  The gravitational clustering hierarchy and dissipative gas processes are both
involved in the formation of bulges. Here we present a simple empirical model
in which bulge material is assembled via gravitational accretion of the visible
companion galaxies. Assuming that merging leads to a starburst, we show that
the resulting winds can be strong enough that they self-regulate the accretion.
A quasi-equilibrium accretion process naturally leads to the Kormendy relation
between bulge density and size. Whether or not the winds are sufficiently
strong and long lived to create the quasi-equilibrium must be tested with
observations. To illustrate the model we use it to predict representative
parameter dependent star formation histories. We find that bulge building
activity peaks around redshift two, with tails to both higher and lower
redshifts.
