DefinePK

Abstract

Offshore structures are different than onshore structures in several sense. Very importantly they differ in Natural frequency and Mass distribution. Natural frequency of onshore structures is much higher than offshore structures. Generally, onshore structures have distributed mass, while offshore structure has the mass concentrated on the top of the platform. Such offshore structures are prone to extreme environmental conditions. Under extreme environmental conditions, offshore structures are vulnerable to damages because of higher response. Structural workability conditions get affected due to damage. Hence the vibratory behaviour needs to be tackled with available damping techniques. Among the available techniques Semi-active control insures that structure should not exceed the response limit for a wider frequency range. This can be achieved by properly modeling the control parameters. Efficiently chosen parameter guaranties the minimization of responses for all types of environmental forces. In this study a 50 mts offshore structure is considered. Linear control of the structure has been modeled for the earthquake force. The structure is subjected to El-Centro earthquake force. The response of the structure was well controlled by the Linear Quadratic Regulator (LQR) Methodology.