The reduced areas of the cross section on the below pictures are represented in blue, while original area in grey.
1-reduction for flange bending:
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2-reduction for shear Vz;Sd:
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3-reduction for shear Vy;Sd:
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4-reduction for Mz;Sd:
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Reduction for Mz;Sd is taken by the most outer parts of the lower flange. And the more it needs the more it will yield inwards. |
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5-reduction for Nx;Sd:
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Reduction for Nxsd should be taken as close as possible to the center. All areas left for this can be used. |
By the absence of the acting forces, not all the reduction steps have to be performed. After all the cross section reduction steps are performed, an area left is the area which will be used for My;Sd. The final UC is performed for the area is used for the My;Sd.