What Is Slab

A slab is constructed to provide flat surfaces, typically horizontal, in building roofs, floors, bridges, and other types of structures. The slab could be supported by walls, by reinforced concrete beams normally cast monolithically with the slab, by structural steel beams, either by columns or from the ground.

Type of slabs based on support conditions are

According to IS 456:2000, The ratio of longer span (L) to shorter span (b) which is (L/B) greater than 2 is known as One way slab.
In practical, One way slab is supported by only two parallel beams or walls. Normally we don’t use one way slabs often.

A one way slab is defined for functions of the book as a flexural member with thickness small relative to other dimensions, supporting (gravity) loads applied normal to and directly above its surface, a span in one direction between parallel supports, and fortified for flexure in this direction only.
One way slabs might be restrained to some degree in the supports or possibly unrestrained. A number of Code provisions reference to “flexural members,” including one and two way slabs, beams, girders, footings, as well as where bending is present together with the axial walls, load, and columns.
In general, when this code provision is intended to use to one way slabs, the term is going to be utilized in the sense of this definition herein.
If the is supported on two opposite sides, it is called a one way spanning slab. In this type of slab, loads are transferred on two opposite as per the above figure.
If the slab is supported at four sides, and if Ly/Lx ≥ 2 one way spanning slab.
For any slab, if Ly = Lx, the slab has a tendency to bend in both directions. With an increase of Ly, the tendency of bending along Ly is reduced and that on Lx is increased.

When Ly/Lx ≥ 2, the slab is called a one way slab. In one way slab, the main reinforcement is provided along Lx ( Short Span)