Modal parameter determination and structural assessment of historical minaret under earthquake and wind loads

This study presents a comprehensive linear time history of a historical masonry minaret called the Grand Mosque Minaret in Bayburt, employing a finite element (FE) model subjected to five distinct real earthquake acceleration records. Ambient vibration tests were conducted within the framework of operational modal analysis (OMA), utilizing enhanced frequency domain decomposition technique to estimate the experimental modal parameters. The FE model, developed under the assumption of linear elastic material behavior, was updated through a vibration-based model updating technique to accurately represent the dynamic characteristics of the structure. Each seismic record was applied as a base excitation, and the corresponding time-dependent structural responses were computed for initial and updated FE models. The analysis yielded critical engineering parameters, including maximum displacement and minimum–maximum principal stress distributions. The results obtained from the FE analyses were evaluated comparatively. Also in this study, the wind loads of the minaret were determined using the TS 498 standard, and structural wind load analyses were performed on the initial and updated FE models. Drift ratio values of the minaret were calculated for earthquake records and wind loads, and the structural performance of the minaret was evaluated comparatively for both models. It has been found that the structural behavior of the minaret was significantly affected by earthquakes. The drift ratio values remained within the controlled damage limit for wind analyses, while earthquake analyses indicated that the minaret was mostly in the collapse limit. The results show that more effective conservation and restoration strategies for cultural heritage structures can be developed by using both FE and experimental methods.