Uplift in Concrete Pier
Uplift in Concrete Pier
(OP)
I have looked thru every reference I have, as well as searched here, and I don't see alot of information regarding uplift on a concrete pier. Let me describe what I'm talking about:
I have a situation where I have a steel column suppported by a concrete pier. The baseplate is 24" x 24", the pier is 28" x 28", and the anchorbolts are 19" apart. The bolts are 1 1/4" bolts. Concrete is 4,000 psi
I am trying to determine the uplift capacity of the pier at different bolt embedment lengths.
I started by looking at the PCI Design Handbook example that uses a (4) headed stud group in a pier with (4) free edges (Figure 6.5.4.2, Case 6). I looked at 24" and 36" bolt embedments. What I found was the uplift capacity at 24" embedment is about 14 Kips, which to me, is surprisingly small. It looks to me like this number is this small because no accounting is made for reinforcing in the pier (plain concrete).
So I have searched high and low for data regarding the uplift capacity with a heavily reinforced pier, but have found nothing that I could really use.
Here's what I'm thinking:
Could I provide a anchor rod/vertical pier reinforcing lap length that would fully develop the vertical pier reinforcing in tension, based upon the pier vertical reinforcing bar diameter, and then provide confinement reinforcing around the anchorbolt group to prevent side blow out, and, reinforce the pier, in the length of pier containing anchor rods, via #4 closed tie sets (one offset front the other by 45 degrees) at 3" o.c. And develope the full uplift capacity of the pier based upon the tension in the pier reinforcing?
I need around 130 Kips of uplift capacity.
Can you guys point me to a good reference for this type of design? THe AISC design guide for base plates and anchorbolts does not address it, and, I don't see anything in my ACI data that addresses it....unless I'm overlooking something....that's why I went to my PCI data, but this does not account for the actual conditions.
I have a situation where I have a steel column suppported by a concrete pier. The baseplate is 24" x 24", the pier is 28" x 28", and the anchorbolts are 19" apart. The bolts are 1 1/4" bolts. Concrete is 4,000 psi
I am trying to determine the uplift capacity of the pier at different bolt embedment lengths.
I started by looking at the PCI Design Handbook example that uses a (4) headed stud group in a pier with (4) free edges (Figure 6.5.4.2, Case 6). I looked at 24" and 36" bolt embedments. What I found was the uplift capacity at 24" embedment is about 14 Kips, which to me, is surprisingly small. It looks to me like this number is this small because no accounting is made for reinforcing in the pier (plain concrete).
So I have searched high and low for data regarding the uplift capacity with a heavily reinforced pier, but have found nothing that I could really use.
Here's what I'm thinking:
Could I provide a anchor rod/vertical pier reinforcing lap length that would fully develop the vertical pier reinforcing in tension, based upon the pier vertical reinforcing bar diameter, and then provide confinement reinforcing around the anchorbolt group to prevent side blow out, and, reinforce the pier, in the length of pier containing anchor rods, via #4 closed tie sets (one offset front the other by 45 degrees) at 3" o.c. And develope the full uplift capacity of the pier based upon the tension in the pier reinforcing?
I need around 130 Kips of uplift capacity.
Can you guys point me to a good reference for this type of design? THe AISC design guide for base plates and anchorbolts does not address it, and, I don't see anything in my ACI data that addresses it....unless I'm overlooking something....that's why I went to my PCI data, but this does not account for the actual conditions.






RE: Uplift in Concrete Pier
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Uplift in Concrete Pier