Dynamic identification of a stone masonry building: influence of damage and of CRM retrofitting

The dynamic identification of a full-scale, two-storey building, made of rubble stone masonry, was achieved. Different configurations were analyzed: unstrengthened masonry and retrofitted masonry, in both undamaged and damaged conditions. Damage was accomplished by testing the building under lateral cyclic loading, to reproduce the seismic effects. The strengthening technique (CRM – Composite Reinforced Mortar) consisted in plastering the outer facades by means of a 30 mm tick mortar coating reinforced with glass-fiber polymer meshes and in introducing transversal connectors injected in the masonry. The mode shapes and natural vibrating frequencies were analyzed and compared, evidencing the effects of damage and of retrofitting. A finite element numerical model was developed, to perform eigenvalue analysis and calibrate the equivalent masonry stiffness for the different configurations.