whether footings behave like rigid or a flexible?

Project:www.sefindia.org
Component:Miscellaneous
Category:support request
Priority:normal
Assigned:ajeet_08
Status:active
Description

Dear All

Sub:-whether footings behave like rigid or a flexible?

Where ever we start footing design the assumption is footing rigid or flexible but problem is that how we will know the footing is rigid or flexible?

There are some Author mention that:
If Kr(Relative stiffness factor)=(EcxD^3)/(12EsB^3)>0.5

Here Es=modulus of elasticity of foundation siol
Ec=modulis of elasticity of concrete

Then footing will be rigid.

So here I would like to confirm this thing is sufficient to check whether footing rigid or not

Regards
Ajeet Singh