Column offset from pier & baseplate centerline
Column offset from pier & baseplate centerline
(OP)
This seems like a straightforward question but, given the picture below, do you see any issues with this offset? The architect is adamant on having the piers flush with the outside face of the foundation wall.
I'm only worried about the locations where we will have braced frames. With the uplift force being eccentric from the anchor rods, I would need to design the plate for the moment from the 2 anchor rods that are farther away. Or, conservatively, assume only the two closer anchor rods are taking all the tension load. Am I thinking about this right? Any thoughts?
Information:
- 2 story library addition
- Small building/small loads
- Low seismic area
The purple lines are the base plate and anchor rod holes. The blue/green lines are the pier. Hopefully this is clear enough.
I'm only worried about the locations where we will have braced frames. With the uplift force being eccentric from the anchor rods, I would need to design the plate for the moment from the 2 anchor rods that are farther away. Or, conservatively, assume only the two closer anchor rods are taking all the tension load. Am I thinking about this right? Any thoughts?
Information:
- 2 story library addition
- Small building/small loads
- Low seismic area
The purple lines are the base plate and anchor rod holes. The blue/green lines are the pier. Hopefully this is clear enough.

RE: Column offset from pier & baseplate centerline
RE: Column offset from pier & baseplate centerline
RE: Column offset from pier & baseplate centerline
I vote for something in between these extremes. Some designers will assume a uniform distribution of base plate compression stress or anchor bolt tension. I think that's erroneous given the relative flexibility of small columns versus the concrete pies etc. I'd estimate the tension in the anchor bolts imagining the column to be connected to the plate via a pin or ball joint (corner condition).
RE: Column offset from pier & baseplate centerline
Being in somewhat of a silo at my current company, this website is invaluable and I really appreciate everyone's help.