Life Cycle Structural Performance Assessment of Offshore Fixed Platforms

Abstract

Structural assessment is a key part of the structural integrity management (SIM) process for ensuring the fitness-for-purpose of offshore fixed platforms. This paper presents a comprehensive life cycle structural performance assessment approach for the offshore fixed platforms. Non-linear pushover analysis is used to perform the structural assessment, in which the platform capacity is characterized in terms of the platform’s reserve strength ratio (RSR). Comparison of the platform RSR and the target RSR specified in the acceptance criteria determine the fitness-for-purpose of the platform. A structural reliability methodology is proposed for the development of the regionally specific acceptance criteria. The annual probability of platform failure is calculated using the first order reliability method (FORM). The assessment results are used to develop a long term risk-based underwater inspection strategy. A case study for the platforms located offshore Eastern Caribbean is used to illustrate the application of the developed structural assessment approach.