To: "SEAOC List Server (E-mail)" <seaint(--nospam--at)seaint.org>
Subject: Re: Expected Yield Strength of Steel?
From: Scott E Maxwell <smaxwell(--nospam--at)engin.umich.edu>
Date: Wed, 28 Jun 2000 17:34:40 -0400 (EDT)
I assume that BOCA 1999 references the 1997 AISC Seismic provisions.
Thus, my response is based off that assumption.
Per section 6.2 of part I of the 1997 AISC Seismic provisions, the
expected yield strength is Ry*Fy, where Fy is minimum yield for the
material (50 ksi in your case) and Ry is 1.5 for A36, 1.3 for A572 gr 42
and 1.1 for other grades for rolled sections. Thus, your expected yield
should be 50*1.1=55 ksi.
The seismic provisions were created and based off of LRFD principles.
However, there is part III which is the ASD alternative. It basically
modifies the LRFD provisions in Part I to an ASD-like approach.
Hope this helps,
Scott Maxwell, PE, SE
On Wed, 28 Jun 2000, Ritter, Mike wrote:
> We are working on a steel building design, and the code (BOCA-99) has
> directed us to use the AISC Seismic Provisions, Part 1 and 3. However,
> it looks like we're getting re-directed into something that looks like,
> well, like LRFD. Anyway, for the moment connection design we now need
> to the "expected yield strength" of the steel. We are specifying ASTM
> A992 (Fy= 50 ksi). Does anybody have the answer? Is this supposed to
> be case by case or can we just say we "expect" it to be around XXX Ksi?
> Do we need to do something, and then verify it with mill test results?
> Thanks for the help, Mike
> Michael D. Ritter, PE
> Senior Structural Engineer
> Lockwood Greene Technologies
> 1201 Oak Ridge Turnpike
> Oak Ridge, TN 37831
> (865) 220-4418
> (865) 220-4310 (fax)