API Recommended Practice 2A-WSD

1 API Recommended Practice 2A-WSDP lanning, Designing, and Constructing Fixed Offshore Platforms Working Stress design TWENTY-SECOND EDITION | NOVEMBER 2014|310 PAGES|$ | PRODUCTNO. G2 AWSD22 This Recommended Practice is based on global industry best practices and serves as a guide for those who are concerned with the design and construction of new fixed offshore platforms and for the relocation of existing platforms used for the drilling, development, production, and storage of hydrocarbons in offshore areas. This publication serves as a guide for the design and construction of new platforms and for the relocation of existing platforms used for the drilling, development, and storage of hydrocarbons in offshore areas. In addition, these guidelines shall be used in conjunction with API 2 SIM for the assessment of existing platforms in the event that it becomes necessary to make a determination of the fitness-for-purpose of the structure. Reference in this document is made to the 1989 edition of the AISC Specification for Structural Steel Buildings Allowable Stress design and Plastic design .

2 The use of later editions of AISC specifications is specifically not Recommended for design of offshore platforms. The load and resistance factors in these specifications are based on calibration with building design practices and may not be applicable to offshore platforms. Research work is now in progress to incorporate the strength provisions of the new AISC code into API offshore design practices . For ordering information: Online: Phone: 1-800-854-7179 (Toll-free in the and Canada) (+1) 303-397-7056 (Local and International) Fax: (+1) 303-397-2740 API members receive a 30% discount where applicable. ContentsPage1 Scope .. 12 Normative References .. 13 Terms, Definitions, Acronyms, and Abbreviations .. and Definitions.. and Abbreviations .. 44 Planning .. Considerations.. Considerations .. Investigation-Foundations .. the design Environmental Conditions .. Types.

3 Categories .. Reuse .. Assessment .. Considerations .. 215 design Criteria and Procedures .. Conditions .. Loads.. and Installation Forces .. 516 Structural Steel design .. Stresses for Cylindrical Members.. Stresses for Cylindrical Members .. Transitions .. 687 Strength of Tubular Joints .. Considerations .. Joints .. Joints .. Joints.. Ring-stiffened Joints .. Joints .. Circular Joint Types .. Joints.. Joints.. 868 Fatigue .. design .. Analysis .. Concentration Factors (SCFs).. Curves for All Members and Connections, Except Tubular Connections .. Curves for Tubular Connections .. Mechanics .. 93vContentsPage9 Foundation design .. Foundations .. design .. Capacity for Axial Compression Loads .. Capacity for Axial Pullout Loads .. Pile Performance .. Reaction for Axially Loaded Piles .. Reaction for Laterally Loaded Piles .. Group Action .. Wall Thickness.

4 Of Pile Sections .. Foundations .. 10310 Other Structural Components and Systems .. design .. Girder design .. Supporting Structure.. Pile-to-structure Connections .. System design .. 11011 Material .. Steel .. Steel Pipe .. for Tubular Joints .. Grout and Concrete .. Protection .. 11812 Drawings and Specifications .. Drawings .. Drawings and Specifications .. Drawings and Specifications .. Drawings and Specifications .. Drawings .. Drawings and Specifications .. Drawings and Specifications .. 12113 Welding.. Details .. and Documentation .. 12514 Fabrication .. Protection .. Material.. and Documentation .. 132viContentsPage15 Installation .. of Jacket from Transport Barge .. Installation .. Installation .. of Installation Welding Equipment .. 14516 Inspection .. Personnel .. Inspection .. , Seafastening, and Transportation Inspection .. Inspection.

5 Documentation .. 15417 Accidental Loading .. Process .. Exposure Category .. of Occurrence .. Assessment .. and Blast Interaction .. Loading .. 16018 Reuse .. Considerations .. 16119 Minimum and Special Structures .. Loads and Analysis .. and Welding .. 169 Annex A (informative) API 2A-WSD , 21st Edition vs 22nd Edition Cross-reference .. 170 Annex B (informative) Commentary.. 184 Bibliography .. for Calculation of Wave Plus Current Forces for Static Analysis .. Shift Due to Steady Current .. of Applicability of Stream Function, Stokes V, and Linear Wave Theory (from Atkins, 1990; Modified by API Task Group on Wave Force Commentary) Factor for Wave Loads on Conductor Arrays as a Function of Conductor Spacing .. Conical Transition .. Joint Detailing .. Joint Detailing .. and Geometric Parameters, Simple Tubular Joints.. of Chord Length, Lc.. Tubular Joint S-N Curve for T = 16 mm (5/8 in.) .. Pile-to-structure Connection with Shear Keys.

