Experimental and numerical analysis of full-scale solid brick masonry walls reinforced with NSM twisted steel bars subjected to cylic loading

The seismic rehabilitation of old masonry buildings is crucial for preserving heritage structures and ensuring safety in earthquake-prone areas. These buildings, often found in historic city centres, were not designed according to modern seismic codes, rendering them vulnerable to seismic actions. This study presents an investigation into the behaviour of full-scale masonry walls made of solid clay brick and cement-lime blended mortar, subjected to cyclic loading, and the corresponding numerical analyses, focusing on a strengthening technique proposed by the authors using near surface mounted twisted steel bars.

The study's findings indicate that the NSM technique substantially enhances the walls' shear strength, ductility, and energy dissipation capacity. Reinforced specimens demonstrated increased drift capacity and dissipated energy compared to unreinforced ones, confirming the effectiveness of the strengthening approach in preventing collapse and mitigating life-threatening risks during seismic events. Additionally, numerical simulations calibrated with experimental data provided insights into the structural response, validating the proposed solution as an effective and minimally invasive retrofit for heritage masonry structures.