Biaxial Bending plus Torsion
Biaxial Bending plus Torsion
(OP)
Folks:
I have to check the design on a cantilevered stub column with biaxial bending and torsion.
This WF column is a corner column on a parking garage supporting barrier cables. The barrier cables are in orthogonal directions. The forces in the barrier cable is causing a biaxial bending and the eccentricity of the cables is producing a torsion (which is counteracting) and hopefully can be minimized by specifying a stressing sequence.
I want to know what approach I should take to check this column. Obviously there are no axial forces on this column. I have never done a biaxial bending + torsion check on an wide flange beam/column. Any references or suggestions is appreciated.
I have to check the design on a cantilevered stub column with biaxial bending and torsion.
This WF column is a corner column on a parking garage supporting barrier cables. The barrier cables are in orthogonal directions. The forces in the barrier cable is causing a biaxial bending and the eccentricity of the cables is producing a torsion (which is counteracting) and hopefully can be minimized by specifying a stressing sequence.
I want to know what approach I should take to check this column. Obviously there are no axial forces on this column. I have never done a biaxial bending + torsion check on an wide flange beam/column. Any references or suggestions is appreciated.






RE: Biaxial Bending plus Torsion
RE: Biaxial Bending plus Torsion
RE: Biaxial Bending plus Torsion
RE: Biaxial Bending plus Torsion
RE: Biaxial Bending plus Torsion
I would resolve the net torsion into shear in the flanges.
Depending on the method/detail of connection, the thickness of web could be one thing you need to check on too.
RE: Biaxial Bending plus Torsion
1) Get a good torsion reference (either the AISC design Guide or the Salmon and Johnson steel book).
2) Follow the methods mentioned in the torsion reference and don't for a second believe that there is anything in Chapter H that will help you for torsion of wide flanges (or any sections that are subject to signifcant warping).
3) Do a quick hand calculation using the "equivalent tee" method of analysis. This essentially converts the torsional warping stresses from a wide flange into weak axis bending stresses on an equivalent tee. This will give you a feel for how significant (or insignificant torsional stresses really are for your member).
RE: Biaxial Bending plus Torsion
RE: Biaxial Bending plus Torsion