Resumen
Following the Zagreb earthquake in March of 2020, a destructive 6.2 magnitude earthquake struck Croatia again in December of 2020. The Sisak-Moslavina county suffered the most severe consequences; many historical and cultural buildings were badly damaged. In the education sector, 109 buildings were damaged. One such building is the case study of this research. The heritage-protected building of the First Primary School in Petrinja is an unreinforced masonry structure, constructed using traditional materials and building techniques. The historical background of the building and the results of the post-earthquake assessment are presented. A numerical calculation of three strengthening methods was performed in 3Muri software: FRCM, FRP, and shotcrete. Non-linear pushover analysis was performed for each model. Finally, the strengthening methods are compared based on the achieved earthquake capacity, cost, and environmental impact.