This is always a great topic of conversation if you want to find differing
My reply would be yes, depending...
The best reference is the "ACI Manual of Concrete Practice". There is an
excellent presentation of theory and practice.
A very crude summary would be:
For pure vertical load, technically no. The drilled and cast in place pile
could be structural plain concrete. (ACI 318.1) Another comparison would be
a Cal-Trans style "rock-column".
Most engineers I know, myself included, would typically include a minimum
amount of reinforcing for cracking control, either .0014 or .0018 times the
gross area. (tied)
If uplift resistance is involved, obviously the force must be transferred to
the pile, and the pile designed as a tension member.
If lateral resistance is provided by the piles, then reinforcement is a
must, and the section should be designed as a beam column, with the required
reinforcement fully developed beyond the "point of fixity" per the
Additionally, if you are designing a reinforced concrete cast in place pile,
I usually use a minimum diameter of 18" to facilitate concrete placement.
My $0.02 worth,
Paul Feather PE
----- Original Message -----
From: Edward Jonson <edjonson(--nospam--at)email.msn.com>
To: SEOC <seaint(--nospam--at)seaint.org>
Sent: Saturday, May 15, 1999 7:24 AM
Subject: Augercast piles
> I have a project in zone 3 with augercast piles, and the soils engineer
> given me the following design criteria: 16 inch dia piles, allowable load
> 100 K, depth to fixity 10 feet.
> My question is, is there a minimum amount of vertical reinforcement?
> Ed Jonson