Sürdürülebilir Kalkınma Amaçları
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 - MakaleAçık Erişim2026Scopus SJRQ1The effect of existing damage on the seismic performance of a historical masonry structure: a site-specific assessment
Tayfur, Bilal; Tunca, Osman; Artar, Musa; Çarbaş, Serdar
This study comprehensively evaluates the structural integrity and seismic performance of a historic masonry mosque, exhibiting significant settlement cracks, through an integrated approach combining field measurements and advanced numerical analyses. The Operational Modal Analysis (OMA) conducted to determine the dynamic characteristics of the structure. Field measurements revealed that the environmental vibrations originating from a nearby tram line causes significant amplitude incrase in one of the main columns. The dynamic characteristics of the structure obtained from field experiments are used to calibrate the numerical model via the Particle Swarm Optimization Algorithm. The calibrated numerical model, taking into account the existing cracks in the structure using contact elements, was subjected to nonlinear analysis in the time domain under 11 site-specific ground motion records selected in accordance with the procedures of the Turkish Building Seismic Code. This analysis examined the seismic performance and damage mechanisms of the structure. The findings revealed that while existing settlement cracks contribute to seismic energy dissipation through frictional sliding and gap opening mechanisms, they may also serve as potential failure initiation points under strong ground motions. This study’s integrated approach, combining dual-purpose OMA application and explicit crack modeling with contact elements, constitutes a novel methodological framework for the realistic seismic assessment of historic masonry structures with pre-existing damage.
AtıfScopus1WoS1OpenAlex2İncele - MakaleAçık Erişim2026Scopus SJRQ1A comparative study of metaheuristic algorithms for thermoeconomic optimization of an Organic Rankine Cycle
Tayfur, Bilal; Turhal, Uğur; Tozlu, Alperen
The efficient recovery of waste heat from biogas power plants via Organic Rankine Cycles (ORC) is essential for sustainable energy but requires satisfying conflicting thermodynamic and economic objectives. This study addresses the need for robust optimization strategies by evaluating nine recent metaheuristic algorithms to identify the most effective methods for maximizing net power while minimizing system costs. A multi-objective thermoeconomic model utilizing the specific exergy costing method was developed for a toluene-based ORC and optimized using algorithms including Dung Beetle, Snake, and NSGA-II. The optimization reduced the unit electricity cost by 9.1% (from $0.088/kWh to $0.080/kWh), with the Dung Beetle algorithm exhibiting superior convergence (Hypervolume 25.90) and the Snake algorithm demonstrating the best solution uniformity (Spread 1.54) with computational speed (0.084 s). These findings underscore that selecting algorithms based on specific exploration-exploitation characteristics is critical for achieving cost-effective and thermodynamically efficient power generation designs.
AtıfOpenAlex2İncele - MakaleYalnız künye2025Scopus SJRQ1Optimized model updating and site-specific seismic assessment of a historical masonry bridge
Tayfur, Bilal
This study comprehensively evaluates an 800-year-old masonry bridge using advanced non-destructive testing techniques, an innovative model update process, and site-specific ground motion analysis. Employing Operational Modal Analysis, Ultrasonic Pulse Velocity, and Schmidt Hammer tests, the research meticulously characterized the structural dynamic properties. The preliminary finite element model was rigorously refined utilizing the Tabu Search optimization algorithm by minimizing discrepancies between numerical and experimental modal parameters. Site-specific earthquake records, carefully selected and prepared in accordance with the Turkish Building Earthquake Code, were applied to conduct detailed time-history analyses across 11 distinct ground motion records. Despite experiencing stresses approaching critical thresholds, the bridge demonstrated remarkable structural integrity. While the findings indicate the bridge’s structural soundness under current seismic hazard analysis criteria, the results notably emphasize that the frequency content similarities between the structure and ground motion are more critical for seismic performance assessment than peak ground acceleration (PGA) values, underscoring the importance of continuous monitoring given the region’s complex tectonic characteristics.
