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http://dx.doi.org/10.5000/EESK.2014.18.6.279

Analysis of Earthquake Responses of a Floating Offshore Structure Subjected to a Vertical Ground Motion  

Lee, Jin Ho (Korea Railroad Research Institute, Maglev Train Research Team)
Kim, Jae Kwan (Seoul National University, Department Civil and Environmental Engineering)
Jin, Byeong Moo (Daewoo E&C, Institute of Construction Technology, Civil Engineering Research Team)
Publication Information
Journal of the Earthquake Engineering Society of Korea / v.18, no.6, 2014 , pp. 279-289 More about this Journal
Abstract
Considering a rigorously fluid-structure interaction, a method for an earthquake response analysis of a floating offshore structure subjected to vertical ground motion from a seaquake is developed. Mass, damping, stiffness, and hydrostatic stiffness matrices of the floating offshore structure are obtained from a finite-element model. The sea water is assumed to be a compressible, nonviscous, ideal fluid. Hydrodynamic pressure, which is applied to the structure, from the sea water is assessed using its finite elements and transmitting boundary. Considering the fluid-structure interaction, added mass and force from the hydrodynamic pressure is obtained, which will be combined with the numerical model for the structure. Hydrodynamic pressure in a free field subjected to vertical ground motion and due to harmonic vibration of a floating massless rigid circular plate are calculated and compared with analytical solutions for verification. Using the developed method, the earthquake responses of a floating offshore structure subjected to a vertical ground motion from the seaquake is obtained. It is concluded that the earthquake responses of a floating offshore structure to vertical ground motion is severely influenced by the compressibility of sea water.
Keywords
Floating offshore structure; Floating offshore wind turbine; Fluid-structure interaction; Compressible fluid; Seaquake; Vertical ground motion;
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  • Reference
1 Gerwick BC, Jr. Construction of Marine and Offshore Structures. 3rd ed. CRC Press; c2007.
2 Chopra AK. Earthquake Response Analysis of Concrete Dams. Advanced Dam Engineering for Design, Construction and Rehabilitation. Springer; c1988. p. 416-465.
3 Fenves G, Chopra AK. Effects of Reservoir Bottom Absorption on Earthquake Response of Concrete Gravity Dams. Earthquake Engineering and Structural Dynamics. 1983; 11(6): 809-829.   DOI
4 Fenves G, Chopra AK. Effects of Reservoir Bottom Absorption and Dam-Water-Foundation Rock Interaction on Frequency Response Functions for Concrete Gravity Dams. Earthquake Engineering and Structural Dynamics. 1985; 13(1): 13-31.   DOI
5 Cook RD, Malkus DS, Plesha ME, Witt RJ. Concepts and Applications of Finite Element Analysis. 4th ed. John Wiley & Sons Inc.; c2002.
6 Riggs HR. Comparison of Formulations for the Hydrostatic Stiffness of Flexible Structures. Journal of Offshore Mechanics and Arctic Engineering. 2009; 131(2).
7 Fung YC. A First Course in Continuum Mechanics. 3rd ed. Prentice Hall; c1994.
8 Malvern LE. Introduction to the Mechanics of a Continuous Medium. Prentice Hall; c1969.
9 Jonkman J, Butterfield S, Musial W, Scott, G. Definition of a 5-MW Reference Wind Turbine for Offshore System Development. NREL/ TP-500-38060. National Renewable Energy Laboratory; c2009.
10 Bir G, Jonkman J. Modal Dynamics of Large Wind Turbines with Different Support Structures. NREL/CP-500-43045. National Renewable Energy Laboratory; c2008.