The Vibration of Fixed Offshore Structures under Ice Action

Abstract

Abstract Ice induced vibration of fixed offshore structures has been observed in different seas, for example: Beaufort Sea, Cook Inlet, Gulf of Bothnia, Bohai Bay, Sea of Okhotsk. It can have a significant impact, as it may lead to failure due to structural fatigue (Bohai Bay) or softening of foundations, or cause problems with the serviceability of platforms. Possible future arctic developments will be in deeper water, where the phenomenon of ice induced vibration may be one factor limiting the maximum water depths for the economic use of fixed (bottom-founded) structures. Therefore it is important to be able to predict the responses of structures of different shapes and sizes to the ice conditions specific to the region of interest, in order to optimize development options. A 2D solution for the numerical study of ice induced vibration of vertical-sided fixed offshore structures based upon common assumptions and mathematical models of ice properties has been developed by St. Petersburg State Polytechnical University and BP. The solution considers the whole process of vibration as it develops in time: successive ice failure, structural response and mutual ice/structure interaction. The model has been applied in order to understand the environmental conditions and structural characteristics that are important to the incidence of ice induced vibrations. Ice induced vibration of fixed offshore structures has been observed in different seas, for example: Beaufort Sea, Cook Inlet, Gulf of Bothnia, Bohai Bay, Sea of Okhotsk. It can have a significant impact, as it may lead to failure due to structural fatigue (Bohai Bay) or softening of foundations, or cause problems with the serviceability of platforms. Possible future arctic developments will be in deeper water, where the phenomenon of ice induced vibration may be one factor limiting the maximum water depths for the economic use of fixed (bottom-founded) structures. Therefore it is important to be able to predict the responses of structures of different shapes and sizes to the ice conditions specific to the region of interest, in order to optimize development options. A 2D solution for the numerical study of ice induced vibration of vertical-sided fixed offshore structures based upon common assumptions and mathematical models of ice properties has been developed by St. Petersburg State Polytechnical University and BP. The solution considers the whole process of vibration as it develops in time: successive ice failure, structural response and mutual ice/structure interaction. The model has been applied in order to understand the environmental conditions and structural characteristics that are important to the incidence of ice induced vibrations.