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RE: Re[2]: MISC - Mill Certification/Higher Yield Stress

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Just my 2 cents worth regarding steel material specifcation

Mills don't supply A36 wide flange shapes any longer.  It is best to specify 
A572 GR50 
(per technical bulliten #3) for wide flange shapes A36 for plates, channels, 
and angles. 
note that A572 can be specified for plate if needed by design.

Lanny J. Flynn, S.E.

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From: 	Daniel.Bernd(--nospam--at)fluordaniel.com
Sent: 	December 31, 1997 7:57 AM
To: 	seaoc(--nospam--at)seaoc.org
Subject: 	Re[2]: MISC - Mill Certification/Higher Yield Stress

     Monte,
     
     You mentioned that are now specifing ASTM 572 grade 50 exclusively,
     the spec for the job that I am currently working on calls for a dual 
     certified A36/A572 50 ksi min. yield steel.  Do you have any comments 
     on that?
     
     daniel.


______________________________ Reply Separator 
_________________________________
Subject: Re: MISC - Mill Certification/Higher Yield Stress
Author:  MGriffi119@aol.com_at_-FDInternet at FDINET
Date:    12/31/97 2:19 AM


Our office standard for ductile frame design was to use A36 material for the 

beams and A572 50ksi for the columns, mostly to ensure strong column weak 
beam
behavior. The design was based on plastic section properties and load 
factors
(AISC Chapter "N"), and our notes specified a maximum yield of 42 ksi for 
the
A36 material. I recently (1995) designed a project with ductile steel moment 

space frames where the fabricator contacted me to say that it was IMPOSSIBLE 

to obtain such material, that 51 ~ 53 ksi was as close as could be 
gotten.......and it would be a range. My response was I thought it could be 
found and had been before, so quit crying and get it. He then got an AISC 
person to call me back to tell me that 42ksi material was not being produced 

in the United States anymore (due to the high quality of the scrap). So I 
was
forced to revise my design for the frames to use 50ksi as the yield for the 
beams also, and this necessitated increasing the column sizes 
considerably(the
beam mill certs came back at 54 ksi). But the SAC committee on ductile frame 

design recommends using values much higher than 36 or 42 ksi for the actual 
yield, since the steel being produced averages 50 to 55 ksi yield, even 
though
it may be graded ASTM A36. Incidentally, our office did a project approx 9 
months before my project, and we got mill certified 42 ksi yield beams, 
exactly as specified......from Japan. Anyway, to be on the safe side, I now 
use 50ksi as design yield stress for everything, plastic design or ASD..... 
and
specify A572 Gr 50 exclusively.
     
                  Monte Griffiths, RCE