An experimental and numerical research, aimed at evaluating the in-plane seismic performance of an innovative steel modular system for the reinforcement of load-bearing masonry walls (named “Resisto 5.9”, designed by Progetto Sisma s.r.l.), is currently underway at the EUCENTRE Foundation in Pavia.

Two different masonry typologies, representing common solutions in Italian existing buildings, were considered up to now in this campaign: one made up with solid clay bricks and lime mortar, with “header bond” pattern, and the other with a typical Italian hollow clay “doppio UNI” unit and cement-lime mortar, assembled in a “Flemish bond” pattern.

The experimental tests included first the complete mechanical characterization of units, mortars, masonry typologies and of the strengthening system components (i.e. steel elements and anchors). In-plane quasi-static tests were performed on different batches of full-scale specimens to investigate the influence of the proposed reinforcement system on the lateral in-plane response of the walls, compared to their unreinforced conditions. The cyclic behaviour of the masonry piers was analysed in terms of elastic stiffness, lateral strength, displacement capacity and energy dissipation, depending on the achieved damage mechanism.

The numerical study of the ongoing campaign consisted of a series of parametric analyses on advanced discontinuous models based on the Distinct Element Method (DEM), considering different wall dimensions, vertical load levels and boundary conditions, in addition to those tested experimentally. Moreover, the numerical campaign was extended also to other possible masonry typologies, varying the bond pattern and the mechanical properties with respect to the experimentally tested solutions.

In this paper, the results of the experimental tests on solid brick masonry together with a preliminary overview of the findings of the numerical study, still ongoing, were reported.