Pull Force and Installation Stresses - Vertical & Horizontal

Calculations

When pipes are installed by HDD, they often experience high tension loads, severe bending, and external fluid pressures. Often these installation loads are more severe than the design service loads. When selecting the appropriate pipe materials for an HDD installation, the designer must consider the pipe properties as well as the borehole profile. These two factors should be considered together in order to choose the best material and profile so that the pipeline can be installed and operated without risk of damage. To ensure that the material and bore-hole profile are suitable for the proposed application, the installation, operational, and combined loads and stresses are analyzed.

Pipe Weight in Air

π‘ƒπ‘–π‘π‘’π‘€π‘’π‘–π‘”β„Žπ‘‘ = 10.68(π·βˆ’π‘‘)𝑑

π‘ƒπ‘–π‘π‘’π‘€π‘’π‘–π‘”β„Žπ‘‘β€“ Weight of the pipe (lbs/ft)
D – Pipe Outside Diameter (inch)
t – Pipe Wall Thickness (inch)

Pipe Exterior Volume

Pipe Interior Volume

Weight of Water in Pipe

(to be calculated only if the pipe is filled with water)

π‘Šπ‘Žπ‘‘π‘’π‘Ÿπ‘ƒ.π‘€π‘’π‘–π‘”β„Žπ‘‘ = π‘ƒπ‘–π‘π‘’π‘–π‘›π‘‘π‘’π‘Ÿπ‘–π‘œπ‘Ÿ.π‘£π‘œπ‘™ βˆ— π‘Šπ‘€π‘’π‘–π‘”β„Žπ‘‘

Displaced Mud Weight

π·π‘–π‘ π‘π‘™π‘Žπ‘π‘’π‘šπ‘’π‘‘π‘Šπ‘’π‘–π‘”β„Žπ‘‘ = π‘ƒπ‘–𝑝𝑒𝑒π‘₯𝑑.π‘£π‘œπ‘™π‘šπ‘’π‘‘π‘€π‘‘

Effective Weight of Pipe

π‘Šπ‘† = π‘ƒπ‘–π‘π‘’π‘€π‘’π‘–π‘”β„Žπ‘‘ + π‘Šπ‘Žπ‘‘π‘’π‘Ÿπ‘ƒβ€’π‘€π‘’π‘–π‘”β„Žπ‘‘ βˆ’ π·π‘–π‘ π‘π‘™π‘Žπ‘π‘’π‘šπ‘’π‘‘π‘Šπ‘’π‘–π‘”β„Ž

Straight section A-B

Friction from Soil

π‘“π‘Ÿπ‘–π‘2 = π‘Šπ‘†πΏ1π‘π‘œπ‘ πœƒπ‘†1πœ‡π‘†π‘œπ‘–π‘™

Drag Forces from Mud

π·π‘Ÿπ‘Žπ‘”2 = πœ‹π·πΏ1πœ‡_π‘šπ‘’

Tension on Section

βˆ†π‘‡2 = |π‘“π‘Ÿπ‘–π‘2| + π·π‘Ÿπ‘Žπ‘”2 βˆ’ π‘Šπ‘ πΏ1π‘ π‘–π‘›πœƒ_𝑠1

Cumulative Pull Load

𝑇2 = βˆ†π‘‡2 +𝑇1

Curved Section B-C

Friction from Soil

π‘“π‘Ÿπ‘–π‘ = |𝑁3πœ‡π‘†π‘œπ‘–π‘™|

Drag Forces from Mud

π·π‘Ÿπ‘Žπ‘”3 = πœ‹π·πΏπ‘Žπ‘Ÿπ‘1πœ‡π‘šπ‘’π‘‘

Tension on Section

Cumulative Pull Load

𝑇3 = βˆ†π‘‡3 + 𝑇2

Straight Section C-D

Friction from Soil

π‘“π‘Ÿπ‘–π‘4 = π‘Šπ‘†πΏπ‘ π‘π‘œπ‘ πœƒπ‘†πœ‡π‘†π‘œπ‘–π‘™

Drag Forces from Mud

π·π‘Ÿπ‘Žπ‘”4 = πœ‹π·πΏπ‘ πœ‡π‘šπ‘’π‘‘

Tension on Section

βˆ†π‘‡4 = π‘“π‘Ÿπ‘–π‘4 + π·π‘Ÿπ‘Žπ‘”4 βˆ’ π‘Šπ‘ πΏπ‘ π‘ π‘–π‘›πœƒπ‘ 

Cumulative Pull Load

𝑇2 = βˆ†π‘‡4 + 3

 