6 Shear Key Details .. design Limitations .. Tubular Connections Shielded Metal Arc Welding .. Process .. Current Field at 60 ft Depth Around and Through the Bullwinkle Platform in a Loop Current Event in 1991 .. of Linear and Nonlinear Stretching of Current Profiles.. of Surface Roughness Height and Thickness .. of Steady Flow Drag Coefficient on Relative Surface Roughness .. Amplification Factor for Drag Coefficient as a Function of K/Cds .. Amplification Factor for Drag Coefficient as a Function of K.. Coefficient as a Function of K.. Coefficient as a Function of K/Cds .. Factor for Wave Loads on Conductor Arrays as a Function of Conductor Spacing .. Example Structure .. Seismic Load Deformation Curve .. Coefficients for Local Buckling of Steel Cylinders Under Axial Compression .. of Test Data with design Equation for Fabricated Steel Cylinders Under Axial Compression .. Equation for Fabricated Steel Cylinders Under Bending.

7 Of Test Data with Elastic design Equations for Local Buckling of Cylinders Under Hydrostatic Pressure (M > ) .. of Test Data with Elastic design Equations for Local Buckling of Cylinders Under Hydrostatic Pressure (M < ) .. of Test Data with design Equations for Ring Buckling and Inelastic Local Buckling of Cylinders Under Hydrostatic Pressure .. of Test Data with Interaction Equation for Cylinders Under Combined Axial Tension and Hydrostatic Pressure (Fhc Determined from Tests) .. of Interaction Equations for Various Stress Conditions for Cylinders Under Combined Axial Compressive Load and Hydrostatic Pressure .. of Test Data with Elastic Interaction Curve for Cylinders Under Combined Axial Compressive Load and Hydrostatic Pressure .. Comparison of Test Data on Fabricated Cylinders with Elastic Interaction Curve for Cylinders Under Combined Axial Load and Hydrostatic Pressure .. Comparison of Test Data with Interaction Equations for Cylinders Under Combined Axial Compressive Load and Hydrostatic Pressure (Combination Elastic and Yield-type Failures).

8 Load Patterns with up to .. Index Betas, API 2A-WSD , 21st Edition, Supplement 1 .. Index Betas, API 2A-WSD , 21st Edition, Supplement 2 .. of Strength Factors Qu for Axial Loading .. of Strength Factors Qu for IPB and OPB .. of Chord Load Factors Qf .. of Chord Axial Load on DT Brace Compression Capacity Comparison of University of Texas Test Data with Chord Load Factor.. Under Balanced Axial Loading Test and FE vs New and Old API .. T-joints Under Axial Loading Test and FE vs New and Old API .. DT-joints Under Axial Compression Test and FE vs New and Old API .. All Joints Under BIPB Test and FE vs New and Old API.. All Joints Under BOPB Test and FE vs New and Old API.. of Frequencies for Detailed Analyses.. Definitions for Efthymiou SCFs .. Air S-N Curve as Applicable to Profiled Welds, Including Size and Toe Correction to the Data .. Curve and Data for Seawater with CP .. Measured Bond Strength vs Cube Compressive Strength.

9 Histogram of the Safety Factors Tests with and Without Shear Key Connections .. Cumulative Histogram of the Safety Factors Tests with and Without Shear Key Connections .. Measured Bond Strength vs. Cube Compressive Strength Multiplied by the Height-to-spacing Ratio.. Ratio vs Reduction in Ultimate Capacity, 1220 mm, 1370 mm, and 1525 mm (48 in., 54 in., and 60 in.) Legs Straight with L = m (60 ft), K = , and Fy = 240 MPa (35 ksi) .. Ratio vs Reduction in Ultimate Capacity, 1220 mm, 1370 mm, and 1525 mm (48 in., 54 in., and 60 in.) Legs Straight with L = m (60 ft), K = , and Fy = 345 MPa (50 ksi) .. Ratio vs Reduction in Ultimate Capacity, 1220 mm, 1370 mm, and 1525 mm (48 in., 54 in., and 60 in.) Legs Bent with L = m (60 ft), K = , and Fy = 240 MPa (35 ksi) .. Ratio vs Reduction in Ultimate Capacity, 1220 mm, 1370 mm, and 1525 mm (48 in., 54 in., and 60 in.) Legs Bent with L = m (60 ft), K = , and Fy = 345 MPa (50 ksi) .. Category Matrix.

10 Loading Conditions .. Current Blockage Factors for Typical Gulf of Mexico Jacket-type Structures .. Coherence Spectrum Coefficients , p, q, r, and .. Shape Coefficients .. Level Criteria and Robustness Analysis .. Factors for Steel Jacket of Fixed Offshore Platforms .. design Reference Wind Speed for Drilling Structures .. Wind Speeds used for Existing Drilling .. Acceleration During design Hurricanes .. of K and Cm for Various Member Situations .. Factors.. Angle for Conical Transitions.. of Joint Classification .. Parameter Validity Range.. for Qu.. for C1, C2, C3.. for Grouted Joints.. Life Safety Factors .. design S-N Curves .. on Fatigue Life for Weld Improvement Techniques .. Factors of Safety for Different Loading Conditions .. Pile Wall Thickness .. Foundation Safety Factors Against Failure .. Factors of Safety .. Steel Plates .. Steel Plates (Continued) .. Steel Shapes.