Seismic performance analyses and restoration of ruined dervish lodge structures on Istanbul’s historic peninsula

This study presents a comprehensive and multidisciplinary approach to the seismic performance assessment and restoration of the Erdi Baba (Abdal Yakup) Dervish Lodge complex, constructed in 1741 on Istanbul’s historic peninsula. The restoration process was carried out in four stages: (i) field and archival surveys to identify original architectural features, (ii) extensive laboratory analyses of collected materials, (iii) seismic performance evaluation using linear, nonlinear, and kinematic limit analyses, and (iv) development and implementation of context-specific restoration practices. Laboratory analyses revealed that the mortar samples generally exhibited low mechanical strength, with calcium carbonate content exceeding 50% in most cases, which indicates weak binding characteristics. SEM-EDX and petrographic examinations confirmed high calcium content and the presence of brick ballast, lime lumps, and flax fibers in the samples, consistent with traditional Ottoman construction materials. Seismic analyses were conducted using Midas Gen software in accordance with the Turkish Building Earthquake Code (TBEC-2018) and the Guideline for Seismic Risk Management of Cultural Heritage Buildings (SRMGHS-2017). This research presents a replicable methodology for the restoration of similar Ottoman-era religious complexes in seismic regions, providing a benchmark for future interdisciplinary studies that integrate historical architecture, materials science, and structural engineering.