A numerical study of brace-viscous damper system of fixed offshore jacket platforms under extreme environmental loads

Abstract

The Arabian/Persian Gulf is a common region where offshore platforms have existed. All types of offshore structures are exposed to extreme environmental loads such as wind, current, and wave loading. They play an important role in affecting the dynamic response leading to higher uncertainty regarding their performance. Therefore, this study contributes to finding alternatives and solutions for the design and rehabilitation of fixed offshore structures using Viscous Dampers (VD). The purpose of adding VD is to optimize the vibrational behaviour and decrease the structural response which provides an effective solution to increase the lifetime, strengthening the structural components with economical repair works. However, a finite element software, ABAQUS is exploited to analyse the Rassalat jacket based on the displacements, stresses, and vibrations before and after adding VD. The diagonal and inverted V-shape of brace VD with different arrangements is compared to select the optimum configuration. Subsequently, the results show that the optimum configuration was able to reduce 52% to 64% of displacements at all levels, and 38% to 54% of connection stresses from levels 1-5. Finally, VD has successfully reduced the structural vibration and provided a uniform structural dynamic response, which will be recommended to use VD in the oil and gas industry.