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Yayın Disaster damage assessment of buildings using adaptive self-similarity descriptor(2016-08) Kahraman, Fatih; İmamoğlu, Mümin; Ateş, Hasan FehmiAssessment of damage caused by a disaster is significant for coordinating emergency response teams and planning emergency aid. In this letter, a robust method for rapid building damage assessment is proposed using pre- and postevent EO images and building footprints. The method uses a local self-similarity descriptor (SSD) for change detection in buildings, which is shown to be robust against variations in global illumination and small local deformations. The use of building footprints helps reduce the false alarms due to changes in nonbuilding areas. Footprint is also used to differentiate small and large buildings, extract the boundary region of a building, and adapt the descriptor computation accordingly. It is shown that the adaptive SSD provides a more accurate measure of local damage on the building. The 2010 Haiti Earthquake and Typhoon Haiyan 2013 Philippines are analyzed with the proposed method, and 75/82% true positive rate and 25/15% false positive rate are obtained for detection of collapsed buildings with respect to the ground truth data of UNITAR/UNOSAT and HOT.Yayın Seismic performance assessment of a post tensioned box girder viaduct(Işık Üniversitesi, 2022-01-31) Arslanboğan, Emir; Umut, Önder; Işık Üniversitesi, Lisansüstü Eğitim Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıIn the 1999 Marmara earthquakes (Kocaeli and Düzce earthquakes), some of the existing bridges and viaducts were completely or partially destroyed and the earthquake performance of the existing bridges and viaducts began to be questioned. Evaluating the seismic performance of existing structures is one of the most important preliminary steps before seismic retrofitting of structures, as well as a way to validate the analysis and design specifications. The subject of this study is the seismic performance evaluation of the Molla Gürani Viaduct, located in front of the Elmalı Dam on the TEM (O-2 highway) in Istanbul, according to the Turkey Bridge Earthquake Code published in 2020 and its annexes. First of all, all kinds of information, documents, projects, reports and test results related to the viaduct were examined, analyzed and tried to be verified. It has been tried to obtain healthy information about the current situation of the viaduct by making visual inspections in the region where the viaduct is located. The seismic performance assesment of the existing viaduct were made with the Nonlinear Time History Analysis method described in TBEC 2020. The three dimensional model of the viaduct was prepared using the SAP2000 software. The moment-curvature relationship of the sections were determined with the XTRACT section analysis program, using the axial loads obtained from the non-linear static analysis results performed under non-seismic loads. The cracked section stiffnesses and other section properties were modified before dynamic analyses. Due to the large stirrup spacing in the columns, unconfined concrete properties were used in the moment-curvature analyses. The bending cracked section stiffnesses of each column were calculated separately and included in the model. The nonlinear behavior has been tried to be characterized by the acceptance of lumped plastic hinges. For each of the pier columns, 2 plastic hinges in both directions are defined in the foundation-column junction area and just below the 1.4 m solid part at the top end of the columns. The Nonlinear Time History analyses was carried out using 7 earthquake records selected by considering earthquake magnitudes, fault distances, source mechanisms and local ground conditions compatible with DD1 and DD2a earthquake ground motion levels defined in TBEC-2020 Chapter 2. Selected ground motion records are scaled according to TBEC-2020 Section 2.5. As a result of the existing situation analysis of the viaduct, it has been observed that the deformations occurring in the elastomeric bearings in the longitudinal and transverse directions for the DD-1 Earthquake Ground Motion Level are higher than the values allowed in the TBEC-2020 section 5.4.5.1. The fact that the superstructure is continuous and that it is anchored to the abutment by tie bars eliminates the possibility of falling off the support in the longitudinal direction. As a result of possible ruptures that may occur because of high deformations in elastomeric bearings, elastomeric bearings may not fulfill their function. In this case, the viaduct superstructure beams are likely to be free in the transverse direction and may pound each others under the effects of earthquakes, despite the 1.50 m gap between them. In the seismic performance evaluation analyses of the viaduct, it has been determined that the shear keys on the abutments do not have the capacity to meet the earthquake loads. In the observations made in the field, it is seen that macro cracks are formed in the shear keys on the abutments. Limiting elastomeric bearings deformation and strengthening shear keys before a possible Istanbul earthquake in the Molla Gürani viaduct are among the some of the most important precautions to be taken immediately before an earthquake.Yayın Quaternary rock uplift rates and their implications for the western flank of the North Anatolian Fault restraining bend; inferences from fluvial terrace ages(Blackwell Publishing Ltd, 2020-10-01) McClain, Kevin P.; Yıldırım, Cengiz; Ciner, Attila; Şahin, Sefa; Sarıkaya, Mehmet Akif; Özcan, Orkan; Güneç Kıyak, Nafiye; Öztürk, TuğbaIn the western flank of the North Anatolian Fault restraining bend (i.e., Central Pontides), the Filyos River incises through the uplifting Karabük Range, creating the ~1.7-km-deep Filyos River Gorge on the hanging wall of the reverse Karabük Fault. Seven fluvial strath terrace levels are preserved in this gorge. optically stimulated luminescence ages from quartz-rich sediments of five terrace levels reveal an average long-term rock uplift rate of 0.45 ± 0.02 mm yr?1 with an unsteady pattern of uplift during the last 542 ± 24 kyr. Uplift rates of 1.52 ± 0.6 and 0.74 ± 0.3 mm yr?1 occurred before 366 ± 19 kyr, followed by lower rates of ~0.1 and 0.31 mm yr?1 through present. These later uplift rates may reflect relatively slower tectonic rates since ~366 kyr, with closer similarity to regional uplift rates of ~0.3 mm yr?1 yielded from the eastern flank of the Central Pontides. The Karabük Range fluvial terraces are near the North Anatolian Fault, meaning pre- ~366 kyr uplift rates may be a glimpse of the highest Central Pontides Quaternary rock uplift rates on uplifting hanging wall blocks activated by the restraining bend. When we consider offshore seismic reflection data, the focal mechanism solution of the Bartın Earthquake, onshore structural data, and regional tectonic geomorphology, the western flank of the Central Anatolian Plateau's northern margin is propagating northward as a growing orogenic wedge with a positive flower-structure geometry.Yayın Disaster damage assessment for buildings using self-similarity descriptor(Institute of Electrical and Electronics Engineers Inc, 2015) Kahraman, Fatih; İmamoğlu, Mümin; Ateş, Hasan FehmiAssessment of damage caused by an earthquake is significant for coordinating emergency response teams and planning emergency aid. In this study, a robust method is proposed for detecting damaged buildings using pre- and post-event satellite images and building footprints. The method uses local self-similarity descriptor for change detection in buildings, which is shown to be robust against variations in illumination and small local deformations. The use of building footprints helps reduce the false alarms due to changes in non-building areas. The 2010 Haiti earthquake is analyzed with the suggested method and 72% true positive rate and 29% false positive rate are obtained for detection of collapsed buildings with respect to the ground truth data of UNITAR/UNOSAT.
