Stochastic responses of three-dimensional offshore platforms

Article type: Research Article

Authors: Chen, Yung-Hsiang

Affiliations: Department of Civil Engineering and Department of Naval Architecture, National Taiwan University, Taipei, Taiwan, Republic of China

Abstract: A general study of the stochastic analysis of three-dimensional offshore platforms subjected to earthquake and sea waves is presented in this paper. The entire offshore platform with pile foundation is mathematically modeled by two separated subsystems; one is the main-structure subsystem, and the other is the foundation subsystem. Pile-soil, foundation-structure, and fluid-structure interactions will be included in analysis. The main-structure subsystem can be idealized as a three-dimensional space frame with the lumped parameter system. The pile-foundation subsystem will be replaced by foundation springs and dashpots supporting the main structure in order to simplify this problem. The dynamic properties of such foundation mechanism are generally frequency dependent and can be determined by using impedance-function technique. As a result the dynamic characteristics of the offshore platform are frequency dependent. The coupling and nonlinear effects of damping term will also be taken into account in analysis. It can be shown that the stochastic analysis will become much more simple and efficient when the concept of generalized complex damping is applied.

DOI: 10.3233/ISP-1980-2731503

Journal: International Shipbuilding Progress, vol. 27, no. 315, pp. 294-304, 1980