Offshore Structures

by El-Reedy

• ISBN13: 9780123854759
• ISBN10: 012385475X
• Format: Hardcover
• Copyright: 2012-07-17
• Publisher: Elsevier Science

Summary

With most of the easy gas and oil reserves discovered and prices rebounding, companies are now drilling far offshore in extreme weather condition environments. As deepwater wells are drilled to greater depths, engineers and designers are confronted with new problems such as water depth, weather conditions, ocean currents, equipment reliability, and well accessibility. Offshore Structure Design, Construction and Maintenance covers all types of offshore structures and platforms employed worldwide. The ultimate reference for selecting, operating and maintaining offshore structures, this book provides a road map for designing structures which will stand up even in the harshest environments. The selection of the proper type of offshore structure is discussed from a technical and economic point of view. The design procedure for the fixed offshore structure will be presented and how to review the design to reach the optimum solution. Nonlinear analysis (Push over) analysis will be presented as a new technique to design and assess the existing structure. Pile design and tubular joint with the effect of fatigue loading will be presented also from a theoretical and a practical point of view. With this book in hand, engineers receive the most up-to-date methods for performing a structural life cycle analysis; implement maintenance plans for topsides and jackets, using non destructive testing. Under water inspection is discussed for hundreds of platforms in detail. Advanced repair methodology for scour, marine growth and damaged or deteriorating members are discussed. Risk based under water inspection techniques are covered from a practical pint of view. In addition, the book will be supported by an online modeling and simulation program with will allow designers to save time and money by verifying assumptions online. One stop guide to offshore structure design and analysis Easy to understand methods for structural life cycle analysis Expert advice for designing offshore platforms for all types of environments Save time and money by verifying designs online

