shearwall vertical reinforcing vs crossties ?
shearwall vertical reinforcing vs crossties ?
(OP)
I'm inspecting on a job right now, high rise CIP concrete, with lots of shearwalls.
One of the shearwall notes reads:
CROSS TIES ARE REQUIRED WHERE AREA OF SCHEDULED VERTICAL REINFORCEMENT
EXCEEDS 0.01 TIMES THE GROSS CONCRETE AREA OF THE WALL. IF CENTER TO
CENTER SPACING OF VERTICAL BARS IS 6" OR SMALLER, CROSS TIES SHALL BE
PLACED AT EVERY OTHER PAIR OF VERTICAL BARS; OTHERWISE, ALL VERTICAL BARS
SHALL BE CONFINED WITH CROSS TIES.
The plan view detail, of course, shows neatly placed #3 cross-ties confining #9 vertical bars; however, in real life there is a 66" lap splice and a #3 bent into a 135-degree hook is never going to wrap around #9's spliced side-by-side.
So I'm curious, out of all the CIP shearwalls I've seen over the years, I've never seen SW verts dog-legged similar to column vertical bars so that the bars can be spliced front-to-back instead of side-to-side.
Is there something in ACI-318 that disallows vertical bars in shearwalls from being dog-legged?
One of the shearwall notes reads:
CROSS TIES ARE REQUIRED WHERE AREA OF SCHEDULED VERTICAL REINFORCEMENT
EXCEEDS 0.01 TIMES THE GROSS CONCRETE AREA OF THE WALL. IF CENTER TO
CENTER SPACING OF VERTICAL BARS IS 6" OR SMALLER, CROSS TIES SHALL BE
PLACED AT EVERY OTHER PAIR OF VERTICAL BARS; OTHERWISE, ALL VERTICAL BARS
SHALL BE CONFINED WITH CROSS TIES.
The plan view detail, of course, shows neatly placed #3 cross-ties confining #9 vertical bars; however, in real life there is a 66" lap splice and a #3 bent into a 135-degree hook is never going to wrap around #9's spliced side-by-side.
So I'm curious, out of all the CIP shearwalls I've seen over the years, I've never seen SW verts dog-legged similar to column vertical bars so that the bars can be spliced front-to-back instead of side-to-side.
Is there something in ACI-318 that disallows vertical bars in shearwalls from being dog-legged?






RE: shearwall vertical reinforcing vs crossties ?
Othwersise, if side-to-side laps are preferred, then the cross ties would have to be altered to be a series of rectangular ties (like in a traditional column) and wrap around pairs of bar lines. Even with that, the corner of the tie may have to wrap on a dummy vertical bar or something. I've rarely had ties in shear walls so I may have to think about that.
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RE: shearwall vertical reinforcing vs crossties ?
There is seldom a need for an offset bend, but they can be used in congested walls. Also remember that lapped bars do not have to be in contact so the hook can go around one bar but not the other unless the design calls for ties around all bars.
RE: shearwall vertical reinforcing vs crossties ?
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: shearwall vertical reinforcing vs crossties ?
In the OP, the note says that bars spaced 6" or less, as would be the case with non-contact laps, require ties on every other bar. I would interpret this to mean that there will be ties on every other bar along the non-contact laps. The rebar detailer may or may not provide enough ties for this condition, so I would discuss it with the supplier or placer early in the project.