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Re: Deformed Mesh Substitution in slab

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John:

I have been reinforcing slabs-on -grade with minimum reinforcement per ACI 
7.12, ie: 0.0018bh.  This works out to #4@ 24" o.c. or #3@12" o.c.  I have 
stayed away from wire mesh due to the placing  problems you mention in your 
post.

What spacing are your smooth dowels?  I use 5/8 dia @ 24" o.c.

In answer to your question:
Questions:  Eventhough the tensile capacity of the proposed mesh matches
the current #4 configuration, is the "doweling" action across the sawcut
joints going to be weakend due to the smaller bar diameter?

When the slab cracks completely through the weakened plane we are left with 
the reinforcing resisting the shear, neglecting any interlocking of the 
concrete. Checking the average shear stress on the dowels versus the #3 mesh 
I get a higher shear capacity using the #3 @ 12, 80ksi mesh then I get with 
3/4" dowels @ 24" o.c.

Va=A*.45Fy , where A= equivalent area per foot. Fy=80ksi, A=0.11 for #3 and 
Fy=36ksi, A=0.22 for 3/4" dowels.

I hope this helps.

Regards,

Tom Jakaby, SE
Jakaby Engineering