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Bu çalışmada binalarda yapay öğrenme destekli yapı sağlığı izleme uygulamaları Dünya Kültür Mirası Listesinde yer alan Ayasofya Camisi titreşim verileri dikkate alınarak gösterilmiştir. Ayasofya’da ilk olarak 1991 yılında kurulan bu ivme sensörleri bugüne kadar birçok büyük ve küçük depremi kayıt altına almıştır. Bu depremler ve uzun dönemli ivme kayıtlarından elde ettiğimiz regresyon analizi modelleri yapının muhtemel hasarının tahmininde kullanılmaktadır

The knowledge of frequencies of vibration of the first modes of minarets is essential to anticipate their behaviour under seismic loads. Masonry minarets are very slender structures with an extensive history of many centuries of construction and damages inflicted by earthquakes. Their construction techniques did not change much throughout the historical epochs, and only very recently, new minarets of the same type were built with Reinforced Concrete. Minarets lately have been the object of several studies because both the monitoring technologies for in-situ vibration observations and the existence of non-linear large-displacement software have become available. Many teams dedicated their attention to analysing frequencies of these structures and a few to study their behaviour. 

The Buyukcekmece district of Istanbul, situated in a region near North Anatolian Fault, faces significant earthquake risk. This study aims to enhance our understanding of seismic hazards in B & uuml;y & uuml;k & ccedil;ekmece by investigating site-specific parameters. We conducted a comprehensive field study involving seismic ambient vibration measurements at 56 selected locations. The horizontal-to-vertical spectral ratio (HVSR) method was employed to analyze the recorded data, and to obtain fundamental frequencies and approximate bedrock depths. These parameters offer insights into the local soil conditions and site amplification characteristics. The findings of this study reveal that the region exhibits intermediate to strong site amplification due to the contrast between alluvial deposits and Paleozoic bedrock. 

This study aims to investigate long-term modal parameter changes in Hagia Sophia in Istanbul as a function of atmospheric parameters. The structure dates back to the 6th century and is on the UNESCO World Heritage list. The primary structural materials of the monument are fired clay bricks, lithic components (limestone, granite), and a characteristic mortar. We determined variations in modal frequencies,  modal damping ratios, and mode shapes over four years, between 2013 and 2017. Transfer functions were used for the estimation of modal frequencies, the half-power bandwidth method for the modal damping ratio, and frequency domain decomposition for mode shapes. The long-term variation of the mode shapes was investigated using the MAC, COMAC, and ECOMAC methods.

Over the last 25 years there have been a series of academic efforts to understand the particulars associated with earthquake performance and vulnerability of Hagia Sophia. Linear and nonlinear structural analyses; literary investigations; non-destructive tests and investigations involving its construction materials, foundations and main structural elements; ambient vibration tests; monitoring its earthquake response with the help of an accelerometric network were among them. More recently the foci of efforts were the analysis of long-term dynamic response of Hagia Sophia to earthquakes and variations in atmospheric conditions, shake table testing of a scaled model of the structure, analysis of recently added tiltmeter recordings, evaluation of strengthening alternatives and monitoring of its static deformations via laser technology. This contribution presents an overall picture of the research efforts carried out so far on earthquake response analysis of Hagia Sophia, emphasizing the studies over the last 5 years. 

Dynamic structural parameters depend on environmental factors such as temperature. Although cases documenting the effect of atmospheric conditions on natural frequency and damping are reported in the literature, studies on how mode shapes are changing over longer periods in the order of years are relatively rare. Mode shapes of historical buildings can be more complicated than of other structures. They are identified from vibration recordings obtained from structural monitoring systems. In this study, the mode shape variations of Hagia Sophia in Istanbul are examined using continuous recordings obtained between years 2013 and 2016. 

