1、Design and Analysis of Stationkeeping Systems for Floating StructuresAPI RECOMMENDED PRACTICE 2SKTHIRD EDITION, OCTOBER 2005ADDENDUM, MAY 2008REAFFIRMED, JUNE 2015Design and Analysis of Stationkeeping Systems for Floating StructuresUpstream SegmentAPI RECOMMENDED PRACTICE 2SKTHIRD EDITION, OCTOBER 2
2、005ADDENDUM, MAY 2008REAFFIRMED, JUNE 2015SPECIAL NOTESAPI publications necessarily address problems of a general nature. With respect to partic-ular circumstances, local, state, and federal laws and regulations should be reviewed.Neither API nor any of APIs employees, subcontractors, consultants, c
3、ommittees, orother assignees make any warranty or representation, either express or implied, with respectto the accuracy, completeness, or usefulness of the information contained herein, or assumeany liability or responsibility for any use, or the results of such use, of any information orprocess di
4、sclosed in this publication. Neither API nor any of APIs employees, subcontrac-tors, consultants, or other assignees represent that use of this publication would not infringeupon privately owned rights.API publications may be used by anyone desiring to do so. Every effort has been made bythe Institu
5、te to assure the accuracy and reliability of the data contained in them; however, theInstitute makes no representation, warranty, or guarantee in connection with this publicationand hereby expressly disclaims any liability or responsibility for loss or damage resultingfrom its use or for the violati
6、on of any authorities having jurisdiction with which this publi-cation may conflict.API publications are published to facilitate the broad availability of proven, sound engi-neering and operating practices. These publications are not intended to obviate the need forapplying sound engineering judgmen
7、t regarding when and where these publications shouldbe utilized. The formulation and publication of API publications is not intended in any wayto inhibit anyone from using any other practices.Any manufacturer marking equipment or materials in conformance with the markingrequirements of an API standa
8、rd is solely responsible for complying with all the applicablerequirements of that standard. API does not represent, warrant, or guarantee that such prod-ucts do in fact conform to the applicable API standard.All rights reserved. No part of this work may be reproduced, stored in a retrieval system,
9、or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.Copyright 2005, 2008 American Petroleum InstituteFOREWORDThis r
10、ecommended practice is under the jurisdiction of the API Subcommittee on Stan-dardization of Offshore Structures.Offshore technology is growing rapidly. In those areas where the committee felt that ade-quate data were available, specific and detailed recommendations are given. In other areasgeneral
11、statements are used to indicate that consideration should be given those particularpoints. Designers are encouraged to utilize all research advances available to them. As off-shore knowledge continues to grow, this recommended practice will be revised. It is hopedthat the general statements containe
12、d herein will gradually be replaced by detailed recom-mendations.Work sites and equipment operations may differ. Users are solely responsible for assess-ing their specific equipment and premises in determining the appropriateness of applying theInstructions. Nothing contained in any API publication
13、is to be construed as granting any right, byimplication or otherwise, for the manufacture, sale, or use of any method, apparatus, or prod-uct covered by letters patent. Neither should anything contained in the publication be con-strued as insuring anyone against liability for infringement of letters
14、 patent.This document was produced under API standardization procedures that ensure appropri-ate notification and participation in the developmental process and is designated as an APIstandard. Questions concerning the interpretation of the content of this publication or com-ments and questions conc
15、erning the procedures under which this publication was developedshould be directed in writing to the Director of Standards, American Petroleum Institute,1220 L Street, N.W., Washington, D.C. 20005. Requests for permission to reproduce ortranslate all or any part of the material published herein shou
16、ld also be addressed to thedirector.Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at leastevery five years. A one-time extension of up to two years may be added to this review cycle.Status of the publication can be ascertained from the API Standards Department, telephon
17、e(202) 682-8000. A catalog of API publications and materials is published annually andupdated quarterly by API, 1220 L Street, N.W., Washington, D.C. 20005.Suggested revisions are invited and should be submitted to the Standards and PublicationsDepartment, API, 1220 L Street, NW, Washington, DC 2000
18、5, standardsapi.org.iiiCONTENTSPage1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 BASIC CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12.1 Introducti
19、on to Stationkeeping Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12.2 Mooring Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62.3 Permanent and Mobile Mooring Systems. . . . . . . . . . . . . . . . . . . . . . . .
20、 . . . . . . .62.4 Design Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122.5 Foreseeable Hazards for Mooring Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123 ENVIRONMENTAL CRITERIA. . . . . . . . . . . . . . . . . . .
21、 . . . . . . . . . . . . . . . . . . . . . .143.1 Environmental Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143.2 Environmental Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153.3 Wind . . . . .
22、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153.4 Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163.5 Current . . . . . . . . . . . . . . . . . . . . . . . .
23、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163.6 Water Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163.7 Soil and Seafloor Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24、 . . . .163.8 Atmospheric Icing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163.9 Marine Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164 ENVIRONMENTAL FORCES AND VESSEL MOTIONS . . .
