Why does standard Welded Wire Mesh does not meet ACI criteria?
Why does standard Welded Wire Mesh does not meet ACI criteria?
(OP)
Hello fellow Structural Engineers,
This may be a dumb point, but 6x6 - W1.4xW1.4 WWM comes up woely short of the ACI requirement of 0.0018.... in a 4" slab, WWM = 0.28 sq in/ft, but ACI requires 0.0018*4*12 = 0.0864 sq in/ft.
what's that all about?
Why does standard Welded Wire Mesh that we always put in slabs not meet ACI shrinkage & temperature criteria (7.12) for slabs with welded wire mesh? Do the joints make up for it instead?
I guess 7.12 is for structural slabs only, and slab-on-grade is not meant to be included.
Mike
This may be a dumb point, but 6x6 - W1.4xW1.4 WWM comes up woely short of the ACI requirement of 0.0018.... in a 4" slab, WWM = 0.28 sq in/ft, but ACI requires 0.0018*4*12 = 0.0864 sq in/ft.
what's that all about?
Why does standard Welded Wire Mesh that we always put in slabs not meet ACI shrinkage & temperature criteria (7.12) for slabs with welded wire mesh? Do the joints make up for it instead?
I guess 7.12 is for structural slabs only, and slab-on-grade is not meant to be included.
Mike






RE: Why does standard Welded Wire Mesh does not meet ACI criteria?
RE: Why does standard Welded Wire Mesh does not meet ACI criteria?
So where are the minimum requirements for slab-on-grade?
Seems like it's just owner/geotech preference?
Mike
RE: Why does standard Welded Wire Mesh does not meet ACI criteria?
DaveAtkins
RE: Why does standard Welded Wire Mesh does not meet ACI criteria?
RE: Why does standard Welded Wire Mesh does not meet ACI criteria?
The new ACI 360-06 changes things AGAIN. They have even changed the name. It is now "welded wire reinforcement" (WWR)instead of welded wire fabric (WWF). It's more PC and marketable I guess. It's a chart for unreinforced but since the slab is only nominally reinforced, it is recommended to use these control joint spacings.
4" slab - about 8'
5" slab - about 12'
6" slab - about 14'
7" slab - about 16'
8" slab - about 17'
There are design methods in ACI, PCA, and WRI. The WRI are free to download. ACI 360-06 contains them all. PCA Slabs on Ground is a good book although dated a bit.
RE: Why does standard Welded Wire Mesh does not meet ACI criteria?
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RE: Why does standard Welded Wire Mesh does not meet ACI criteria?
Does anybody actually do this?
I really think the contractor would try to have architect all over me if I tried to make them install CJ at 8'!
FWIW, my old firm probably puts in multiple million sq. ft. of 4" SOG per year with a 20-30' (depending on the engineer) CJ spacing and I've never heard of a problem.