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RE: Welded Wire Reinforcement

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Ms. G. Kelly:
 
I thank you for your time in explaining; a major part of which you already had done before.
 
Although you have tried to touch base on my contention, vis-a-vis merit  in use of 12x12-W18xW18 in place of rebars of dia 1/2 @ 12" O.C, I still beg to disgree with you on this.
 
12x12-W18xW18 mesh is often used in SOG of thickness 12" (300 mm) and is not an out-of-stock item; it is readily available, atleast in this part of the world.
 
Welded Wire Fabric mesh (plain or deformed) are always produced which follow the specs of yield/tensile strengths greater than reinforcing steel, as noted in my last mail.
 
However, I do agree here that use of Welded Wire Fabric mesh end up costing more, at least theoretically, than those of rebars. But you must appreciate the fact that mesh is used, by and large, for compelling reasons rather than technical. It has lot of merits: is easy to handle and saves time for cutting, bending, fabricating and placing. There are many a occasion where use of mesh helps (and is preferred, no matter how expensive, as compared to rebars) for example: in slabs/walls with "openings". I have designed Feed Mills with numerous openings in slabs (of multi-storeyed building) where its extremely difficult to work with rebars; mesh is the best alternative. The SOG of maintenance buildings (with openings for various services) and Heli Pad (with openings for embedded lights) are some of few examples where mesh helps.
 
Finally: I am impressed with you pre-occupations. How do you manage time? You must have done a lot of training on "time management", I guess!!
 
I end  here with appreciation for your "quality" input on this List. Best regards,
 
Syed Faiz Ahmad; MEngg, M.ASCE
Senior Structural Engineer
Saudi Oger Ltd
Riyadh, Saudi Arabia
 
 
 
-----Original Message-----
From: GSKWY(--nospam--at)aol.com [mailto:GSKWY(--nospam--at)aol.com]
Sent: Monday, October 20, 2003 4:59 PM
To: seaint(--nospam--at)Seaint.org
Subject: Welded Wire Reinforcement

Certain individuals expressed indignation and outrage because Gene Corley did not disclose the fact that he did work for the "anti-fire sprinkler campaign" when he wrote an article in the Chicago Sun-Times about fire sprinklers.  Consequently,  I indicated that I did work for CRSI in my post about fibers.

I do work (writing and editing technical documents) for a number of associations besides CRSI;  I also do work (writing and editing technical documents and marketing material) for material suppliers,  consulting companies, and contractors.  However, my posts on this list are my personal opinions; they do not necessarily reflect the opinions of any of my clients.

With respect to the use of welded wire reinforcement to replace reinforcing bar - the original post asked about the use of welded wire reinforcement in a wall.  A wall would typically be considered a structural element, and thus subject to the requirements of ACI 318.  ACI 318 requires that when yield strength is taken as greater than 60 ksi, it be measured at 0.35% of the gage length.  The yield strengths in ASTM A82 (65 ksi) and ASTM A496 (70 ksi) are measured at 0.5% of the gage length.  Thus, these numbers cannot be used when welded wire reinforcement is used in a wall.

Welded wire reinforcement is actually used quite a bit in precast structural elements, for example precast jail cells.  The mesh used in the walls looks to be something like 6 x 6- W4.0 x W4.0.  As far as I know,  the mesh is always used at 60 ksi for precast structural elements.  To use it at greater than 60 ksi would require additional testing and to my knowledge this is not typically done.

With respect to using a 12 x 12 - W18 x W18 mesh,  I don't think  this is a stock item.  Ivy steel and probably many other mesh suppliers will make mesh with any wire size and spacing you want but there is usually a (very large) minimum order for anything custom.  As a result the mesh ends up costing a lot more than bar.

Gail Kelley