Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2025/r/gumushane/14264
  Performance evaluation and optimization of nontraditional inerter-based tuned mass damper for seismic control of multi-story buildings considering SSI effects

  Araz, Onur

  This article presents the optimum design and performance evaluation of a control system that can be an alternative to traditional inerter-based tuned mass damper (TMDI) used in reducing vibrations in a multi-story building under earthquake effects considering soil-structure interaction (SSI). The optimum design of this system, known as NIDVA-C4 in the literature, has been carried out previously considering the randomly excited undamped main system. The key novelty of this work is to demonstrate the applicability of this system to suppress earthquake-induced vibrations in a multi-story building and to deliver more accurate and reliable results by integrating SSI effects into the optimization framework. Due to the difference in location and connection, this system is called N-TMDI in this paper. A case study from the literature featuring a ten-story building is used to implement the design process, assess performance, and conduct comparisons. The optimum parameters of the N-TMDI are obtained using the hybrid PSO-SA algorithm in the frequency domain. Validation using real earthquake records under varying soil conditions confirms the reliability of the proposed optimization framework. The coupled dynamic equations of motion for the structure - N-TMDI, accounting for SSI effects, are formulated and solved in the time domain using the Newmark-β method. An extensive parametric analysis is conducted to evaluate the effectiveness of the N-TMDI in improving the seismic response of the buildings. The results consistently demonstrate the effectiveness of the proposed protection strategy across a wide range of parametric configurations, highlighting its potential as a viable seismic mitigation strategy for a multi-story building.

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• MakaleYalnız künye2025/r/gumushane/13940
  Influence of PGA/PGV ratio on the seismic performance of buildings with different slenderness ratios considering soil-structure interaction

  Araz, Onur

  In this study, the seismic performance of buildings equipped with tuned mass damper (TMD) having different slenderness ratios, subjected to ground motions with varying a wide range of PGA/PGV ratios is investigated, considering soil-structure interaction (SSI). A methodology based on hybrid Genetic Algorithm-Particle Swarm Optimization (GA-PSO) algorithm is proposed to determine the optimal parameters of TMD. For this purpose, three buildings (i.e., 3-story, 6-story, and 12-story buildings) are considered and the dynamic properties of these buildings are determined according to the provisions specified in ASCE-7. These buildings, which are frequently encountered in the traditional building stock, represent low, medium, and high-rise buildings, respectively. In the numerical analysis, three different soil types (i.e., SC, SD, and SE) and 80 ground motions are also considered. These records are divided into three different classes: high, intermediate, and low frequency content. The Newmark integration method is used to determine the dynamic responses of the structures in the time domain analysis. Numerical results show that the frequency content of ground motion and the slenderness ratio have a significant effect in reducing the peak displacement and acceleration responses of structures. The findings also demonstrate that when the PGA/PGV ratio is greater than 2, TMD shows mostly sufficient control performance for all buildings and all support conditions.

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• MakaleAçık Erişim2024/r/gumushane/12735
  Integration of a CNN-based model and ensemble learning for detecting post-earthquake road cracks with deep features

  Reis, Hatice Catal; Turk, Veysel; Karacur, Soner; Kurt, Ahmet Melih

  A safe and healthy infrastructure is essential for humanity. Maintenance and repair of roads, which are of great importance, especially in transportation, is essential. Roads can sometimes be damaged due to natural disasters or human factors. In this study, roads damaged as a result of the natural disaster and the 6 February 2023 Gaziantep-Kahramanmaras earthquakes, which had devastating/fatal consequences, were studied. In recent years, the use of machine learning methods in the automatic detection process of road cracks has become widespread. Here, deep learning architectures generally based on multilayer convolutional neural networks have become a popular solution, mainly thanks to their high discrimination power in visual data. In this study, it was aimed to automatically detect cracks on the roads in Gaziantep (Nurdagi) and Adiyaman provinces after the earthquake. The data set used in the experimental process consists of two categories: uncracked and cracked, and was collected by the researchers. ResNet152 deep learning architecture, traditional machine learning algorithms, and an ensemble learning (EL) model were used to classify cracks. Among the machine learning algorithms used in the experiments are support vector machine (SVM), K-nearest neighbors, Adaptive Boosting, and Naive Bayes. In the experimental process, ResNet152 architecture was used for feature extraction, and classification was carried out with machine learning algorithms. In addition, the EL method has been used to improve the success of machine learning algorithms. According to experimental results, the SVM algorithm and EL method gave the most successful results with 98.68% accuracy values. The proposed method can benefit experts in the automatic classification of road cracks. The study can contribute to activating rapid coordination and transportation networks in natural disasters that cause fatal and destructive causes, such as earthquakes.

