LAUSR

Abstract Continuous operation of fixed offshore structures forms one of the most important aspects in the global oil and gas industry. In this paper, functional considerations for damaged fixed offshore platforms were studied through the application of pushover analysis. A case study was used to model non-linear behaviors of the structure, and a three dimensional model of South Pars development phase-20 offshore jacket in the Persian Gulf was simulated using Bentley SACS 5.7 software. Analysis of an intact offshore jacket was performed to calculate the ultimate base shear as an indicator of the jacket's ultimate strength to compare with the damaged jacket's base shear, this proportion represented as reserve strength ratio and damaged strength ratio, indicated the sensitivity of the platform. Eighteen scenarios simulated damage to the platform's braces and legs, regard to the eight load combinations used for each case. Significant behavioral changes caused by damage to the upper-level members rendered the jacket non-operational. Damage to the legs increased damage sensitivity by as much as 4 times more than intact condition. Brace damage due to position increased the sensitivity about 1.4 times, particularly in the direction of lateral loading, to which a damaged brace made its maximum resistance contribution.