Transverse Reinforcement in Drilled Piers

[MikeDTDS]

I'm working on pier reinforcement design for CIDH foundation piers.

I work in California and am struggling with ACI recommended minimum steel ratios. The California Building Code (CBC) refers to ACI 318 to determine minimum transverse steel ratio and spacing. CBC refers to ACI 318 Chapter 21 and ACI 318 Chapter 21 refers to ACI 318 Equation 10-5. Equation 10-5 requires transverse steel ratio near 5% for 16" to 18" diameter piles.

My experience in construction and judgement tell me that 5% is way to high. Also, I have frequently built other engineer's designs where steel ratio is closer to 1% or 2%.

Can someone PLEASE point in the direction of an appropriate reference for transverse reinforcement design in CIDH piers?

 

[JAE]

Well, ACI 318 doesn't apply to drilled piers (see 1.1.6). So technically the column tie requirements aren't specifically applicable to piers (ACI 336 is for piers)

However, it always seemed to me that the upper portions of the drilled pier would tend to behave more like a column than a soil confined shaft of concrete.

 

[MikeDTDS]

JAE - I agree that ACI 318 excludes piers but the CBC for pier design specifically references ACI 318 and FHWA Augercast Design/Construction Manual references the same ACI equation 10-5 in their reinforcement design recommendations. Lastly, I don't see any refinforcement recommendations in ACI 336.

If ACI 336 is truly the correct reference can you be more specific?

 

[slickdeals]

Maybe you can look in ACI 543