İnşaat Mühendisliği Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1943

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Browsing İnşaat Mühendisliği Bölümü Koleksiyonu by Institution Author "Şadan, Bahadır"

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    Book Part
    Comparison of the Observed and Numerical Performance of a Seismic Isolated Hospital
    (International Association for Earthquake Engineering, 2024) Şadan, B.; Sahin, B.; Tüzün, C.; Demircioglu-Tumsa, M.B.; Erdik, M.
    The southeastern region of Turkiye was struck by powerful earthquakes on February 6, 2023, with magnitudes measuring M7.7 and M7.6. These earthquakes resulted in significant damage, destruction, and loss of life, affecting both Türkiye and extending into northern Syria. Among the approximately 100 isolated buildings in Turkiye, 11 isolated hospitals were located in the impacted region. This paper presents a comprehensive assessment of the seismic performance of the seismically isolated Osmaniye State Hospital during the Kahramanmaras earthquakes. The evaluation comprises site observations and numerical analysis utilizing ground motion records obtained from the nearest accelerometers. Site observations involved monitoring the movements of the isolators located at the moats around the perimeter of the hospital. Using a borescope allowed for detailed internal inspection of the isolation bearings, facilitating close-up examination of the isolators and enabling the identification of movement scuff marks on the sliding surfaces. These observations were used to estimate the maximum isolation bearing movement and determine the residual displacement offset of the bearings. The observed displacements of the isolation system were compared with the design values to assess the performance of the seismically isolated structure. Discrepancies between the observed and designed displacements provide valuable insights into the actual behavior of the isolation system. A nonlinear time history analysis was conducted using ground motion records obtained from the nearest accelerometers to further analyze the seismic response. This numerical analysis allowed for the simulation of earthquake excitations and the evaluation of the dynamic behavior of the seismically isolated Osmaniye State Hospital. The combination of site observations and numerical analysis yielded important findings regarding the seismic performance of the seismically isolated Osmaniye State Hospital during the Kahramanmaras earthquakes. The comparison between observed and design displacements provided insights into the efficacy of the isolation system, while the numerical analysis further validated the structural response. These findings contribute to improving the design and implementation of seismically isolated structures. © 2024, International Association for Earthquake Engineering. All rights reserved.
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    Article
    Deprem Yalıtımlı ve Geleneksel Binalarda Tesisatlar İçin Sismik Koruma Hesabı ve Gereksinimi
    (2023) Şadan, Bahadır
    İnşaat mühendisleri, olası büyük bir deprem senaryosu için, binanın taşıyıcı elemanlarını ve içinde yaşayan insanların can güvenliğini sağlamak için tasarım yapmaktadırlar. Halbu - ki, büyük bir deprem sonrası mali kayıp tabloları incelendiğinde, mali kayıpların en büyük bölümünü yapısal olmayan elemanlardaki hasarın oluşturduğunu görebiliriz. Dışarıdan bakıldığında hasarsız gözüken, taşıyıcı elemanlarında hasar olmayan bir binanın içerisine girildiğinde, sadece kendi ağırlığını taşımak için askılanmış ve doğru sismik koruma uygulan- mamış tesisatların, tavaların ve diğer tavana asılı ekipmanların, yüksek deprem ivmesi nedeni ile hasar gördüğü ve binanın kullanılamaz hale geldiği gözlemlenebilir. Bu durum özellikle deprem sonrası hemen hizmet vermesi gereken kritik binalar için (ör. hastaneler, ulaşım ve haberleşme yapıları vb.) daha büyük önem taşımaktadır. Sağlık Bakanlığı bu bağlamda, 2013 yılında yayınladığı bir genelge ile, 1. ve 2. derece deprem bölgesindeki, 100 ve üzeri yatak kapasiteli tüm devlet hastanelerinde sismik izolatörler ile deprem yalıtımını zorunlu hale getirmiştir. Deprem yalıtımı, binaya etkiyen deprem ivmelerini dolayısı ile deprem kuvvetlerini çok büyük oranda sönümleyerek, sadece bina taşıyıcı siste- minin değil aynı zamanda diğer muhteviyatın (tesisatlar, ivmeye hassas cihazlar vb.) deprem sırasında korunmasını sağlamaktadır. Fakat bu azaltma deprem etkilerini tamamen yok et- mediği için tesisatlarda sismik koruma yapılmasına gerek olmadığı anlamına gelmemektedir. Bu bildiride, 18 Mart 2018, 30364 sayılı Resmi Gazete’de yayınlanarak, 1 Ocak 2019 tarihi itibari ile resmi olarak yürürlüğe giren Türkiye Bina Deprem Yönetmeliği’ne (TBDY) göre elektrik ve mekanik tesisatların sismik koruma hesabı tariflenmektedir. Ayrıca yine TBDY’e göre deprem yalıtımlı binalarda sismik koruma hesabı gereksinimi irdelenmektedir.
