Non Linear Soil Structure Interaction: Impact on the Seismic Response of Structures

The paper presents results of incremental dynamic analyses (IDA) of a simple structural system with consideration of non linear soil structure interaction. The analyses are facilitated using a non linear dynamic macroelement for the soil-foundation system. Three base conditions are examined, namely fixed base, linear foundation and non-linear foundation including uplift and soil plasticity. IDA curves are produced for a variety of intensity and damage parameters describing both the maximum and the residual response of the system. The results highlight the beneficial role of foundation non linearities in decreasing the ductility demand in the superstructure but point out the need to carefully assess the variability of the response when non linearity is allowed at the foundation design.