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I agree with Muneeb Badar's post.

Dear Rana, Please check the reference from ETABS Concrete design manual. This is what I am saying. Thanks Muneeb

Dear mhdhamood, in your next comment you are asking which axial force to use, top shear wall or bottom shear wall whcih will cause rotation. Dear these shear forces can not be used to check the slab thickness as these are inplane shear forces when transferred from shaer wall to slab or from slab to shear wall. Even IF YOU PROVIDE THE THICKNESS FOR THIS SHEAR, IT WILL NOT BE EFFECTIVE IN CASE OF EARTHQUAKE AS YOU PROVIDED THE THICKNESS WHERE IT IS NOT REQUIRED. You have to increase the thickness in the basis of inplane bending not on the basis of out out of plane bending. Thanks Muneeb

Dear mhdhamood, Yes I am saying this to check the shear for gravity. Actually, what you are saying is 100% correct but this design should be inplane. I ll explain again. When earthquake comes and there will be rotations then these rotations will not be out of plane. These will b e inplane. So thats why you need to design the slab for inplane forces for lateral loading and thickness of slab for out of plane forces. Thats the concept of code. This is the reason the ACI chapter 21 allows us to design the slab member on gravity for out of plane forces and then design the slab for lateral forces for inplane forces. So there are two types of design for Slab in case of earthquake if building is in high seismic zone 1- Out of plane design which is based on gravity analysis which includes the ordinary flexural reinforcement and shear reinforcement if required 2- Inplane design which includes the Tension reinforcement, shear reinforcement and shear fricktion reinforcement. Seconldy if your building is in high seismic areas you can not use these same load combinations which you wrote above. If as per ASCE if your building is in seismic deisign category D, E and F then you need to modify these load combinations.