A dam-foundation seismic interaction model, to be used in the frame of the FEM (Finite Element Method) codes for the study of dam-foundation-reservoir systems, was recently implemented and tested by RSE. The model was developed to overcome the main deficiencies (above all the excessive conservativeness of the results) of traditional and simplified methods.

The model can ideally reproduce the same behaviour of the actual semi-unbounded foundation, representing the seismic wave propagation in a computation domain delimited by artificial boundaries. The model is adopted, in comparison with the traditional massless approach, to simulate the seismic response of Monticello Dam subjected to a low intensity earthquake occurred in 2015 not far from the dam site.

The case study of Monticello Dam (Napa County, California, USA) allows to compare the simulated behaviour of the dam with the seismic records, available both at the foundation and at the dam crest. The results of the study enable to assess the reliability of the seismic wave propagation model for its use in real cases and to highlight the advantages of using the model as an alternative to traditional analysis approaches.