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RE: Cranes: Curved Track Monorail

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David,

I would ignore FEM to begin with and try to evaluate your monorail 
structure.  Part of the rolling process causes severe distortion of 
the rolled shape at the ends for monorails with small radii.  Will 
the ends need to be cut off and do you need to weld new straight ends 
on the curved part?  If the curved part is long, you may choose to 
place several supports along the curve.  You will have torsion and 
moment at each of these supports.  As to whether they are roll-guided 
or slope-guided depends on the support conditions.  If it is tight to 
a concrete slab, you will probably have both roll-guided and slope-
guided.   

However, if it is connected to another steel beam, there is potential 
for the beam to roll at the supports and it will not be slope-guided. 
 If you can, try to ensure that he curved part is continuous with the 
straight tangents so that you get better restraint of the curved 
part.  Once you get all of this sorted out, you can resort to FEM but 
I wonder how engineers (I belong to the OF school) managed to design 
these before computers.  I have been in a plant with a curved 
monorail that was built in 1918.   

No matter what you design, the contractor will likely want to change 
the configuration.  Ask for a U and he'll want to provide 2 J's, or 
vice versa.   

Best of Luck,
Gary



On 5 Jan 2005 at 12:46, Padmanabhan Rajendran wrote:

> The end condition will be something between
> "torsionally fixed" and torsionally pinned". Mere
> addition of stiffener plates, between the top and
> bottom flanges, at the end supports will not make the
> ends torsionally fixed. I suggest you analize it for
> the two extreme end conditions and design
> conservatively. Don't forget local effects and load
> path for various load components. 
> 
> As I mentioned in my earlier response, this problem is
> an ideal candidate for FEM. Any attempt to reduce it
> to make it amenable for hand calculation will invite
> several assumptions, and you are likely to get as many
> set of assumptions as there are engineers who may air
> their opinion.
> 
> Rajendran
> 
> Rajendran
> 
> --- David Maynard <davemaynard(--nospam--at)ceincorp.com> wrote:
> 
> > Again, to revisit this issue, I was looking at the
> > torsional analysis needed
> > for this monorail, and the end conditions got me
> > slightly perplexed.  Let me
> > refresh your memory on the situation.  The hoist is
> > an underhung monorail
> > hoist with a support structure located above the
> > monorail.  The monorail
> > (likely S section) will be hung using bolts through
> > the top flange of the
> > monorail to the bottom flange of the support
> > structure (likely WF sections).
> > 
> > Torsion of the monorail is an obvious consideration,
> > especially with a hoist
> > capacity of 10 Tons.  Now, with the above hanging
> > connection as described,
> > what would be the description of the "Physical
> > Condition" and the "Torsional
> > End Condition" for analysis???
> > 
> > Thanks for the information.  I really appreciate it.
> > 
> > Dave Maynard, PE
> > Gillette, Wyoming
> > --
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