Lumped Parameter Models for Time Domain Soil-Structure Interaction Analysis: Consistent vs Simplified Formulations and Effects on the Linear and Nonlinear 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 defi-nition 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 simpli-fied 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 ap-proach in the frequency domain as benchmark. Results demonstrate that simplified models can be sufficient in most cases to obtain a relia-ble prediction of the superstructure response.