Auger Cast Piles 2

[SperlingPE]

The tolerance for location for the auger cast piles is +/- 3".
Several piles have been placed from 4" to 11" from required location.
Most of the piles are overlaid by a continuous pile cap.
All of the misplaced pile caps are still under the continuous pile cap.
However, they may be closer to the center line of the pile cap or closer to the edge of the pile cap or closer to each other (all depends on which way from their required location they were placed).
The piles under the continuous auger cast pile were designed to be staggered about the center line and the pile cap was designed for such placement.

Is there any remedy for this situation?

 

[jayrod12]

You could rerun the analysis of the pile cap to see if it will still distribute the loads. Also check your piles for spacing requirements and if they are too close the load carrying capacity might have to be reduced.

11" is a long way off of what was specified it's like they closed their eyes when drilling the holes.

Sometimes when we've come across piles in the wrong locations (or something else that causes them to be useless) we will get the contractor to cut off the piles below the pile cap, pour new piles and redesign the pile cap.

 

[Michel60]

Good afternoon Sperling,

Based upon the as-built locations you'll need to determine the center of resistance for the pile group (being out of tolerance will create an eccentricity from the center of load vs. the center of resistance) and see how much of an effect it has on the distribution of load amongst the individual piles. If the eccentricity is large some piles within the group may exceed their design capacity. The remedies could include placing additional piles to counteract the eccentricity, addition or strengthening of grade beams to resist additional moment, getting the geothech to increase allowable pile/pile group capacities based upon field data, etc. Also typically the project specification will include language that describes required remedies for work performed out of tolerance, normally including the addition of piles at the installers expense. I'd look there before offering any other options.

regards,
Michel

 

[msquared48]

Depending on the amount of eccentricity encountered, you may be able to avoid having to reset pile by adding grade beams transverse to the main grade beam to counter any induced torsional effects.

Mike McCann
MMC Engineering

 

[SperlingPE]

All of the suggested checks for the reinforcing are in the works.
Thanks for confirming what I am needing to do.

The specs do cover what needs to be done if additional piles are required.
However, I am constrained by property line for any additional pile caps/grade beams.
Also, note that the piles in question have capacity, so am optimistic that they won't be over loaded.