EVALUATION OF NON LINEAR SSI EFFECTS FOLLOWING AN EQUIVALENT LINEAR APPROACH

The purpose of this paper is to investigate the influence of the non-linear soil behavior on the dynamic structural response. Several soil-structure analyses are performed, assuming an equivalent linear approximation to represent the non-linear soil behavior in a coupled FEM-BEM approach. A parametric study is carried out including the mechanical properties of both the soil foundation and the structure as well as the characteristics of the input motion. The differences found between the linear and the equivalent-linear dynamic SSI approach demonstrate the importance of a proper soil behavior evaluation. A technique to derive the soil portion influenced significantly by the presence of the structure is presented. This limit defines a neighborhood of the soil where non-linear behavior may be decisive for the global response of the structure. The results show the dependency of this influence zone on the structure’s characteristics and indicate when a more refined non-linear soil behavior evaluation must be done.

Keywords:

non-linear Soil-Structure Interaction , equivalent-linear approximation , influence zone