Double Rebar Matt?
Double Rebar Matt?
(OP)
I do not do a lot of concrete design other than foundations, footings and occasional beams in foundation walls.
On past projects, whenever i've designed above grade concrete walls, regardless of whether the wall needed it or not, we always put a double rebar matt similar to (2) layers or matts of #4 bar at 12" oc E.W.
On elevators and bank vaults we've always done it this way, with an assumed understanding that this was code for such applications.
Other than elevator or bank vault applications, is there a reason for having a double matt of rebar in above grade concrete walls even when the stress for a single layer is well below 50%?
The majority of concrete, cantilevered retaining or basement walls only have ONE layer of rebar.
Why two?
Thank you!
On past projects, whenever i've designed above grade concrete walls, regardless of whether the wall needed it or not, we always put a double rebar matt similar to (2) layers or matts of #4 bar at 12" oc E.W.
On elevators and bank vaults we've always done it this way, with an assumed understanding that this was code for such applications.
Other than elevator or bank vault applications, is there a reason for having a double matt of rebar in above grade concrete walls even when the stress for a single layer is well below 50%?
The majority of concrete, cantilevered retaining or basement walls only have ONE layer of rebar.
Why two?
Thank you!






RE: Double Rebar Matt?
I don't know if that applies in your case, or if there are other code requirements that also steer you toward two layers.
RE: Double Rebar Matt?
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RE: Double Rebar Matt?
RE: Double Rebar Matt?
I always go with one centered layer in walls < 10" unless loads demand a double layer. I also know of no such requirement for elevator walls.
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: Double Rebar Matt?
But for most typical buildings I would agree with the above. One layer (unless required for strength reasons) at t < 10", at t > 10" use 2 layers.
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Double Rebar Matt?