Analysis of the experimental behavior of a based isolated building during a release test

In this article, the dynamic behavior of a base isolated structure located in Augusta City (Italy) is analyzed during ambient noise and during several release tests. On the 22th of May 2013, through different release tests, several accelerometers have been installed within the structure and on the surrounding soil in order to acquire the dynamic response of the structure and the effects of soil-structure interaction. During the experimental campaign, the dynamic behavior of the structure has been monitored before, during and after each test, comparing the dynamic characteristics in the different phases and evaluating possible damages on nonstructural elements. Particularly, the base-isolated structure has been characterized in terms of eigenfrequencies, equivalent viscous damping factor and mode shapes in ambient noise (considering the superstructure as a fixed-base structure) and during the release tests (monitoring the dynamic behavior of superstructure, base isolation system and underground floor). The aim of this article is to analyze the experimental behavior of the based isolated building and evaluate soil-structure effects in terms of energy released into the ground and maximum acceleration produced on the surrounding structures during the released tests.