Sensitivity of jack-up reliability to wave-in-deck calculation

This document represents a study undertaken by MSL Engineering Limited for the Health and Safety Executive (HSE) to determine the effects of air gap erosion and subsequent hull inundation on a typical Jack-Up structure. A wave-in-deck loading model was developed (" The MSL Model ") and a sensitivity study was performed to assess the important factors affecting the loads generated during inundation. In addition, a typical Jack-Up structure was modelled using the USFOS structural analysis package in order to determine the dynamic response of a Jack-Up to storm loading where inundation occurs. The effects of response to previous waves, foundation modelling complexity and hull inundation levels were assessed by performing a number of short duration time-domain analyses. This report and the work it describes were funded by the HSE. Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the prior written permission of the copyright owner. ii FOREWORD This document represents a study undertaken by MSL Engineering Limited for the Health and Safety Executive to determine the effects of air gap erosion and subsequent hull inundation on a typical Jack-Up structure. A wave-in-deck loading model was developed (" The MSL Model ") and a sensitivity study was performed to assess the important factors affecting the loads generated during inundation. In addition, a typical Jack-Up structure was modelled using the USFOS structural analysis package in order to determine the dynamic response of a Jack-Up to storm loading where inundation occurs. The effects of response to previous waves, foundation modelling complexity and hull inundation levels were assessed by performing a number of short duration time-domain analyses.