Plastic moment calculation AASHTO LRFD

[D. Rojas]

Hi everyone, I'm working on a spreadsheet for composite steel bathtub girders and I'm stuck on trying to make it work for any case listed in the table D6.1-1.
For instance, when I take into account the top and bottom steel reinforcement in the slab, for a given steel section I get that cases from 2 to 6 apply and taking a look on each one I can ignore cases 3 and 5 bc Y falls out of my slab thickness, leaving me with cases 2, 4 and 6.
I've seen other design examples and this particular calculation is not reviewed in depth, the usual practice is to conservatively neglect the existent reinforcement.

any suggestion will really appreciated.

Regards

 

[Settingsun]

Only one case will apply for a given cross-section. Work out which case, then calculate Y.bar, then calculate Mp. Note that Y.bar is defined differently for different cases.