Dear Kuranage, it is an interesting question.
Load distribution in slabs depends on the way the slab is supported and if this support is really working as a restriction for deflections or rotations (shear studs also play an important role here). For composite beams (with steel deck) you should be using ribs in one direction. These ribs direct the load to girders, and this should be a one-way slab. If you are using ribs in longitudinal and transverse directions, so you have a two-way slab.I suggest you visit the webpage of the Steel Deck Institute: https://www.sdi.org/. There you could find free resources on this subject.Regards, AG
Thank a lot for your valuable comments.