Investigation of offshore wind turbine structure behavior under seismic loads

Abstract

The main purpose of this thesis is to perform the soil-structure interaction analysis using the three-dimensional finite element analysis where the comparison between the finite element results for homogeneous soils including clay and sand are achieved This study uses SHAKE91 analysis software to transfer seismic accelerations which measured from the top of soil and then applies the seismic load in the finite element analysis The seismic load is the acceleration histories in different soil medium which simulated by SHAKE91 and the finite element software performs the integration of these accelerations to displacements for the dynamic analysis There are two kinds of soil behaviors which are discussed for simulating the interaction behavior in the thesis From the analyses in the study the influences of the offshore upper structure behavior caused by the different materials of the soil behavior will be specified Finally we will get member forces in the finite element analysis In the finite element model beam elements are used to simulate the superstructure and piles while p-y t-z and Q-z elements are used to simulate the soil behavior This thesis then validates the results of these soil elements with the theoretical results This thesis also contains the steel design procedures according to the code of the American Petroleum Engineering Institute (API) load resistance factor design (LRFD) The steel design includes tension compression bending shear hydrostatic and combined-loading members The validations of above members are achieved in this study and all the design procedures are highly accurate

Date of Award	2016 Aug 15
Original language	English
Supervisor	Shen-Haw Ju (Supervisor)