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Question regarding Fp forces with Omega naught...

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List -

I am designing an external steel elevator tower that attaches to a five
level concrete building.  The steel tower projects out from the concrete
building in both plan and elevation.

The tower is being designed to resist Fp forces.  When designing the
steel column (using ASD) in axial compression or in axial tension per
section 2213.5.1, or while designing brace connections per section
2213.9.3.1, what Omega naught factor do I have to use?

In Table 16-O, Rp and ap factors are indicated, with no mention of
Omega naught.  If the calculated Fp forces are about 1.4g's and there is
no mention of Omega naught, would it be prudent to use Omega naught
equal to 1 in both cases?  This is not clearly addressed in the 1997 UBC
code.

Is it not true that Rp & ap factors (Table 16-O) when used together
would provide similar amplification as Omega naught and R factors (Table
16-N) when used together?

My preliminary calculations indicate 1.4g's for Fp forces, and if I
assumed an Omega naught factor equal to 2.8, the connection would need
to be designed for 4.0g's.  This design force seems much too high.  Any
insight into this problem would be greatly appreciated.

-Derek Beaudoin

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