1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

Seismic performance analysis of a stone masonry building dating back to the 15th century, a period in which seismic norms were non-existent, can give us invaluable information about the knowledge and expertise of builders from that time. By analyzing buildings made in previous centuries we find not only numerous aspects from which we can learn, but also many defects which we need to be aware of. Especially when those buildings have become a part of their respective cultural heritage, just like the building observed in this paper.
The observed building is a monastery on the island of Badija in the Korčula archipelago in Croatia. Initially, the load-bearing structure was built with massive three-layer stone walls and floors with wooden beams. Throughout the centuries the structure has undergone numerous reconstructions, the last of which involved strengthening with concrete walls and composite floor slab.
The numerical model was made and showed that the building does not have sufficient load capacity to seismic load. The linear analysis was made in accordance with Eurocode 8-3 and the load capacity of the structure was determined. Further analysis showed that the critical load-bearing structure was not up to present seismic norms, even concluding that major parts of the building would be in danger of failure. Results show that in case of an earthquake with a return period of 475 years the building would sustain critical damage and possibly failure. The critical parts of the structure and dominant failure mechanisms are determined. Based on the obtained results, retrofit measures of seismic strengthening are proposed.