Should I use Buried Pipe Modeler for carrier/casing pipe

Hi, gentlemen,
I got a 14" carrier pipe with a 18" casing pipe to cross the highway. The carrier pipe is only inserted into the casing pipe. I am working on piping stress analysis on 14" carrier pipe using CAESAR II. Should I use Buried Pipe Modeler for carrier pipe? It seems that the carrier pipe is the same as the pipe on the ground.

The carrier pipe in itself isn't in contact with the ground. It's simply supported in the casing pipe (if it is) and it can freely expend over the length in the casing pipe. I would model the small part in the casing pipe is normal above ground piping.

Got it, thanks.