Curved Section D-E

 

Friction from Soil

π‘“π‘Ÿπ‘–π‘ = |𝑁3πœ‡π‘†π‘œπ‘–π‘™|

Drag Forces from Mud

π·π‘Ÿπ‘Žπ‘”3 = πœ‹π·πΏπ‘Žπ‘Ÿπ‘1πœ‡π‘šπ‘’π‘‘

Tension on Section

 

Cumulative Pull Load

𝑇3 = βˆ†π‘‡3 + 𝑇2

Straight Section E-F

Friction from Soil

π‘“π‘Ÿπ‘–π‘6 = π‘Šπ‘†πΏ2π‘π‘œπ‘ πœƒπ‘†2πœ‡π‘†π‘œπ‘–π‘™

Drag Forces from Mud

π·π‘Ÿπ‘Žπ‘”6 = πœ‹π·πΏ2πœ‡π‘šπ‘’π‘‘

Tension on Section

βˆ†π‘‡6 = |π‘“π‘Ÿπ‘–π‘6| + π·π‘Ÿπ‘Žπ‘”6 + π‘Šπ‘ πΏ1π‘ π‘–π‘›πœƒ_𝑠1

Cumulative Pull Load

𝑇6 = βˆ†π‘‡6 +𝑇5

Tensile Stress at a Point

Allowable Tensile Stress

π‘‡π‘†π‘‘π‘Ÿπ‘’π‘ π‘ .π‘Žπ‘™π‘™π‘œπ‘€ = 0.9π‘†π‘€π‘Œπ‘†

Bending Stress at a point

Allowable Bending Stress

Hoop Stress at a point

Allowable Hoop Stress

a. If 0.55π‘†π‘€π‘Œπ‘† β‰₯ A
b. If 0.55 SMYS ≀ π‘Ž ≀ 1.6 π‘†π‘€π‘Œπ‘†
c. If 1.6 SMYS ≀ π‘Ž ≀ 6.2 π‘†π‘€π‘Œπ‘†
d. Otherwise

Unity Check – Tensile and Bending Stress

Unity Check – Tensile, Bending & Hoop Stress

Input Parameters

  1. To create a new case, click the β€œAdd Case” button
  2. Select the Pull Force and Installation Stresses – Vertical application in the HDD Steel Pipe 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

Pipe and Operational Characteristics:

  • Nominal Pipe Size(in)
  • Wall Thickness(in)
  • Pipe Grade
  • Pipe Outside Diameter(in)
  • Pipe Entry Angle (Β°)
  • SMYS – Specified Minimum Yield Strength(psi)
  • Design Factor
  • Young’s Modulus of Elasticity(psi)
  • Poisson’s Ratio
  • Coefficient of Friction: Pipe – Soil (0.21 – 0.3)
  • Coefficient of Friction: Pipe – Rollers (0.1)
  • Fluid Drag Coefficient (0.03 – 0.05) (psi)
  • Mud Weight (lbs./ftΒ³)
  • Water Weight(lb./ft)
  • Pipe Filled with Water:

Installation and Site Characteristics:

  • Measured Length: Section A-B
  • Pipe Entry Angle (Β°)
  • R1 – Radius of Curvature
  • Measured Length: Section B-C
  • Measured Length: Section C-D
  • Pipe Exit Angle (Β°)
  • R2- Radius of Curvature
  • Measured Length: Section D-E
  • Pipe Exit Angle (Β°)
  • Measured Length: Section E-F
  • Pipe Above Ground Section on Rollers
  • Angle of Pipe Above Ground on Rollers
  • Maximum Load Factor
  • Safety Factor

