flat slab and flat plate

Slab directly supported on columns( without beams or beams only at the perimeter of the building) are called  Flat slabs or flat plates.

What is the Difference between flat slab and flat plate?

Flat 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.

Flat slabs can bridge larger spans when compared to flat plates. Due to shear demand and deflection requirement the span flat plates can bridge is very small. 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] and flat slabs are used for spans of 20 to 30 ft[6 to 9 m].

Flat slab or plates can be analyzed using several methods of structural analysis. Some of these methods are:

✅DDM(direct design method),

✅EFM(equivalent frame method),

✅FEM(finite element method),

✅Grillage method,

✅Yeild line  method and

✅Strip method of analysis.

 Flat slab( notice the column head and drop panel at the column slab junction).

Flat plate(notice the direct connection between the slab and the column).