Spiral Ties in CFA Piles (Canadian Code)

[efFeb]

Good Afternoon,
I've received a contractor request to switch to spiral ties in CFA piles, but looking at the Canadian code there is a minimum spiral tie pitch of 75mm. Has anyone done this before? This seems impractical and difficult to do, but I wonder if I am overlooking a clause that may excuse this requirement for piles.
Thanks so much,

 

[hokie66]

Minimum or maximum?

 

[dik]

Max spacing... Spiral ties have really good confinement; is it for full length? They add a lot of steel. I usually use 10M ties at 36" o/c or 48" o/c, with 3 or 4 @ 6" o/c at the top... just to tie the vert bars together if I'm using more than 1 vert. What is the dia? 40 years back I started reinforcing 16" friction piles with a single #5 (15M) it was common at the time to see 4#4s, and it is common to day to see a single 20M bar in these environs. For larger diameter piles, it is common to see 4 or more vertical bars, but not spiral ties. If no tension, then check development length of your pile vert to see if you can avoid a hooked bar. I generally use bar lengths of 6m and the rest of the pile is unreinforced. 6m because common bar length is 18m and cut into 3...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[EireChch]

I have heard many people say that CFA piles are reinforced with one single central bar. Its interesting to me as I have never seen it done, I asked a more experienced Piling contractor in the UK and he said he hadnt either.

Must be a non-UK thing