ISO INTERNATIONAL STANDARD 19902 Second edition 2020-11 Petroleum and natural gas industries Fixed steel offshore structures Industries du pétrole et du gaz naturel - Structures en mer fixes en acier Reference number IS0 19902:2020(E) OSI @ISO 2020 IS0 19902:2020(E) COPYRIGHTPROTECTEDDOCUMENT @IS02020 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: +41 22 749 01 11 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2020 - All rights reserved IS0 19902:2020(E) Contents Page Foreword. xiv Introduction... 1 Scope 2 Normative references 3 Terms and definitions... 4 Symbols . .10 5 Abbreviated terms .. 14 6 Overall considerations.. .16 6.1 6.1.1 General.. 16 6.1.2 Jackets. 16 6.1.3 Towers... 6.1.4 Jack-ups... 6.2 Planning.... 18 6.2.1 18 6.2.2 Hazards... 18 6.2.3 Designing for hazards . 19 6.2.4 Design situations and criteria.... 61 6.2.5 Designforinspectionandmaintenance... 19 6.2.6 Foundations and active geological processes .. .20 6.2.7 Regulation.... .20 6.3 Service and operational considerations.... 20 6.3.1 General considerations... 6.3.2 Water depth.. .20 6.3.3 6.3.4 Access and auxiliary systems... 21 6.4 6.5 Environmental considerations... .21 6.5.1 General..... 6.5.2 Selecting design metocean parameters and action factors... ..22 6.6 6.7 Assessment of existing structures... 23 6.8 Structure reuse ... 23 7 General design requirements. .23 7.1 General. ..23 7.2 7.3 Incorporatinglimitstates 24 7.4 Determining design situations. ..24 7.5 Structural modelling and analysis.... 7.6 Design for pre-service and removal situations.... 25 7.7 Design for the in-place situation... 25 7.8 Determination of component resistances.. 7.8.1 General. 7.8.2 Physical testing to derive resistances.. ..26 7.8.3 Resistances derived from computer simulations validated by physical testing........ 26 @ IS0 2020 - All rights reserved ili IS0 19902:2020(E) 7.8.4 Resistances derived from computer simulations validated against 7.8.5 Resistances derived from unvalidated computer simulations ... 26 7.9 Strength and stability checks .... 26 7.9.1 Action and resistance factors... 7.9.2 Strength and stability equations .... 26 7.9.3 Unfactored actions .... 27 7.10 Robustness..... 27 7.10.1 7.10.2 Damage tolerance .... 27 7.11 Reserve strength.... 7.11.1 7.11.2 Existing structures .. 29 7.12 Indirect actions.... 29 7.13 8 Actions for pre-service and removal situations. .30 8.1 8.1.1 Coverage 30 8.1.2 Design situations.. .30 8.1.3 Actions ..... 8.2 General requirements.. 31 8.2.1 Weight control .. 8.2.2 8.2.3 Action effects .. 31 8.3 Onshore lifting. 33 8.3.1 8.3.2 8.3.3 Effect of tolerances.... 34 8.3.4 8.3.5 8.3.6 Member and joint strengths... 35 8.3.7 Lifting attachments ... 8.3.8 Slings, shackles and fittings .... 8.4 Fabrication... 36 8.5 8.5.1 Direct lift 8.5.2 Horizontal movement onto vessel. 36 8.5.3 Self-floating structures .. 8.6 Transportation.. 8.6.1 General. 37 8.6.2 Metocean conditions.. ...37 8.6.3 8.6.4 Other considerations.. .38 8.7 Installation... .38 8.7.1 8.7.2 Launched structures.. 38 8.7.3 Crane assisted uprighting of structures .. ..38 8.7.4 8.7.5 Member flooding... 39 8.7.6 Actions on the foundation during installation.. 39 9 Actions for in-place situations... 39 9.1 General. 39 9.2 Permanent actions (G) and variable actions (Q) iv @ IS0 2020 - All rights reserved IS0 19902:2020(E) 9.2.1 Permanent action 1, G1 .. 40 9.2.2 Permanent action 2, G2.... 9.2.3 Variable action 1, Q1 .. .40 9.2.4 Variable action 2., Q2.. 9.2.5 Unintentional flooding ..