Return to index: [Subject] [Thread] [Date] [Author]

RE: ASD biaxial bending allowable stress

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Title: RE: ASD biaxial bending allowable stress

>When axial loads due to torsion
>ie. warping torsion) are included in
>equation H1-3, to which allowable stresses
>should these stesses be compared?
>Are they compressive stresses or
>flexural stresses?

Torsional loadings on W-shapes generally create pure torsional shear stresses, warping torsional shear stresses and warping normal stresses. The details of how to combine those in with other load combinents (axial forces and strong- and weak-axis bending moments) is covered in AISC Design Guide No. 9 Torsional Analysis of Structural Steel Members. It can be done by summation of like stresses and comparing to the design stress (LRFD) or allowable stress (ASD). Or, there is a conservative interaction check provided in that design guide that allows the overall summation of effects similar to that for beam-columns.

I'd be more specific in this email, but it is too hard to reflect all the information and equations. The designguide is available here:

    https://www.aisc.org/publications/shop.asp?action="">

Charlie