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.

AtıfWoS11

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Öztekin, Ertekin

Purpose - A lot of triaxial compressive models for different concrete types and different concrete strength classes were proposed to be used in structural analyses. The existence of so many models creates conflicts and confusions during the selection of the models. In this study, reliability analyses were carried out to prevent such conflicts and confusions and to determine the most reliable model for normal- and high-strength concrete (NSC and HSC) under combined triaxial compressions. The paper aims to discuss these issues. Design/methodology/approach - An analytical model was proposed to estimate the strength of NSC and HSC under different triaxial loadings. After verifying the validity of the model by making comparisons with the models in the literature, reliabilities of all models were investigated. The Monte Carlo simulation method was used in the reliability studies. Artificial experimental data required for the Monte Carlo simulation method were generated by using artificial neural networks. Findings - The validity of the proposed model was verified. Reliability indexes of triaxial compressive models were obtained for the limit states, different concrete strengths and different lateral compressions. Finally, the reliability indexes were tabulated to be able to choose the best model for NSC and HSC under different triaxial compressions. Research limitations/implications - Concrete compressive strength and lateral compression were taken as variables in the model. Practical implications - The reliability indexes were tabulated to be able to choose the best model for NSC and HSC under different triaxial compressions. Originality/value - A new analytical model was proposed to estimate the strength of NSC and HSC under different triaxial loadings. Reliability indexes of triaxial compressive models were obtained for the limit states, different concrete strengths and different lateral compressions. Artificial experimental data were obtained by using artificial neural networks. Four different artificial neural networks were developed to generate artificial experimental data. They can also be used in the estimations of the strength of NSC and HSC under different triaxial loadings.

AtıfScopus5·WoS5·OpenAlex6

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