Civil Engineering / İnşaat Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/13
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Article Art and Construction Related Qualities of 14th‒15th Century Monuments in a Rural Landscape on the Western Coast of Türkiye(KeAi Communications Co., 2024) Hamamcıoğlu Turan, Mine; Aktaş, Engin; Toköz, Özge DenizThis study aims to contribute to the understanding of the evolution of art and construction in the early settlements established by Turkish communities on the far west Asian coast by focusing on two developed examples in Urla Peninsula. Conventional surveying and evaluation techniques of architectural restoration and civil engineering were utilized. Key findings include the understanding of the hierarchy of rural settlements in the studied landscape: old Çesme the most developed village of peninsula in the 16th century. It was positioned along a valley in distance to coast, but in control of harbor that played significant role in commerce between Europe and Asia. Its mosque and tomb, dated to late 14th – early 15th centuries, used to crown it. Cylindrical minaret tower of mosque, domed tomb tower on a cubical base and squinch in the transition zone of mosque are evidences for Central Asian roots. Usage of local lime stone, re-usage of andesite blocks, framing of the stone blocks with bricks, and pendentive in tomb refer to Roman-Byzantine constructions. The study presents the development of Turkish art and construction on the far west Asian coast in the 14th‒15th centuries. Findings will be a guide for related conservation management in similar contexts. © 2024 The Author(s)Article Citation - WoS: 3Citation - Scopus: 4Effects of Steel Fiber Type and Ratio on the One-Way Bending Behavior of Hybrid Fiber Reinforced Concrete Thin Panels(Elsevier Sci Ltd, 2024) Saatci, Selcuk; Cetin, Fatma Sirin; Aloui, Sarra; Naseri, JamalullahPerformance of hybrid fiber reinforced concrete (HyFRC) determined through standardized material tests usually correlates well with the structural performance. However, for thin panels, this correlation may be disturbed due to the fiber orientation and small crack surfaces, and more detailed investigations are required. In this study, effects of steel fiber type and ratio on the one-way bending behavior of HyFRC thin panels was investigated through concrete mixes obtained by using three different steel fiber types and polyvinyl alcohol (PVA) fibers. 45 dog bone shaped, notched specimens were cast and tested under direct tension to investigate the direct tension behavior of used HyFRC. Nine panels of 2500 x 500 x 50 mm in dimension were tested under three-point bending, and nine panels of 1240 x 500 x 50 mm in dimension were tested under four-point bending. An in-verse analysis to obtain crack width-stress variation in three-and four-point bending specimens was also per-formed and behavior of steel fiber reinforced concrete specimens with and without PVA addition were compared. It was found that steel fiber type and ratio was consistently the dominant factor for all types of tests on HyFRC specimens. Addition of PVA fibers in HyFRC specimens either resulted in a similar or worse behavior for direct tension and three-point bending compared to their steel fiber only counterparts. Adverse effect of PVA fibers was more pronounced in three-point bending tests. On the other hand, PVA addition had a more positive effect in four-point bending tests. Inverse analyses performed on three-point bending tests revealed that stress levels develop between crack surfaces in these thin panels were significantly lower compared to direct tension stress levels. However, under four-point bending, these tensile stresses were closer to direct tension stresses, especially for specimens with shorter steel fibers. Loading conditions were found to be an effective factor in the behavior of HyFRC thin panels.Article Citation - WoS: 3Citation - Scopus: 3Ensemble and Optimized Hybrid Algorithms Through Runge Kutta Optimizer for Sewer Sediment Transport Modeling Using a Data Pre-Processing Approach(Elsevier, 2023) Safari, Mir Jafar Sadegh; Gül, Enes; Dursun, Ömer Faruk; Tayfur, GökmenUncontrolled sediment deposition in drainage and sewer systems raises unexpected maintenance expenditures. To this end, implementation of an accurate model relying on effective parameters involved is a reliable benchmark. In this study, three machine learning techniques, namely extreme learning machine (ELM), multilayer perceptron neural network (MLPNN), and M5P model tree (M5PMT); and three optimization approaches of Runge Kutta (RUN), genetic algorithm (GA), and particle swarm optimization (PSO) are applied for modeling. The optimization and ensemble hybridization approaches are applied in the modeling procedure. For the case of hybrid optimized models, the ELM and MLPNN models are hybridized with RUN, GA, and PSO algorithms to develop six hybrid models of ELM-RUN, ELM-GA, ELM-PSO, MLPNN-RUN, MLPNN-GA, and MLPNN-PSO. Ensemble hybrid models are developed through coupling the ELM and MLPNN models with the M5PMT algorithm. The data pre-processing approach is applied to find the best randomness characteristic of the utilized data. Results illustrate that the RUN-based hybrid models outperform the GA- and PSO-based counterparts. Although the MLPNN-RUN and MLPNN-M5PMT hybrid models generate better results than their alternatives, MLPNN-M5PMT slightly outperforms MLPNN-RUN model with a coefficient of determination of 0.84 and a root mean square error of 0.88. The current study shows the superiority of the ensemble-based approach to the optimization techniques. Further investigation is needed by considering alternative optimization techniques to enhance sediment transport modeling. © 2023 