Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Ergün, Mustafa(4)
- Altunisik, Ahmet Can(2)
- Aymelek, Abdullah(2)
- Okur, Fatih Yesevi(2)
- Tayfur, Bilal(2)
- Türker, Temel(2)
- Yanik, Yusuf(2)
- Altunişik, Ahmet Can(1)
- Ates, Sevket(1)
- Ateş, Şevket(1)
- Demirtas, Betul(1)
- Demirtaş, Betül(1)
- Genç, Ali Fuat(1)
- Günaydin, M.(1)
- Günaydin, Murat(1)
- Güneş, Erdi(1)
- Mosallam, Ayman S.(1)
- Sunca, Fezayil(1)
- Yildirim, Omer(1)
- Yildirim, Ömer(1)
- Yurdakul, Muhammet(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ1Structural condition assessment of the Bamsı Beyrek observation terrace in Bayburt, Türkiye, on autonomous updated FEMs
Ergün, Mustafa; Tayfur, Bilal; Güneş, Erdi
This study involves detailed numerical and experimental investigations to assess the current structural condition of the Bamsı Beyrek steel observation terrace in Bayburt, Türkiye. The numerical dynamic characteristics of the structure were obtained by free vibration analysis conducted on the preliminary finite element model, while the experimental ones were determined through ambient vibration testing. The ultimate finite element models representing the actual state of the structure were developed through the model updating process based on the principle of minimizing the differences between numerical and experimental dynamic characteristics via the Teaching-Learning Based Optimization Algorithm. Load types and their characteristic values, potentially impacting the observation terrace during its service life, were identified according to national and international code standards. The internal forces obtained from the analysis conducted on the updated model under the influence of these loads were combined using various load combinations. The structure was then statically and dynamically checked based on the most critical responses calculated from these combinations. Structural responses are evaluated based on distributions in PMM ratios on the structure, PMM ratios of all elements according to the combination that causes the most adverse values, and maximum displacements. Consequently, considering all the findings obtained from the assessments conducted on the finite element model, which reflects the current state of the observation terrace under various loads, it has been concluded that the structure is statically and dynamically reliable and does not require any repair or strengthening procedures.
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İncele - MakaleYalnız künye2025Scopus SJRQ2Modal testing and full-scale seismic evaluation of a historical minaret according to 2023 Kahramanmaraş earthquake and TBEC 2018 design spectrum
Demirtas, Betul; Yanik, Yusuf; Aymelek, Abdullah; Türker, Temel; Yildirim, Omer
PurposeMinarets, which were constructed from different types of materials, are slender and tall structures. Minarets could vary in terms of the construction technique, geometry and material. The seismic vulnerability and dynamic behavior of minarets could be different because of these reasons. Full-scale evaluation of minarets includes both experimental and numerical investigations. Experimental methods provide knowledge on the in situ conditions. The structural analysis and performance evaluation can be performed by using numerical methods. In this paper, full-scale structural evaluation of the Trabzon Fatih Mosque Minaret was presented by using experimental and numerical methods.Design/methodology/approachFirstly, the finite element (FE) model of the minaret was generated by ANSYS software. Then, experimental measurements were carried out under environmental vibrations with newly developed vibration system. Afterwards, the initial FE model of the minaret was updated by using manual updating method according to the experimental measurement results. For the seismic performance assessment of the historical minaret, the time history and response spectrum analyses were performed on the initial and updated FE models using the acceleration records of 2023 February Kahramanmaras earthquake and TBEC 2018 codes. The results were evaluated comparatively, revealing that the nonlinear analyses produced higher values compared to other methods. Additionally, variations were observed in the updated FE model results compared to the initial FE model. Finally, it was seen that the minaret did not have sufficient strength against Kahramanmaras earthquake load, so it could collapse under such an earthquake.FindingsBy employing model updating method, the average absolute difference was substantially reduced from 9.12% to 2.11%. The maximum displacements increased with the effect of model updating in all analyses. It was also seen that the spectrum analyses results had lower values than the time-history analyses results and the displacement of the updated FE model was found to be approximately 8% greater than that of the initial FE model in the nonlinear analyses. The maximum/minimum principal stresses decreased in the updated model in the linear analyses. Also, it was determined that the equivalent stresses were higher in linear analyses. It was seen that the cracks occurring in the nonlinear analyses were concentrated more intensely at the bottom region, the transition segment and around the balcony of the minaret. The concentration of damage in these regions suggested that special attention was needed to increase structural durability. The drift ratios were calculated as 0.0056 and 