Nonlinear Vlasov Foundation Model for Performance Assessment of Cyclically Loaded Structures

Shallow foundations are the commonly used components in modeling of civil engineering structures. They typically rest on varying depths of soil. Winkler's model is the simplest model to deal with the structure and soil. The Winkler model represents the soil beneath the foundation as a system of similar but mutually independent elastic springs and it is assumed that the foundation reaction at particular point is proportional to soil displacement at that point. This model is associated with closely spaced elastic springs. But in reality these springs should be dependant on each other and need to be non-linear. To address these drawbacks, Vlasov model has been proposed. In this paper a new finite element formulation was developed to simulate the cyclic performance in which the soil can be viewed as a semi-infinite inelastic element that can resist bending, in addition to the well-known Winkler effect. The tensionless character of the foundation results in the creation of lift-offs between the beam and foundation is also being considered. The validity of the model is established by correlation of analytical results with experimental tests. The predictions made by the new element such as energy dissipation and capacity are in good agreement with the experimental results.