Dear All,

I have a concern about the buried soil modeler in CAESAR II.

1) In buried piping portion, are the restraint stiffness calculated for the pipe-soil interactions for both the horizontal and vertical pipe sections?

2) If Yes, then I would like to understand how CAESAR II does this for the vertical portion of pipe.
Does it linearize the depth of soil cover (input in basic soil modeler as "buried depth to top of pipe") to calculate soil stiffness in vertical pipe section OR the burial depth input is taken same throughout in arriving restraint stiffness for vertical and horizontal pipe section.
I have a vertical section of pipe of around 3m getting buried.

I'm trying to attach the above detail in image, but am not able to do so. I'll be thankful for detail regarding this response too!

1) Yes, though caution is needed with long vertical sections.
2) CAESAR assumes the depth you provided it applies to the entire vertical section of pipe. It may be worthwhile to have a separate "average depth" soil model for your vertical run(s).

My experience with buried pipe and CAESAR is that the results are not very sensitive to different soil models and depths. Perhaps others can chime in with their own experiences.

Thanks Michael for your response.

Normally the result is not so sensitive by varying different soil models and depths, but in this case (unfortunately I'm not able to attach image - and would like guidance here too!)

- the deeply buried horizontal header is having 25 similar branch connections coming out at regular interval.

- vertical buried branch section is about 2.5 - 3m deep.

- There is increased loads & stresses at the branch connections, simply due to soil stiffness restraining the branch movement along the pipe.

As the burial depth is reduced from:
1) basic soil modeler & simultaneously by
2) clicking corresponding nodes in buried model input (as per height defined)
loads and hence stresses reduces significantly.

What I'm thinking is, stiffnesses corresponding to 3000 mm of soil cover, defined in basic soil modeler is getting applied to the branches as well.
As expected, CAESAR II is not averaging or varying soil stiffness, which it should have done based on pipe layout.

This is becoming increasingly conservative for higher buried depth.

Kindly suggest!

Click "Switch to Full Reply Screen" and click the "File Manager" link.

You can split up your vertical section into smaller sections and use soil models of varying depths. E.G. meter 0-1 can be at a depth of 0.5, meter 1-2 can be at a depth of 1.5, etc.

Thanks Michael for your prompt response!