Buoyancy Analysis & Concrete Weights Spacing

The buoyancy of a pipeline depends upon the weight of the pipe, the weight of the volume of water displaced by the pipe, the weight of the liquid load carried by the pipe and the weight of the backfill. As a conservative analytical practice, consider the pipeline empty for two reasons; so, the weight of the liquid will be considered as an additional safety factor and the possibility of the pipeline not being in use during a period of time.

This calculation is used to determine downward forces and weights of a specified pipe resulting in the proper spacing of weights to counter the buoyance forces. The calculation does not account/allow for depth of water or burial.

Buoyance Force
PTLB Design & Stress Analysis_2.7 Intro Image.png
Where:
πΉπ΅Β βˆ’ Buoyancy Force(lbf)
π·π‘œβˆ’ Pipe outside diameter including coating (in)
π›Ύπ‘€Β βˆ’Unit weight of fluid/water (lb/ft3)

 

Weight of steel pipe in the air
PTLB Design & Stress Analysis_2.7 Intro Image 2.png
Where:
π‘Šπ‘ƒΒ βˆ’ Weight of bare pipe in air (lbf)
π·π‘œπ‘Β βˆ’ Pipe outside diameter (in)
π‘‘Β βˆ’ Pipe wall thickness(in)

 

Weight of pipe coating in the air
PTLB Design & Stress Analysis_2.7 Intro Image 3.png
Where:
π‘Šπ‘Β βˆ’ Weight of coating in air(lbf)
π›Ύπ‘Β βˆ’ Unit weight of coating(lb/ft3)

 

Weight of product in the pipe
PTLB Design & Stress Analysis_2.7 Intro Image 4.png
Where:
π‘Šπ‘π‘ŸΒ βˆ’ Weight of product in pipe(lbf)
π›Ύπ‘π‘ŸΒ βˆ’ Unit weight of product in pipe(lb/ft3)

 

Downward force of the pipe
Β PTLB Design & Stress Analysis_2.7 Intro Image 5.png

 

Net Controlling Force
PTLB Design & Stress Analysis_2.7 Intro Image 6.png
Where:
πΉπ‘›π‘’π‘‘Β βˆ’ Net controlling force(lbf)
𝑆𝐹 = Safety Factor

 

Downward force of the concrete weight
PTLB Design & Stress Analysis_2.7 Intro Image 7.png
Where:
π‘‰π‘€π‘‘Β βˆ’ Weight of concrete(ft3)
π›Ύπ‘€π‘‘βˆ’Unit weight of concrete(lb/ft3)
π›Ύπ‘€βˆ’Unit weight of fluid/water(lb/ft3)

 

Concrete weight spacing
PTLB Design & Stress Analysis_2.7 Intro Image 8.png

 

Input Parameters

  1. To create a new case, click the β€œAdd Case” button
  2. Select the Buoyancy Analysis & Concrete Weights Spacing application from the Steel Pipe – Design and Stress Analysis module.
  3. Enter Case Name, Location, Date and any necessary notes.
  4. Fill out all required fields.
  5. Make sure the values you are inputting are in the correct units.
  6. Click the CALCULATE button.

 

  • Nominal Pipe Size(in)
  • Wall Thickness(in)
  • Corrosion coating thickness (MIL) Unit Weight of product in pipe(lbs./ftΒ³)
  • Volume of Concrete weight(ftΒ³)
  • Unit Weight of Water(lbs./ftΒ³),
  • Unit Weight of Concrete(lbs./ftΒ³)
  • Unit Weight of Corrosion Coating (lbs./ftΒ³)

PLTB Liquid_DesignStress_2.7 Input Rev_092420.png

Outputs/Reports

  1. View the results.
  2. If an input parameter needs to be edited be sure to hit the CALCULATE button after the change.
  3. To SAVE, fill out all required case details then click the SAVE button.
  4. To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
  5. To generate a REPORT, click the REPORT button.
  6. The user may export the Case/Report by clicking the Export to Excel/PowerPoint icon.
  7. To delete a case, click the DELETE icon near the top of the widget.

 

  • Buoyancy Force(lbf/ft)
  • Weight of Pipe in Air(lbf/ft)
  • Weight of Coating in Air(lbf/ft)
  • Weight of Product in Pipe(lbf/ft)
  • Downward Force of the Pipe(lbf/ft)
  • Net Controlling Force(lbf/ft)
  • Downward Force of the Concrete Weight(lbf)
  • Concrete Weight Spacing(ft)

PLTB Liquid_DesignStress_2.7 Output Rev_092420.png

Related Links

Pipeline HUB β€” User Resources

Table of Contents
Table of Pages
Table of Contents
  1. Pipeline HUB User Resources
  2. AC Mitigation PowerTool
  3. API Inspector's Toolbox
  4. Horizontal Directional Drilling PowerTool
  5. Crossings Workflow
  6. Hydrotest PowerTool
  7. Pipeline Toolbox
  8. Encroachment Manager
  9. PRCI AC Mitigation Toolbox
  10. PRCI RSTRENG
  11. RSTRENG+
  12. Ad-hoc Analysis
  13. Database Import
  14. Data Availability Dashboard
  15. ESRI Map
  16. Report Builder
  17. Crossings Workflow
  18. Hydrotest PowerTool
  19. Investigative Dig PowerTool
  20. Hydraulics PowerTool
  21. External Corrosion Direct Assessment Procedure - RSTRENG
  22. Canvas
  23. Definitions
  24. Pipe Schedule and Specifications Tables