Within the scope of this thesis, a reliability based risk assessment, based on Monte Carlo simulation was used to analyse the safety levels of Esenk&ouml / y Fishery Harbor main breakwater, Sea of Marmara, Turkey. In the past, in reliability-based risk assessment methodology in Turkey, the design conditions were only wave characteristics, tidal range, storm surge, wave set-up and the structural system parameters. However in this study, the tsunami risk which was considered as a major design parameter is included in the computations. In this study, development of a structural stability criterion in coastal engineering was suggested to achieve a common definition of reliability including the tsunami risk. The model introduced in this study is a practical technique in the reliability-based risk assessment of breakwaters subject to tsunami risk. In order to determine the occurrence probability of design condition, which is a function of storm waves, tidal range, storm surge and tsunami height, the Monte Carlo simulation, was applied. From the reliability-based risk assessment model applied to Esenk&ouml / y Fishery Harbor as a pilot study in Turkey it was found that, inclusion of the tsunami risk increases the failure risk of the structure, and as lifetime of the structure increases, the impact of tsunami risk on the failure mechanism is more reflected. For Esenk&ouml / y Fishery Harbor main breakwater, tsunami was not the key design parameter when compared to storm waves. However, in regions with great seismic activity, tsunami risk may be very noteworthy depending on the frequency and the magnitude of the tsunami.

Orientador: Celso Kazuyuki Morooka / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-16T19:35:21Z (GMT). No. of bitstreams: 1 Stefane_Wania_M.pdf: 1299302 bytes, checksum: 5e10da42a4a2b40651a938ac99f33efb (MD5) Previous issue date: 2010 / Resumo: O presente trabalho propõe um procedimento para calcular a probabilidade de falha por fadiga em um SCR (Steel Catenary Riser), identificando os principais parâmetros e avaliando a influência destes na probabilidade desse tipo de falha. São consideradas nesse procedimento as condições oceanográficas, tais como esforços de ondas, correntezas e movimentos da plataforma, e as incertezas presentes no dano acumulado total à fadiga ¿ dado pela regra de Miner-Palmgren. A metodologia adotada é probabilística e se baseia no Método de Confiabilidade de Primeira Ordem (FORM). Uma função de falha para o SCR é definida considerando-se a resistência e os carregamentos aplicados no riser, a aleatoriedade das condições oceanográficas e as características mecânicas do SCR. Neste trabalho, o procedimento proposto foi implementado em um programa comercial e aplicado para um caso reportado na literatura e para outro caso, considerando dados obtidos via Petrobras, de um campo marítimo brasileiro em operação. Os resultados de probabilidade de falha por fadiga, bem como de vida útil, são discutidos e avaliados para diferentes localizações ao longo do comprimento do SCR. Estes resultados mostraram-se bons quando comparados com os resultados encontrados na literatura. Através destes resultados verificou-se a sensibilidade da probabilidade de falha por fadiga para os principais parâmetros, sendo o parâmetro m da curva S-N o mais influente. / Abstract: The current work presents a procedure to evaluate the probability of fatigue failure for an offshore Steel Catenary Riser (SCR), through identification and assessment of the influence of the main parameters involved in the probability of failure due to fatigue mechanism. Ocean conditions such as waves, currents and platform motions, as well as uncertainties due to total cumulative damage given by Miner-Palmgren¿s rule, are considered in this procedure. A probabilistic methodology is adopted, which is based on the First Order Reliability Method (FORM). A failure function for the SCR is defined considering the structural strength and the loads acting on the riser, as well as the random nature of ocean conditions and mechanical properties of the SCR. The suggested procedure was implemented and applied for two practical cases. The first case uses data from literature and the second one considers data from a typical Brazilian offshore operation field by Petrobras. In the calculations, results for the probability of failure are, as well as the riser service life, discussed and assessed at different locations along the SCR length. Good results were obtained from the analysis as they are comparable and very close to the results observed in literature. From those results, the sensitivity of the probability of failure due to fatigue for a SCR could be verified. It could also be observed that the m parameter from SN curve has shown to be the most effective parameter. / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo