Browsing by Author "Askan, Aysegul"

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Evaluation of Successful Seismic Bridge Design Practice in Turkey
(ASCE-Amer Soc Civil Engineers, 2014) Okuyucu, Dilek; Kale, Ozkan; Erdil, Baris; Caner, Alp; Askan, Aysegul; Akansel, Vesile Hatun
On October 23, 2011, a destructive earthquake of Mw=7.1 occurred in Eastern Turkey. The event occurred on a previously unknown fault with a thrust mechanism and resulted in 604 deaths and major structural damage to the buildings. The highways at the Van earthquake zone were open to service of rescue operations, aid trucks, and regular traffic immediately after the devastating event. As a success story, the bridges closer to the fault line than the towns of Van and Erci were observed to have minimal damage, such as minor support movements and cracks at the shear keys. Among the 14 highway bridges in the region evaluated by the authors, only two adjacent bridges, Bendimahi-II, had minor structural cracking along the column height. As expected, the bridges of concern were observed to perform in the essentially elastic state. The main focus of this study was to evaluate the seismic bridge design practice in Turkey, which resulted in a successful seismic performance of the earthquake-zone bridges. As an illustrative example, Bendimahi-II bridge, the closest one to the fault line, was studied through an analytical investigation.
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.