Browsing by Author "Ozdogan, Dursun Burak"

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Dynamic Identification and Collapse Mechanisms of Unreinforced Masonry Heritage: A Comprehensive Study of Erzurum Atatürk House
(Pergamon-Elsevier Science Ltd, 2025) Okuyucu, Dilek; Eslek, Tumer; Ozdogan, Dursun Burak; Lacin, Tugce; Mercimek, Omer; Kocaman, Irfan
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.
A Historical Seismic Event Revisited: Stochastic Ground Motion Modeling of the 1859 Erzurum Earthquake and Validations with Structural Damage
(Springer, 2025) Ozdogan, Dursun Burak; Okuyucu, Dilek; Askan, Aysegul; Kocaman, Irfan
Erzurum is one of the major cities in T & uuml;rkiye with high seismic hazard, having a well-documented history of destructive earthquakes. The June 2, 1859 earthquake (Mw = 6.1) caused severe damage to the city, but no ground motion records exist because it occurred before the instrumental measurement period. This study aims to simulate and validate a simulated ground motion record for this historical earthquake using the stochastic finite-fault method. In this approach, fault geometry, stress drop, crustal properties, and local site effects were incorporated to generate realistic acceleration time histories. The simulated record was validated through comparisons with empirical ground motion models and historical damage reports. For validation, detailed finite element models of Erzurum Ulu Mosque and Murat Pasha Mosque were developed and calibrated using Operational Modal Analysis (OMA) data, and nonlinear time-history analyses were performed to assess the consistency of observed and simulated damage patterns. The findings demonstrate that stochastic ground motion simulations can provide reliable insights into historical seismic events, offering a robust framework for reassessing earthquakes without instrumental records and contributing to the understanding of the seismic performance of masonry heritage structures.