Friday, September 9, 2011

RE: Old Structural Mesh BF912

Daryl, Neil & David:

Thanks for all your replies and valuable information. I don't think we have
budget for sample testing. I found 1963 CRSI handbook in our office
library. Under Concrete Joist Construction, for 3" top slab, 4 x 12 - 8/12
Welded Wire Fabric listed, which makes sense changing from 9 gauge (0.1483"
Dia.) in 1930's to 8 gauge (0.1620" Dia.) in 1960's. The existing drawings
are in very good condition. The reinforcing BF912 Mesh can be read without
any difficulty in typical detail and general notes. My best guess for BF is
British Fabric! Anyway, the existing 3" slab cannot support increased
concentrate loads. We are going to field verify the locations of existing
joists & install new raised floors for storage.

Thanks again and have a great weekend,

Martin

-----Original Message-----
From: David B. Merrick, SE [mailto:mrkgp.se@gmail.com]
Sent: Thursday, September 08, 2011 9:41 PM
To: seaint@seaint.org
Subject: RE: Old Structural Mesh BF912

I wonder if the written BF letters are actually BW for Birmingham Wire
or British Wire

I would preliminarily assume a square wire mesh of 12" with a 9 guage
wire. My experience the strengths will be very close to standard loads
if not then try 9 inch square with 12 gage.

Watch out for less steel in gages rated by American Wire or Browne & Sharpe

The Carnegie steel hand book of 1926 showed the following wire gage
sizes, in inches, and all wire had a design strength of 20 ksi

9ga= 0.418 12ga= 0.109 Birmingham Wire BWG or Stubs Iron Works
9ga= 0.114423 12ga= 0.080808 American Wire or Browne & Sharpe
9ga= 0.1483 12ga= 0.1055 American Steel & Wire Co formerly
Washburn & Moon
9ga= 0.145 12ga= 0.105 Trenton Iron Company
9ga= 0.144 12ga= 0.104 British Imperial Standard Wire SWG
9ga= 0.1398 12ga= 0.0991 Standard Birmingham Sheet and Hoop BG

David Merrick, SE

----------------------------------------------------------------------------
--
From: nma [mailto:nma@nma-se.com]
Sent: Thursday, September 08, 2011 4:26 PM
To: seaint@seaint.org
Subject: Re: Old Structural Mesh BF912

>From Singleton - Copyright 1933, 1937,1947 - textbook at Cal Poly - 1950's:

Page 5: Welded Wire Mesh possibly interpreted as longitudinal steel: 9
gage at 4" spacing, transverse steel 12 gage at 12" spacing. Area/foot -
long: .052 in2, transverse steel: .009 in2. Obviously this would be for a
one-way type of slab. I can't find anything on what the "BF" is. It might
be B(?)Fabric!

My CRSI handbook is 1952 (first one) and they have a 4 x 12 - 9/12 listed
for One-Way Types.

Neil Moore, PE, SE


On 9/8/2011 11:15 AM, David Topete wrote:
That's a tough one to figure out. Any good leads yet? I'll check our
office library, but it sounds like a proprietary call-out. My guess is the
9 means a No. 9 wire. Maybe spaced at 12"o.c. Good luck with this one.
On Wed, Sep 7, 2011 at 2:25 PM, Martin Li <mli@tb-engr.com> wrote:
All,

We are working on a project that involves an existing reinforced concrete
building with the drawings dated 1937. The reinforcing specified for 3"
slab over joists is BF912 Mesh. Does anyone know BF912 Mesh?

TIA

Martin Li, P.E.


--
David Topete, SE

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