With regard to minimum reinforcement in thick sections, ACI 350R recommends:
"Concrete sections 24 in. or thicker may have the minimum temperature and
shrinkage reinforcement at each face based on a 12 in. thickness."
> -----Original Message-----
> From: Vyacheslav Gordin [mailto:scgordin(--nospam--at)hotmail.com]
> Sent: Wednesday, May 26, 1999 9:11 AM
> To: seaint(--nospam--at)seaint.org
> Subject: Reinforcement of massive pedestals
> I need to design a footing for a large vertical vessel in a highly
> seismically-active area. Soils are good, though, and allow
> the footing pad
> to be 20'x20'x36." The loads (including considerable weight
> and seismic
> shear and uplift/pullout) are applied through three
> baseplates @120 degrees
> connected to a 12'x12'x4'-6" pedestal centered on the
> footing. The pedestal
> height is dictated by the technological process.
> Within the contact areas I installed rebar cages similarly to
> short tied
> "columns." I also tied the tops of the three "columns"
> together with rebars
> to resist considerable shear.
> Unsure about the reinforcement of the rest of the pedestal.
> Both the ACI
> 0.0018 and Caltrance's 0.0025 reinforcement ratios appear to
> be excessive.
> Any thoughts about how to reinforce the pedestal away from
> the areas of
> contact (apparenly, minimum reinforcement)?
> Steve Gordin, S.E.
> Irvine CA