In this paper, two existing Japanese dams: Tagokura gravity dam and Kurobe arch dam, are extensively studied. Earthquakes were recorded on each dam, allowing back analyses through comparison of simulated and recorded data at the base and crest of the dams. Currently, in engineering practice, the main approach for dynamic analysis of concrete dams with finite-element method is still based on coarse simplification: fluid-structure interaction is generally taken into account with Westergaard added-masses and soil-structure interaction is considered using massless foundation. But an increasing number of authors show that these simplified approaches tend to overestimate stresses. Consequently, a more advanced model taking into account the mass of the foundation, viscous-spring boundary input model and potential-based fluid finite elements with absorptive boundaries is proposed. The dynamic response of each dam is simulated using data recorded at the foundation and the response is compared to the data recorded at sensor located at the dam’s crest.