0.0076 for the initial and updated FE models in the linear analyses, respectively. The initial FE model remained the CD limit, but the updated model reached the limit in CP. The drift ratios were calculated as 0.0087 and 0.0093 for the initial and updated FE models in the nonlinear analyses. Both the FE models reached the CP limit. It could be concluded that the minaret did not have sufficient strength against Kahramanmaras Earthquake, so it could collapse under such an earthquake. The drift ratios were calculated as 0.0041 and 0.0043 for the initial and updated FE models in the spectrum analyses. Both the FE models remained within the CD limit.Originality/valueThis paper aimed to evaluate effects of FE model updating on the dynamic and seismic behaviors of the historical Fatih Mosque Minaret in Trabzon. Structural behavior of the minaret was investigated using both experimental and numerical methods. For this purpose, 3-D FE model generated with ANSYS software of the minaret was updated according to the ambient vibration test results. Ambient vibration tests were conducted by measurement system, which was developed by our research team. The manual model updating method was utilized to minimize the differences between numerical and experimental results by varying the material properties. The linear-nonlinear time history analyses and response spectrum analyses were carried out to evaluate the seismic performance of the initial and updated FE models using the acceleration records of 2023 February Kahramanmaras Earthquake records and TBEC 2018 codes.
AtıfWoS11İncele - MakaleYalnız künye2024Scopus SJRQ1Evaluation of the seismic performance pre- and post-restoration of a masonry clock tower's FE model updated via experimental and optimization methods
Ergün, Mustafa; Tayfur, Bilal
This article presents comprehensive numerical and partial experimental studies to determine the seismic performance of the recently restored masonry clock tower in Bayburt before and after restoration. The numerical dynamic characteristics of the structure are obtained by free vibration analysis conducted on the preliminary finite element model, while the experimental ones are determined through ambient vibration testing. The ultimate finite element models reflecting the actual state of the structure pre- and post-restoration are created through a model updating process based on the principle of minimizing the differences between numerical and experimental dynamic properties via the Tabu Search Algorithm. Dynamic analyses of the models are carried out by the mode superposition method in the time domain, using eleven earthquake ground motion records selected considering the tectonic structure of the region and scaled to the design spectrum explicitly established to the site. Seismic responses are evaluated based on displacement, maximum-minimum principal stress, and maximum-minimum principal strain. The maximum principal stress value, the most critical parameter jeopardizing the safety of masonry structures, is 2.069 MPa before the restoration reaches 2.489 MPa, with an increase of approximately 20.3 % after the restoration. Since this value is less than the tensile strength of the masonry material, 3.120 MPa, it is not at a level that poses any risk to the structure. Other structural reactions also remain below the limit values. Therefore, according to today's seismic hazard analysis criteria, it can be said that the clock tower is safe. However, the North Anatolian Fault Zone, with high tectonic activity passing just south of the city, has the potential to produce severe earthquakes that may affect the region in the future. Therefore, it is necessary to periodically monitor the seismic behaviors of the historical masonry structures in Bayburt and take essential precautions based on the results.
AtıfScopus12WoS11OpenAlex13İncele - 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 künye2022Scopus SJRQ1Nondestructive Experimental Measurement, Model Updating, and Fatigue Life Assessment of carsamba Suspension Bridge
Günaydin, Murat; Sunca, Fezayil; Altunisik, Ahmet Can; Ergün, Mustafa; Okur, Fatih Yesevi
This paper includes the structural condition assessment of a 164-m suspension bridge in accordance with numerical and experimental methods. A finite-element model was developed using SAP2000 software so that the assessment of the bridge could be calculated numerically. The operational modal analysis method was also used to obtain experimental dynamic characteristics. In this context: (i) numerical dynamic characteristics of the bridge were obtained and compared with the experimental dynamic characteristics, (ii) a model updating procedure was carried out to minimize the differences between the numerical and experimental natural frequencies, (iii) static and dynamic analyses of the bridge were carried out by using the initial and updated finite-element models, (iv) fatigue life assessment of the bridge was investigated, and (v) the utility of the bridge for pedestrians and vehicles was checked according to various regulations. The results showed that updating the finite-element model had a significant role to play in the static and dynamic behavior of the bridge. The results also demonstrated that the bridge was designed to be extremely safe against static, dynamic, and fatigue loads. Finally, it was concluded that the bridge investigated behaves as a girder bridge rather than a suspension bridge.
