Mathe Engineering Statik Bauelemente

calculate approx. structural floor depths?

How to calculate approximate structural floor depths for different Building Types?
1. 4 storey apartment block (maximum room width = 3.75m)
2. Multi storey frame - office building, 8m x 8m grid
3. Multi storey frame – department store, 15m x 7.5m grid

For each of the building types above,I have to propose 2 structural options
and calculate the approximate structural floor depths for all options proposed.
Using sketches; plans and sections of typical bay and indicate load paths for each of the options proposed.

Can anyone help?