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RE: diaphragm deflection

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If you use a program like Risa2D or 3D you can impose a
specific deflection at the top of the panel. Use Icr for
your analysis and iterate if it significantly different from
the resulting design. Don't use a fixed base, rather model
the 5' back span. It is a little less stiff than a fixed
base. Also this will allow you to obtain the force at the
footing and the tie force at the slab.

> -----Original Message-----
> From: David Adie [mailto:dadie(--nospam--at)]On Behalf Of
> seaint-return(--nospam--at)
> Sent: Friday, February 25, 2000 6:56 AM
> To: seaint(--nospam--at)
> Subject: diaphragm deflection
> To Mark E. Deardorff, SE,
> Thank you for responding. Yes there are dock panels with a
> finished grade of
> 4'-0" below the finished floor and a top of footing at
5'-0" below the
> finished floor.
> To Frank E. McClure,
> Thank you for responding.  The 8" deflection number was
not my actual
> deflection - it was just a number for example.  I got a
> of all the
> recent fema publications when I attended a local seminar
> recently.  However,
> this design is under 1997 UBC.
> To both and anyone else,
> After talking with an associate it seems like the
> approach would
> be resonable.  Model the panel as a cantilever with a
> base, load up
> the panel until it matches my diaphragm deflection, get
> moment based on
> this load (force * finished floor to roof), check the
> vertical steel in the
> panel to see if it can handle said moment.
> If anyone thinks this procedure has "holes", please speak
>  If anyone has
> a better way to go about this, please speak up.  If not,
> just go on my
> way.
> Thank you.
> david adie
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