Stiffness of weight coated subsea pipeline

Hi esteemd experts,
please, do You take into account stiffness of weight coating (cement) in Your analysis to evaluate the stress on equipment and/or any other part of the subsea pipeline that is not weight coated?
Thanks.
Best regards

Alessio

Historically, we only treat it as a hindrance, not a boon, for purposes of code stresses.

If increased stiffness exacerbates stresses and loads, you are incumbent to consider such effects within your analysis and route accordingly. Generally, increased stiffness is beneficial for piping, as long as poor piping practices are avoided.

I could envision that one could make a facsimile of cement coating by modeling the system as jacketed pipe, but there aren't any "cement" material options built in to CAESAR, which you'd need to research for yourself.

Thanks Mr. Fletcher,
I'm waiting for a training about ASME B31.4, meanwhile I'm studying the code and I'm performing some "experiment" by Caesar.

As regards weight coating, I made two model of an existing subsea pipeline.

The first has a carbon steel jacket featuring elastic modulus, density, outside diameter and thickness of reinforced concrete; the jacket is anchored by Cnode to inner 40" carbon steel pipe every two meters.

I used carbon steel for the jacket because thermal expansion coefficients are almost identical for this material and reinforced concrete.

The second has carbon steel pipe only but featuring:

- Equivalent elastic modulus;
- Density and thickness of insulation the same as reinforced concrete.

Results (displacements, stress on parts of pipeline WITHOUT weight coating and loads on restraints) are quite different.

Best regards

Alessio