AtıfWoS17OpenAlex18İncele - MakaleYalnız künye2019Scopus SJRQ1Dynamic analyses of experimentally-updated FE model of historical masonry clock towers using site-specific seismic characteristics and scaling parameters according to the 2018 Turkey building earthquake code
Genç, Ali Fuat; Ergün, Mustafa; Günaydin, M.; Altunişik, Ahmet Can; Ateş, Şevket; Okur, Fatih Yesevi; Mosallam, Ayman S.
This paper presents a dynamic analysis considering site-specific seismic characteristics for a masonry clock tower located at the city of Çorum, Turkey according to the new Turkish earthquake code. Finite element model of the tower was modeled using ANSYS software in order to determine numerical dynamic characteristics of the structure such as natural frequencies and mode shapes. Non-destructive experimental measurements were performed to extract the experimental dynamic characteristics. Experimental results were used as a reference parameter for finite element model updating to reflect the current structural behavior of clock tower. Model updating procedure was carried out by changing of initial material properties of structural stone elements, and maximum differences were reduced from 23.44% to 4.90%. Numerical results indicated that displacements have an increasing trend with the height of the clock tower. Furthermore, the maximum displacements occurred at the top point between the values of 18.88 mm to 42.5 mm. Numerical results also showed that both the maximum and minimum principal stresses occurred at the upper body (clock zone) walls and transition segment between the values of 1.08 MPa/2.86 MPa and − 0.87 MPa/−3.00 MPa, respectively. The maximum and minimum principal strains occurred at the upper body (clock zone) walls between the values of 0.65E-3/1.56E-3 and − 0.78E-3/−1.50E-3, respectively. It is also concluded that non-destructive experimental measurement is very useful method to evaluate in-situ structural identification, validate and update the initial finite element model for further analyses.
AtıfScopus46WoS43OpenAlex51İncele - MakaleYalnız künye2014Scopus SJRQ2Comparison of the dynamic responses of gülburnu highway bridge using single and triple concave friction pendulums
Yurdakul, Muhammet; Ates, Sevket; Altunisik, Ahmet Can
The main object of this study is to determine and compare the structural behavior of base isolated long span highway bridge, Gülburnu Highway Bridge, using single concave friction pendulum (SCFP) and triple concave friction pendulum (TCFP). The bridge is seismically isolated in the design phase to increase the main period and reduce the horizontal forces with moments using SCFP bearings. In the content of the paper, firstly three dimensional finite element model (FEM) of the bridge is constituted using project drawings by SAP2000 software. The dynamic characteristics such as natural frequencies and periods, and the structural response such as displacements, axial forces, shear forces and torsional moments are attained from the modal and dynamic analyses. After, FEM of the bridge is updated using TCFP and the analyses are performed. At the end of the study, the dynamic characteristics and internal forces are compared with each other to extract the TCFP effect. To emphasize the base isolation effect, the non-isolated structural analysis results are added to graphics. The predominant frequencies of bridge non-isolated, isolated with SCFP and isolated with TCFP conditions decreased from 0.849Hz to 0.497Hz and 0.338Hz, respectively. The maximum vertical displacements are obtained as 57cm, 54cm and 44cm for non-isolated, isolated with SCFP and isolated with TCFP conditions, respectively. The maximum vertical displacement reduction between isolated with TCFP bearing and isolated with SCFP bearing bridge is %23. Maximum axial forces are obtained as 60619kN, 18728kN and 7382kN, maximum shear forces are obtained as 23408kN, 17913kN and 16249kN and maximum torsional moments are obtained as 24020kNm, 7619kNm and 3840kNm for non-isolated, isolated with SCFP and isolated with TCFP conditions, respectively.
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