ISO INTERNATIONAL STANDARD 19905-1 Third edition 2023-10 Oil and gas industries including lower carbon energy Site-specific assessment of mobile offshore units Part 1: Jack-ups: elevated at a site Industries du pétrole et du gaz, y compris les énergies a faible teneur en carbone-Evaluation spécifique du site d'unités mobiles en mer Partie 1: Plateformes auto-eélévatrices : Surélévées sur un site Reference number IS0 19905-1:2023(E) os1 @ IS0 2023 IS0 19905-1:2023(E) COPYRIGHT PROTECTED DOCUMENT @IS02023 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either Iso at the address below or ISo's.member body in the country of the requester. IsO copyright office CP 401 · Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +4122 749 0111 Email: [email protected] Website: www.iso.org Published in Switzerland ii @IS0 2023 - All rights reserved IS0 19905-1:2023(E) @ Contents Page Foreword. viii Introduction xi 1 Scope. 2 Normative references... 3 4 Symbols and abbreviated terms ... .15 4.1 4.1.1 General..... 15 4.1.2 Symbols used in A.6... 17 4.1.3 19 4.1.4 Symbols used in A.8... 21 4.1.5 Symbols used in A.9 and Annex E.. 4.1.6 Symbols used in A.10 25 4.1.7 Symbols used in A.11 26 4.1.8 Symbols used in A.12 .. 4.2 Abbreviated terms... 5 Overall considerations.. 32 5.1 General. 5.1.2 Competency.... 5.1.3 Planning.... 33 5.1.4 Assessment situationsandassociatedcriteria 5.1.5 5.1.6 Regulations... 33 5.1.7 Classification of unit..... ..34 5.2 5.3 Selection of assessment situations ... 5.4 Determination of assessment situations 37 5.4.1 37 5.4.2 Reaction point and foundation fixity... 5.4.3 Extreme storm event approach angle. 37 5.4.4 Weights and centre of gravity.... 5.4.5 Hull elevation .. 37 5.4.6 Leg length reserve.. 38 5.4.7 Adjacent structures... 5.4.8 Other.... 38 5.5 Exposure levels.. .38 5.5.1 5.5.2 Exposure level L1. .38 5.5.3 Exposure level L2 .. 38 5.5.4 Exposure level L3 ... 5.5.5 Exposure level for earthquake... 39 5.6 Analytical tools ... 39 6 Data to assemble for each site .. .39 6.1 Applicability... 39 6.2 Jack-up data... 6.3 Site and operational data .. 40 6.4 Metocean data ... .40 IS0 2023 - All right reserved ii IS0 19905-1:2023(E) 6.5 Geophysical and geotechnical data. .41 6.6 Earthquake data.. 6.7 Ice data.. .42 7 7.1 7.2 General, 42 7.3 Metocean actions ... .43 7.3.1 .43 7.3.2 Hydrodynamic model.. 43 7.3.3 Wave and current actions... 7.3.4 7.4 Functional actions ... .44 7.5 Displacement dependent effects.... .44 7.6 7.7 Earthquakes... .44 7.8 Ice actions. .44 7.9 8 Structural modelling .. .44 8.1 8.2 Overall considerations.... 45 8.2.1 Genera.. ..45 8.2.2 8.2.3 Levels of FE modelling .. 45 8.3 Modelling the leg... .46 8.3.1 8.3.2 Detailed leg ... .46 8.3.3 Equivalent leg (stick model)... .46 8.3.4 Combination of detailed and equivalent leg .... 8.3.5 Stiffness adjustment.... .46 8.3.6 Leg inclination ... 46 8.4 8.4.1 8.4.2 Detailed hull model.. .46 8.4.3 Equivalent hull model.. ..46 8.5 Modelling the leg-to-hull connection ... 47 8.5.1 General. 47 8.5.2 Guide systems. 47 8.5.3 47 8.5.4 Fixation system ... 8.5.5 Shock pad-floating jacking systems... 8.5.6 8.6 Modelling the spudcan and foundation ....... 47 8.6.1 Spudcanstructure 47 8.6.2 8.6.3 .48 8.7 Mass modelling..... 8.8 Application of actions ...... 8.8.1 8.8.2 Functional actions due to fixed load and variable load .50 8.8.3 Hull sagging ... .51 8.8.4 8.8.5 Inertial actions ... 51 8.8.6 Large displacement effects.... 8.8.7 Conductor actions.... iv IS02023-Allrightreserved IS0 19905-1:2023(E) 8.8.8 Earthquake actions... 51 8.8.9 9 Foundations ... 52 9.1 Applicability... 9.2 9.3 Geotechnical analysis of independent leg foundations... 52 9.3.1 Foundationmodellingan