Table of Contents

Preface	p. xv
The Author	p. xvii
Introduction to Offshore Structures
Introduction	p. 1
History of Offshore Structures	p. 1
Overview of Field Development	p. 2
Field-Development Cost	p. 4
Multicriteria Concept Selection	p. 8
Feed Requirements	p. 9
Types of Offshore Platforms	p. 10
Different Types of Offshore Structures	p. 14
Minimal Offshore Structure	p. 19
Preview of This Book	p. 20
Bibliography	p. 21
Offshore Structure Loads and Strength
Introduction	p. 23
Gravity Loads	p. 23
Dead Load	p. 23
Live Load	p. 26
Impact Load	p. 29
Design for Serviceability Limit State	p. 29
Helicopter Landing Loads	p. 31
Crane Support Structures	p. 38
Wind Load	p. 42
Stair Design	p. 46
Gravity Loads	p. 46
Wind Loads	p. 47
Offshore Loads	p. 47
Wave Load	p. 48
Current Force	p. 55
Earthquake Load	p. 60
Ice Loads	p. 65
Other Loads	p. 66
Design for Ultimate Limit State (ULS)	p. 67
Load Factors	p. 67
Extreme Environmental Situation for Fixed Offshore Platforms	p. 68
Operating Environmental Situations-Fixed Platforms	p. 69
Partial Action Factors for Platform Design	p. 70
Collision Events	p. 75
Vessel Collision	p. 75
Fires and Explosions	p. 76
Material Strength	p. 77
Steel Groups	p. 77
Steel Classes	p. 81
References	p. 90
Offshore Structure Platform Design
Introduction	p. 93
Preliminary Dimensions	p. 101
Approximate Dimensions	p. 101
Bracing System	p. 102
Jacket Design	p. 104
Structure Analysis	p. 107
Global Structure Analysis	p. 108
The Loads on Piles	p. 112
Modeling Techniques	p. 113
Dynamic Structure Analysis	p. 118
In-place Analysis According to ISO 19902	p. 123
Cylinder Member Strength	p. 124
Cylinder Member Strength Calculation According to ISO 19902	p. 124
Cylinder Member Strength Calculation	p. 134
Tubular Joint Design	p. 142
Simple Joint Calculation API RP2A (2007)	p. 143
Joint Calculation According to API RP2A (2000)	p. 153
Fatigue Analysis	p. 156
Topside Design	p. 174
Grating Design	p. 175
Handrails, Walkways, Stairways and Ladders	p. 179
Boat Landing Design	p. 180
Boat Landing Calculation	p. 182
Riser Guard Design	p. 185
Boat Landing Design Using the Nonlinear Analysis Method	p. 186
Boat Impact Methods	p. 187
Tubular Member Denting Analysis	p. 188
Riser Guard	p. 192
On-Bottom Stability	p. 193
Bridges	p. 196
Crane Loads	p. 197
Lift Installation Loads	p. 197
Vortex-Induced Vibrations	p. 199
Helideck Design	p. 200
Structure Analysis and Design Quality Control	p. 206
Bibliography	p. 211
Geotechnical Data and Pile Design
Introduction	p. 213
Investigation Procedure	p. 213
Performing an Offshore Investigation	p. 214
Drilling Equipment and Method	p. 215
Wire-Line Sampling Technique	p. 215
Offshore Soil Investigation Problems	p. 216
Soil Tests	p. 218
In-Situ Testing	p. 221
Cone Penetration Test (CPT)	p. 223
Field Vane Test	p. 229
Soil Properties	p. 231
Strength	p. 233
Soil Characterization	p. 236
Pile Foundations	p. 237
Pile Capacity for Axial Loads	p. 239
Foundation Size	p. 244
Axial Pile Performance	p. 245
Pile Capacity Calculation Methods	p. 260
Pile Capacity under Cyclic Loadings	p. 266
Scour	p. 269
Pile Wall Thickness	p. 271
Design Pile Stresses	p. 272
Stresses Due to Hammer Effect	p. 272
Minimum Wall Thickness	p. 275
Driving Shoe and Head	p. 276
Pile Section Lengths	p. 277
Pile Drivability Analysis	p. 278
Evaluation of Soil Resistance to Driving (SRD)	p. 278
Unit Shaft Resistance and Unit End Bearing for Uncemented Materials	p. 279
Upper- and Lower-Bound SRD	p. 279
Results of Wave Equation Analyses	p. 281
Results of Drivability Calculations	p. 281
Recommendations for Pile Installation	p. 281
Soil Investigation Report	p. 284
Bibliography	p. 287
Fabrication and Installation
Introduction	p. 293
Construction Procedure	p. 293
Engineering of Execution	p. 295
Fabrication	p. 296
Joint Fabrication	p. 302
Fabrication Based on ISO	p. 303
Jacket Assembly and Erection	p. 316
Weight Control	p. 328
Weight Calculation	p. 328
Loads from Transportation, Launch and Lifting Operations	p. 335
Lifting Procedure and Calculations	p. 336
Lifting Calculations	p. 337
Lifting Structural Calculations	p. 342
Lift Point Design	p. 344
Clearances	p. 344
Lifting Calculation Report	p. 346
Load-out Process	p. 355
Transportation Process	p. 358
Supply Boats	p. 358
Anchor-handling Boats	p. 358
Towboats	p. 358
Towing	p. 359
Drilling Vessels	p. 364
Crew Boats	p. 364
Barges	p. 365
Crane Barges	p. 366
Offshore Derrick Barges (Fully Revolving)	p. 367
Jack-up Construction Barges	p. 368
Transportation Loads	p. 370
Launching and Upending Forces	p. 372
Installation and Pile Handling	p. 376
