| The severe marine environment of the Bohai Bay in winter and the soft structure of the offshore platform make the vibration of the offshore platform structure particularly prominent.Platform vibration not only affects the safety of the structure,but also destroys equipment,affects the normal life and health of staff.` In order to reduce the structural vibration,to meet the requirements of structural safety and normal use,the paper analyzes the dynamic calculation of the new high disaster prevention structure system "offshore platform-rocking column structure system" under ice load,and analysis its ice-resistant performance.To form a set of ice-resistant design method of the rocking column structure system suitable for offshore platform,and validating the design method reasonably.The main research work is as follows:1.On the based of JZ20-2 offshore platform,a novel offshore platform with rocking column has been presented.By comparing the dynamic response of JZ20-2 offshore platform with rocking column subjected to 100-year ice loads.The results show that the displacement and acceleration of platform with rocking column are significantly reduced.In order to model the platform,a general FEM analysis program called ANSYS is adopted to analysis the stiffness ratio of link bars and rocking column.Through the study,we can find that the platform have a good damping effect in a certain stiffness of link bars and rocking column.Considering the effect of ice loads,economy and feasibility,the stiffness ratio of link bars and rocking column are eventually determined,and a set of ice-resistant design method for offshore platform of Bohai Bay is proposed.2.Based on the design method of JZ20-2 offshore platform structure system with rocking column,change the original rigidity of the offshore platform,the corresponding proportionally adjusted rocking column stiffness and ice force size,the dynamic response of the offshore platform with different stiffness under ice force was calculated and analyzed.The results show that the rigidity of the offshore platform is too small or too large,and the vibration effect of the structural system is not obvious,and even the dynamic response is increased.3.Taking the JZ20-2MUQ platform offshore in Bohai Bay as an example to verify the effectiveness of the above ice-resistant design method.That is designed with the above design method for JZ20-2MUQ platform rocking column and connecting bars stiffness,and the dynamic response calculation under ice force load is carried out to analyze the damping effect and prove the validity of the design method.The dynamic calculation of the new rocking structure with two different platforms under seismic load is carried out,and analyze its seismic performance,to proved that the ice-resistant design method is also applicable to seismic loads,and to proved the applicability of the above ice-resistant design method more fully.4.Integrated marine environment and other external factors,in this paper,a new structure system of offshore platform with rocking column is optimized specific: Since the above analysis only considers the main direction of the ice force,in order to reduce the impact of lateral ice force,the optimization of the hinge points of the rocking column and the foundation is carried out,so that the rocking column can not only limit the rotation,but also can resist lateral ice force.Considering the corrosion of the sea,taking the floating box on the rocking column can effectively reduce the rocking column buoyancy,the floating box connection to optimize the analysis to ensure reliable connection of the floating box and the sea construction convenience.The rocking column will also be affected by the ice force,which will seriously affect the structural safety.So the skin effect of electric heating technology will be applied to the rocking column ice melting method,in order to achieve real-time control rocking column and the sea interface temperature.To ensure that the rocking column does not freeze or timely melting ice,reduce structural vibration,and protect structural safety. |
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