Cyclic behaviour of stone masonry walls strengthened by grout injection

This research aims at studying the improvements introduced by the grout injection strengthening technique for the structural rehabilitation of old masonry buildings. Initially, cyclic shear tests were carried out on two unstrengthen rubble stone masonry specimens of equal dimensions, built using limestone and hydraulic lime mortar, representing the reference sample for the evaluation of the effectiveness of the grout injections strengthening technique. Secondly, damage panels were strengthened by injecting of hydraulic lime-cement based grout, and the cyclic shear tests were repeated. These tests allowed for an evaluation of the failure mode, force–displacement diagrams, and the definition of various behavioural parameters such as ductility, energy dissipation, cyclic stiffness, equivalent viscous damping ratio and lateral drifts. The results obtained showed that these strengthening technique were successful in allowing the damaged specimen recovering the initial characteristics and in successfully restoring their load carrying capacity.