Loading...

Time-variant Reliability Analysis of Offshorre Structure Subject to Multiple Hazards

Faraji, Iman | 2015

684 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47931 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Golafshani, Ali Akbar; Mahsuli, Mojtaba
  7. Abstract:
  8. The main purpose in this study is the determination of offshore structures reliability index over time by considering the simultaneous effects of natural hazards. Importance of this study stems from the effect of events associated with time which induces high amount of uncertainties on offshore structures performance during their life time. Extreme wave, marine current, earthquake, fatigue, corrosion and marine growth hazards are considered in this paper. The intensity and occurrence time of all hazards are time dependent parameter. In addition some of these hazards have the possibility to coincidence and the interaction effect. Whereas, the previous studies in this field, the effect of each these phenomena has been considered separately and time-independent. In contrast, in this paper, a probability method based on reliability analysis for offshore structure assessment is presented. In this framework, a library of probabilistic models is used for predicting hazards intensity and structural demand under those hazards. Uncertainties in these models are described with random variables that are model input. The structural failure are determined with a system of limit states. A variety of structural failure modes and the relation between each other are shown in this system. Finally, the reliability index of the offshore structure calculated over time based on scenario sampling method which is extended based on Monte Carlo sampling. As a case study, this method is applied to SPD2 platform designed for Persian Gulf region and the reliability variation of this platform is calculated over 50 years interval. These results give a fundamental information for riskbase and rational decision-making process in such cases as, extending the operation life and the need of inspection or retrofit plan. These results could also be used for determining the performance level of structures
  9. Keywords:
  10. Offshore Structures ; Probability Model ; Monte Carlo Method ; Time-variant Reliability ; Scenario Sampling ; Multi-hazards

 Digital Object List

 Bookmark

No TOC