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Re: Spiral tie reinforcing

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Steve Uthoff wrote:
> >I am detailing spiral ties for drilled piers with seismic forces.  It's been
> >a while since I've detailed spirals, and I can't find a copy of ACI 315
> >detailing manual right now.  I'm wondering about a few things.
> >
> >1.  Would spiral ties be smooth wire (ASTM A82) or deformed wire (ASTM ???).
> > I think smooth wire is typically used.
> >
> >2.  If so, how would you splice smooth wire?  Is a lap splice OK?  Is 48 bar
> >diameters enough?   In ACI-318, Chapter 12, I can only find splice
> >guidelines for deformed bars and smooth wire fabric.
> >
> >3.  My instincts tell me you should weld smooth bar splices.   ASTM A82
> >doesn't come out and say that the wire is weldable (no chemical properties
> >listed), but I assume you go straight to ASTM A185 for WELDED wire fabric
> >and know that you can weld it.
> >
> >Steve Uthoff


You should use deformed bar, I don't think anyone should use smooth bar
nowaday.  Per ACI318-83, the clear spacing between spiral turns should
not exceed 3 in. or less than 1 in. or 1 1/3 times the maximum size of
coarse aggregate.  Spirals should also be provided with 1 1/2 extra
turns at both top and bottom.  Splice can be done by either butt weld or
tension lapped in field, 48 diameter minimum, but not less than 12 in.

Good luck,

Tom Chiu, SE