Nonlinear structural assessment of self-installing platforms in the Indian Ocean for offshore wind turbines using push-over analysis

Abstract

The Indian offshore wind energy industry is gaining momentum, driven by strong coastal wind resources and national efforts toward clean energy, economic development, and climate change mitigation. However, the installation of wind turbines in deep-water regions poses significant technical and economic challenges. This study explores the development and assessment of a novel Self-Installing Platform (SIP) tailored for a 10 MW offshore wind turbine at a depth of 75 meters. The SIP aims to overcome current installation limitations by eliminating the need for heavy-lift vessels, thereby reducing cost, increasing efficiency, and enhancing deployment flexibility. A coupled numerical modelling approach is employed, integrating structural analysis using SACS software and geotechnical evaluation through PLAXIS 3D, including the modelling of a suction bucket foundation. The platform’s performance is analysed under a range of environmental conditions, including extreme wave and wind loads, over a design life of 100 years. Nonlinear static pushover analysis is conducted to determine the maximum load capacity and assess system resilience. Results demonstrate that the SIP meets structural safety requirements, with Reserve Strength Ratios (RSRs) exceeding 2.5 in all directions, and maintains acceptable displacement levels under critical load cases. Additionally, the study identifies the most vulnerable structural sections under extreme E180° loading, enabling targeted design improvements. Overall, the SIP exhibits robust structural and geotechnical performance, proving to be a viable, cost-effective solution for deep-water offshore wind turbine installations. This research contributes valuable insights into the behaviour of self-installing platforms in harsh marine environments and supports the advancement of sustainable offshore wind energy infrastructure installation, especially in challenging deep-water environments.