Heritage Conservation in Crisis: A Case Study on Post-Earthquake Church Restoration in Samos Island, Greece

Abstract. This paper details the methodology for recording, documenting, and restoring six historic Orthodox churches on the island of Samos, Greece, severely damaged by 2020 Aegean Sea earthquake, occurred on October 30. An interdisciplinary team from the Faculty of Engineering from Aristotle University of Thessaloniki led this 12-month project, funded by the Greek Ministry of Culture. The restoration process began with a thorough on-site data collection, employing advanced 3D surveying techniques like Terrestrial Laser Scanning (TLS), photogrammetry, Unmanned Aerial Vehicles (UAVs), and traditional topographic methods including GNSS. This was complemented by historical documentation. The collected data included images, videos, measurements, and reports and were processed to create detailed 3D models of each church's interior and exterior, along with 2D CAD orthoimages for precise measurements and architectural documentation. Structural assessment utilized these 3D models and on-site identification of the load-bearing stone masonry systems. Bearing capacity under seismic loads was evaluated using Equivalent Static Analysis, adhering to regulatory frameworks (EC8-3, Greek KADET). Material mechanical properties were quantified through laboratory testing of samples from the structures. Strengthening proposals prioritize safety, compatibility, reversibility, and minimal intervention, guided by predicted failure modes. Demand/capacity ratios, considering both loads and displacements, were calculated for the defined performance level, accounting for the churches' functional use and monumental value. The proposed strengthening solutions aim to upgrade the load bearing capacity of the structures after ensuring the out of plane stability of the walls forming the facades.