From: "Sprague, Harold O." <SpragueHO(--nospam--at)bv.com>
Date: Wed, 28 Jun 2000 17:04:36 -0500
The current AISC Seismic Provisions force you into LRFD. If you elect the
ASD methodology of Part III, you will find that it is very similar to the
old plastic design. Part III is not worth the problems. Smile and go forth
into the Part I LRFD sunlight or walk off the LRFD cliff depending on you
disposition to LRFD.
ASTM A992 steel has a yield point from 50 ksi to 65 ksi.
Apparently you are using an SMF. If so, you need to get FEMA 267 and FEMA
267A which is the product of SAC. All will be made clear. SAC is due for
another wisdom dissemination at the end of summer.
Read AISC Seismic Provisions Part I, Sections 6.1 & 6.2. Section 6.1 says
you can't specify greater than 50 ksi yield and 6.2 tells you what Ry to use
to get the Fye. You will fall into the "other" category with A992 and use
Ry = 1.1. You can also test.
My portable pocket hysteresis loop lab broke down the other day and I am
relegated to braced frames.
> -----Original Message-----
> From: Ritter, Mike [SMTP:mritter(--nospam--at)lgt.lg.com]
> Sent: Wednesday, June 28, 2000 3:24 PM
> To: SEAOC List Server (E-mail)
> Cc: Campbell, Steve G. (Oak Ridge); Barclay, George; Bowling, Kevin;
> Daugherty, Darrel
> Subject: Expected Yield Strength of Steel?
> 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)