In case of two way slab the ratio of the long span to the short span is

Concept:

Slabs:
Slabs are considered as plane element or plate elements which are classified based on aspect ratio.

Aspect ratio:

It is defined as ratio between longer span (Ly) of the slab to shorter span (Lx) of the slab.

\({\rm{Aspect\;ratio}} = \frac{{{{\rm{L}}_{\rm{y}}}}}{{{{\rm{L}}_{\rm{x}}}}}\)

Types of slab based on aspect ratio 

1) One way slab:

Slab spanning in one direction

\( \frac{{{{\rm{L}}_{\rm{y}}}}}{{{{\rm{L}}_{\rm{x}}}}}>2\)

2) Two way slab:

Slab spanning in both the direction

\( \frac{{{{\rm{L}}_{\rm{y}}}}}{{{{\rm{L}}_{\rm{x}}}}}<2\)

Explanation:

The ratio of the long to short dimension of the slab is greater than X

By comparing to Aspect ratio of one way slab

i.e \( \frac{{{{\rm{L}}_{\rm{y}}}}}{{{{\rm{L}}_{\rm{x}}}}}>2\)

We get X = 2