ok, you have a solid mesh (for 3D elements). if you planned things, you'd have a line of nodes that you could make into a beam.
two things,
1) i'd suggest modelling the column as a single beam with the properties of the composite concrete and rebar(?)
2) at a minimum i think the "beam" should be modelled as a rod (if it is rebar). if it is something substantial (like an I-beam) then modelling as a beam Might be ok ... remember the solid elements only have translational freedoms so you'll need to think about constraining the bending freedoms in the beam (maybe only the torsion, Mz).
3) consider posting in the structural forum, they deal with this type of structure more often.
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