A multilevel approach to the damage assessment and the seismic improvement of masonry buildings in Italy

The prediction of damages on masonry buildings subjected to seismic actions requires a detailed knowledge of the structure from survey and investigations. The current practice in Italy is to take into account only a limited number among the modes of failure, which are the ones suggested by the Italian Code for the design of the retrofitting intervention. Some failure modes are neglected assuming an implicit resistance capacity of certain structural typologies or considering that the retrofitting measures are able to prevent from them. On the contrary, the effects of the last earthquake in the central Italy have pointed out the limited efficiency of the most in use retrofitting techniques. It follows that the possibility of predicting damages is related to the knowledge of all the possible mechanisms of progressive deterioration or failure, to be obtained by means of an in-field damage assessment after an earthquake. A multilevel approach for the inspection is here proposed, which consists in the survey of the characteristics of the masonry (technological and mechanical) and of the seismic behaviour of the building (observation of the damage mechanisms activated by the earthquake and check of the connections between structural elements).