Overall Settlement and Rotation of Foundation
The foundation settlement is substantially influenced by the overall stiffness of the system represented by foundation structure and foundation soil given by:
modulus of elasticity of footing
weighted average of the deformation modulus up to depth of influence zone
footing dimension in the direction of searched stiffness
For k > 1 the foundation is assumed to be rigid and as a representative point for the determination of its settlement is assumed the characteristic point (distant by 0.37 times the foundation dimension from its axis).
For k < 1 the foundation structure is assumed to be compliant and as a representative point for the determination of foundation settlement is assumed the foundation center point.
The foundation rotation is determined as a difference of settlements of individual edges centers.
Rotation of spread footing - principle calculation