A friend is building a really nice house…ok so it’s really expensive…almost the same thing. I was at the site with her today and she was pointing out some stuff while I was not listening cuz I was looking at details. It’s a concrete slab with thickened edge, reinforced with rebar throughout. There is an offset in one wall, liike for a bay window. The offset is about 2 feet by 4 or 5 feet. There are two rows of top & bottom rebar along the perimeter, tioed together with bent stirrups, and it looks like maybe #6 bar, with #4 throughout the slab. I had expected to see an offset in the rebar also, but they cut it and tied it together at the joints. There’s no overlap like you would expect, like whern the specs call for an overlap of 8x the diameter etc. It looks kinda like this
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except that it’s 5 pieces of steel: the left & right ends, the two diagonals, and the offset. She did not have a set of foundation dwgs so I couldn’t see what the engr spec’d. Am I worrying about nothing?
Whenever you are asked if you can do a job, tell’em “Certainly, I can!” Then get busy and find out how to do it. T. Roosevelt
Replies
The most likely place for an issue to develop and the place where reinforcment steel is most needed is where the concrete changes direction.
If the specs called out #6 in the perimeter, I'll bet you that they called out the overlap.
It may be called out like "continuous" instead of speccing an overlap. Did they lay overlap Ells in the corners?
In any case, the contractor is just wasting your friends money doing the popout reinforcement like that.
Did the inspector see it?
BTW, it's not of 8x the diameter, it is, IIRC, 42x. I always use 48x 'cuz the math is easier, the inspector doesn't have to guess or measure, and the little bit of extra steel is cheap. With #8 and bigger I might want to save those pennies.
SamT
No, they didn't use ell-splices at the joints. If they had, I wouldn't have asked the question.
It has not reached the inspection stage yet, so I feel less obnoxious about bringing it to their attention. Like that would bother me anyway :)
I knew the lap was a function of the dia, but at the moment I couldn't remember the number so I just made up something as an example.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
I think it shoulda been:
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/
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/
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Three pieces shown... the open 'u' shape is extended into the slab at least 12" and tied across the next piece in the mat. If you were feeling fresh you could make two more bends and tie it alongside that piece also, but the embedment is enough.
All the overlaps I've ever done have been 30 bar diameters.
That would work for the top bar, but the bottom bar is 18-24" down into the footing trench. Anyway, I brought it to the HO's attention last night, and he's going to politely ask the builder.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt