Bolted connections are rigid links connecting geometry. As such, results in the immediate area are suspect and not accurate. Proceed with caution.
my understanding of the formulation of the bolt connectors is this:
-beam element is the bolt.
beam is connected to part via rigid coupling - to the selected bearing surfaces.
bearing surfaces are: the washer bearing area only for non close fit and both the cylindrical surfaces and the washer surfaces for close fit. For screws you have a cylindrical area at the thread end regardless of close fit or not.
for the foundation bolt the ground end of the beam is fixed in all 6 DOF.