Purpose This study seeks to examine and evaluate the seismic susceptibility of historic masonry structures in Annaba, situated in seismically active regions, employing nonlinear analysis with the 3Muri program. The study aims to discover effective strengthening measures while considering practical feasibility and the availability of local resources. Design/methodology/approach A multi-phase process was applied to a sample historic masonry structure in Annaba. The approach commenced with a comprehensive architectural and structural survey, encompassing precise geometric documentation of longitudinal and transverse sections, along with meticulous mapping of all observable fractures and structural deficiencies. A numerical model was constructed utilizing the 3Muri software, which applies the equivalent frame method for the nonlinear analysis of masonry structures, based on the gathered data. Nonlinear static (pushover) analyses were conducted to assess the seismic performance of the building in its current state. Multiple reinforcement scenarios, including CFRP reinforcement and a hybrid Steel Frame + CFRP solution, were simulated by altering mechanical properties to reflect retrofit interventions. Structural performance indicators and fragility curves were utilized to compare the behavior before and after retrofitting. Findings Analyses indicate a substantial deficiency in the seismic resilience of structures in Algeria, intensified by material degradation due to environmental exposure. Reinforcement and restoration are crucial, and our findings indicate that utilizing carbon fiber reinforced polymer (CFRP) strikes an optimal balance between efficiency and practicality, resulting in a reduction exceeding 50% in components vulnerable to severe damage, while markedly enhancing flexibility and resistance to collapse. The integration of a steel frame and CFRP yields the most significant enhancement in seismic performance, leading to the maximum decrease in possible damage at all performance levels. Originality/value This study investigates a viable method for seismic evaluation and preservation of brick heritage structures in Algeria. It incorporates comprehensive surveys, sophisticated numerical modeling, and fragility-based evaluation with restoration strategies according to the accessibility of local materials and the economic circumstances in Algeria. This study introduces one of the initial extensive implementations of the 3Muri program for the fortification of brick heritage structures with carbon fiber reinforced polymer (CFRP) within the Algerian environment.
Seboui et al. (2026) studied this question.