my question is about the dynamic friction loads in the output of a dynamic analysis; I am not exactly sure what to do with them... are they real friction loads? if so, how come they are sometimes even larger than the vertical dynamic loads?

thanks in advance,

In CAESAR II dynamic analysis, modeled restraint friction is replaced with two springs mutually perpendicular to each other in the plane perpendicular to the restraint. The stiffness is based on 1) the restraint's coefficient of friction, 2) the normal load from the static load case identified in the Control Parameters, and 3) the "Stiffness Factor for Friction", also defined in the Control Parameters.
So once you get to dynamics, the (sliding) friction load is based on the calculated position of the pipe times this stiffness - no more mu*N.

so to my understanding those dynamic friction loads have to be considered by civil/structure. right?

My guess? Yes, but you provide the normal load and they will determine their own friction component.