When the ratio of the long span to short span is less than 2, the slab is known as a slab spanning in two directions (two way slab).  The basic steps of two way slab design are:

Choose layout and type of slab. (Type of slab is strongly affected by architectural and construction considerations).
Choose slab thickness to control deflection. Also, check if thickness is adequate for shear.
Choose design method. (Equivalent frame method – use elastic frame analysis to compute positive and negative moments or Direct design method – uses coeficients to compute positive and negative slab moments) Calculate positive and negative moments in the slab
Determine distribution of moments across the width of the slab (based on geometry and beam stiffness).
Assign a portion of moment to beams, if present
Design reinforcement for moments from step 5 and 6. The steps 3-7 need to be done for both principal directions.
Check shear strengths at the columns.

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