Vulnerability Analysis and Seismic Retrofit of a Strategic Building

The seismic vulnerability analysis of a strategic building is presented in this paper. A refined finite-element model was set up on the basis of available experimental results, and updated on the basis of new experimental analyses on materials and structure. As demonstrated by an experimental vibration analysis, the structural behavior is influenced very much by the irregularity of the building and the presence of an adjacent building with no seismic joint. The results indicate a high vulnerability of the building to seismic actions, and the inadequacy of the pile foundation - for which a specific nonlinear analysis was performed - to support horizontal seismic loads. A retrofit intervention, based on the insertion of a seismic isolation system and the realization of a seismic joint with the adjacent building, was proposed, which allows the reduction of horizontal forces in the piles and the torsional movements of the structure. © 2016 American Society of Civil Engineers.