Experimental study on the determination of shear strength of strengthened and unstrengthened masonry walls

The results of a research project carried out on masonry panels obtained from historical structures affected by the Umbria-Marche earthquake of 1997–1998 are presented. The aim of the work was to characterize the behavior of the historical masonry typical of the studied areas and to study the effectiveness of a new strengthening technique (Reticolatus), proposed for reinforcing rubble stone masonry walls (double-leaf walls), when the fair-face masonry must be kept. Specifically, the proposed technique consists of embedding a continuous mesh of high strength steel cords in the mortar joints after a first repointing, and then anchoring this to the wall by means of steel eyebolts. According to such an aim, in situ tests, able to determine the correct parameters describing masonry behavior, were performed. The shear strength and the shear elastic modulus were measured.