Foundation response is a complex interaction of the foundation itself, the superstructure, and the soil.
That interaction may continue for a long time until final equilibrium is established between the
superimposed loads and the supporting soil reactions.
In many projects, designers of superstructure simulate soil as springs with subgrade reaction which mean
that soil is one layer with liner reaction. This simulation neglects settlement of soil, types and properties
of soil layers, underground water table and surrounded structures. The same happened in preparing the
soil investigation and the soil report for any project which take only the loads transferred from the
structure or assumed uniform distribution and do not take into consideration the effect of structure
elements stiffness.
This paper presents a study to evaluate the effect of various factors on the stresses distribution under the
foundation and on columns loads such as Soil type (modulus of subgrade reaction), Footing depth,
Superstructure stiffness (slabs thickness-beams depth) and Number of stories. Numerical analyses were
carried out in more than 300 model adapting three dimensional finite element software program
(SAP2000 version 16).
The study concluded that the columns loads can be redistributed by controlling the relative stiffness
between columns – slabs, columns – beams and columns – raft to achieve uniform stresses distribution
under the foundation.