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RE: For the Record

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Ms. G. kelly,
 
Thanx for updating on the "actual" status of your professional engagements. I was actually sort of misled by your very "own" posting on this List (a very recent one) wherein you are on "record" stated to be associated with CRSI.
 
Beauty is in the "eyes" of the "beholder". This is the reason I am able to notice a "marked" improvement in your recent postings. You may choose to disagree; this is your prerogative.
 
I have noted your comment on 12x12-W18xW18 as an alternate to # 4 rebars @12"x12" spacing. You are trying to equate the "area of steel" of a welded wire fabric mesh to that of a "reinforcing steel" by apple-to-apple comparison. I most respectfully beg to DISAGREE with you on this account.
 
I agree a 12x12-W18xW18 wire fabric mesh will produce area of steel of 0.18 Sq. in. as compared to 0.20 sq.in  which is the actual area of steel in case of # 4 rebars spaced @ 12"x12". But you seem to forget that Reinforcing Steel has a lesser "yield strength" as compared to a welded wire which are noted below just in case it got slipped out of your mind:
 
                      
                                                                            Tensile Strength, Psi                  Yield Strength, Psi
 
              Plain Wires:         W 1.2 and above                       75,000                                    65,000
                                         under W 1.2                             70,000                                    56,000
 
            Deformed Wires        D 31 thru D 4                         80,000                                    70,000
                                            under D 4                              80,000                                    70,000
 
So, if the loading and span (panel dimension in case of SOG) and also the Concrete grade (also, soil properties in case of SOG) is constant, the area of steel obtained after analysis shall tend to be lesser, always, in case of wire fabric mesh  (by virtue of comparatively higher yield strength) as compared to those for equivalent dia of reinforcing steel. So, a 12x12-W18xW18, on this account, is a fair substitute/alternative for a # 4 rebar @12"x12".
 
I hope you understand the point. Your comment on the same shall be awaited. 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: Thursday, October 16, 2003 5:01 PM
To: seaint(--nospam--at)seaint.org
Subject: For the Record

For the record, I am not an employee of CRSI.  I do work for them in the sense that I write and edit technical publications for them.  Writing and editing technical publications is a large part of my consulting business.  I threw in the reference to CRSI lest I be accused of having a bias against fibers.  I don't,  I see nothing wrong with putting cat hair in concrete.  

I also don't see that my postings have improved.  In fact, I think all of my postings have been both tremendously witty and very informative.  In particular,  I try to make sure there is some element of useful information in each post.

For example,  I would not  recommend that someone use 12x 12 - W18 x W18 mesh.  This is not what I consider useful information.  Although I am sure a company like Ivy Steel would make it, it would probably cost several times more than using bars.  

If I were to post on that subject though,  I would note that wire mesh is typically specified at the same size as bar  when doing work in accordance with ACI 318.  (A W18 wire is not equivalent to a #4 bar,  since the 18 indicates the area is .18 sq. in. versus a #4 bar which is 0.20 sq. in.)

If this were a slab on grade,  you would not have to use an equivalent amount of steel.     If this were a slab on grade,  one could  use the yield strength allowed by ASTM and CSA, rather than what is allowed by ACI 318.  ASTM and CSA measure the yield strength at a strain of 0.5 % versus ACI 318 which requires the yield strength be measured at a strain of 0.35%.  The ASTM and CSA minimum yield strengths are 65 ksi for plain wire reinforcement and 70 ksi for deformed wire reinforcement.  

The yield strength measured at 0.35% strain is higher than 60 ksi, but not enough so to make it worthwhile for a contractor to seek approval for a specification change, which they would need to, if they were using less steel.

Gail Kelley


In a message dated 10/16/2003 3:10:00 AM Eastern Daylight Time, sfaiz(--nospam--at)saudioger.com writes:


Ever since you joind CRSI the quality of your postings on this LIST has considerably improved and do show the colors of a person engaged in Research. Keep up the good work!

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: Thursday, October 16, 2003 5:30 AM
To: Seaint(--nospam--at)seaint.org
Subject: Re: Water Proof Membrane


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