Assessment of Aged Offshore Jacket Type Platforms Considering Environmental Loads and Degradation Parameters

Offshore steel structures are a common investment in oil and gas industries operating in shallow to medium depth seas. These structures have become increasingly popular since the mid-19th century, with a typical design life of 30-50 years. Despite their popularity, the structural integrity of existing offshore structures remains a controversial topic. Environmental loads and material degradation have been identified as significant factors that can compromise the structural integrity of offshore structures. To address this issue, this study aims to investigate the reserved strength capacity of a selected offshore structure located in the Malaysian Seas. The study will explore the effect of oceanographic data, variations in vertical load, and corrosion on the structure’s main members. To determine the impact of each variable on the reserved strength ratio (RSR) of the structure, several pushover analyses were conducted with different variables. Previous literature has shown little or no relationship between seawater wave height, gravity loads, and corrosion allowance on submerged steel members and the RSR of offshore structures. However, this study aims to fill this gap in knowledge by examining these variables’ effects on the RSR of offshore structures. The study’s findings indicate that even a slight increase in wave height can significantly impact the structure’s RSR due to the increase in lateral loading, potentially leading to severe damage to structural components and the foundation model. Additionally, gravity loads had an adverse effect on the RSR of the structure when more than double the vertical load was added. Corrosion allowance was also found to impact the RSR, particularly when assuming significant wall thickness corrosion in primary members. Overall, the findings of this study have important implications for the design and maintenance of offshore structures. The results suggest that engineers and operators should pay close attention to the potential impacts of environmental loads, such as wave height and gravity loads, and material degradation, such as corrosion allowance, on the structural integrity of offshore structures. This information can be used to optimize the design and maintenance of offshore structures, leading to safer and more efficient operations. © 2023 Tech Science Press. All rights reserved.