AtıfScopus5WoS3OpenAlex4İncele - MakaleAçık Erişim2024Optimization Of Cantilever Retaining Wall Design Using Improved Teaching-Learning-Based Optimization Algorithms
Tayfur, Bilal; Kamiloğlu, Hakan Alper
Retaining structures play a crucial role in geotechnical engineering to support soil levels, prevent slope failure, and create flat surfaces for construction. Designing these structures involves optimizing internal and external stability while minimizing material usage and cost. This study focused on optimizing reinforced concrete cantilever retaining walls using the Teaching-Learning Based Optimization (TLBO) algorithm and an improved version (I-TLBO) with agents. In the context of the study, geometric-structural design variables, geotechnical -structural constraints, and optimization processes were examined. Minimizing weight and minimizing cost of the wall were the objectives considered in the cantilever retaining wall design process. The optimization results were compared with other algorithms in the literature, such as genetic algorithms, evolutionary strategies, and particle swarm optimization. The improved TLBO algorithm demonstrated superior performance, achieved lower design dimensions, and reduced costs. It provided more efficient solutions that pushed design constraints closer to their limits, resulting in a cost-effective and structurally sound cantilever retaining wall design. As a result of the study, the I-TLBO algorithm was found to be more cost and weight-effective than other methods in the optimization of cantilever retaining wall design.
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İncele - MakaleYalnız künye2024Scopus SJRQ1Optimum design of steel frames against progressive collapse by guided simulated annealing algorithm
Tayfur, Bilal; Daloğlu, Ayşe T.
In this paper, a Guided Simulated Annealing (GSA) algorithm is presented to optimize 2D and 3D steel frames against Progressive Collapse. Considering the nature of structural optimization problems, a number of restrictions and improvements have been applied to the decision mechanisms of the algorithm without harming the randomness. With these improvements, the algorithm aims to focus relatively on the flawed variables of the analyzed frame. Besides that, it is intended to be more rational by instituting structural constraints on the sections to be selected as variables. In addition to the LRFD restrictions, the alternate path method with nonlinear dynamic procedure is used to assess the risk of progressive collapse, as specified in the US Department of Defense United Facilities Criteria (UFC) Design of Buildings to Resist Progressive Collapse. The entire optimization procedure was carried out on a C# software that supports parallel processing developed by the authors, and the frames were analyzed in SAP2000 using OAPI. Time history analyses of the removal scenarios are distributed to the processor cores in order to reduce computational time. The GSA produced 3% lighter structure weights than the SA (Simulated Annealing) and 4% lighter structure weights than the GA (Genetic Algorithm) for the 2D steel frame. For the 3D model, the GSA obtained 3% lighter results than the SA. Furthermore, it is clear that the UFC and LRFD requirements differ when the acceptance criteria are examined. It has been observed that the moment capacity of the entire frame is critical when designing according to UFC.
AtıfScopus5WoS5OpenAlex1İncele - 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 künye2023Scopus SJRQ3An Investigation on the Behavior of 3D Steel Frames Under Progressive Collapse Effect Using Nonlinear Dynamic Analysis
Tayfur, Bilal; Daloǧlu, Ayșe T.
In this study, the nonlinear dynamic analysis of steel structures against progressive collapse was examined, and the adequacy and validity of the analysis duration defined in the regulation were investigated. In addition, the effects of the seismic resistance and design against progressive collapse constraints on the structure were investigated. An optimization algorithm was used in order to conduct the iterative process with appropriate sections. The frames were analyzed to perform one cycle as recommended in the UFC, and then the analysis duration was extended until at least five cycles had been completed. When the UFC was considered only, it was observed that while some of the designs were classified as safe within the duration specified in the UFC, the structural integrity was seen to get into danger in the subsequent cycles. When constraints related to seismic effect are also included in the process, it was seen that the threat disappeared for the frames examined. In addition, it was observed that the steel frame resisted progressive collapse scenarios by creating formations like Vierendeel beams.
