Before design of RCC Slab | RCC Slab Design | IS 456 Provision to design a slab

The design of RCC slab is the most critical thing to design. So let's look one by one how to design them all

Type of Slab: It is important to identify the type of slab so that to proceed with the design. while we discuss types of slabs it generally comes to your mind that it would be one way or two. but we don't consider it a support condition. it very easy to identify to support the condition of the slab so that we can find the moment accordingly.

Support condition of the slab:

As we see in the above picture slab is just supported by their ends. Now if you follow IS456 for a design that You can simply get the moment as wl2/8 or 0.125wl2. If you follow Table 26 of IS456 then this will be the maximum value of moment (ax, ay > 0.125).

Continuous Slab: Having more than three support is called a continuous slab.

If you see in the picture 9 slab is theirs. Continuous something related to its edge conditions. if we consider slab.1 it two edges are not continuous and two edges are continuous. The value of moments at their support will be different. If we see table 26 of IS 456 then it is called Two adjacent edges discontinuous. By following this you will get bending moment Coefficients at the continuous edge as well as mid-span of the slab after that you just have to use the equation 

Mx =ax.w.lx2

My =ax.w.lx2

to get the BM at moments on strips of unit width spanning Ix and ly respectively.

Slab 2 -  Two long edges discontinuous

Slab 5 -  Interior panel

Similarly, you can get the moment each and every slab pannel.

(Fig. S) 

Slab S' (Fig. S) -  Three Edge Discontinuous (Short Edge)

Hope you get how to calculate the moment of the slab.Once you do that you can simply calculate the reinforcement for the slab.