Friday, February 20, 2009

Re: ASCE 7-05: RSA Procedure per 12.9

> If you have not done so already, download FEMA 450-1 and FEMA 450-
> 2.  These are the NEHRP Provisions, and more importantly a detailed
> commentary, which were the base documents for the current IBC/ASCE
> Seismic requirements.

I actually have both books open right here in front of me - got 'em about a year ago. Aren't you impressed?

> Think of the 85% rule as just a minimum code value without trying to
> read much else into it.

Yeah, that makes sense. In fact, I figured that as long as the 0.85*V/Vt is equalled or exceeded, I'm okay.

> You have to be very careful with words and use of "scaling" as the
> way RISA uses the term is NOT the same as the code uses it.

I kinda figured that out, too, but it's good to have someone verify my thinking.

> As a side note, be sure you have checked the box for Use Dominant
> Mode for Signage.

Okay, now I have to admit to a great deal of embarrassment. PUBLICLY. Until you explained this I THOUGHT "SIGNAGE" MEANT YOU WERE DESIGNING A SIGN!!!

Okay, stop laughing, that's enough. I've got it figured out now.

*BLUSH*

> As for the 100%/30% orthogonal effect, this should be handled within
> your load combinations.

I got this figured out, too. I put both directions in each load case, and I also am using the SRSS in those load cases (because I think it needs it - or is "use dominant mode for signage" taking care of that?)

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