SLAB ON GRADE

Soil-structure analysis is done considering the soil as a Winkler spring operating in compression only. The rigidity brought by the soil is distributed to the joints of the plate’s elements composing the raft. The equivalent soil rigidity is function of the subgrade modulus of the soil as well as the nodal tributary area of the plates. The function in the GSE automatically calculates the nodal tributary areas to save users’ time. The foundation can be supported by either: ground springs, regular springs, fixed supports, piles or imposed displacements allowing flexible modeling for the user. The analysis of the model allows to calculate several important parameters for the design of the foundation. While considering the various load combinations, the nodal displacements of the slab on the ground make it possible to check the stability and deflections of the structure. According to the deflection, the stiffness and the tributary area calculated for each of the nodes, the exerted pressure of the slab on the ground is calculated. This data makes it possible to verify the sizing of the foundations by ensuring that the bearing capacity of the soil is not exceeded. The use of the finite element method makes it possible to take into account the flexibility of the foundation and its effect on the behavior of the structure. The use of unidirectional springs in compression makes it possible to check the uplifting of the slab.