Lumped Parameter Models for time domain Soil-Structure Interaction analysis: consistent vs. simplified formulations and effects on the superstructure response

Due to the frequency-dependency of soil-foundation impedances, the dynamic interaction analysis of linear and nonlinear systems in time domain according to the sub-structure approach requires the definition of suitable Lumped Parameter Models (LPMs) with frequency independent parameters to simulate the soil-foundation compliance. This paper investigates effects on the superstructure response resulting from the use of different LPMs. In particular, consistent and simplified LPMs are considered and the linear response of single bridge piers founded on different pile foundations is studied. The effectiveness of selected LPMs is evaluated using results obtained from a direct approach in the frequency domain as benchmark. Results demonstrate that simplified models can be sufficient in most cases to obtain a reliable prediction of the superstructure response.