WWF Smooth Vs Deformed 1

[bigmig]

I was reading today in an article from Structure magazine that smooth WWF is not a recognized slab
reinforcement in the ACI. I guess I have been doing it wrong for many years. Just curious if this is just news to me,
or if it is commonly accepted with my peers.

Thanks in advance.

https://www.structuremag.org/?p=16967

 

[KootK]

I'll welcome the opportunity to get schooled on this but it is news to me as well. I was under the impression that:

a) Temperature and shrinkage reinforcement, such as that occurring in many SOG's, still had to be developed.
b) Smooth wire WWF was developed at the cross wires without placing reliance on bond to the wire being developed.

 

[dik]

Surprise here, too, Koot... thought it was b)

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Harbringer]

SOG would fall under ACI 360 and there is a section in ACI 360 for WWF.

The quote references plain WWF not being recognized for ACI 318 for structural slabs. Different documents.

 

[Greenalleycat]

In New Zealand mesh is used all the time in 'structural' slab on grade applications
A mesh reinforced slab has a low capacity, sure, but that's fine - you just use supplementary reo until the demand drops to match capacity
Houses etc rely on mesh reinforced slabs all over the show for transmitting lateral loads etc etc
It's definitely not ideal in every situation (e.g, suspended concrete floors acting as lateral diaphragms should use deformed bars) but it's a load of rubbish to say that they don't work as structural slabs on grade...it's been done for decades

Putting my conspiracy hat on... <hat on>
I do a lot of work with post-earthquake houses and resolving insurance disputes
'Structural function' has insurer/lawyer speak written all over it
Feels to me that insurers are trying to setup a framework for denying claims in the future because the mesh reinforced slab 'does not have a structural function'
This is not an imagined argument, as we have this argument on the regular with insurers and other engineers when it comes to repairing different damaged elements in houses - it has huge implications for repair specs under an insurance policy
But of course, the argument may be real but the conspiracy may not be
</hat off>

 

[BridgeSmith]

Based on the preceding paragraphs, I read that as applying to structural slabs, including those that happen to be on grade (designed per ACI 318). This would not apply to a SOG that does not support structural loading (designed per ACI 360).

 

[HTURKAK]

In my zone, when you say WWF everyone will understand deformed wire fabric which consist of cold drawn steel
wire mesh. In general mild steel ( St 37 ),is used and cold drawn out from higher diameter steel bars ( e.g. 8 mm st 37 bar cold drwan, the dia reduces 6.5 mm ) . Due to cold-working,their strength is higher than that of mild steel (St45/50). The WWF manufactured with longitudinal and transverse wires (at right angles to one another) joined by resistant spot welding .

When i look

CHAPTER 2—NOTATION AND TERMINOLOGY
reinforcement, deformed—Deformed reinforcement is defined as that meeting the reinforcement specification in this code.No other reinforcement qualifies.This definition permits accurate statement of development lengths. Bars or
wire not meeting the deformation requirements or welded reinforcement meeting the spacing requirements ”plain reinforcement,” for code purposes, and may be used only for spirals.


The spacing requirement for WWF is 10 in. for the transverse wires.

In this case, if the WWF composed of plain bars satisfies the spacing requirement , may be treated as deformed bars due to welded transversal bars.
Is this interpretation missing something? am i wrong ?




He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..

Luke 6:48

 

[Seppe]

The author of the article appears to be incorrect here.

ACI 318 does recognize bond between concrete and welded plain wire reinforcement, achieved via bearing and shear strength that develops at the welded crosswire intersections given that the smooth surfaces of the wires needing to be developed are otherwise unable to create this bond/friction. Section 20.2.1.7.3 requires the spacing of these intersections to not exceed 12 inches for WPWR.

Additionally, Table 20.2.2.4(a) makes no distinction precluding WPWR from use in flexural applications, which would include all manner of slabs and beams.

 

[BridgeSmith]

AASHTO also has provisions for the use of plain wire WWR, and does not limit the locations where it can be used.

 

[TLHS]

Are people using WWF for structural applications? I've used it in slabs on grade, as crack control on things that are basically plain concrete from a stress standpoint and as a supplemental layer in some weird detailing types of things where I may want to make sure there's surface reinforcement but the strength design has some other load path.

In anything other than that, you basically end up in the mesh sizes that are just prearranged rebar just to hit minimum steel in most applications.

 

[Seppe]

We use structural mesh quite a bit, actually. Mostly with the tilt-up walls and industrial slabs we design, but we also allow it in foundations and elevated slabs.

It’s more for the contractor than anything else given it can help speed up their placement operation.

Simplest approach for us on everything other than SOG is to design and detail with rebar but allow the mesh as an alternate if that’s the direction the contractor elects to go.

That said, we don’t really specify plain. It’s all deformed WWR.

 

[BridgeSmith]

We've just started using WWR for our bridge approach slabs, but we're using D20 and D31, which is deformed 1/2" and 5/8" 'wires'. Seems suspiciously like #4 and #5 deformed bars, but whatever.