The Effectiveness Of Liquid Damper Controlling The Dynamic Responses Of The Jacket Type Platforms

Offshore fixed metal platforms have unique characteristics. In specific location such as shallow waters, oil platform may be physically connected to seabed. The most important advantage of such platforms is their stability. Considering their connection to seabed, effective wind and water forces cause very small displacement in platforms. Quays and offshore platforms in the sea are affected by complicated and destructive forces of wind, waves, ocean currents, earthquake, and even forces resulted from vortices. These forces cause large displacements in platforms or quays, imposing negative effect on safety and serviceability of marine structures, in terms of exploitation. Through such approach, analyzing sea hydrodynamic parameters, and rocking motion of metal platform under torque of irregular JONSWAP wave have been aimed at, in addition to numerical analysis of tuned liquid damper (TLD) performance in dynamic responses’ control of offshore jacket platforms, and damping fixed platform’s vibration with consideration of dynamic interaction of waves and structure. The results show performance of liquid separator on offshore fixed platforms to reduce vibration effects resulted from waves and other dynamic forces on upper structure of platform. The damper formed by one or more fluid (usually water) tanks could be installed on platform deck. Hydrodynamic forces created by water turbulence within tank(s) help structural response control, as resistant forces against vibration. Also, using dampers may be considered as an effective method of confronting environmental forces in the sea. These dampers make considerable increase in energy dissipation capability, with no considerable increase in the system hardness. In seismic rehabilitation of structures, using dampers is considered as one of the methods to reduce lateral forces resulted from wind and earthquake.

Keywords:

Offshore fixed metal platforms , of tuned liquid damper , JONSWAP , AQWA , fluid turbulence