Experimental assessment of in-plane behaviour of three-leaf stone masonry walls

• We carried out shear compression tests on 16 three-leaf stone masonry panels, before and after injecting NHL grout.
• Non-injected panels underwent external leaf separation at lower displacement levels.
• Injected walls presented enhanced behaviour and increased mechanical parameters.
• The use of scaled specimens may be considered representative of the tested masonry.

This paper presents an experimental campaign on multi-leaf stone masonry panels, scales 1:1 and 2:3, in both original conditions and strengthened with grout injections. The panels were subjected to horizontal in-plane cyclic loading combined with vertical loading for different pre-compression levels, and provided important information on failure mechanisms, maximum displacement capacity, shear strength and other mechanical parameters, such as shear modulus and tensile strength. Further analysis provided results on other parameters which mainly characterise the behaviour of three-leaf masonry under seismic loads, i.e., stiffness degradation, energy dissipation, and viscous damping.The main aim of this study was to gather information on the static and dynamic behaviour of three-leaf stone masonry structures in non-injected and injected conditions, in order to accurately characterise their mechanical behaviour. In particular, the effectiveness of injections of hydraulic lime-based grout as a reinforcement technique was assessed and validated.