It looks like the truss you're modeling for the wide-span slab in your project should be much deeper and higher capacity. It would be beneficial to have trusses connected to the columns on 2 axis perpendicular to this truss beam. It is important that the lattice beam struts meet the upper floor columns. Mega crosses with several floors can be considered. It is important to keep the columns in both directions against the capacity and translation. Deflection, displacement, relative floor drift etc. It is important to pay attention to the controls. Paying attention to TDY 2007 Clause 2.3.2.4 (b), global stability, floor diaphragm, vibration (footfall) etc. it is important to do many additional analyzes/controls.