Reliability analysis of offshore structures under wave load

• Main Author: Yee, Sidney Ziliang.
• Other Authors: Liu Yu
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Civil engineering::Water resources
• Online Access: http://hdl.handle.net/10356/16022
• Institution: Nanyang Technological University

Offshore structures, in particular fixed platforms form the backbone of the offshore industry, with over 7000 such structures dotted about the oceans of the world. The traditional offshore installation utilizes a welded steel tubular framework (jacket) to support the topside, which provides a stable platform for drilling/processing operations. As the oilfields closer to shore have been depleted over the years, there is a need for exploration and exploitation of further and deeper oilfields. The increased depth and exposure to harsher environmental conditions provides new challenges for engineers and designers, who have to ensure minimal disruptions to operations, and above all safety of workers. Therefore, there is a need for rigorous structural and reliability analyses to be carried out. In this report, the objective of the final year project will be stated. This project is a continuation of a previous final year project: ST-54-AB RELIABILITY ANALYSIS OF OFFSHORE STRUCTURES UNDER WAVE LOAD, whereby static wave loads were applied on the structure by the past students. However, it might not be appropriate to do so as wave loading is dynamic in nature. Therefore in this project we will be carrying out dynamic analysis on the same model to compare the results. Reliability analysis using stochastic methods, in particular the Monte Carlo simulation method, will also be discussed at length. Computer-aided design software such as GTSTRUDL and GTSELSOS, which are used widely in the offshore industry, are utilized for the purpose of this project. MATLAB will be employed to perform the Monte Carlo simulation. The results from the structural and reliability analyses will be presented at the end, with discussions and recommendations for amendments to design (if any).