Investigation of the Corrosion Effects on the Ultimate Strength of Fixed Offshore Jacket Structures During Different Time Durations

In this paper, the effect of corrosion on the ultimate strength of fixed offshore jacket structures, which are among the most widely used structures in both oil and gas and renewable energy industries, is investigated. The effects of corrosion over different periods of time have been considered as a uniform reduction in the thickness of the members and other types of corrosion and their effects have not been considered in this study. The fixed offshore jacket structure considered in this study belongs to one of the gas platforms in phase 19 of South Pars gas field, which has a lifespan of 25 years. The ultimate strength of the structure is obtained by pushover analysis and it is expressed using the reserve strength ratio. For this purpose, the structure has been modeled and analyzed in SACS software, which is one of the most widely used finite element softwares in this field. According to the results of this study, if the assumptions made about corrosion occur, the ultimate strength of the structure after it reaches its lifespan will be reduced by approximately 20%, such that the value of the reserve strength ratio of the structure is 1.7 when no corrosion is applied, but it reduces to 1.3 considering the amount of corrosion applied after the design life of the structure (i.e., 25 years). This downward trend is mainly to be continued over the following years.