Effects of Redundancy in Bracing Systems on the Fragility Curve Development of Steel Jacket Offshore Platform

Azad, Samdani; Punurai, Wonsiri; Sinsabvarodom, Chana; Asavadorndeja, P.

doi:10.4186/ej.2019.23.1.123

Cited by 3 publications

(3 citation statements)

References 11 publications

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“…An incremental triangular load pattern is applied, and the load increment is continued till the collapse occurs. Figure 2 illustrates the pushover curve obtained from the nonlinear analysis for the model that has good agreement with the results of Azad et al [40]. The fundamental frequency of the structure is 0.68 Hz, which matches with the free vibration analysis of Punurai et al [41].…”

Section: Validation Of the Modelsupporting

confidence: 81%

Influence of Optimal Intensity Measures Selection in Engineering Demand Parameter of Fixed Jacket Offshore Platform

et al. 2021

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This research identifies the significant optimal intensity measures (IM) for seismic performance assessments of the fixed offshore jacket platforms. A four-legged jacket platform for the oil and gas operation is deployed to investigate the seismic performance. The jacket platform is applied with nonlinearly modeled using finite element (FE) software OpenSees. A total of 80 ground motions and 21 different IMs are incorporated for numerical analyses. Nonlinear time-history analyses are performed to obtain the jacket structure’s engineering demand parameters (EDP): peak acceleration and displacement at the top of the structure. Four important statistical parameters: practicality, efficiency, proficiency, and coefficient of determination, are then calculated to find the significant IMs for seismic performance of the jacket structure. The results show that acceleration-related IMs: effective design acceleration (EDA), A95 parameter, and peak ground acceleration (PGA) are optimal IMs, and the acceleration-related IMs have good agreements with the acceleration-related EDP.

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Section: Validation Of the Modelsupporting

confidence: 81%

Influence of Optimal Intensity Measures Selection in Engineering Demand Parameter of Fixed Jacket Offshore Platform

et al. 2021

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“…To approximate the vibration response, a program written in MATLAB is used. For the considered identification problem, a benchmark offshore platform described in Azad et al is used. The geometry and structural characteristics are taken as is from Punurai et al…”

Section: Offshore Structural Model Descriptionmentioning

confidence: 99%

“…Structures may lose all strength and collapse due to failure of a single member . If the location of damage occurs in members near the sea level, the safety factor decreases significantly . On the contrary, the structures become unstable if there is damage in the members close to the foundation.…”

Section: Introductionmentioning

confidence: 99%

A novel hybridized metaheuristic technique in enhancing the diagnosis of cross‐sectional dent damaged offshore platform members

Punurai

Azad

Pholdee

et al. 2019

Computational Intelligence

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Offshore jacket platforms are widely used for oil and gas extraction as well as transportation in shallow to moderate water depth. Tubular cross‐sectional elements are used to construct offshore platforms. Tubular cross sections impart higher resistance against hydrodynamic forces and have high torsional rigidity. During operation, the members can be partially or fully damaged due to lateral impacts. The lateral impacts can be due to ship collisions or through the impact of falling objects. The impact forces can weaken some members that influence the overall performance of the platform. This demonstrates an urgent need to develop a framework that can accurately forecast dent depth as well as dent angle of the affected members. This study investigates the use of an adaptive metaheuristics algorithm to provide automatic detection of denting damage in an offshore structure. The damage information includes dent depth and the dent angle. A model is developed in combination with the percentage of the dent depth of the damaged member and is used to assess the performance of the method. It demonstrates that small changes in stiffness of individual damaged bracing members are detectable from measurements of global structural motion.

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Asset Life Extension Management of Aging Offshore Fields

Altmann¹,

Sherif²,

Nicolson³

2022

Day 3 Thu, March 24, 2022

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With many of the offshore platforms around the globe well past their design life, developing targeted and cost-effective approaches to reassess and manage the life extension of these facilities is critical for operators. Although standards such as API RP 2SIM and ISO 19901-9 provide an excellent framework for management of the structural integrity of individual platforms, operators that manage a significant number of facilities need to develop strategies for overseeing the life extension of a fleet of aging multidiscipline assets, with the objective of maximizing return while maintaining an acceptable level of risk. The paper presents a systematic risk matrix based approach to provide a predictive assessment of the residual lives of the offshore facilities using the available design and condition data, re-assessment results based on asset specific or grouped approaches, and existing inspection results and strategies. Weighting of the influence of each parameter, adapted for different asset classes to capture state-of-the-art approaches within each discipline or system, is used to predicted residual life. This method has the ability to handle sparse data and incorporate recent or planned modifications. The increased likelihood of failure with time due to damage or degradation, as well as other threats such as obsolesce, is captured through time dependent factors to provide an estimate of the residual life. The method used provides a flexible assessment of the health and residual life estimates for assets from a sub-system through to a full field perspective based on the existing risk tolerance and management strategies of the operator. This provides operators with a valuable tool to assist in optimizing the life cycle costs for the field. If the overall risk profile is not acceptable, then high level what-if analyses can be performed and incorporated into the risk model to review likelihood or consequence reducing measures as the facilities age. This may include additional assessments (e.g. platform specific ultimate strength or fitness-for-service assessments of major equipment), changes to fabric maintenance or risk based inspection plans, load reductions, upgrading of instrumentation and control systems, implementation of strengthening, modification or repair programs, or decommissioning. Advisian has successfully applied this approach for both offshore and onshore assets. Unlike most life extension programs which are typically limited to a single discipline, this method provides a flexible multidisciplinary approach with the ability to incorporate findings covering topside structures, pipelines, piping, rotating and static equipment, electrical and instrumentation for a whole of field assessment.

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Effects of Redundancy in Bracing Systems on the Fragility Curve Development of Steel Jacket Offshore Platform

Cited by 3 publications

References 11 publications

Influence of Optimal Intensity Measures Selection in Engineering Demand Parameter of Fixed Jacket Offshore Platform

Influence of Optimal Intensity Measures Selection in Engineering Demand Parameter of Fixed Jacket Offshore Platform

A novel hybridized metaheuristic technique in enhancing the diagnosis of cross‐sectional dent damaged offshore platform members

Asset Life Extension Management of Aging Offshore Fields

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