min reinf in equipment foundation

huangyhg

min reinf in equipment foundation
hi,
i am to provide main (vertical) reinf in an equipment foundation which is octagonal foundation with each side =1574mm. depth of this fdn is 1.5m out of which 300mm above ground.
i am struggling to provide min reinf into this foundation. aci318 cl 10.9 says that ther should be min reinf = 0.01ag whic result in huge no of bars of very big dia. is there any other ref clause which can actually reduce this value.
btw this is high seismic zone area so actually cl 10.8.4 is not applicable in reduciog the gross area.
thanks
looks like you are defining it as foundation element but, providing minimum required reinforcement for column.  for footing the min. required reinf. is = .002ag.
and this minimum is for temp and shrinkage.
but, shouldn't this pedestal be treated as a compression element, rather than a flexural element.
then all the footing should be as they carry compression force from columns.
the definition of column per aci-318 is-
alright, so which clause is the one which define reinf area as 0.002ag, (blame it to my limited knowledge of aci)
moreiver do i need to provide 3d reinf cage to avoid any shrinkage cracks within the core. is there any clause on this issue. i have see this kind of 3d cage for m/c foundation blocks. is it not valid here ?
aci-318- 10.5.4.
what kind of equipment is this? there may be significant dynamic loads involved.
but what about the clause in chapter 15, "footing"(sorry , the code is not in front of me)of aci318 which says that at least reinf equal to 0.005ag should be extended from supporting element(bsae slab) to the supported slab.
49merc, there is no dynamic load on this foundation. it is just a vertical vessel.

the 0.005ag provision would be for a pedestal extending above the footing to the column (typically) bearing elevation.  it does not apply to the footing itself.
that's the amount of vertical reinforcement required at the interface between column and footing to transfer force from column to footing.