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Drilled Pier/Caisson Reinforcement

Drilled Pier/Caisson Reinforcement

Drilled Pier/Caisson Reinforcement

(OP)
I am analyzing a guyed tower that rest on a 6' diameter by 50' deep drilled caisson. The major forces applied to the foundation is the down force and some minor shear force. The pier has only (18) #6 bars, which is not even close to 0.5% required by ACI, but since there is virtually no moment in the caisson but just a compressive load, do I still need to provide a minimum of 0.5% of steel reinforcement?
Thanks.

RE: Drilled Pier/Caisson Reinforcement

You are more than adequate.  Last week I had similar pier geometry (6 ft DIA., 45 ft embedment with 14 #7 bars). The PhiMn value was 3,600 k-ft and PhiPn value was 1,600 kips.  The vertical capacity was 500 kips & uplift was approx. 220 kips.

RE: Drilled Pier/Caisson Reinforcement

ACI 318 doesn't apply to drilled piers.

I don't recall if ACI 336.1 (drilled piers) requires the 0.5% but I don't believe it does.

 

RE: Drilled Pier/Caisson Reinforcement

(OP)
Is there a minimum reinforcement requirement for drilled piers or as along as PhiMn value is greater than PhiPn value than I should be o.k.?

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