Dec 2014, AutoPIPE V8i 09.06.01.10

Problem:

In the Virtual Anchor Length equation (La = Co * Lm), how can the value for Co be adjusted?

Solution:

From the online help:

Co = Dimensionless constant which lies in the range from 1.0 ("stiff" soils) to about 2 (soft soils).

The magnitude of "Co" can be greater than 2.0 if the longitudinal yield strength (P1 ) is not achieved by the soil.Comparison of analysis results for similar system models with various virtual anchor lengths indicate that estimated values of "Co" should be limited to the following range (unless a larger value can be justified):

1.5  </=  Co  </=  2.0

The system model can be terminated and anchored at a distance away from a bend (or tee) equal to the virtual anchor length (La) without any loss of accuracy to the analyzed results. Depending on the overall configuration of the piping system and the type of analysis to be performed, the inclusion of Zone 3 in the system model may or may not be necessary or desirable. This decision is left to the judgement of the Engineer/modeler.

In conclusion, AutoPIPE does not currently (v.09.06.xx.xx and lower) allow the value of "Co" to be adjusted by the user. It is set at a constant value of Co = 2.0. With regards to modeling, having an adjustable value of "Co", the virtual anchor length "La" value will only be shorten by a small order of magnitude.

See Also

Model Soil Properties with Soil Calculator

Bentley AutoPIPE

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