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion ResearchReview Citation - WoS: 42Citation - Scopus: 49Utilization of Waste Materials in the Stabilization of Expansive Pavement Subgrade: an Extensive Review(Elsevier, 2023) Tanyıldızı, Muhammed; Uz, Volkan Emre; Gökalp, İslamExpansive soils, also known as swell-shrink soils, are one of the most problematic soils in highway construction and exhibit significant volume changes by swelling and shrinking while wet and dry, respectively. These changes in soil cause cracks, heaves, differential settlements, and damages to the overlying pavements leading to high maintenance costs. The annual average maintenance cost of structures built on expansive soils ranges from $9 to $15 billion, with 50% of the expenses associated with highways and streets. Chemical stabilization techniques such as cement and lime stabilization are one of the most efficient ways to treat expansive soils. However, there is a need to develop environmentally friendly approaches to stabilize expansive soils due to worldwide growing interest in sustainable developments and concerns about greenhouse gas emissions and climate change. In this context, using waste materials in soil stabilization has been considered an important issue for sustainability concerns. The aim of the current study is to review the relevant studies performed to improve the geotechnical and engineering properties of expansive subgrade soils of pavements by using waste materials arising from industrial, agricultural, and other activities in the last decade. In the organization of this study, characteristics of expansive soils including plasticity, compaction, strength & stiffness, microstructural characteristics, shrink-swell properties, and durability were focused to point out the effect of the waste materials. The overall results obtained throughout the scope of the current study indicated that the use of waste materials in soil stabilization improves the engineering properties of expansive soils, significantly. This paper also provides key information and creates awareness for researchers and sector representatives about sustainable soil stabilization.Article Citation - WoS: 9Citation - Scopus: 8Effect of Drainage Conditions on Cpt Resistance of Silty Sand: Physical Model and Field Tests(Springer, 2023) Ecemis, Nurhan; Arık, Mustafa Sezer; Taneri, HazalThe influence of drainage conditions on cone penetration test (CPT) resistance and the excess pore pressure during cone penetration in sand and silty sand are examined using field and physical model tests. Drainage can generally occur in saturated clean sand and silty sand under certain conditions. This work aims to understand and explain the effect of sand and silty sand drainage conditions on CPT resistance and pore pressure through the coefficient of consolidation (c h) and penetration rate (v). The physical model test results indicate the significant effect of excess pore pressures and their dissipation rates, depending on the coefficient of consolidation (silt content) and the penetration rate on cone resistance. For the same relative density, normalized CPT resistance decreases as there is a reduction in c h (or an increase in silt content) or an increase in penetration rate. The difference in CPT resistance in silty sand is attributed to drainage conditions. Finally, the results revealed in this study and the field test data reported in the literature were combined to develop an equation for the effect of drainage conditions on excess pore water pressure and CPT resistance. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Article Citation - WoS: 11Citation - Scopus: 12An Improved Passive Tuned Mass Damper Assisted by Dual Stiffness(Elsevier, 2023) Roozbahan, Mostafa; Turan, GürsoyA tuned mass damper (TMD) is one of the oldest and most commonly used passive control devices attached to structures to absorb lateral loads of energy from main systems. In the last decades, several novel tuned mass dampers have been designed to increase the performance of TMDs in decreasing the structural responses during excitation vibrations. Moreover, several formulations and numerical optimization methods have been developed to optimize the TMDs parameters. This paper proposes a novel passive tuned mass damper with dual stiffness (DSTMD). The DSTMD includes mass, primary and secondary springs, dashpot, and motion limiting chamber. The performance of DSTMDs depends on their properties such as mass, primary and secondary stiffness, damping coefficient, and the length of the motion limiting chamber. Thus, a metaheuristic optimization algorithm, called the Mouth Brooding Fish algorithm, was used to optimize the DSTMDs parameters. The effectiveness of the optimum DSTMD on two different linear ten-story structures under several earthquakes has been studied and compared with the effectiveness of classical optimum TMDs. According to the study, optimum DSTMDs generally show better effects for certain excitations, and as an average performance, they are superior compared to the classical optimum TMDs in reducing maximum displacement of the buildings. At last, structural yielding is considered, and the performance analysis on this structure shows that the DSTMD has a superior effect in reducing the maximum displacement and is among the best methods for the calculated absolute yielding amount.Article Citation - WoS: 13Citation - Scopus: 14Boron Removal From Geothermal Brine Using Hybrid Reverse Osmosis/Microbial Desalination Cell System(Elsevier, 2023) Jarma, Yakubu A.; Kabay, Nalan; Baba, Alper; Ökten, Hatice Eser; Gören, Ayşegül YağmurAgriculture sector leads worldwide as the most water consuming sector with water demand. Since natural water resources cannot keep up with the demand, a shift from conventional water resources