Bibliography	p. 381
Corrosion Protection
Introduction	p. 383
Corrosion in Seawater	p. 385
Corrosion of Steel in Seawater	p. 387
Choice of System Type	p. 390
Geometric Shape	p. 395
Coatings and Corrosion Protection of Steel Structures	p. 397
Corrosion Stresses Due to the Atmosphere, Water and Soil	p. 401
Classification of Environments	p. 402
Mechanical, Temperature and Combined Stresses	p. 404
Cathodic Protection Design Considerations	p. 406
Environmental Parameters	p. 406
Design Criteria	p. 407
Protective Potentials	p. 408
Negative Impact of CP on the Structure Jacket	p. 408
Galvanic Anode Materials Performance	p. 410
CP Design Parameters	p. 411
Design Calculation for CP System	p. 423
Design Example	p. 434
General Design Considerations	p. 437
Anode Manufacture	p. 438
Installation of Anodes	p. 439
Allowable Tolerance for Anode Dimensions	p. 440
Internal and External Inspection	p. 441
Bibliography	p. 442
Assessment of Existing Structures and Repairs
Introduction	p. 445
API RP2A: Historical Background	p. 446
Environmental Loading Provisions	p. 446
Regional Environmental Design Parameters	p. 452
Member Resistance Calculation	p. 453
Joint Strength Calculation	p. 453
Fatigue	p. 454
Pile Foundation Design	p. 455
Den/HSE Guidance Notes for Fixed Offshore Design	p. 455
Environmental Loading Provisions	p. 456
Joint Strength Equations	p. 457
Fatigue	p. 457
Foundations	p. 457
Definition of Design Condition	p. 458
Currents	p. 458
Wind	p. 458
Waves	p. 459
Deck Air Gap	p. 460
Historical Review of Major North Sea Incidents	p. 460
Historical Assessment of Environmental Loading Design Practice	p. 461
Environmental Parameters for Structure Design	p. 461
Fluid Loading Analysis	p. 462
Development of API RP2A Member Resistance Equations	p. 463
Allowable Stresses for Cylindrical Members	p. 464
Axial Tension	p. 464
Axial Compression	p. 464
Bending	p. 465
Shear	p. 466
Hydrostatic Pressure	p. 467
Combined Axial Tension and Bending	p. 468
Combined Axial Compression and Bending	p. 468
Combined Axial Tension and Hydrostatic Pressure	p. 469
Combined Axial Compression and Hydrostatic Pressure	p. 469
AISC Historical Background	p. 471
Pile Design Historical Background	p. 471
Effects of Changes in Tubular Member Design	p. 475
Failure Due to Fire	p. 476
Degree of Utilization	p. 478
Tension Member Design by EC3	p. 479
Unrestrained Beams	p. 480
Example: Strength Design for Steel Beams	p. 482
Steel Column: Strength Design	p. 483
Case Study: Deck Fire	p. 485
Case Study: Platform Failure	p. 490
Strength Reduction	p. 492
Environmental Load Effect	p. 493
Structure Assessment	p. 493
Assessment of Platform	p. 497
Nonlinear Structural Analysis in Ultimate Strength Design	p. 503
Structural Modeling	p. 507
Determining the Probability of Structural Failure	p. 510
Offshore Structure Acceptance Criteria	p. 511
Reliability Analysis	p. 512
Software Requirement	p. 514
Case Study: Platform Decommissioning	p. 518
Scour Problem	p. 523
Offshore Platform Repair	p. 523
Deck Repair	p. 523
Load Reduction	p. 525
Jacket Repair	p. 527
Dry Welding	p. 529
Example: Platform Underwater Repair	p. 533
Example: Platform "Shear Pups" Repair	p. 534
Case Study: Underwater Repair for Platform Structure	p. 535
Case Study: Platform Underwater Repair	p. 535
Clamps	p. 536
Example: Drilling Platform Stabilization after Hurricane Lili	p. 541
Grouting	p. 542
Composite Technology	p. 547
Example: Using FRP	p. 549
Case Study: Conductor Composite Repair	p. 550
Fiberglass Access Decks	p. 550
Fiberglass Mud Mats	p. 553
Case Study: Repair of the Flare Jacket	p. 554
Case Study: Repair of Bearing Support	p. 557
Bibliography	p. 559
Risk-Based inspection Technique
Introduction	p. 563
SIM Methodology	p. 564
Qualitative Risk Assessment for Fleet Structures	p. 565
Likelihood (Probability) Factors	p. 566
Consequence Factors	p. 595
Overall Risk Ranking	p. 602
Underwater Inspection Plan	p. 606
Underwater Inspection (According to API SIM 2005)	p. 606
Baseline Underwater Inspection	p. 607
Routine Underwater Inspection Scope of Work	p. 608
Inspection Plan Based on ISO 9000	p. 609
Inspection and Repair Strategy	p. 613
Flooded Member Inspection	p. 616
Anode Retrofit Maintenance Program	p. 620
Assessment Process	p. 620
Collecting Data	p. 620
Structure Assessment	p. 622
Mitigation and Risk Reduction	p. 628
Consequence Mitigation	p. 629
Reduction of the Probability of Platform Failure	p. 630
Occurrence of Member Failures with Time	p. 632
Bibliography	p. 633
Index	p. 635
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