A two-dimensional finite element program for the non-linear dynamic analysis of offshore jack-up units under storm loading is described. The program aims to incorporate consistent and reasonable levels of approximation of all the major system parameters; this is in contrast to many previous approaches, which have tended to model some aspects of the problem in great detail while adopting a very simplified approach to others. Accurate modelling of the jack-up legs is achieved using an Eulerian formulation of beam-column theory. The complex non-linear behaviour of the spudcan footings is represented by a recently developed work-hardening plasticity model, which represents a considerable advance over the simple pinned footing assumption which is most frequently used for jack-up analysis. Several options for calculating wave kinematics are available, including Stokes' fifth order wave theory. The resulting non-linear equations are solved in the time domain using implicit integration algorithms. Results for some representative test cases are presented. (C) 1998 Elsevier Science Ltd. All rights reserved. References: 15
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