Numerical Study of the Floating Gravity Base Structure Mooring

Movable floating types of structures are good alternative to onshore structures for construction in remote areas. A mooring system of these structures should be safe under joint loads from waves, current and wind. An example of a mooring system analysis using the software ANSYS-AQWA is presented in this study. Dynamic analysis of a floating object with six degree of freedoms in the time domain was carried out on the case study of a gravity base structure moored to a berth in the Kola Bay, Russia. Motions of the floating object and mooring cables tension are to be identified for two different mooring systems with different position and materials of mooring lines under wind, regular waves (with four periods) and current conditions. Motions of the floating object and cables tensions are increased following the increase in the wave period. Polyester cables showed better ability in tension utilization in comparison with wire ropes. One of the considered mooring systems was preferred based on the conducted study. Results of presented numerical modelling can be used to provide the necessary level of safety by mooring system designing.