Experimental Dynamic Analysis and Seismic Rehabilitation of Palazzo Margherita in L'Aquila.

The studies carried out for the retrofit of Palazzo Margherita, the City Hall in L’Aquila, seriously damaged by the 2009 earthquake, are shown. The building and the tower were first analyzed by means of ambient vibration tests, in order to find out the dynamic characteristics of the structure even in a damaged situation. On the basis of the results obtained and of the microzoning analysis results, the base isolation was proposed as the most suitable solution for the seismic retrofit of the structure, because it allows to obtain a good structural result without altering the architectural features of the superstructure. The new isolation system is based on the realization of an isolated platform under the building foundation without any intervention on the building itself. The system can be used for single buildings but also for complex structures, typical of the Italian historical centres