Pressure distribution under rigid and flexible footings

For rigid and thick footings, pressure distribution under the footings is generally presumed to be linear. If symmetrical and uniform loadings are exerted on the footings, bearing pressure is uniformly distributed. Though if unsymmetrical loads are encountered then a trapezoidal shape of bearing reaction would result. 

For flexible footings on compressible and weak soils, bearing pressures under footing would not be linear. A detailed investigation of soil pressures is essential in order to determine the bending moment and shear forces of the structure.