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Re: More on Lintels

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If you are getting some torsion load in the member, then the actual
rotation may not be a problem depending on how much it is and how the
masonry is detailed to handle it.

Your problem will likely be torsional stresses in the steel beam.  Open
shapes (wide flange, channel, angle, etc) don't handle torsion too well.
Torsion normally just adds to the shear stress, but in open shapes, the
torsion will also effect the bending stresses.  Thus, if you have done
just a check of the bending stress without accounting for torsion, then
you likely have a problem...it is rather likely that once the additional
bending stresses due to torsion are added that the beam will "fail"
(exceed allowable bending stresses).  This is a big reason why it is
typically a good idea to use a closed section (HSS, tube, pipe, etc) to
resist torsion...the only torsional effects are on the shear stress.

I suggest that you obtain the AISC Design Guide on torsion (don't recall
the number).

HTH,

Scott
Ypsilanti, MI


On Fri, 16 Aug 2002, seaosc seasoc wrote:

> Hello All
> A lintel, wide flange shape with bottom plate, carries masonry load min bearing only at ends, having an eccentricity causing torsion load, it is designed for the vertical loading and the tensional stress and is about 20 feet long 3" eccentricity and within the allowable 0.3" deflection requirement and combined stress is less then 0.66Fy.  
> 
> Is there a requirement to be concerned about the rotation of the member if the above is satisfied?
> 
> Thank youGet more from the Web.  FREE MSN Explorer download : http://explorer.msn.com
> 


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