Modelling results of walls on top of beams

[generick]

Hello all,

I am using ETABS concrete frame design to give me the moments and shear values needed to design my beam. In this case, there is a wall on top of the beam and I have compared the moments for the following:

Case 1: No modifiers
Pos moment ~ 20.2 k-ft
Neg moment ~ -35.4 k-ft

Case 2: Changed the walls in-plane stiffness to 0.01 (F11 & F12)
Pos moment ~ 70 k-ft
Neg moment ~ -163.4 k-ft

Based on these results, I would expect to see the moments on case 2 but this would mean that I would design my beam assuming no composite action between the wall and beams – however, we normally indicate on our structural notes to not impose loads until concrete members attain the specified compressive strength. This leads me to thinking that my approach is rather conservative and that in reality, the beam will be supported during construction while they pour the walls – meaning, there is composite action.

Overall, I am curious to see how other engineers go about designing beams with walls on top in structural softwares.

Thanks and appreciate any insight/comments.