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Re: PL stair stringer

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Thank Harold, Charlie and Eldon for your response.

Brad
----- Original Message -----
From: Sprague, Harold O. <SpragueHO(--nospam--at)bv.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Tuesday, March 14, 2000 7:08 AM
Subject: RE: PL stair stringer


> Brad,
>
> Reference "Metal Stairs Manual", National Association of Architectural
Metal
> Manufacturers.  You won't find a very sophisticated technique, but it has
> been used for a lot of years.    They just drop the allowables to 20 ksi
for
> plate stringers.  The problem is very complicated in that the treads act
as
> stiffening elements for the stringers, but the stiffening elements do not
> extend up into the compression zone of the plate.  The ability to stiffen
> the stringer also varies with the tread types.  Pan stringers provide more
> stiffening than open grate treads.
>
> Generally I assume the NAAMM technique is accurate for metal pan stairs.
> But I use channels for open grating treads.  You can spend a huge amount
of
> time in modeling and designing and get a result that is no better than the
> NAAMM technique.  I use the NAAMM technique in practice until I get
> something that makes me nervous.  Then I design it, have it constructed,
and
> load test it.  Every strange design that I have seen that was tested,
proved
> the NAAMM to be O.K.
>
> There is only one problem.  I have not been able to contact NAAMM in
Chicago
> at 312-922-622 or at http://www.naamm.org/.  Maybe one of our AISC
> colleagues can shed some light on the current disposition of NAAMM.
>
> Regards,
> Harold Sprague
>
>
> > -----Original Message-----
> > From: Brad Friederichs [SMTP:brad(--nospam--at)vesolutions.net]
> > Sent: Monday, March 13, 2000 9:08 PM
> > To: seaint(--nospam--at)seaint.org
> > Subject: PL stair stringer
> >
> > Fellow Engineers,
> >
> > How are plate stringers for stairs designed for bending (incl lateral
> > stability)?
> >
> > What equation is used for lateral torsional buckling?
> >
> > Thanks for your help.
> >
> > Brad Friederichs
>
>