If you just graphically model them as large bends in Caesar, then Caesar will assume these are effectively just very very large radius fittings, ie. pre-bent pipe. The roped bends are elastically bent, the pipe would try to straighten out if you dug it up. To really model them in Caesar, I think you would have to model the piping as straight, then impose displacements on it to get it to the roped shape you want, then the bending stresses due to roping would appear in the modelled pipe results.

Is this worth the effort? I don't think so. Unless you are going over a mountain range, I would model the pipeline layout as flat and just manually add on the roping bending stresses to the Caesar results after.

What diameter pipe are we talking about? Would have to be significant OD for lay of the land roping to have much effect.