Thank you all for your replies. As with many aspects of the Code, this looks like one where it's best to "Just do it", and I will henceforth. "I'm trying to keep my mind right, boss".
Although I'm still looking for the logic - if you have a lack of redundancy in your framing system that could lead to a possible failure of the framing system, how would that lead to a possible failure of the foundation, thus requiring an increase factor for the foundation? It seems you are making the foundation stronger to make up for a deficiency in a separate structural component. I can see a need for foundation redundancy but only if the foundation itself has some deficiency that makes you need an additional reliability factor. I see rho as an assurance factor for the framing itself; a penalty factor on the framing some have called it. It is related to the framing, some configurations of which have proven unreliable. But foundations have not been proven to need some means of redundancy, have they?
Not meaning to argue, just looking for engineering logic.
Bob G.
From:
Sent: Tuesday, August 19, 2008 9:22 AM
To:
Subject:
I'm designing a steel framed structure in Seismic Category D. For the steel framing,
Thanks for any help you can offer.
Bob Garner, S.E.
R. Garner
Moffatt & Nichol
Tel.: (619) 220-6050
Fax.: (619) 220-6055
e-mail: rgarner@moffattnichol.com