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Re: IBC 2000 Seismic maps

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>From one of the dumb old guys that learned about being an Engineer back in
the days before the powers that be thought that there were such things as
earthquakes on the east coast - I'm attempting to make some sense out of a
building design that states the following:
Effective peak velocity-related acceleration Av = 0.06
Effective peak acceleration Aa = 0.06
Seismic Hazard Exposure Group I
Seismic Performance Category B
Soil Profile Type B

The referenced codes are 1994 Standard Building Code & ASCE 7-95

Along with my lack of experience with earthquake design, I've just been in
business on my own for about a year, so I don't have the referenced
documents.  I do have a copy of FEMA 368 & 369, but the terminology is
slightly different.  I also went to the USGS Hazard Map site & got a
printout , but quite frankly I unsure of what the numbers are telling me.

Will some of the more knowledgeable of you please lend a hand and comment on
the following:

1) Is the Soil Profile Type the same as Site Class in FEMA 368 (i.e., good
rock)?
2) Is the Seismic Hazard Exposure Group similar (but reversed) to the
Seismic Use Group in FEMA 368 (i.e. this structure is a III), & the Seismic
Performance Category the same as the Seismic Design Category in FEMA 368
(i.e. this structure is a B).
3) What is the %g from the USGS Map site (Av or Aa)?
4) I assume that the FEMA Ss is the USGS 0.2 sec value, & S1 is the 1.0 sec
value; but which value do you use, the 10%, the 5%, or the 2%?  And how do
you decide?
5) What are the PGA values on the USGS site?

Before you flame me for getting in over my head, let me explain that I'm not
designing the building.  I design stairs & design/check connections for
fabricators.  I have this project to design the stairs & out of the blue,
the contractor asked if the stairs were designed for earthquake.  My gut
tells me that there is no problem, but guts don't do you much good in court,
so I'm trying to learn a new (& exciting) aspect of this business.

Thanks in advance for any assistance you may be able to lend.

Scott A. Dunham, PE
Dunham Engineering Services
Dothan, AL
334-678-6948

----- Original Message -----
From: "Roger Turk" <73527.1356(--nospam--at)compuserve.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Saturday, March 16, 2002 4:17 PM
Subject: RE: IBC 2000 Seismic maps


> Jason Kilgore wrote:
>
> . > For more accurate Ss and S1 values, click on "Hazard by Zip Code" or
> . > "Hazard by Lat/Lon". Then enter the USPS zip code or
Latitude/Longitude
> . > and the page will return values that are more accurate than reading of
a
> . > large-scale map.
>
> And how accurate is the value you get when one building has one value, and
> another building on an adjacent lot has another value because they are in
> different ZIP code areas?
>
> The answers that you get with such precision are wholly inaccurate.
>
> A. Roger Turk, P.E.(Structural)
> Tucson, Arizona
>
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