Precast pile driving issues

[Forensic74]

If a precast concrete pile is cast at the plant with its top head out-of-square, does anyone have a feel for how badly it can be out-of-square before it gets risky to damage the pile? I know pads are placed on top of the pile so Im assuming there is some play in the spec?

 

[CELinOttawa]

The rule I was taught was to calculate the cross sectional area and ensure that it is at least 90% of the design cross section.

More importantly you should be considering the long term durability. If you are out of square, you need to check that your minimum covers have been achieved where they will matter.

 

[BUGGAR]

First question, how did it leave the plant in the out-of-square condition? We apply ACI tolerances to piles (don't make me look them up) and use neoprene pads.
We've never had (accepted) a pile that was out of tolerance. Most of our piles are driven to a specified blow-count and cut off in the field. The pile butts in the field have no problem meeting ACI tolerances and that's a field cut.

 

[CELinOttawa]

Not necessarily the US... And even if it were, mistakes do happen, though rejecting on for the lack of in-spec would be simple in most jurisdictions.

Forensic: What's your location?

 

[Forensic74]

USA

The piles arrive on site with heads out of square (top end not perpendicular to the longitudinal axis) say up to 1/2-inch out of square, the piledriving contractor tries to drive them and the top 10 feet of the piles spall apart. Seems like a stupid decision to attempt to install them unless there is a standard method to accommodate out of square piles.

 

[CELinOttawa]

That doesn't sound like it would happen due to out of square, but is more likely due to poor to insufficient pile strength. Many possible factors there...