Reliability Analysis of Strength of Offshore Jackets in Indian Western Offshore

Singh, Divjot; Kumar, Dinesh

doi:10.2118/178113-ms

Cited by 1 publication

(2 citation statements)

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“…Reserve strength ratio (RSR) is defined as a ratio between a platform collapse load and a lateral environmental load, typically a 100-year return period (RP) load in terms of base shear or moment shear [5,25,56]. Therefore:…”

Section: Methodsmentioning

confidence: 99%

“…The CFD method results compare Structural reliability assessment using pushover analysis is widely used to calculate the reserve strength ratio and probability failure of offshore structures. Fairly recent studies had been performed by [5,[22][23][24][25][26], which involved the structural reliability assessment. The pushover analysis had been performed by the authors to calculate the reserve strength ratio.…”

Section: Introductionmentioning

confidence: 99%

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Structural Integrity of Fixed Offshore Platforms by Incorporating Wave-in-Deck

Azman¹,

Husain²,

Zaki³

et al. 2021

JMSE

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The structural integrity of offshore platforms is affected by degradation issues such as subsidence. Subsidence involves large settlement areas, and it is one of the phenomena that may be experienced by offshore platforms throughout their lives. Compaction of the reservoir is caused by pressure reduction, which results in vertical movement of soils from the reservoir to the mud line. The impact of subsidence on platforms will lead to a gradually reduced wave crest to deck air gap (insufficient air gap) and cause wave-in-deck. The wave-in-deck load can cause significant damage to deck structures, and it may cause the collapse of the entire platform. This study aims to investigate the impact of wave-in-deck load on structure response for fixed offshore structure. The conventional run of pushover analysis only considers the 100-year design crest height for the ultimate collapse. The wave height at collapse is calculated using a limit state equation for the probabilistic model that may give a different result. It is crucial to ensure that the reserve strength ratio (RSR) is not overly estimated, hence giving a false impression of the value. This study is performed to quantify the wave-in-deck load effects based on the revised RSR. As part of the analysis, the Ultimate Strength for Offshore Structures (USFOS) software and wave-in-deck calculation recommended by the International Organization for Standardization (ISO) as practised in the industry is adopted to complete the study. As expected, the new revised RSR with the inclusion of wave-in-deck load is lower and, hence, increases the probability of failure (POF) of the platform. The accuracy and effectiveness of this method will assist the industry, especially operators, for decision making and, more specifically, in outlining the action items as part of their business risk management.

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Section: Methodsmentioning

confidence: 99%