WHAT ADITIONAL CONSIDERATIONS SHOULD BE TAKEN TO MODEL HIGH TEMPERATURE PIPES WITH STEAM TRACES?

It seems unlikely that your steam tracers would greatly stiffen the pipes moment of inertia. However one could derive a combined moment of inertia I suppose to see how much stiffer the tracer would make the pipe... see a book on statics roark and young etc.

If your tracer does stiffen the pipe significantly (>5%)I suspect it would be directional in nature, unfortuantely the beam pipe elemnet that CAESAR II as well as all other pipe flex beam element programs use is a circular tube with symetric properties about the neutral axis.

In your flexibility analyses, consider the temperature the pipe may rise to if the tracing is on but with no flow in the line.

My openion is that the tracer will not affect the inertia of the traced pipe because the way of fixation between the two members is not anchor. The only effect is the additional weight which can be represented by uniform load.

When people talk about tracers sometimes they mean tubing starpped on and bedded in heat transfer cement, not very likely to change I.

However I have seen tracers made of half pipes angles or channels welded to the headers with steam in their annulus spaces these will stiffen up the header.

I agree it is unlikely but the question was vague and did not specify how or what the tracers were hence ny vague response.