Effect of Soil Structure Interaction Analysis on the Response of Fixed Offshore Jacket Structure

Abstract

Offshore jacket platforms are being extensively used for the exploration of oil and natural gas. Nowadays these structures are being suggested for supporting offshore wind turbines. The jacket structures are fixed to sea bed using piles. These piles penetrate into the soil and transfers structural loads to the soil. The soil structure interaction of the piles should be studied for the safety of the structure. In the present study, the soil structure interaction (SSI) of the jacket structure is studied by developing a MATLAB code and performed static analysis using stiffness method. Structural elements are modeled using three dimensional beam elements. The modulus of sub-grade reaction of the surrounding soil is estimated using Vesic equation. The spring stiffness of the surrounding soil along the length of the piles of the jacket is estimated using Newmark distribution. Wave force on the structural elements of the jacket structures is estimated using Morison’s equation. The deflection of the topside and at the sea bed is presented in this paper. The effect of the marine growth on the static and dynamic response is also studied and concluded that the response of the structure and the natural period of the structure are increased when the marine growth is present.