Seismic Retrofitting of Unreinforced Masonry Buildings in Italy
The Italian heritage building stock is dominated by unreinforced masonry buildings widespread on the whole territory with rammed earth buildings peculiar of some regions. A major effort is given to strengthen or retrofit these buildings in order to improve their safety under seismic loading as well as to preserve them as memory of the ancient art of builders and as constitutive elements of the anthrop-environment. This paper describes traditional seismic retrofit interventions adopted in Italy. These retrofitting interventions, revised according to the modern technologies, derived from historical concept of aseismic devices (i.e. metallic tie-rods, circumferential tie-rods, buttresses, “diatoni”, wall connections, partial reconstruction of walls) suggested to the builders’ crafts by observation of earthquake damage and imposed by the past technical rules. A good degree of confidence on the feasibility, compatibility and effectiveness of these techniques for URM buildings is guaranteed after having been extensively tested during the centuries. Recently, technical national code-guidelines for the seismic retrofit of existing URM masonry buildings have been prepared with the specific purpose to help practitioner engineers to implement these solutions.