The bridge of Konitsa over the Aoos river, in Epirus, Greece, was built in 1869. It is one of the most important stone arched bridges in the Balkans, listed by the Hellenic Ministry of Culture (1982). The bridge, damaged by the Ottoman Army in 1913, was restored the same year by French engineers using reinforced concrete. Structural deterioration, located mainly in the area damaged by the explosion and subsequently repaired, led to the study of the bridge by the National Technical University of Athens (NTUA), in the framework of a Contract among the Prefecture of Epirus, the Municipality of Konitsa (owner of the bridge), the Ministry of Culture and NTUA. The entire study includes the exhaustive documentation of the bridge, its numerical modelling and assessment at its current state, the selection of adequate interventions and the numerical investigation of the efficiency of the proposed interventions. During this process, one of the main issues was the treatment of the concrete intervention of 1913. For the choice and for the design of the restoration measures, a calculation methodology was adopted, based on the findings of the documentation of the bridge, while taking into account the critical phases (construction, damage and repair) over its lifetime. This work has proven the available safety of the bridge under its self-weight, as well as the need for reconstruction of the RC jacket at the intrados of the arch, which was applied as a repair measure to the bridge in 1913.