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RE: RISA-3D Steel WF Torsion

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Bill - 

You will want to review the Member Torsion spreadsheet results to get a
better indication of what shear stresses are being induced in the member
from the torsional loading.  Whenever wide flange members are failing in
shear, this is the first place that I would look.

Sincerely,  

Josh Plummer, SE
 
RISA Technologies

-----------------
From: "Alex Nacionales" <alex1961(--nospam--at)telus.net>
To: <seaint(--nospam--at)seaint.org>
Subject: RE: RISA-3D Steel WF Torsion

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Try checking your frame model and make sure that all columns supporting the
beams which are failing have the correct support condition (fixed or
pinned). I had a similar problem when I forgot to put a support condition to
column below a beam.

_____  

From: bill(--nospam--at)polhemus.cc [mailto:bill(--nospam--at)polhemus.cc] 
Sent: Thursday, April 16, 2009 1:57 PM
To: seaint(--nospam--at)seaint.org
Subject: RISA-3D Steel WF Torsion

I'm getting some anomalous results from a rather complicated steel frame run
on RISA-3D. I'm doing RSA with this, and I have already noticed some
peculiar results (at least for this "statics-based" puke).

When I look at the "Shear Check" plot on-screen, I'll see a lot of failures
of wide-flange members (mostly beams), many with rather large "understrength
factors" (if you will; I guess we used to say "overstress"), between 3.0 and
4.0.

But when I look at the specifics of a given member, I don't see any large
shears at all. I'm inclined to think it might be a torsion problem showing
up, but even the torsion doesn't seem that great (although it is present).

Any thoughts?



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