Structural Floatover Analysis for Heavy Floating Production Unit by Inertia Balancing Method

Abstract This paper presents a systematic methodology for converting unbalanced dynamic impact reactions obtained from naval floatover time-history simulations into a balanced structural model suitable for verification. Dynamic simulations often produce unsteady and non-equilibrium load cases, making direct structural assessment challenging. To overcome this, the proposed approach resolves reactions at Leg Mating Units (LMUs) and Deck Support Units (DSUs) to the topside’s Center of Gravity (COG) and introduces corresponding inertial forces and moments to achieve global equilibrium. This method differs from conventional industry practices, which typically rely on simplified static approximations, by ensuring dynamic consistency between simulation outputs and structural models. Application with a real project of 32,000-tonne topside demonstrates that the approach enables accurate equilibrium modeling, ensuring structural integrity checks remain valid and design limits are not exceeded during installation. By bridging the gap between dynamic naval analyses and static structural requirements, this methodology enhances confidence in the safety and reliability of float-over operations.