Torsion in Beams
Torsion in Beams
(OP)
Does anybody have a spreadsheet fo calculating torsional capacity of steel beams?
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RE: Torsion in Beams
RE: Torsion in Beams
RE: Torsion in Beams
For WF sections, however, you are on your own. You should try to avoid it as much as possible.
RE: Torsion in Beams
BA
RE: Torsion in Beams
RE: Torsion in Beams
Here is the procedure:
1) For torsion, think of the I beam as having been split at the center. Hence forming two Tee beams.
2) If the original beam was warping restrained at the ends, then your tee beam will be a fixed-fixed beam. If your original beam did NOT restrain warping, then your tee beams will be simply supported.
3) Break your torsional load into a force couple applied at the centroid of the Tee. Apply these point load or distributed load to each tee beam individually and analyze using simple beam theory.
4) The simple beam theory will develop weak axis bending moments (and flange bending stresses) in the Tee that are similar to the warping stresses that you'd get from a more rigorous analysis.
This analogy is relatively simple and should always be conservative... at least compared to the actual warping stresses in the flanges. Therefore, there is little danger to using it.
One of the things that I like it this method can be expanded out in situations where the rigorous methods become too difficult. Such as when you want to model a boundary condition that is somewhere between warping fixity and a warping pin. Or, when you have multiple unusual loading conditions.
Josh
RE: Torsion in Beams
This is the method I generally use as well...though I just think of it as a plate since the stem of the "T" is useless.
RE: Torsion in Beams
if there is bending in the beam too, do you think it is satisfactory to sum the stresses (from bending) and the stresses calculated above (from torsion ) and check that is doesn't overstress the steel. I'm thinking this approach neglects the effects of lateral torsional buckling....
RE: Torsion in Beams
RE: Torsion in Beams
RE: Torsion in Beams
However, I've only ever seen it as saying to ignore the web and simply take the torque out in the flanges.
Would be interesting to see some fancy FE comparisons.
RE: Torsion in Beams
RE: Torsion in Beams
Which is falling apart - manual or beam? :)
RE: Torsion in Beams
As far as the beams, I try to resign from where I'm working every time I design one :)
RE: Torsion in Beams
RE: Torsion in Beams
It is pretty interesting.
Appendix A - Results of FEM to study the effect of Slab/Deck translational restraint on spandrel beams.
Some info to read.
RC
All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke
RE: Torsion in Beams