Drilled Pier Reinforcing
Drilled Pier Reinforcing
(OP)
This is a survey: What is your practice in establishing amount (if any) of longitudinal reinforcing in drilled piers that do do not have any moment other than that due to piers placed off-center?
For starters:
1) ACI would let you use plain concrete if that works.
2) The FHWA publication on drilled shafts recognizes the ACI approach, but goes on to say that FHWA prefers to use ACI requirements for reinforced columns.
3) CRSI 2002 Design Handbook recommends at least 1/2 percent longitudinal reinforcement, extending 3 shaft diameters (10' minimum) into the top of the pier, assuming adequate lateral support by the surrounding soil.
For starters:
1) ACI would let you use plain concrete if that works.
2) The FHWA publication on drilled shafts recognizes the ACI approach, but goes on to say that FHWA prefers to use ACI requirements for reinforced columns.
3) CRSI 2002 Design Handbook recommends at least 1/2 percent longitudinal reinforcement, extending 3 shaft diameters (10' minimum) into the top of the pier, assuming adequate lateral support by the surrounding soil.






RE: Drilled Pier Reinforcing
RE: Drilled Pier Reinforcing
thread507-186921: Full Length Reinforcing in Large Diameter Pier?
thread256-6852: Augered Piles
thread256-166950: Unreinforced caissons ???
Most of the drilled piers I've designed were in expansive clay regions and the vertical bars were based on two criteria:
1. An uplift force provided by the geotechnical engineer. This usually was some function of the clay and the pier diameter.
2. A minimum amount of 0.0075 x Ag
where Ag = gross area of the pier.
Item 2 would provide these results for various shaft diameters:
18" - 6 #5
24" - 6 #7
30" - 8 #8 (or 10 #7)
36" - 12 #8
RE: Drilled Pier Reinforcing
RE: Drilled Pier Reinforcing
RE: Drilled Pier Reinforcing
Archeng- Lenton is one proprietary name for the couplers. I think NMB splice is another.
RE: Drilled Pier Reinforcing
RE: Drilled Pier Reinforcing
RE: Drilled Pier Reinforcing
RE: Drilled Pier Reinforcing
I hope there is a foundation or earthquake person to correct me if I am wrong; for piles that are in a seismic area but are not part of the lateral resistance of the building, I think some bending should still be considered. There is horizontal movement in the layers of soil beneath the building that is not uniform. In other words, there are layers of soil shifting at different rates and causing bending in deep foundations that are only supposed to be part of the gravity carrying members of the building. Do any codes require a minimum amount of reinforcing in all piles on a site of a certain seismic category?
RE: Drilled Pier Reinforcing