Study On The Vibration Resistant Design Of Pipeline System On The Offshore Platforms In Ice Zone

The sea ice is the dominant environmental force for the offshore structures in the Bohai Bay. In the present design the maximum bearing capacity under the limited ice load is considered, but the effect of structures and facilities induced by dynamic ice force are neglected. Based on full-scale tests of the offshore structures in Bohai Bay, it is found that sea ice can induce the periodic load and make the offshore jacket structures vibrate with major acceleration. For the jacket platforms used to produce natural gas, there are complicated natural gas pipelines. Ice-induced vibrations could lead to the associated accidents of pipelines on the platform, such as fatigue fracture of pipe and looseness of flanges, which makes all kinds of economy losses for the platform.In this paper, the failure problem of the pipeline systems on the platform is researched by spot test, monitor, and numerical simulation. It is pointed out the major criterion of the failure mode and this kind of failure mode is inevitable. In order to improve the condition the pipeline ice-resistant rank should be enhanced. In this paper, the dynamic response of pipeline systems under the ice-induced vibration is analyzed, and it is found that the ice-induced vibration effects pipeline acutely. So it is necessary to consider the effects on pipeline induced by dynamic force during the design. Finally giving an example, for the pipeline systems of the JZ20-2 platform which is service and the ones of the JZ21-1WHPA platform which is about to go into production in Bohai Bay, author analyzes the effects on it induced by dynamic ice force, points out the methods of reducing vibration by improving braces, and develops the pipeline systems design on offshore platforms, which will be helpful to pipeline systems on the new ice-resistant platforms.