25、 . . . . . . . . . . . . . . . . .164.1 Basic Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164.2 Guidelines for the Evaluation of Environmental Forces and Vessel Motions . . .164.3 Simplified Methods . . . . . . . . . . . . . . . . . . .
26、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165 MOORING STRENGTH ANALYSIS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175.1 Basic Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175.2 Mooring Anal
27、ysis Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195.3 Vessel Offset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195.4 Line Tension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
28、 . . . . . . . . . . . . . . . . . . . . . . .195.5 Statistics of Peak Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205.6 Strength Analysis Based on Frequency Domain Vessel Dynamic. . . . . . . . . . . .205.7 Strength Analysis based on Time Domain Ves
29、sel Dynamics . . . . . . . . . . . . . . . .225.8 Strength Analysis Based on Combined Time and Frequency Domain Vessel Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .225.9 Thruster Assisted Mooring (TAM) . . . . . . . . . . . . . . . . . .
30、 . . . . . . . . . . . . . . . . . .225.10 Transient Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .246 FATIGUE ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .246.1 Basic Considerati
31、ons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .246.2 Fatigue Resistance of Mooring Components . . . . . . . . . . . . . . . . . . . . . . . . . . . .256.3 Fatigue Analysis Formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32、 . . . . . .276.4 Fatigue Analysis Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .307 DESIGN CRITERIA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .307.1 Vessel Offset. . . . . . . . . . . . . . .
33、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .307.2 Line Tension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .307.3 Line Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
34、 . . . . . . . . . . . . .307.4 Anchoring Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .307.5 Fatigue Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .317.6 Corrosion and Wear . .
35、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .317.7 Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .327.8 Supporting Structures . . . . . . . . . . . . . . . . . . . . . . . . . . .
36、 . . . . . . . . . . . . . . . . . . .32vPage8 MOORING HARDWARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .328.1 Basic Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .328.2 Mooring Line Comp
37、onents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .328.3 Winching Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .338.4 Monitoring Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38、 . . . . . . . . . . . .349 DYNAMIC POSITIONING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .349.1 Basic Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .349.2 Design and Analysis . . . . . . .
39、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .349.3 Operating Personnel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3610 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
40、 . . . . . . . . . . . . .36APPENDIX A INTRODUCTION TO MOORING COMPONENTS. . . . . . . . . . . . . . . .39APPENDIX B RECOMMENDED WIND SPECTRUM . . . . . . . . . . . . . . . . . . . . . . . . .59APPENDIX C SIMPLIFIED METHODS FOR THE EVALUATION OFENVIRONMENTAL FORCES AND VESSEL MOTIONS . . . . . . . .
41、 . .63APPENDIX D DRAG EMBEDMENT ANCHOR DESIGN. . . . . . . . . . . . . . . . . . . . . . 83APPENDIX E PILE AND PLATE ANCHOR DESIGN AND INSTALLATION . . . . .93APPENDIX F DETERMINATION OF AVAILABLE THRUST . . . . . . . . . . . . . . . . 119APPENDIX G MOORING STRENGTH RELIABILITY . . . . . . . . . . .
42、 . . . . . . . . . . . 125APPENDIX H MOORING DESIGN FOR VORTEX INDUCED MOTIONS (VIM) 129APPENDIX CH COMMENTARY ON APPENDIX HMOORING DESIGN FOR VORTEX INDUCED MOTION (VIM). . . . . . . . . . . . . . . . . . . . . . . . . 135APPENDIX I GLOBAL ANALYSIS GUIDELINES FOR DEEPWATER FLOATING SYSTEMS . . . .
43、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145APPENDIX J MOORING STRENGTH AND FATIGUE ANALYSIS EXAMPLES 171APPENDIX K GULF OF MEXICO MODU MOORING PRACTICE FOR HURRICANE SEASON. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183Tables1 Recommended Analysi
44、s Methods and Conditions. . . . . . . . . . . . . . . . . . . . . . . . . 192 Intact and Damaged TAM Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233 M and K Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
45、 . 264 Comparison of B-T and T-T Fatigue Life. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 Tension Limits and Safety Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306 Drag Anchor Safety Factors . . . . . . . . . . . . . . . . . . . . . . . .
46、 . . . . . . . . . . . . . . . . . . 317 Safety Factors for Pile, Plate, and Gravity Anchors (Dynamic Analysis). . . . . . . 31B.1 Coefficients for NPD 2-Point Coherence Spectrum . . . . . . . . . . . . . . . . . . . . . . . 60C.1 Wind Force Shape Coefficients . . . . . . . . . . . . . . . . . . . .
47、 . . . . . . . . . . . . . . . . . . . 67C.2 Wind Force Height Coefficients (for 1-Minute Wind) . . . . . . . . . . . . . . . . . . . . . 67C.3 Wind Velocity Time Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67D.1 Estimated Maximum Fluke Tip Penetration
48、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89E.1 Recommended NcFactor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97E.2 Suction Pile Safety Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112E.3 De
49、sign Factors for Finite Element Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112F.1 Correction Factor for Inflow Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121F.2 Thrust Losses in Reverse Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121J.1 Fairlead Motion Complex RAO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173J.2 Tension Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176J.3 Environmental Condition, Mean Loads and
