Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2025Scopus SJRQ1Investigation of environmental effects through long-term vibration monitoring on the structural behavior and seismic performance assessment of the Hagia Sophia Bell Tower
Yanik, Yusuf; Türker, Temel; Öztürk, Hasan Tahsin; Demirtaş, Betül; Aymelek, Abdullah; Yildirim, Ömer; Çalik, İsmet
This study presents development and application of a high-precision, multi-channel vibration measurement system to monitor structural behavior of Hagia Sophia Bell Tower. The research focused on assessing the dynamic characteristics of the tower, both through experimental measurements and numerical simulations. The study began by conducting an in-depth analysis of the tower's dynamic properties using finite element (FE) models, enabling the identification of experimental frequencies. Long-term monitoring was carried out using the newly developed vibration measurement system, complemented by a digital sensor that enabled simultaneous recording of environmental conditions such as temperature and humidity. These parameters were continuously monitored to assess their potential impact on the frequencies and dynamic responses of the tower. Subsequently, regression analyses were performed to establish the relationship between environmental factors, and the tower's structural behavior. The experimental data were used to update FE models, ensuring a more accurate representation of the tower's actual behavior under varying conditions. Earthquake analyses were also conducted on the FE models to evaluate the seismic performance. The results of the study confirmed that vibration testing, combined with environmental monitoring, was a highly effective method for detecting changes in structural behavior. The findings highlighted the significant influence of environmental factors on the dynamic characteristics, with frequency variations reaching an average of 3.6%. These effects should be considered in ongoing monitoring. It was demonstrated that updating FE models reduced numerical errors below 2.5%. These findings gave importance of integrating long-term monitoring with FE model updating, providing more accurate protection and assessment strategies.
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İncele - MakaleYalnız künye2024Scopus SJRQ1Variations of natural frequencies of masonry minarets due to environmental effects
Yanik, Yusuf; Aymelek, Abdullah; Yildirim, Ömer; Demirtaş, Betül; Türker, Temel
It is very important to distinguish the reason of change in natural frequencies of structures either caused by a possible damage or environmental conditions (temperature and humidity). In this study, the changes in the dynamic properties of masonry and reinforced concrete minarets under environmental effects, such as temperature and humidity, were investigated. The masonry minarets of İskenderpaşa, Hacı Kasım, and Tavanlı Mosques and the reinforced concrete minarets of Karadeniz Technical University, Dilaveroğlu and Papatya Mosques in Trabzon were monitored by ambient vibration test method, and the relationship between natural frequencies and temperature and humidity was tried to be determined. For this purpose, the natural frequencies of these minarets were measured at certain intervals under different temperature and humidity conditions over a period of approximately 6 months. The vibration measurement system which was developed by our research team was used in the measurements. From the data collected by these measurements, the variation intervals of the natural frequencies (the smallest and the highest values), the percentages of change and their relations with temperature and humidity were revealed. This relationship was determined using linear–non-linear simple and multiple regression analyses. From this study, it was found that the natural frequencies change under environmental effects, such as temperature and humidity, and this rate of change was approximately 7%. There was moderate correlation in Tavanlı, Dilaveroğlu, and Papatya Minarets, and strong correlation in Hacı Kasım Minaret.
AtıfScopus16WoS17OpenAlex16İncele - MakaleYalnız künye2023Scopus SJRQ1Full-scale structural evaluations of İskenderpaşa minaret
Aymelek, Abdullah; Yanik, Yusuf; Demirtaş, Betül; Yildirim, Ömer; Çalik, İsmet; Türker, Temel
Nowadays, innovative methods have been used for observing and structural evaluating of historical structures. In this paper, it is presented the full-scale structural assessments of a minaret after a Finite Element model calibrating according to vibration test results. Also, the structural behaviours under earthquake and wind loads were identified by considering the environmental effects on the selected masonry minaret of İskenderpaşa Mosque. First of all, modal analysis was executed on the three-dimensional Finite Element model created according to field survey in ANSYS Workbench. In-situ vibration tests were implemented at different intervals by using developed vibration measurement system. The experimental modal parameters were attained from collected signals. The experimental results were used as reference values in model calibration of this minaret to reflect the existing structural behaviour. Model calibration process was carried out on the initial model both by changing of material properties of masonry wall and by taking into account the interactions with mosque walls and ground. Full-scale structural evaluation was carried out under earthquake and wind loads on both the initial and the calibrated models in the weak direction of this minaret. The top displacements, drift ratios, principal stress values and their distributions were determined. It was shown that the analyses on the calibrated model produce more realistic structural behaviour.
AtıfScopus21WoS20OpenAlex22İncele