Dynamic Analysis of Offshore Structure with the effect of soil structure interaction

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  Anis Mohamed Ali   |      Mohammed J K Essa   |      Samoel M Saleh   |   

In the present study, the dynamic analysis of jacket type offshore structure under the action of sea wave is carried out. The finite element method is adopted for the solution of the problem. The effect of soil-structure interaction on the dynamic behaviour of the offshore structure is taken into account due to the deformation of the soil caused by the motion of the structure, which in turn modify the response of the structure. The supporting elastic foundation is represented by Winkler type model having normal and tangential module of sub-grade reaction. These modules may be constant or vary linearly or non-linearly along embedded length of the pile that support the offshore structure. the pile tip condition also considered. A time domain solution is recommended. The generalised Morison's equation is used to calculate the wave force and Aliys linear theory to describe the flow characteristics. Both free and forced vibration analysis are studied. The dynamic response have been obtained by model analysis in conjunction with Wilson method. As an example, a modified model of an actual jacket type offshore platform is analysed under the action of sea wave.