Design Research On Adding Cone To Mitigate Ice-induced Vibration For Ice-resistant Platform

There are many marginal fields spreading in Bohai sea. In order to saving cost, people usually chose economical jacket platform whose structure is relatively simple to develop these oil fields. Moreover, the ice-induced vibration of platforms is very serious because these oil fields are located in the ice-infested sea. To solve this kind of problem, ice breaking cones have been added on the leg of platforms at tidal zone and achieved good result.While, the design of cones being used at present is mostly depended on the designer’s experience rather than some standard, which lead to some problems during the period of use. Based on the research result of numerous domestic and overseas scholars, this paper summarizes the design flow of ice-breaking cone——conceptual design, primary design and detailed design and contents of each section. In addition, author analyses and evaluates the ice resistance effect of some representative cones installed on the leg of platforms and summarizes the design defect which will provide instruction and valuable experience for cone design.With the further deepening of the oil field development in Bohai sea, some new engineering problems caused by ice load have been found on some accessory to jacket platforms. The reason of these accidents is that these structures are nearly not protected by ice breaking cone. Concerning this kind of problem, author design a protecting cone for accessory structures using the cone design criteria. The difference between protecting cone and traditional ice-breaking cone in each design stage (conceptual design, primary design and detailed design) will be expounded in this paper which includes the design criteria and difficulties. Besides, the global strength of the protecting cone and the original cone also has been checked. Finally, the impact of the structure of the platform due to the protecting cone’s installation is analyzed based on the data obtained by field monitoring on the platform and the results shows that there is little change of the mechanical property of the platform. The protecting cone put forward in this paper has been used on some platforms in Bohai sea and worked just fine which provides thought and solutionto protect the accessory structures on the platforms from ice load.