Global jack-up rig behaviour next to a footprint

M. J. Jun, Y. H. Kim, M. S. Hossain, M. J. Cassidy, Y. Hu, S. G. Park

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

This paper reports the effect of the global behaviour of three-legged jack-up rigs due to the reinstallation of spudcan footings next to seabed footprints. Two reinstallation scenarios are discussed: (i) two legs first installed on flat ground, and then the third leg installed near a footprint (representing what is known as leg-by-leg preloading); and (ii) the three legs installed simultaneously (representing simultaneous preloading). The spudcan-soil interaction was simulated using a coupled Eulerian-Lagrangian (CEL) approach. A simplified global jack-up model was developed by considering an equivalent beam model for the hull and legs. The results of the jack-up installations are compared against the responses of the more common modelling of a spudcan with a fixed head condition. A detailed parametric study assessing the consequences of spudcan-footprint interactions, such as the risk of the jack-up and spudcan sliding towards the footprint centre, overturning of the jack-up rig and of structural failure of the jack-up leg due to excessive stresses, is also discussed. The ability of a recently developed novel spudcan with a flat base and 4 holes, coupled with the global jack-up model, to mitigate the consequences of spudcan-footprint interactions is highlighted.

Original languageEnglish
Pages (from-to)421-441
Number of pages21
JournalMarine Structures
Volume64
Early online date28 Dec 2018
DOIs
Publication statusPublished - 1 Mar 2019

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