Investigations for the knowledge of multi-leaf stone masonry walls

The use of stone masonry is very common in many historic constructions, both architectural monuments and whole urban centers. Such architectonical heritage is often located in areas characterized by a medium-high seismic hazard and frequently reveals mechanical damage due to the constructive peculiarities of masonry. It is characterized by scarce or no connection through the thickness and by a possible substantial presence of voids, being consequently affected by brittle collapse mechanisms. In order to understand the mechanical behavior of such masonry, to properly analyze it, to design the most suitable conservation strategies and the most effective consolidation interventions, it ought to start from a clear description of its typological and morphological characteristics. Some different available walls classifications were used for this purpose, together with detailed data-bases, aimed to specific analyses. In particular, an existing extensive data-base was enriched with the analysis of other almost 100 walls sections. It was thus identified a wall “model” sufficiently representative of the existing typologies. On the basis of those preliminary information, a comprehensive experimental research has been recently performed at the University of Padua. Seventeen physical models were built and tested with destructive and non-destructive techniques, before and after the application of different consolidation techniques. Results confirmed that grout injection is the most effective consolidation technique for this kind of masonry. Some of the goals scored by the performed research and discussed in the present papers are: (i) the clarification of the current classifications of stone walls to identify some typical walls typologies; (ii) the design and the validation of a physical model sufficiently representative for laboratory researches. Finally, the use of non-destructive techniques (in particular, sonic waves and tomography), for a non-invasive evaluation of the conditions of stone walls, in order to have useful information for a proper design and control of the intervention, is discussed.