Retrofit of Existing Masonry Structures with Hysteretic Dampers and External Concrete Walls

This paper proposes a displacement-based method for the design of an energy dissipating system aimed at the seismic upgrading of existing masonry structures. The dissipating system is composed of hysteretic dampers (ADAS) and external concrete walls. The devices are installed within the concrete walls at the floor level and connected to the structures via steel connectors. The design method is based on a simplified model of the overall structure-dissipating system. This model was verified through comparisons with a more refined model. The proposed displacement-based design procedure is based on the knowledge of the nonlinear static response of the existing structure. The design procedure was tested by means of inelastic time-history analyses considering four masonry test structures with different types of hysteretic behaviour. The analyses were carried out considering two groups of spectrum compatible ground motions. The results of the analyses were then compared with the seismic response expected from design.