Evaluating Dynamic Response of Jack-up Platform in Granular Soil

In order to model real behavior of jackup platforms subjected to environmental conditions, a nonlinear dynamic analysis considering soil-structure interaction subject to wave loading is investigated. For this purpose, spudcans behavior, soil nolinear behavior near the structure, contact phenomena at the interface of the soil and foundation such as gapping as well as geometrical nonlinear behavior of the structure are considered. The soil which is used in this study is assumed to be granular with varying friction angles. Beam on Nonlinear Winkler Foundation method (BNWF) is a suitable model for soil media modeling. For wave loading two methods were used, monochrome wave and irregular waves representing a sea state. Results of this study show that inelastic behavior of the soil causes an increase in displacement at hull elevation and permanent unequal settlement in soil below the foundations which is increased by decreasing friction angle of soil. In fact spudcans and the underlying soil cause a relative fixity at support of the platform which changes dynamic response of structure compared to the case where the structure is assumed to have a fixed support.