AtıfScopus1WoS1OpenAlex2İncele - MakaleAçık Erişim2021Scopus SJRQ2Hybrid tabu search algorithm for weight optimization of planar steel frames
Tayfur, Bilal; Yilmaz, Hamid; Daloğlu, Ayşe T.
In this study, a hybrid metaheuristic algorithm called Hybrid Tabu Search (HTS) is proposed for the weight optimization of planar steel structures. The effectiveness of HTS lies in improving the initial conditions of a tabu search algorithm with a greedy search algorithm and a swap operator used in the phase of section selection. The effectiveness of the proposed method is tested and validated on three different benchmark examples. C♯ software is developed to perform the structural analyses. Numerical results obtained by using HTS showed that the proposed method achieved significantly lighter frame weights in most of the benchmark examples. When the method was examined in terms of computational efficiency, HTS was at a level that can compete with other algorithms examined within this study, although it did not provide a significant advantage.
AtıfScopus17WoS15OpenAlex15İncele - MakaleAçık Erişim2020Scopus SJRQ4Analysis of shear walls for a suitable opening
Can, Ömer; Tayfur, Bilal
The main purpose of shear walls in reinforced concrete structures is to resist the lateral forces affecting the structure. However, the openings created for architectural reasons significantly change the behaviour of the shear wall and cause short column formation and sudden collapse of the structure due to the openings on them. In this study, opening shear walls were analysed analytically. Twenty-nine different frames were selected and analysed according to predetermined parameters such as frame height, frame spacing, shear wall thickness, opening/frame height ratio, concrete flexibility, modulus and moment of inertia of frame columns. In this context, a total of 5200 linear elastic analyses were performed. The analysis was carried out on seven different parameters. As a result of the analysis, it has been found that there is a non-linear relationship between the opening width and the stresses in the columns, and a nonlinear relationship is predicted that it can directly trigger short column formation.
AtıfScopus1WoS1İncele - MakaleAçık Erişim2018Farklı Yüksekliğe Sahip Boşluklu Perde Duvarlara ait Davranış Eğrilerinin SAP2000 OAPI ile Elde Edilmesi
Can, Ömer; Tayfur, Bilal
Bu çalışma kapsamında, perde duvarlarda açılan veya bırakılan pencere boşluklarının çerçeve davranışı üzerindeki etkileri incelenmiştir. Bu bağlamda, perde/çerçeve yüksekliği oranı sabit tutularak 5 farklı serbest kolon boyunun elde edilmesini sağlayacak 5 model belirlenmiştir. 5 farklı perde duvar yüksekliğine sahip çerçeveler SAP2000 OAPI aracılığıyla C# yazılım dili kullanılarak modellenmiştir. Açıkta kalan ve kısa kolon oluşumuna sebep olan boşluklara 1 cm artırımlarla kanat duvarlar eklenerek analizler yapılmıştır. Analizler çerçevenin kanat duvarsız halinden tam dolu duvar haline kadar devam ettirilmiştir. Bu sayede çerçevelere ait kanat duvar boyuna bağlı davranış değişim grafikleri elde edilmiştir. Modelleme esnasında perde duvar malzemesi, kanat duvar artırımları arasındaki kuvvet aktarımının doğru şekilde gerçekleşebilmesi için 1 cm2 meshlere ayrılmıştır. Çerçevelere ait ötelenme değerleri ve kısa kolon oluşumu beklenen kesitlerdeki iç kuvvetlerin değişimi yüksek hassasiyetle kayıt altına alınmıştır. Bu bağlamda toplam 750 farklı analiz gerçekleştirilmiştir. Bu analizler neticesinde serbest kolon boyunun kısalmasına bağlı olarak, yanal ötelenme kapasitesinin de doğrusal olmayan biçimde azaldığını ve kısa kolon oluşumu ihtimalinin arttığı görülmüştür.
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