Difference between Flat slab and Flat plate slab

Slab directly supported on columns without beams are called Flat slabs or flat plates.

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Taxonomy - Flat slab/plate or waffle slab [LFLS]
Figure of Flat Slab & Flat Plate Slab

Followings are the difference between Flat slab and Flat plate slab:

Serial No. Flat Slab Flat Plate Slab
  1Flat slab is one with either drop panel or column capital (or both at the same time) that helps reduce shear stress on the column slab junction.On the other hand, flat plates are slabs systems with the slab connected to the column directly.
  2Flat slabs can bridge larger spans because of higher shear capacity & deflection control.Flat slabs can bridge smaller spans because of lower shear capacity & deflection control.
  3According to MacGregor and Whites book, mechanics and design of reinforced concrete Structures, flat slabs can be used easily for spans upto 30 ft [upto 9 m]According to MacGregor and Whites book, mechanics and design of reinforced concrete Structures, flat plates are most economical for spans from 15 to 20ft [4.5 to 6 m]
Fig: Flat Slab
Fig: Flat Plate Slab