Dünya kültür mirası listesinde yer alan Ayasofya, inşasından bu yana birçok büyük depreme maruz kalmış, hasar almış ve onarılmıştır. Bu çalışmada Ayasofya’nın dinamik davranış parametrelerinin 2013-2017 yılları arasındaki değişimi incelenmiştir. Bunun için Ayasofya Yapı Sağlığı İzleme Sistemi verilerinden faydalanılmış ve yapının modal frekansları, modal sönümleme oranları ve mod şekillerindeki değişimin çevresel etkiler ile etkileşimi araştırılmıştır. Yapının modal frekansları, ivme kayıtlarının Fourier genlik spektrumları kullanılarak belirlenmiştir. Modal sönümleme oranları yarım güç bant Genişliği yöntemi (half-power band width) ve logaritmik azalım (logaritmic decrement) yöntemleri ile hesaplanmıştır. 

This study aims to determine the dynamic (Modal parameters such as modal frequencies and mode shapes) and static properties (Geometry and material properties) of the Cevizlibağ Overpass and to examine the earthquake performance. In this context, the building was analyzed under the earthquake levels defined in the 2018 Turkish Earthquake Code. As a result of these analyzes, the total shear force capacity of the structure and the amount of shear force demanded from the structure were calculated using different earthquake levels. 

Bu çalışmada, değişen atmosferik koşulların ve depremlerin sanat tarihinin en önemli eserlerinden biri olan ve UNESCO dünya kültür mirası listesinde bulunan Ayasofya'nın modal parametreleri üzerindeki etkileri incelenmiştir. İlk olarak, Ayasofya'nın sıcaklık, rüzgâr hızı, nem ve yağış miktarı gibi atmosferik faktörlere bağlı frekans değişimi gözlemlenmiştir. İvme kayıtları yarım saatlik segmentlere bölünmüş ve bu segmentlerin kısa zamanlı Fourier dönüşümü metodu kullanılarak Fourier büyüklük spektrumları elde edilmiştir. Bu spektrumlardan elde edilen frekans değerleri birleştirilerek bir yıllık frekans değişimi elde edilmiş, tek tek atmosferik faktörler ile kıyaslanmış ve sonuçlar değerlendirilmiştir. 

The Mihrimah Sultan Mosque in Edirnekapı, Istanbul is a 16th century building by Architect Sinan. The building was damaged in the earthquakes of 1719, 1766, 1814, 1894 and 1999 during which many masonry buildings in the city were also affected as indicated by historical records. A large earthquake is expected to hit Istanbul in the near future. For this reason, evaluation of the earthquake safety of Istanbul’s historical structures is very important. This paper dwells on our studies on the Mihrimah Sultan mosque, which can be summarized under three main titles: (1) Structural analyses; (2) Structural health monitoring; and (3) Assessments using non-destructive testing methods. 

The changes in natural vibration frequencies of buildings are important parameters in earthquake engineering that are calculated using data obtained from building health monitoring systems and are related to damage. However, it is not true that these changes in the dynamic properties of the structure are always associated with damage. It is known that atmospheric factors such as temperature, wind, humidity and precipitation influence the natural vibrations of the structures to a certain degree. Therefore, to relate the changes in the modal parameters of the structures to the structural deformations, a machine learning algorithm should be developed which also takes into account the atmospheric conditions. In this way, abnormalities that may indicate structural deformations can be estimated with a much higher accuracy.

Dynamic response characteristics of Hagia Sophia in Istanbul appears to be significantly dependent on environmental factors. It has recently been shown that the structure’s modal vibration frequencies show a strong correlation with temperature (Çaktı and Dar, 2015). In this study, the interaction between the modal damping ratio of Hagia Sophia and the atmospheric factors is examined. For this purpose, continuously recorded accelerations in the time span between 2013 and 2017 from the nine stations of the Hagia Sophia Structural Health Monitoring System are utilized. The damping ratios are estimated using 2 hours windows by half-power-band-width method over a period of five years. 

The main objective of this study is to investigate long-term dynamic response of Hagia Sophia in Istanbul to earthquakes and atmospheric conditions. It is aimed to display the variation in time and frequency domain dynamic response parameters of Hagia Sophia due to external sources and to identify behavioral patterns that can be associated with changes in the atmospheric conditions. At the same time the vibration levels throughout the structure are studied to identify anything that stand out and can be interpreted as possible local or general structural problems.