Pier Anchor Bolts - ACI 318, Appendix D ?
Pier Anchor Bolts - ACI 318, Appendix D ?
(OP)
So, I'm designing a canopy similar to a gas station canopy. The columns are supported on concrete piers which are 6'-10" tall from the footer (top of footer is 2' below grade). The columns are designed such that they are moment resisting at the base and the canopy is pinned at the top.
I initially used ACI 318, Appendix D, for design of the column anchor bolts, using hf = 12". But I've heard others use a different method where the length of the anchor (hf) is based on the development length of the column rebar. I was going to use 8 -#8 rebar for the column, but that would give me about a 48" ld, which seems a bit too long for an anchor bolt.
I'm wondering who out there uses this method of anchor bolt design and how they implement it?
I initially used ACI 318, Appendix D, for design of the column anchor bolts, using hf = 12". But I've heard others use a different method where the length of the anchor (hf) is based on the development length of the column rebar. I was going to use 8 -#8 rebar for the column, but that would give me about a 48" ld, which seems a bit too long for an anchor bolt.
I'm wondering who out there uses this method of anchor bolt design and how they implement it?






RE: Pier Anchor Bolts - ACI 318, Appendix D ?
Some years back I attended a seminar by S. K. Ghosh Associates on this. They provided an excellent guide for anchoring bolt groups where the loads exceed what is in appendix D.
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
A couple comments -
1) In order to use the pier reinforcing they want to be within a few inches of the anchors (plan dimension offset).
2) I would use the Asreq'd/Asprovided to reduce the developement length. If you're using (8) #8 for the 1%, that's likely going to be way more than you need for a tension member - take advantage of it.
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
I also like to use anchor plates and nuts or just nuts on the anchor.
Like EIT said, if the pier steel is not close to the anchor, I don't rely on it as being effective in transferring the forces.
Attached is a decent paper on the matter by some guys at Bechtel, I think...
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
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RE: Pier Anchor Bolts - ACI 318, Appendix D ?
We are Virginia Tech
Go HOKIES
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
Is it this publication from SK Ghosh?
http://se
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RE: Pier Anchor Bolts - ACI 318, Appendix D ?
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
We are Virginia Tech
Go HOKIES
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
We are Virginia Tech
Go HOKIES
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
That looks like it. What I have is the pdf from the seminar, and that drawing on the cover is one example from the pdf.
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
You're right, I posted the wrong one. Thanks for catching that. Here is the article I meant to post.
RE: Pier Anchor Bolts - ACI 318, Appendix D ?
I wouldn't read too much into how they came up with the loads.
In order to actually determine the tension in the rods due to an overturning moment you need to analyze the column-baseplate-anchor rod assembly and take into account the stiffness of the plate, bearing of the plate on concrete, and the anchor rod layout.
For a simple approach your intuition is right. A moment on the bolt group, M, would result in tension in two bolts and compression in the others. M/d(the distance between bolts) would give you a rough number for tension & compression.