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    Conference Object
    Citation - WoS: 6
    Citation - Scopus: 7
    Near-Fault Earthquake Ground Motion and Seismic Isolation Design
    (Springer International Publishing Ag, 2023) Harmandar, Ebru; Erdik, Mustafa; Demircioglu-Tumsa, Mine B.; Şadan, Bahadır; Tuzun, Cuneyt; Ulker, Omer
    Seismic isolation is one of the most reliable passive structural control techniques with adequately established standards for the earthquake protection of structures from earthquakes. However, it has been shown that the seismic isolation systems may not function the best for the near-fault ground motions, since in the proximity of a capable fault, the ground motions are significantly affected by the rupture mechanism and may generate high demands on the isolation system and the structure. In fact, several earthquake resistant design codes state that the seismically isolated structures located at near-fault sites should be designed by considering larger seismic demands than the demand on structures at far-field sites. When the fault ruptures in forward direction to the site most of the seismic energy arrives in coherent long-period ground velocity pulses. The ground-motion prediction equations (GMPEs) typically cannot account for such effects with limited distance metrics and lack adequate data at large magnitudes and near distances. For the reliable earthquake design of the isolated structure in near fault conditions that meets the performance objectives, the 3D design basis ground motion(s) need to be appropriately assessed. Measures in the design of the isolation system, such as modifications in the stiffness and damping characteristics, as well as in the limitation of vertical effects are needed. The behavior of the base-isolated buildings under near-fault (NF) ground motions with fling-step and forward-directivity characteristics are investigated with a rational assessment of design-basis near-fault ground motion, are investigated in a parametric format. The parametric study includes several variables, including the structural system flexibility; number of stories; isolation system characteristic (yield) strength, and the isolation periods related to the post-elastic stiffness. Furthermore, the effect of additional damping by viscous dampers were tested for some selected cases. Important findings observed from the parametric performance results and the overall conclusions of the study are provided.
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    Article
    Citation - WoS: 27
    Citation - Scopus: 41
    Performance of High-Damping Rubber Bearings for Seismic Isolation of Residential Buildings in Turkey
    (Elsevier, 2021) Murota, N.; Tuzun, C.; Mori, T.; Şadan, Bahadır; Wakishima, K.; Suzuki, S.; Sutcu, F.; Erdik, M.
    The applicability of high-damping rubber bearings for seismic isolation of residential buildings in Turkey is studied using numerical and experimental approaches. Seismic isolation system composed of high-damping rubber bearings is designed according to the recently updated Turkish Building Seismic Code-2018 (TBSC2018). Three model buildings of different height at assumed seismically active area are chosen from an actual building database, on which, equivalent lateral force procedure, and time history analyses are carried out. The seismic responses of the buildings are evaluated and the seismic isolation system's efficiency is confirmed. It is pointed out that the requirements in the new code in terms of the maximum allowable shear strain of elastomeric isolators are excessively conservative for those isolators with much larger capacity which is verified by sufficient test data, and as a result, designed isolator size becomes larger than necessary from a practical aspect. In order to verify the isolator design without compliance of shear strain limitation in the code, full-scale prototypes of high-damping rubber bearings are specially designed, developed and are subjected to dynamic loading test under test protocol specified in the code. The specific values of test conditions, such as compressive force, shear displacement and frequency, are developed referring several projects in Turkey. The results are comprehensively discussed and the applicability of high-damping rubber bearing for seismic isolation of residential buildings in Turkey is concluded with numerical and experimental approaches and a possible modification of TBSC2018 regarding maximum shear strain is proposed.
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    Conference Object
    Citation - WoS: 6
    Citation - Scopus: 5
    State of the Art in Application of Seismic Isolation and Energy Dissipation in Turkey
    (Springer International Publishing Ag, 2023) Şadan, Bahadır
    This paper summarizes the passive structural control system applications and other related developments in Turkey, emphasizing the period between 2019 and 2022. The country hosts state-of-the-art seismic isolation applications, relatively greater in size, and use more isolators in each project (415 isolators per building on average) compared to the other seismic isolation projects worldwide. Construction of the world's largest seismic isolated building, Istanbul Basaksehir Pine and Sakura City Hospital, covering more than 1 million square meters of area and employing more than 2000 seismic isolators, was completed and has been in service since May 2020. 1915 Canakkale Bridge, constructed in memory of the great war of Canakkale during World War I, is now the world's longest suspension bridge with a 2023m main span length. Eight massive hydraulic dampers were used at the main deck and 48 at the approach viaducts in combination with 72 seismic isolators. Construction of a residential building complex in Istanbul consisting of 16 isolated blocks covering more than 170,000 m(2) area and having 454 seismic isolators is coming to an end very soon. Historical Nusretiye Clock Tower in Istanbul was relocated a few meters over seismic isolators. Historical Goztepe Railway Station in Istanbul was retrofitted to accommodate an additional railway line using seismic isolation technology. Seismic codes for buildings and bridges now include rules for the seismically isolated design of structures. Additionally, all seismic isolation designs must be peer-reviewed by law. A new seismic isolator testing facility was established in Eskisehir to respond to the demand for the large number of isolators that need to be tested.