to unconventional ones is needed. While geothermal water was gaining importance for its energy content, small-scale (<10 L/s) energy plants were not required to reinject their spent geothermal brine. As geothermal resources align with agricultural areas in Western Anatolia, discharge of untreated brine might have severe adverse effects on crop yields and soil quality. In this study, we investigated use of spent geothermal brine for irrigation after treatment with Reverse Osmosis/Microbial Desalination Cell (RO/MDC) hybrid process. Treatment efficiencies for B, COD, As, Li, Fe, Cr concentrations and energy production values were determined. Treated water was initially evaluated for irrigation considering three quality categories (I, II, and III) comprised of parameters such as electrical conductivity (EC), total dissolved solids (TDS), and sodium adsorption ratio (SAR), along with sodium, chloride and boron concentrations. Additionally, magnesium adsorption ratio (MAR) and permeability index (PI) were used to evaluate for irrigation suitability. Although B concentrations in MDC-treated permeate (3.29 mg/L) and concentrate (2.99 mg/L) streams were not low enough to meet Quality I criterion (<0.7 mg/L), they can be still utilized in irrigation of moderate-to-high tolerant plants. Furthermore, PI and MAR parameters pointed to suitability for irrigational use. © 2022Article Citation - WoS: 13Citation - Scopus: 12Identification of Groundwater Potential Zones in Kabul River Basin, Afghanistan(Elsevier, 2021) Tani, Hamidullah; Tayfur, GökmenGroundwater (GW) plays a vital role in the socio-economic growth of Kabul River Basin (KRB) in Afghanistan. Since the GW resources in the basin have not been properly managed, there is a need for sound strategies by first identifying the potential GW zones. This study assesses the potential groundwater zones for the KRB using the Geographic Information Systems (GIS) and the Analytic Hierarchy Process (AHP). In this direction, seven different thematic maps of rainfall, lithology, land use/land cover, slope, soil, drainage density, and lineament density are first prepared using the GIS. The AHP is then employed to assess the weights of different themes. Finally, the weighted overlay option in the GIS is used to generate the map of the groundwater potential zones (GWPZ). The Very Good zones are mostly located in the downstream and central parts of the KRB, covering around 1543 km(2) area. The Good and the Poor zones are found to be randomly distributed, covering about 39 444 km(2) and 27 658 km(2), respectively. The Very Poor zones are located in the west, southwest, and in some central parts of the basin, covering about 2272 km(2). It is found that only 18% of the total average annual precipitated water of 6.88 x 10(9) m(3)/year infiltrates into the subsurface and ultimately contributes to recharging of the groundwater.Article Citation - WoS: 10Citation - Scopus: 10A Reconnaissance Study in Izmir (bornova Plain) Affected by October 30, 2020 Samos Earthquake(Elsevier, 2021) Nuhoğlu, Ayhan; Erener, Mehmet Fahrettin; Hızal, Çağlayan; Kıncal, Cem; Erdoğan, Devrim Şüfa; Özdağ, Özkan Cevdet; Akgün, MustafaOn October 30th of 2020, 14:51 (GMT+3:00), Izmir city was hit by an earthquake of Mw = 7.0 magnitude (according to USGS). A rupture of 30-40 km of a west-east normal fault, which is roughly 12 km north to Samos Island caused significant damage, particularly in Izmir (Bornova plain). This study aims to present the preliminary field investigations, evaluation of structural damage as well as the possible geotechnical phenomenon affecting the damage that occurred. In this context, an extensive analysis of spectral characteristics of the earthquake and local site effects is presented. Field investigations reveal that there is a significant amplification of the rock acceleration along with a basin effect in the region, which results in a wider constant acceleration region. In addition, analysis of earthquake records shows a remarkable level of soil nonlinearity. Considering all these aspects, a detailed assessment of structural damage observed in Izmir Bayrakli District is presented. It is evident that, structures of poor construction details behaved as if they were affected by a near field earthquake. The structures to be constructed in alluvial zones such as Manavkuyu neighborhood should be designed considering the effects of soil amplification including basin effects and soil nonlinearity. To fulfill this aim, comparative results of 1D/2D/3D ground response analyses should be performed, for revising current earthquake codes.Article Citation - WoS: 12Citation - Scopus: 15Probabilistic Investigation of Error Propagation in Frequency Domain Decomposition-Based Operational Modal Analysis(John Wiley and Sons Inc., 2021) Hızal, Çağlayan; Aktaş, EnginEach operational modal analysis (OMA) technique may produce significant errors during the identification procedure due to the applied methodology, environmental/operational conditions, and instrumentation. Consequently, those errors can adversely affect the quality of identified parameters. In this context, this study aims at providing a comprehensive discussion on the propagation of predictions errors in the frequency domain OMA. To mitigate the prediction errors those considered to be induced by modeling and measurement errors, an extended formulation is presented based on a recently developed Modified Frequency and Spatial Domain Decomposition technique. A comprehensive investigation is presented for the probabilistic modeling of output power spectral density (PSD), considering prediction errors. Numerical and real data applications are conducted to show the effectiveness of the proposed methodology.
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