“Experimental Behaviour of Masonry Walls Strenghtened by Reinforced Mortar Slabs and Subjected to in-Plane Loads”

One of the main technical strategies for seismic upgrading of ordinary masonry buildings, often utilized after earthquakes, consist in strengthening walls by means of thin reinforced mortar slabs applied at one or both sides of the wall and linked to it. This type of technical provision has been currently employed in Italy and widely utilized after the 1976 Friuli earthquake. In spite of this, no experimental investigation has been performed until now to asses structural behaviour of the composite structure masonry wall-reinforced mortar slabs. In this work an experimental investigation has been carried out on masonry wall panels strengthened with different technical and executive strategies commonly used for ordinary masonry of private building. To evaluate shear strength of strengthened masonry walls, four wall test units (panels) with dimensions of 100x100x25cm and subjected to in-plane loads have been experimented. One of the wall panel was made of ordinary masonry, one was strengthened by a reinforced mortar slab applied only on one side, one had reinforced mortar slabs on both sides but anti-adherent sheaths between the masonry panel and the slabs to simulate the case of bad realization of the upgrading, and one had slabs on both sides and perfectly adherent to it. The study shows the importance of realizing a good adhesion between the masonry wall and the reinforced mortar slabs. Indeed increase of 26% in strength of about has been observed in the composite wall panel with perfectly adherent slabs in comparison to the composite wall panel with anti-adherent sheaths between the wall and the slabs.