chujutalli Offshore Renewable Energy Group-GERO/COPPE, Ocean EngineeringDepartment, Federal University of Rio de Janeiro

Presenting Author Biography: John H. Chujutalli is a distinguished researcher in the field of Ocean Engineering, with an emphasis on naval and offshore structures, as well as offshore wind turbine structures and numerical welding simulation. He earned his Ph.D. in Ocean Engineering from the Alberto Luiz Coimbra Institute for Graduate Studies and Research in Engineering (COPPE) at the Federal University of Rio de Janeiro (UFRJ) in 2017 and completed his postdoctoral research at the same institution in 2020. Currently, Chujutalli serves as the lead researcher in structures at the Ocean Renewable Energy Group (GERO).

Authors:

John H. Chujutalli Offshore Renewable Energy Group-GERO/COPPE, Ocean EngineeringDepartment, Federal University of Rio de Janeiro
Mojtaba Maali Amiri Offshore Renewable Energy Group-GERO/COPPE, Ocean EngineeringDepartment, Federal University of Rio de Janeiro
Milad Shadman Offshore Renewable Energy Group-GERO/COPPE, Ocean EngineeringDepartment, Federal University of Rio de Janeiro
Segen Farid Estefen National Institute for Ocean Research-INPO