Singly symmetric I-sections with different classes of flanges

[hamza41]

Hello everyone,

I'm calculating a runway beam with a combined section of W920x223 and a cap channel MC460x63.5. The W section is class 1 and the channel is class 3. Would you please confirm the following:
- the combined section is supposed to be 3.
- the upper equivalent flange is class 3.
- the bottom flange is class 1.
- according to CSA (it should be the same for AISC) should I calculate the upper equivalent flange with My and S_max and the lower flange with Mp and Z_min ?
- for the transverse moment should I calculate the upper equivalent flange as a class 3 ?

Thank you for your help