
	Applies To

	Product(s):	AutoPIPE,
	Version(s):	2004, XM, & V8i
	Environment:	N/A
	Area:	Modeling
	Subarea:
	Original Author:	Bentley Technical Support Group

Attention: Please see the following AutoPIPE help sections:

Help > Contents> Contents Tab>

1. Reference Information> Pipe Soil

This section will provide information on

a. Model Discretization

b. Defining Soil Points in AutoPIPE

c. Soil Restraint Properties in AutoPIPE

d. Calculation of Soil Restraint Properties - AutoPIPE Method

e. Calculation of Soil Restraint Properties - ASCE Method

f. Comparison of Soil Restraint Properties

g. Soil overburden stresses application on AutoPIPE points

2. Modeling Approaches> Example systems> PIPE-SOIL Interaction: Transition Example.

The purpose of the following example system is to demonstrate the procedure required to

a. Calculate soil properties using AutoPIPE and ASCE method

b. Verification of values with hand calculations

c. Determine the location of critical piping points to be defined for the above to below ground (transition) piping system shown in the Figure below.

In this example, the piping system is subjected to a temperature rise of 230°F, and an internal pressure of 100 psi. For simplicity, a single soil will be assumed to interface with the pipe over the entire length of the buried portion of the system.

This online help section will provide step by step procedure of modeling soil properties in AutoPIPE.

Comments, Quesions, and Answers about Soil Properties:

What will be the yield displacement value for following

- yield displacement to calculate longitudinal loose clay soil spring stiffness;
- yield displacement to calculate longitudinal loose sandy soil spring stiffness;

Answer: Per the onlne help for this parameter,

Longitudinal Yield Displacement, y1L [inch]
Enter the longitudinal yield displacement. The value is used when calculating the soil resistance, p1, in the longitudinal direction.
Defaults: Low = D/60, High = D/25.

Also, per the AutoPIPE soil example (mentioned above):

For medium sand, assume the value of yield displacement to be d/45.

Bentley is not able to provide a specific values for modeling, must use engineering judgement or consult a soil engineer when determing values such as this. In addtion, AutoPIPE's Soil calculator can consider high, low, and avg values when generating soil spring stiffenss values based on soil parameters.