Vibration Control of Offshore Platforms Using the Mega-Frame Theory

The successful use of mega-frame theory for big buildings on the ground to control the vibration reminds us to investigate a new kind of platform using the theory. The concept platform is made up of major columns and major beams. The major columns stand vertical and horizontal load. The major beams endure the horizontal load and averagely transfer the weight of the platform to the columns. The static analysis, mode analysis and simulation of vibration control are performed for the concept platform and other three types of platforms for comparisons. It is concluded that the concept platform is feasible in functionality since the platform has high holistic intensity and can avoid the partial breakage because of the columns of the MFPs being more equal burden under static loadings as compared with other kinds of platforms. It can also avoid the big distortion under the severe external loadings because of the MFPs having the equal mass and stiffness distribution. And the displacement of MFPs is very small under the randomexternal loadings. Furthermore, the MFPs will have similar structures and suitable for blocking manufacturing.