Pipe Anchor Force Analysis

The following analysis determines stresses and deflections in pipelines at the transition from below ground (restrained) to above ground (unrestrained) to determine if an anchor is required for above-ground pig traps or other piping facilities.

Internal pressure, temperature change, the flexibility to absorb a degree of lateral anchor movement is not considered in this calculation.

Tensile stress due to Poisson effect

Where:
𝜗 − Poisson′s Ratio = 0.3
𝑃 − Design Pressure(psig)
𝑑 − Inside pipe diameter(in)
𝑡 − Pipe wall thickness(in)

Compressive stress due to temperature change

Where:
𝐸 − Young′s Modulus of Elasticity 𝐸=29 x106.
𝛼 − Coefficient of Thermal Expansion for steel α = 6.5 x10−6[in/in℉]
∆𝑇 = 𝑇𝑜 −𝑇𝑖
𝑇𝑜 − Operating Temperature(℉)
𝑇𝑖 − Installation Temperature(℉)

Net longitudinal stress at beginning point (A) of the transition

Where the strain will be 𝜀=0, fully restrained

Net longitudinal stress at endpoint (B) of the transition

Net strain at point (B) will be:

Soil resistance force based on Wilbur’s formula for average soil

Where:
𝐷 − Outside pipe diameter(in)

Length of transition zone

Where:
𝐴 − Pipe metal area(in2)

Total pipe movement at point (B) will be:

Anchor force

Input Parameters

Select the Pipe Anchor Force Analysis application from the Steel Pipe – Design and Stress Analysis module
To create a new case, click the “+” button
Enter Case Name, Location, Date, and any necessary notes
Fill out all required fields
Make sure the values you are inputting are in the correct units
Click the CALCULATE button

Nominal Pipe Size(in)
Wall Thickness(in)
Design Pressure(psig)
Installation Temperature and Operating Temperature(°F)
Poisson’s Ratio
Young’s Modulus of Elasticity(in)
Thermal Expansion Coefficient(1/°F).

Output Parameters

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

Hoop Stress(psi)
Compressive Stress Due to Temperature Change(psi)
Net Longitudinal Stress at Point A(psi)
Net Longitudinal Stress at Point B(psi)
Net Longitudinal Stress at Point B(in/in)
Soil Resistance(lbf/ft)
Length of the Transition Zone A-B(ft)
Total Pipe Moment at Point B(in)
Anchor Force(lbs.).