CSA A23.3 Spiral tie spacing requirements for piles

[canwesteng]

Is anyone aware of a way to weasel out of the maximum spiral pitch in CSA A23.3? Specifically regarding clause 7.6.4.3 (7.6.4.4 in 2004), giving the max clear of 3". Contractors often want to use spirals for piles (understandable as they hold their shape well), but usually just suggest swapping tie spacing with spiral pitch. I'm thinking there must be a way to weasel out of this, otherwise why are yards even set up to make spirals at an 8"/10"/12" pitch?

 

[hokie66]

My point about the spacing of ties is that if you use a 3' spacing, your longitudinals are not doing any good. May as well leave them out.

 

[dik]

They hold the top portion together in case of adfreezing or heave or movement due to our highly plastic clays... I'll keep them...

Dik

 

[jayrod12]

I agree with dik. That's likely because we practice in the same locale. We are less concerned about lateral or compressive contribution from pile/caisson reinforcement. Around here it's either frost jacking or pure uplift we need it for.

 

[dik]

jayrod... it also accommodates any small eccentricities that may be located near the top of the pile... loading is generally so small compared to the concrete x-section that reinforcing is not needed to contribute to the axial strength.

Dik