PEMB Anchor Bolt Eccentricity
PEMB Anchor Bolt Eccentricity
(OP)
All,
Anchor bolts are the PEMB responsibility (to a point), but embedment, etc. is mine as the foundation engineer. Since PEMB building footings are rarely concentric with the footings, I see the anchor bolts being loading eccentrically for uplift. I know that the metal building people are assuming concentric resistance from footings, etc. Any thoughts on this? I can easily design the footing for uplift, but I'm worried about the anchor bolts being underdesigned based on how I design the footing.
My guess is that this is rarely considered based on my experience with PEMB foundations and seeing other designs, etc. But I'm not a big fan of just assuming.
Thanks
Nick
Anchor bolts are the PEMB responsibility (to a point), but embedment, etc. is mine as the foundation engineer. Since PEMB building footings are rarely concentric with the footings, I see the anchor bolts being loading eccentrically for uplift. I know that the metal building people are assuming concentric resistance from footings, etc. Any thoughts on this? I can easily design the footing for uplift, but I'm worried about the anchor bolts being underdesigned based on how I design the footing.
My guess is that this is rarely considered based on my experience with PEMB foundations and seeing other designs, etc. But I'm not a big fan of just assuming.
Thanks
Nick






RE: PEMB Anchor Bolt Eccentricity
RE: PEMB Anchor Bolt Eccentricity
RE: PEMB Anchor Bolt Eccentricity
RE: PEMB Anchor Bolt Eccentricity
RE: PEMB Anchor Bolt Eccentricity
RE: PEMB Anchor Bolt Eccentricity
RE: PEMB Anchor Bolt Eccentricity
I wouldn't worry about this at all. Design your foundation such that it doesn't rely on a moment being taken into the bolts or the column and such that there isn't a large rotational displacement required to actually make that happen. If this is true and they've detailed their baseplates and columns in a standard way, you should be fine. In extreme load cases you might see yielding in the plate or bolts or column base, but that small moment will release. If the pin base assumption didn't work, we'd have had structures falling down all over the place for a hundred years.