auger cast piles

[chahnz]

Gentlemen,

During installation of an ACIP, the drill rig being used broke down. The pile was drilled down to the tip elevation, and then the malfunction prevented the installation of grout. The auger was removed without grouting the hole. Is it possible to "re-drill" the open hole, place the grout, and still have an acceptable pile?

Thank you in advance for any help with this matter.

 

[GeoPaveTraffic]

Redrilling should be fine. The grout take should be 20% or so greater than normal. If the pile is in clay and the capacity is mainly derived from skin friction, you may have a little less capacity. Under those conditions I would check with the structural to see how much load is needed from the pile.

 

[TDAA]

I have the same concern for the skin friction, if it is required. You might also want to consider stepping up an auger size to increase the end bearing and surface area for skin friction. If you determine just redrilling the pile is not sufficient, keep you contractor in the loop. You are likely looking at additional work that the owner should not have to pay for (looked like it is the contractor’s equip/actions creating this situation), and I’m sure the contractor will have something to say about cheaper alternate methods.

 

[oldestguy]

I had a case where the grout did not meet strength requirements a few days later. Fortunately the piles had no reinforcing.

The contractor drilled out the green grout and installed new in the same places. It is likely that he did not exactly follow the old piles and probably disturbed a lot of ground. These were friction piles and the power plant sitting on top has not moved.

I'd keep a close watch on the pressure gage and make sure it is functioning.