Extending Life of Fixed Offshore Installations by Integrity Management: A Structural Overview

Nabavian, Mohammad; Morshed, Ali

doi:10.2118/138386-ms

Cited by 4 publications

(1 citation statement)

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“…The steel jacket structures were originated in the Gulf of Mexico and spread worldwide as typical shapes of fixed offshore platforms. There are more than 6,700 platforms in operation worldwide, and 30% of them have been in operation for more than 20 years (Nabavian and Morshed 2010). Many of these platforms are operating beyond their original design life.…”

Section: Introductionmentioning

confidence: 99%

Seismic Performance Evaluation and Retrofit of Fixed Jacket Offshore Platform Structures

El-Din

Kim

2015

J. Perform. Constr. Facil.

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In this study the seismic performances of the fixed-base jacket structures with various bracing configurations were evaluated by nonlinear static and dynamic methods, and the effects of various retrofit schemes were compared. It was observed that the conventional retrofit methods of increasing member size were somewhat effective in increasing the strength of fixed steel jacket platform structures but were not so effective in increasing ductility. However, the ductility of the structures retrofitted with buckling-restrained braces turned out to be increased significantly. In the structures with conventional bracing, plastic hinges or buckling generally occurred at the upper half of the jacket structures. On the contrary, they were more uniformly distributed along the structure height in the structure retrofitted using buckling restrained braces. The capacity curves obtained from incremental dynamic analysis generally corresponded well with those obtained from nonlinear static analysis using a lateral load pattern proportional to the first mode shape of the jacket structure.

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Section: Introductionmentioning

confidence: 99%

Seismic Performance Evaluation and Retrofit of Fixed Jacket Offshore Platform Structures

El-Din

Kim

2015

J. Perform. Constr. Facil.

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Safety of Oil/Gas Offshore Platforms Designed According to European Provisions under the Action of Pulse-Like Ground Motions

Konstandakopoulou

Pnevmatikos

Papagiannopoulos

et al. 2020

IOP Conf. Ser.: Mater. Sci. Eng.

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Oil and gas offshore platforms are important civil constructions, which are loaded by various types of environmental actions such as wave loads and wind forces. These actions usually govern the platforms’ structural design, while seismic action appears to have minor influence. Nonetheless, numerous offshore structures have been founded in earthquake-prone regions where the structural design can be strongly affected by earthquake action. Many studies have investigated the seismic behaviour of oil and gas offshore platforms examining traditional seismic records. This study investigates the application of simple pulses, i.e., exponential, triangular, rectangular and sinusoidal pulse waveforms, as an earthquake excitation for offshore platforms. To the best of the authors’ knowledge, this is the first time that the aforementioned set of simplified ground motions have been applied to assess the nonlinear seismic behaviour of offshore oil/gas platform. It should be mentioned that pulses could make important information concerning the dynamic response available considering that many intense seismic events enclose actually an acceleration pulse, which can lead to a nonlinear structural response. It is worth noticing that a small number of works have examined the nonlinear response of the platform and most of the previous works assumed fixed boundary conditions ignoring the soil-structure interaction. On the contrary, this study investigates the structural response of 3-D platforms under the action of simplified pulses, considering also the soil-pile-platform interaction. It should be mentioned that the structural design of these special structures fulfils the Eurocode 8 standards. Finally, this work investigates the effect of angle of earthquake waves incidence.

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Seismic Design of Offshore Structures under Simplified Pulse-Like Earthquakes

et al. 2020

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Oil and gas offshore structures are essential infrastructures which are subjected to several categories of environmental loads such as wave and wind actions. These loads commonly designate the structural design of offshore platforms. Additionally, several offshore platforms are founded in earthquake-prone areas and the design of them is intensely affected by seismic ground motions. To be sure, various investigations have studied the earthquake response of offshore structures under the action of far-field seismic events. However, the inelastic behavior of platforms under the action of simple pulses has not been examined yet, where the latter loads can successfully simulate near-fault earthquakes. This work investigates, for the first time to our knowledge, the dynamic inelastic response of offshore platforms subjected to triangular, exponential, sinusoidal, and rectangular pulses. Thus, three-dimensional offshore structures are examined also considering the dynamic soil-pile-platform interaction effects, satisfying all the pertinent provisions of European Codes and taking into account geometric and material nonlinearities as well as the effects of the different angles of incidence of seismic waves on the overall/global response of offshore platforms.

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Extending Life of Fixed Offshore Installations by Integrity Management: A Structural Overview

Cited by 4 publications

References 0 publications

Seismic Performance Evaluation and Retrofit of Fixed Jacket Offshore Platform Structures

Seismic Performance Evaluation and Retrofit of Fixed Jacket Offshore Platform Structures

Safety of Oil/Gas Offshore Platforms Designed According to European Provisions under the Action of Pulse-Like Ground Motions

Seismic Design of Offshore Structures under Simplified Pulse-Like Earthquakes

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