Evaluation of design procedures for passive systems and application to a case study

The purpose of this paper is to study the application of metallic, viscoelastic solid and viscous-fluid passive energy dissipation devices for improving the seismic response of buildings. First the principal aspects of the response and the simplified mathematical models of the devices were examined. Then a design procedure was applied to the three types of devices. This procedure, which is well known, is aimed at obtaining a prefixed reduction of one response parameter and it is based on the definition of an equivalent linear system and on the use of response spectrum. A numerical investigation was carried out with the purpose to evaluate the design procedure. Time-history analyses were performed by applying five selected earthquake records to one and multi-story RC frames. The results confirm the effectiveness of the design methodology, especially for structures dominated by the response of first mode. The results allow also to compare the performance of the different dissipative systems. Finally a study for the application of viscous-fluid passive dissipative systems for the seismic retrofit of an existing RC building is presented.