Comments, Questions, and Answers on this modeling approach in AutoPIPE

Overview:

Please see the following AutoPIPE help section:
Help > Contents> Contents Tab> Modeling Approaches> Modeling Approaches> Cuts: Cold Spring

From online help:

A cold spring is used to reduce thermal forces on vessels, pumps, and other types of equipment connected to a piping system. The force reduction is achieved by fabricating the pipe slightly shorter than the required dimension and then pulling it into place during erection (at the ambient temperature). This creates a state of internal pre-stress which is opposed to the stress that results from the (high) temperatures encountered under operating conditions.

When a cut-short is specified at a point, AutoPIPE applies the cut to the section of pipe preceding the current point. Thus, a cut cannot be defined at the first point in the pipe system. In addition, a cut cannot be specified at a bend.

In AutoPIPE, create a model as described on both: "Cuts: Cold Spring" and "Model 1: Cut-Short (high operating temperature" with the following exceptions; apply cut short on the horizontal leg to U1 load case, and cut short on the vertical leg to U2 load case (see Forum page: cut-short analysis).

Item #1:

I am having trouble making sense of the cold spring (cut short) utility in Autopipe. 

Answer: Cut short is better explained by a series of images and load sequencing:

Gr+T1: No cut short is applied:

Gr+T1+U1: cut short is applied to the horizontal pipe run only:

Gr+T1+U2: cut short is applied to the vertical pipe run only:

Gr+T1+U1+U2: cut short is applied to both the vertical and horizontal pipe runs:

Notice the affect it has on the anchors for the respective load cases, 

Conclusion, cut short does provide a reduction in anchor loads when correctly applied.

See Also

Modeling Approaches

Bentley AutoPIPE

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