Drilled Pier Cold Joint
Drilled Pier Cold Joint
(OP)
A Contractor of mine poured the first 25 feet of a 3' dia 30' drilled pier foundation designed to support a steel lattice transmission structure before he realized the foundation was off by the correct drilling location by about a foot. Construction halted and the top 5' haven't been poured and the anchor bolts have not been set. The anchor bolts can be placed in the correct location within the rebar cage, but obviously the required clear cover to the anchor bolt is inadequate for loading.
My inclination is to demand that the foundation be dug up and reconstructed, but the contractor insist that forming up an additional foot around the correct anchor bolt location will be adequate. What sources can I quote considering the obvious cold joint will be exactly where the tension and compression failure cone will be? I don't doubt that a solution could be made without digging up the mistake I'm just having difficulty finding sources on construction joint in drilled piers.
I know that a drilled pier is just a continuously supported column and construction joints can occur at the intersection of beams and columns yet I imagine this is a different case where the cold joint is in the most undesirable and unplanned place. What source details the connection of emergency cold joints?
My inclination is to demand that the foundation be dug up and reconstructed, but the contractor insist that forming up an additional foot around the correct anchor bolt location will be adequate. What sources can I quote considering the obvious cold joint will be exactly where the tension and compression failure cone will be? I don't doubt that a solution could be made without digging up the mistake I'm just having difficulty finding sources on construction joint in drilled piers.
I know that a drilled pier is just a continuously supported column and construction joints can occur at the intersection of beams and columns yet I imagine this is a different case where the cold joint is in the most undesirable and unplanned place. What source details the connection of emergency cold joints?





RE: Drilled Pier Cold Joint
ACI Committee 309, "Guide for Consolidation of Concrete (ACI 309R-05),"
American Concrete Institute, Farmington Hills, MI, 2005, p. 19.
RE: Drilled Pier Cold Joint
I would be nervous in your case with what is being proposed. I would insisted they install a new shaft or sister shafts. Contractors are always trying to put the liability on the engineer to cover up for their mistake. There is a reason why cold joints in drilled foundations are not a standard of practice whether you know the reason or not!
RE: Drilled Pier Cold Joint
RE: Drilled Pier Cold Joint
RE: Drilled Pier Cold Joint
If the soil permits, you might need to either install a parallel pier or connect the adjacent pier on the same tower to counter any off-center loads.
As for the cold joint, make sure the surface of the existing is clean and the reinforcement is clean and in good condition. Make certain that the reinforcement extends a full development length into the concrete above the joint (or as required for uplift), and the anchor bolts lap an appropriate length with the reinforcement. If there is doubt about this, hooks or field installed heads can be put on the bars to anchor the concrete above the joint to the pier below.
RE: Drilled Pier Cold Joint