This is a question discussed in civilera course forum some time back.
Is a RCC pedestal needing Reinforcement when it is molnolithic with columns ?
A pedestal is generally a compression member. IS 456 also says that the effective length should not exceed three times the least lateral dimensions.
What ever it is, if the column is modelled, analysed and designed for its full length as actual, then we are meeting the design requirement with the section of the column itself.
The pedestal is then provided for 3 reasons
To reduce the moment in the footing
To reduce shear in the footing
To reduce the Punching Shear in the footing
I will write a separate blog on these 3 points some time later. Our current question is on the steel requirement in pedestal.
The pressure from the soil subjects the footing to bend and the pedestal is compressed. The column itself is designed for a huge compression from the floor loads. Therefore the pedestal will need only a nominal reinforcement
The Video below will give more clarity on this topic.