shear-bending interaction 1

[curiousinvite]

"At a composite beam cross-section, the web(s) of the steel beam will normally be subject to
combined vertical shear and bending. The design moment capacity of such a cross-section is
assumed to be reduced once the shear stresses in the steel web(s) are sufficiently large. Shear
reduces the capacity of the web(s) to support longitudinal stresses induced by bending. This effect is
termed moment-shear interaction."- How does shear reduces design moment capacity of steel beam ?

 

[Tomfh]

If the web is highly stressed in shear, its longitudinal strength is reduced (axial/shear interaction theory). This reduces the moment capacity. Codes have various formulas to account for it.

 

[SWComposites]

Metals yield when the VomMises stress reaches Fty. VM stress is a combination of shear and axial stresses.

Plus there is potential web buckling due to combined loading.