Dynamic response assessment of an offshore jacket platform with semi-active fuzzy-based controller: A case study

Abstract

The present study investigates the dynamic responses of offshore jacket platforms using a passive and semi-active tuned mass damper (TMD, SATMD), where the control action is achieved by a fuzzy logic controller (FLC) under environmental (i.e., wind, water waves, sea currents) and seismic loadings. Since the studied structure failed to meet recent codes requirements adequately, the suppressing effect of a SATMD is considered as a way to retrofit structural performances under hydrodynamic loadings. After extraction of the dynamic properties of the jacket-type structure, simulations of an installation system with and without a TMD have been performed, and the effectiveness of TMD is quantified.In order to exploit the potential of the structure to overcome all types of excitations, the SATMD comes complete with a fuzzy-algorithm-controller, acknowledging that the use of a passive TMD is only a preliminary attempt to reduce the structure's dynamic responses. Comparison of the results indicates a significant response value reduction in acceleration, base shear, overturning moment, velocity and lateral displacement of a case study of steel jacket platforms.