Dynamic Identification and Collapse Mechanisms of Unreinforced Masonry Heritage: A Comprehensive Study of Erzurum Atatürk House

Abstract

This study presents a comprehensive seismic assessment of the historical Erzurum Atat & uuml;rk House, a representative example of unreinforced masonry (URM) structures in Turkey's high-seismicity region. The research combines experimental and numerical approaches, including operational modal analysis (OMA), detailed finite element modeling, and nonlinear dynamic analyses using nine recorded ground motions. The OMA identified the structure's first three natural frequencies at 3.458 Hz (N-S translation), 3.984 Hz (E-W translation), and 4.264 Hz (torsional mode), with MAC values exceeding 0.9, confirming the accuracy of the calibrated numerical model. Nonlinear time-history analyses revealed critical vulnerabilities, with peak displacements exceeding acceptable limits for all considered seismic scenarios (including 2023 Kahramanmaras, earthquakes). The structure exhibited brittle failure mechanisms characterized by Rapid stiffness degradation; Significant tensile cracking at wall-floor junctions; Out-of-plane failures in upperstory walls; Diagonal shear band formations. Material characterization showed low tensile (0.3-1.07 MPa) and compressive (3-10.71 MPa) strengths, typical of historical masonry with weak lime-based mortars. The force-displacement relationships demonstrated limited energy dissipation capacity, with strength degradation occurring at approximately 10,000 kN lateral load. These findings provide fundamental insights into the seismic behavior of historical URM buildings and establish a methodological framework for their assessment. The study highlights the critical need for further research on performance-based evaluation methods for cultural heritage structures in seismic zones.