A slab in terms of its dimensions consists of a thickness(depth), length and width. Understanding this concept will correctly Enable you to calculate and apply slab loading.

In reinforced concrete design, the weight of concrete is usually taken as 24kN/m³. So let’s look at an example.

A reinforced concrete slab is to be constructed having a length of 5m, width of 3m and depth of 200mm. The slab loading can be calculated as follows.

## Calculating slab load in kN/m²

Note that 200mm = 0.2m..

..and weight of concrete is 24kN/m³

In most design calculations the unit of the slab load is in kN/m². In this case the slab load is calculated by multiplying 24kN/m³ by thickness (depth) of slab which is 0.2m

So 24kN/m³ × 0.2m = 4.8kN/m²

## Calculating slab load in kN

To represent the slab load in kN, just multiply the unit weight concrete which is 24kN/m³ by the volume of the slab.

Note that the volume of the slab is length x width x depth

So 24kN/m³ × 0.2m × 5m × 3m = 72kN

In practice, you will be calculating slab loading from structural plan or floor panel arrangement. A typical structural plan is shown below.