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
  • Length of the Straight Section A-B
  • Length of the Curved Section B-C
  • Length of the Straight Bottom Section C-D
  • Length of the Curved Section D-E
  • Length of the Straight Section E-F
  • Total Length of the Borehole

  • Effective Submerged Weight (lb./ft)
  • Pull Load Section on Rollers (lb.)
  • Pull Load Straight Section 0-1 (lb.)
  • Pull Load at Point 1 (lb.)
  • Pull Load Curved Section 1-2 (lb.)
  • Pull Load at Point 2 (lb.)
  • Pull Load Straight Section 2-3 (lb.)
  • Pull Load at Point 3 (lb.)
  • Pull Load Curved Section 3-4 (lb.)
  • Pull Load at Point 4 (lb.)
  • Pull Load Straight Section 4-5 (lb.)
  • Total Pull Load at Point 5 (lb.)
  • Maximum Allowable Pull Force (lb.)

Pass/Fail:

  • Allowable Tensile Stress (psi)
  • Total Tensile Stress (psi)

Pass/Fail:

Select Point of Interest (B)

  • Tensile Stress(psi)
  • Allowable Tensile Stress(psi)
  • Bending Stress(psi)
  • Allowable Bending Stress(psi)
  • Hydrostatic Mud Pressure(psi)
  • External Hoop Stress(psi)
  • Allowable Elastic Hoop Buckling
  • Combined Load Interaction at Point
  • Unity Check: Tensile and Bending
  • Unity Check: Tensile, Bending, and External Hoop

Select Point of Interest (C)

  • Tensile Stress(psi)
  • Allowable Tensile Stress(psi)
  • Bending Stress(psi)
  • Allowable Bending Stress(psi)
  • Hydrostatic Mud Pressure(psi)
  • External Hoop Stress(psi)
  • Allowable Elastic Hoop Buckling
  • Combined Load Interaction at Point
  • Unity Check: Tensile and Bending
  • Unity Check: Tensile, Bending, and External Hoop

Select Point of Interest (D)

  • Tensile Stress(psi)
  • Allowable Tensile Stress(psi)
  • Bending Stress(psi)
  • Allowable Bending Stress(psi)
  • Hydrostatic Mud Pressure(psi)
  • External Hoop Stress(psi)
  • Allowable Elastic Hoop Buckling
  • Combined Load Interaction at Point
  • Unity Check: Tensile and Bending
  • Unity Check: Tensile, Bending, and External Hoop

Select Point of Interest (E)

  • Tensile Stress(psi)
  • Allowable Tensile Stress(psi)
  • Bending Stress(psi)
  • Allowable Bending Stress(psi)
  • Hydrostatic Mud Pressure(psi)
  • External Hoop Stress(psi)
  • Allowable Elastic Hoop Buckling
  • Combined Load Interaction at Point
  • Unity Check: Tensile and Bending
  • Unity Check: Tensile, Bending, and External Hoop

Select Point of Interest (F)

  • Tensile Stress(psi)
  • Allowable Tensile Stress(psi)
  • Bending Stress(psi)
  • Allowable Bending Stress(psi)
  • Hydrostatic Mud Pressure(psi)
  • External Hoop Stress(psi)
  • Allowable Elastic Hoop Buckling
  • Combined Load Interaction at Point
  • Unity Check: Tensile and Bending
  • Unity Check: Tensile, Bending, and External Hoop

Related Links

Table of Contents
Table of Pages
  1. Pipeline HUB User Resources
  2. AC Mitigation PowerTool
  3. API Inspectors Toolbox
  4. Horizontal Directional Drilling PowerTool
  5. Crossings Workflow
  6. Pipeline Toolbox
  7. Encroachment Manager
  8. PRCI AC Mitigation Toolbox
  9. PRCI Thermal Analysis for Hot-Tap Welding
  10. PRCI River-X
  11. PRCI RSTRENG
  12. RSTRENG+
  13. Ad-hoc Analysis
  14. Database Import
  15. Data Availability Dashboard
  16. ESRI Map
  17. Report Builder
  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