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 from the difference of settlements of center and of individual edges.
Rotation of spread footing - principle calculation