An experimental analysis has been carried out on the long-term behaviour of composite specimens and walls made with historical brickwork. The test pieces were subjected both to static and to cyclic loading tests (accelerate static creep) and to freezing-thawing thermo-hygrometric tests in order to study the durability of different strengthening mortars. The acoustic emission (AE) monitoring technique was also used to assess the damage localization and to predict the time to failure of the strengthened walls during fatigue tests. The AE is a very effective non-destructive technique that permits to estimate the amount of energy released during fracture propagation. Damage evolution during fatigue compressive loading, in terms of measured strains and the AE counting number, can be divided into three stages; fatigue life can be predicted from the slope of the AE counting number rate diagram. Starting from an AE monitoring, a special methodology has been developed to predict the service life of creep damaged masonry structures. The novelty of this work consists in the experimental confirmation that the AE technique is able to analyse the creep curves of masonry strengthening mortars. Therefore, it demonstrated that by the AE technique, it is also possible to evaluate the durability of strengthening materials subjected to load histories in the time. Copyright © 2013 John Wiley & Sons, Ltd.

Diagnostics is a very important tool of knowledge in the field of historical buildings. In particular, non-destructive techniques allow to deepen the study of the mechanical characteristics of the historical walls without compromising the artistic value of the monumental building. A case study of the use of sonic and impact tests was described, performed using the same instrumented hammer, for the characterization of the masonry walls at the Sanctuary of Santa Maria delle Grazie at Varoni, one of the churches damaged in the 2016 Amatrice earthquake. Sonic tests showed the presence of a discontinous masonry texture, as well as confirming the ineffectiveness of the strengthening work made by injections of lime mortar. The impact test allowed us to obtain the elastic modulus of the omogeneous stones of the masonry. The results obtained from the non-destructive techniques were confirmed by the flat jacks test carried out on the building, confirming the great potential of the non-destructive diagnostics suitable for analyzing important structural parameters without affecting the preservation of historical masonry structures.

The big earthquake of August 24, 2016 and subsequent major shocks severely damaged many historic villages in Central Italy and dramatically showed the intrinsic vulnerability of the diffused architectural heritage. The St. Agostino church is one of the collapsed historical buildings, being inside the epicentre village of Amatrice. During the long seismic earthquake swarm, progressively the church was damaged and monitored. This multidisciplinary study of the damage of the church includes correlations of all the data derived from three steps geomatics surveys (3D aerial and terrestrial models): the archival drawings and images documenting previous events distressing the building, the previous strengthening intervention, and finally the seismic site response analysis (from Amatrice’s accelerometric station). Through a back analysis carried out by a finite elements model, it was possible to understand the seismic vulnerability of this historical building, in relation to the previous interventions and damage events. The proposed methodology, based on the interdisciplinary data analysis, provides useful information for the next strengthening projects of damaged historical monument.