Mechanical behavior of historic masonry structures strengthened by bed joints structural repointing

A study on mechanical behaviour of brick masonry structures subjected to overloading phenomena is here presented. Such structures suffer a very specific damage, represented by diffused thin cracks, which can lead to long terms effects up to a sudden collapse. A strengthening technique, based on the insertion of steel bars in the bed joints is proposed. Experimental tests and numerical analyses showed that the presence of the bars allows control of the cracking phenomena, keeping the structure in the desired safety conditions. Two case studies, recently carried out by the Polytechnic of Milan on masonry towers are also discussed. Finally, the application of the strengthening technique to two masonry churches is briefly described