There used to be minimums in the AISC design guide for base plates, but they went away in the second edition of that design guide. I don't believe there are minimum requirements anymore, just what you need to develop the required strengths per ACI 318 appendix D.
just to clarify...i am looking simply for a min embed length rule. strength is a separate issue that i've taken care of...i was just wondering if there's some min out there, perhaps for serviceability, for cover, etc, but it sounds like there used to be a min that was removed from the base plate design guide.
There is really no set minimum. AISC previously had a table with minimums (see Table 8-26 of 2nd Edition LRFD Manual) which ranged from 12db to 17db prior to the "Appendix D" craze. Personally I generally use 12" min. for typical gravity columns.
I agree with other posts that there is no minimum embedded length for anchor bolts in tension.
Strength and embedded lengths are related because the strenth is the smaller of tensile strength of bolts or pull-out resistance.
However for shear there is recommended 10d or 12d spacing requirements either from concrete edge or between bolts because of the conical failure mode. If the bolt is too close to edge then it will spall off in shear or if the bolts are too close to each other then there is overlapping of critical regions.
