Kira,
Regarding support SIF you are asking about, the support analysis is a different part which is generally carried out by support group in FEA or the similar software. Some companies may not have specially allocated support group, but any how they have designed specific supports for specific loading & pipe size. This you can find in support spec in the form of allowable loads on the weakest part of the support assembly. Also allowable loads in particular direction i.e. longitudinal (axial), lateral (loads on guides) & of course vertical load are given.
The purpose of telling all these things is that, when a support engineer derives these loads, he has already taken care of all these stress intensifying factors due to the geometry of the support assembly.
Therefore what remains to our side is the analysis of pipe treating support as rigid (normally) or in some extensive analyses with actual support stiffness (composite analysis case). Of course a stress engg. should cross check the loads coming on supports with the allowables from support spec.
In case of trunion, we weld it to pipe directly so making it as an integral part of it, so it becomes mandatory to consider SIF at that point.
I hope this will clear the things.
Thanks/Salamat.
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