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
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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
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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
