Top layer or reinforcement in column footings
Top layer or reinforcement in column footings
(OP)
What is the top layer of steel for in a reinforced concrete spread footing?
I have seen multiple structural designs where some engineers specify a layer of steel at top and bottom of footings and others where engineers only specify the bottom of the footing.
The only two reasons I see it being necessary is either for uplift changing the direction of bending in a footing or temperature and shrinkage min. steel requirements. Just looking for some guidance. Thanks.
I have seen multiple structural designs where some engineers specify a layer of steel at top and bottom of footings and others where engineers only specify the bottom of the footing.
The only two reasons I see it being necessary is either for uplift changing the direction of bending in a footing or temperature and shrinkage min. steel requirements. Just looking for some guidance. Thanks.






RE: Top layer or reinforcement in column footings
RE: Top layer or reinforcement in column footings
RE: Top layer or reinforcement in column footings
After posting I read in the RISAfoundation manual that their program will use a top layer when the footing goes into "partial uplift" designed for the negative moment induced by the uplift action.
It seems to me that for simplicity, a lot of engineers just place whatever amount of steel used in the bottom (based on design) in the top of the footing also. Just wanted to make sure I wasnt missing something. Thanks for the responses.
RE: Top layer or reinforcement in column footings
RE: Top layer or reinforcement in column footings
If is is smaller bars, then it could be minimum reinforcing or for uplift.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Top layer or reinforcement in column footings
RE: Top layer or reinforcement in column footings
RE: Top layer or reinforcement in column footings
Never, but never question engineer's judgment
RE: Top layer or reinforcement in column footings
Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it
RE: Top layer or reinforcement in column footings
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RE: Top layer or reinforcement in column footings
RE: Top layer or reinforcement in column footings
RE: Top layer or reinforcement in column footings
Can you explain your above comment with regard to consolidation?
RE: Top layer or reinforcement in column footings
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Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it
RE: Top layer or reinforcement in column footings
With top bars in deep sections, it is usually necessary to revibrate to prevent plastic settlement cracks.
Those settlement cracks illustrated in the link due to different thickness are a worse situation than the ones over the bars.
RE: Top layer or reinforcement in column footings
I have never seen it. Makes good sense and it is good to know.
Our guys do run vibrators in the footing during the whole placement. Maybe we're getting lucky?
RE: Top layer or reinforcement in column footings