Study of Structural Optimization of a Jacket Platform under Earthquake Loading

Abstract

In this thesis, a study of finite element linear time history analysis (Extreme Level Earthquake, ELE) is performed for a jacket platform located in the Gulf of Suez. The analysis is performed according to the earthquake offshore standard API-2EQ. PEER Ground Motion Database is used for selection and scaling of applied earthquake records. One set of three earthquake components (two horizontal and vertical) of acceleration time history records is considered. Each earthquake component applied in one direction considering gravity, buoyancy and hydrostatic pressure loads. Buckling is not considered in this study. In addition, a study is presented a proposal method of topology optimization of jacket platforms. It is an automated gradually iterative method. The utilized topology optimization is performed under the earthquake loading. This optimization process is utilized in three ways: the first is risk categorization of existing jacket bracing; the second is the generation of topology optimized shape of newly designed platforms; and the third is the retrofitting of existing platforms. Two of these are adopted in this thesis. The third approach is a combination of the other approaches. By implementing the optimization process, weight reduction is achieved compared to the original weight of the existing platform. In addition, success in topology optimization of jacket bracing of existing platform is leading to risk categorization of jacket bracing. Risk categorization of individual members according to their impact on the