Mitigating ice-induced jacket platform vibrations utilizing a TMD system

Field observations conducted on oil platforms in the Bohai Sea revealed that the offshore jacket structures, which can withstand the maximum static ice force, might suffer from severe vibrations when ice sheets pass through the legs of the structure. It has been proved that, when the natural frequency of narrow or flexible structures is close to or coincides with the predominant frequency of cyclical ice forces, severe ice-induced vibrations will be evoked. Excessive and consistent vibration will cause the discomfort of working crew, failure of deck facilities even structural fatigue failure. Therefore, it is imperative to seek economical ways to reduce the vibrations to an acceptable level. Based on full-scale tests and technical feasibility, the strategies of vibration mitigation are investigated and compared in this paper. The primary studies demonstrate that adding a Tuned Mass Damper (TMD, also called a Dynamic Vibration Absorber, DVA) is a feasible and practical approach to reduce vibrations. The efficiency of optimally designed TMD and one-directional conceptual TMD device has been presented in this study. Field ice load time history was used as loading scenario to assess the performance of TMD system. The results show that the supplemental device can favorably reduce the dynamic response of platform.

[1]  Qiusheng Li,et al.  Vibration control of steel jacket offshore platform structures with damping isolation systems , 2007 .

[2]  Jizu Xu,et al.  TLD Technique for Reducing Ice-Induced Vibration on Platforms , 1999 .

[3]  Luís Sousa,et al.  Optimal cross-section and configuration design of cyclic loaded elastic-plastic structures , 1996 .

[4]  Toshio Ueda,et al.  Suppression of wind-induced vibration by dynamic dampers in tower-like structures , 1992 .

[5]  K. A. Blenkarn,et al.  Measurement and Analysis of Ice Forces on Cook Inlet Structures , 1970 .

[6]  Garry Timco,et al.  Ice loading on Danish wind turbines: Part 2. Analyses of dynamic model test results , 2005 .

[7]  Q J Yue,et al.  Random Ice Forces on Conical Structures , 2003 .

[8]  C J Montgomery,et al.  Dynamic response of bridge piers to ice forces , 1980 .

[9]  Garry Timco,et al.  Ice loading on Danish wind turbines: Part 1: Dynamic model tests , 2005 .

[10]  T. T. Soong,et al.  Passive Energy Dissipation Systems in Structural Engineering , 1997 .

[11]  Robert Frederking,et al.  Model tests of ice forces on fixed and oscillating cones , 1982 .

[12]  James T. P. Yao,et al.  CONCEPT OF STRUCTURAL CONTROL , 1972 .

[13]  Tuomo Karna.  Mitigation of steady-state vibrations induced by ice , 1994 .

[14]  Qianjin Yue,et al.  ICE-INDUCED JACKET STRUCTURE VIBRATIONS IN BOHAI SEA , 2000 .

[15]  R. S. Jangid,et al.  Passive control of offshore jacket platforms , 2005 .

[16]  Bijan Samali,et al.  Performance of tuned mass dampers under wind loads , 1995 .

[17]  Q. Yue,et al.  Ice Problems in Bohai Sea Oil Exploitation , 2003 .

[18]  Mohamed Abdel-Rohman,et al.  Structural control of a steel jacket platform , 1996 .