Precast Column Attachment
Precast Column Attachment
(OP)
Have a precast job, working on a entrance way to a building. They are using precast beams and columns to support the entryway.
The question I have is the precaster wants to make the columns in pieces. The top is a 1'-0" piece, then a 6 foot piece on a 2'-0" piece at the bottom. I see why they want to break it up, forming it in 1 piece would be horrendous. They are proposing to join it all together with threaded rods in one piece and grouted to the next.
I have no uplift, and moment is minimal. The beams are concentric at the top, but would consider some accidental eccentricity.
The connections take the shear fine, I am questioning stability. Im worried if someone hits them with a car, etc.
Thoughts?
The question I have is the precaster wants to make the columns in pieces. The top is a 1'-0" piece, then a 6 foot piece on a 2'-0" piece at the bottom. I see why they want to break it up, forming it in 1 piece would be horrendous. They are proposing to join it all together with threaded rods in one piece and grouted to the next.
I have no uplift, and moment is minimal. The beams are concentric at the top, but would consider some accidental eccentricity.
The connections take the shear fine, I am questioning stability. Im worried if someone hits them with a car, etc.
Thoughts?






RE: Precast Column Attachment
I don't see why that would be horrendous. There must be something missing from your description of the situation?
These connections can take certainly moment if they are designed with that intent in mind. Certainly, you'd have stiffness discontinuities at each joint that would be tough to assess accurately. I wouldn't sweat it for something with minimal axial load though. Behavior would probably be governed by stiffness in the 6' segment anyhow.
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: Precast Column Attachment
Its a architectural piece too, square pieces and round pieces, all in same column. I will ask why they are doing it.
its well over designed, almost 2'-0" dia for maybe 10-20K load. Its more for the architecural look. Usually its a steel post with cladding, this time all precast.
Thanks
RE: Precast Column Attachment
Sounds like that's probably our answer. I don't think that there's anything much to be worried about here.
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: Precast Column Attachment
Dik
RE: Precast Column Attachment
Still, I agree with the above; this should be doable with threaded rod if they want to go that route.
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
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