girders w/sweeps

[chicopee]

Would the formulae for bending and shear applicable to straigth beams (assume simply supported) apply to simply supported beams w/ sweeps? Are there correction factors?Where could I find such info. for such beams?

 

[Qshake]

Simply put, no. You can very quickly include the terms for torsion of a simple beam by using any one of the energy methods available.

If you're not up to going that far back to school, you could possible find coefficients for the problem in either Roark's Stress and Strain or Practical Stress Analysis by Blake.

 

[tincan]

Help out a greay beard, what's a sweep?

 

[Qshake]

A minor horizontal curvature normal to the web.

 

[tincan]

Qshake
Thanks for the description. I've always known them as "Horizontally Curved Girders". You're right torsional warping stresses can jump up and bite you.
Thanks, Tincan.

 

[chicopee]

QSHAKE- THIS IS ACADEMIC ONLY BECAUSE I AM JUST INTERESTED ON HOW THE EVALUATION FOR SHEAR AND BENDING STRESSES WOULD BE CONDUCTED ON BEAM W/ A SWEEP. FROM YOUR STATEMENT ABOUT TORSION CAN THAT ADDITIONAL STRESS BE VECTORIALLY ADDED TO THE CLASSICAL SHEAR DIAGRAM OF A SIMPLY SUPPORTED STRAIGTH BEAM TO GET A "RESULTANT" DIAGRAM FROM WHICH A "RESULTANT" BENDING DIAGRAM CAN BE DEVELOPED?

 

[Qshake]

Chicopee,

Torsion may be "simply" included in the equation for stress or deflection and will affect any allowable stress equation since the interaction of all (as many components you're including) components are usually compared to unity.

Beyond that above you'll have to investigate what component of torsion is added or subtracted to the shear diagram and similarly with bending. A good stress block diagram is in order.

 

[tincan]

"Torsion Analysis of Rolled Steel Sections" by Bethlehem Steel is a good tutorial on warping stresses.
"Horizontally Curved Girders" Highway Structures Design Handbook Vol 1 by United States Steel is a "how-to".
Both of these are old prints, but worth while if you can find them. Otherwise check out a good textbook on advanced steel structures.

Best, Tincan.