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• MakaleAçık Erişim2024/r/gumushane/12534
  Effect of PGV/PGA ratio on seismic-induced vibrations of structures equipped with parallel tuned mass dampers considering SSI

  Araz, Onur

  Tuned mass damper is one of the effective methods used to reduce dynamic loads in structures under the influence of environmental loads such as earthquakes, wind, and traffic loads. In the current TMD design, the fixed base approach is mostly considered when determining the dynamic properties of the structure. However, in cases where the structure-soil interaction (SSI) is important, the frequency values of the structure are significantly different from those obtained for the fixed foundation approach. This situation negatively affects the performance of TMD operating in a narrow frequency range. Therefore, using a control system consisting of multiple TMDs connected in parallel (MTMD) instead of a single TMD may be a promising solution for the control of structural vibrations. In this study, a parameter design and efficiency assessment of MTMD for reducing the seismic responses of the structure considering SSI is studied. The particle swarm optimization (PSO) algorithm is adopted to obtain the optimum parameters (i.e., damping ratio, frequency ratio, and frequency bandwidth) of the MTMD. The effects of different support conditions, number of TMD units, and peak ground velocity (PGV) / peak ground acceleration (PGA) ratio on the performance of MTMD are also evaluated comprehensively. The dynamic responses of the structure are obtained under 42 near -fault ground motions from the time history analysis. The results reveal that ground motions with low PGV/PGA ratio can significantly increase the responses of the structure for both with and without SSI cases. Moreover, it has been observed that optimized TMDs placed parallel to the top floor of the structure are effective in reducing the seismic responses of a ten-story building considering SSI.

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• MakaleYalnız künye2023/r/gumushane/14467
  Full-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.

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• MakaleYalnız künye2023/r/gumushane/12684
  Optimum tuned tandem mass dampers for suppressing seismic-induced vibrations considering soil-structure interaction

  Araz, Onur; Noroozinejad Farsangi, Ehsan

  In recent studies, it has been stated that tuned tandem mass dampers (TTMD) will be a practical mechanical solution to reduce the dynamic responses of structures under seismic excitations. However, since TTMD is tuned based on the dominant frequency of the superstructure, ignoring the soil-structure interaction (SSI), it may cause a notable deterioration in the control performance of the control devices. Thus, a methodology for the optimum design of TTMD positioned on the top story of a high-rise building due to near-fault pulse-like ground motions considering potential SSI effects has been investigated in this paper. Firstly, the TTMD is located on the top story of a well-known 40-story shear building, and the equations of motion for soil-structure-TTMD interaction are derived. Based on the sequential quadratic programming (SQP), the tuning parameters of TTMD are then found for different support conditions in the frequency domain. The efficiency of SQP is also compared with two meta-heuristic algorithms (i.e., simulated annealing and pattern search algorithms). The effectiveness of optimum TTMD is tested using 30 near-fault pulse-like ground motions using time-domain analyses. Numerical results showed that the optimum TTMD is more effective in suppressing the maximum displacement and inter-story drift of the building, considering SSI. It is also found that the frequency content of the earthquake, as well as the pulse period of the earthquake and soil type, has a significant effect on the control performance of the TTMD.

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• MakaleYalnız künye2022/r/gumushane/11488
  Optimization of multiple tuned mass dampers for a two-span continuous railway bridge via differential evolution algorithm

  Araz, Onur; Kahya, Volkan

  The study aims at proposing a methodology for optimization of multiple tuned mass dampers (MTMD) in reducing the multi-resonance vibrations of continuous bridges due to moving train loads. The equations of motion for time-domain analysis are derived for obtaining train-induced vibrations of a two-span continuous railway bridge with equipped MTMD-1 and MTMD-2 devices when the vehicle-bridge interaction (VBI) is considered. The bridge and the train are modeled as a Bernoulli-Euler beam with constant section and a series of moving sprung masses of identical length, respectively. To reduce the multiple resonance vibrations of a two-span continuous railway bridge, the MTMD-1 and MTMD-2 are tuned to the first mode and the second mode of the bridge, and they are attached to the midspan of each span, respectively. The optimum parameters of the both MTMD systems are investigated using the differential evolution (DE) method. The criterion chosen to obtain the optimum parameters is the minimization of the first two resonance peaks of the bridge. The influence of the different mass ratios and the number of TMD units in the MTMD system on the optimum parameters of the both MTMD systems and corresponding displacement responses of the bridge are also investigated. The results show that the VBI effect does not have much effect on the resonant train speeds and the control performance of TMDs. Therefore, the optimum parameters of TMDs can be obtained quickly by modeling the train as a series of moving forces for the vibration control of railway bridges.

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• MakaleAçık Erişim2018/r/gumushane/15141
  Resistance of Axially Loaded T- and X-Joints of Elliptical Hollow Sections at Elevated Temperatures – A Finite Element Study

  Ozyurt, E.; Wang, Y.C.

  This study presents the results of a numerical study to develop a method to calculate the static strength of welded Elliptical Hollow Section (EHS) joints at elevated temperatures. Extensive numerical simulations using the non-linear finite element package, ABAQUS v6.14–1 on EHS T- and X-joints under brace axial compression or tension and pre-stress in chord member with different type of joint orientations at elevated temperatures over a wide range of diameter ratio have been conducted. The adjustments required to be made to the equations of joint resistance under ambient temperature conditions for estimating joint resistance at elevated temperature conditions are investigated in this study. The FE simulation results have been compared with the calculation results of a number of existing methods at ambient temperature. It has been found that the method proposed by Packer et al. gives the best agreement with the authors' simulation results at ambient temperature. At elevated temperatures, for T- and X- joints with braces in compression welded to the wide sides of chords, replacing the ambient temperature yield strength of steel by the elevated temperature value in the current design method overestimates the ultimate load carrying capacity of axially loaded EHS T- and X-joints due to inability of the ambient temperature calculation equations to take into consideration EHS flattening at high temperatures. For these cases, it is recommended to calculate the joint strength reduction factor at elevated temperatures according to the Young's modulus of steel.

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