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Öğe Comparison of the monitoring of surface deformations in open-pit mines with Sentinel-1A and TerraSAR-X satellite radar data(Springer, 02.06.2024) Gül, Yavuz; Poyraz, Bekir; Poyraz, FatihIn case necessary precautions are not taken in surface mines, serious accidents and loss of life may occur, particularly due to large mass displacements. It is extremely important to identify the early warning signs of these displacements and take the necessary precautions. In this study, free medium-resolution satellite radar images from the European Space Agency’s (ESA) C-band Sentinel-1A satellite and commercial high-resolution satellite radar images (SAR, Synthetic Aperture Radar) from the Deutsches Zentrum für Luft- und Raumfahrt’s (DLR) X-band TerraSAR-X satellite were obtained, and it was attempted to reveal the traceability and adequacy of monitoring of deformations and possible mass displacements in the dump site of an open-pit coal mine. The compatibility of the results obtained from the satellite radar data with two devices of Global Positioning System (GPS) which were installed in the field was evaluated. Furthermore, the velocity results in the Line Of Sight (LOS) direction and vertical deformation velocity results obtained with all three approaches (GPS/Sentinel-1A, GPS/TerraSAR-X, and Sentinel-1A/TerraSAR-X) were compared. It was observed that the results were statistically equal and the directions of movement were similar/compatible. The result of this study showed that deformations at mine sites can be monitored with sufficient accuracy for early warning with free Sentinel-1A satellite data, although the TerraSAR-X satellite offers a higher resolution.Öğe Determination of long-term deformation behaviours with InSAR data at a dump site of an open-pit coal mine in Turkey(Elsevier, 11.02.2024) Gül, Yavuz; Poyraz, BekirDump sites with broken overburden layers in surface mines have the risk of instability due to their loose bulk structures. In this study, deformations at a dump site of the Kangal/Kalburçayırı open-pit coal mine and their long-term behaviours were revealed with InSAR data for a total period of 4.5 years. Firstly, 9-periods involving different time ranges were created considering the presence of LiCSAR products. Then, the deformation velocities of each period were calculated by LiCSBAS software using LiCSAR products. The area where high deformations were concentrated from the LiCSBAS result products was determined and divided into 4 zones for more detailed evaluations. At the final stage, the period-deformation velocity graphs were drawn separately for each zone with the data obtained using two different approaches from the deformation velocities of all periods, and long-term deformation behaviours were determined. More reliable future behaviour projections could be made considering the current increasing or decreasing trend of deformation behaviours. It was revealed that vertical deformations at the dump site had an increasing trend in the first periods and a decreasing trend in the later periods. Maximum vertical deformation velocities ranging between -111.4 mm/year and -178.0 mm/year in the first 4 months reached the highest values (ranging from -141.9 mm/year to -261.8 mm/year) at the end of two years and decreased to values ranging from -33.0 mm/year to -44.3 mm/year in the later periods. It was found that horizontal deformation velocities ranged between +0.5 mm/year and +55.4 mm/year in the east-west direction and between -7.0 mm/year and -56.8 mm/year in the west-east direction, were approximately 5 times lower than vertical velocities and did not have a constantly increasing or decreasing trend in any direction. It was observed that deformations exhibited a behaviour resulting from the structural property of the dump bulk material. The results of the evaluations showed that the risk of instability gradually decreased at the dump site. The methodology of this study can enable the determination of similar areas that may pose a threat in a short time, the prioritization of risky areas, the planning of more detailed studies, and taking the necessary measures in a timely manner.Öğe Hydrological Considerations in Designing Roadways: Avoiding Hydroplaning(2022) Cavdar, Sevgi; Uyumaz, AliHigh water levels on lanes poses high risk to the safety on highways. Since drainage structures are mostly focused on water spread issue at sideways, consequences of the buildup flow on the surface is overlooked . This study addresses whether optimizing cross slopes prevents hydroplaning. Water depths obtained using kinematic wave equation were tested against several studies for verification. Wide range of rainfall intensities and cross slopes were covered. Findings revealed that cross slope optimization for grades up to 10% prevents hydroplaning for intensities below 250mm/hr with widths up to 15m. The findings also shows cross slope optimization must be considered simultaneously with inlet design work.Öğe Impact of Slope Orientation on Inlet Spacing: Gutter Flow Analyses(MDPI, 2022) Cavdar, Sevgi; Uyumaz, AliA roadway’s capacity to drain itself is of utmost importance for the safety and comfort of its users. Standing water and any amount of channelized flow on roadways create nuisances to the users, and the extent of encroachment into the lanes and the water-film thickness over the lanes are crucial for motorists with relatively high speed. Guidelines cover a wide range of subjects from size and type of inlets, which capture the channelized flow for conveyance into enclosed drains, to the decision for slope orientation, but the guidelines seem to lack in checking the depth of channelized flow. HEC-22 (the urban drainage design manual of US Department of Transportation) endorses limiting the flow depths to curb height (as if the concern is no longer the roadway users) and fixes the criterion for the inlet spacing (restricted to 90 to 150 m) to maximum allowable flow spreads. This study analyzed the maximum allowable inlet spacing via setting three criteria: fixed maximums to flow depth, spread for the channel flow, and to over-lane water-film thickness. The impact of slope orientation on inlet spacing is tested along with some other factors for roadways of two types (local and highway). The results were graphed for various uniform slope orientations under a wide range of rainfall intensities for the determined inlet spacing values. This was performed by combining a kinematic wave equation solution to dismiss the conditions that lead to hydroplaning depths when using the Rational Method and Manning’s equation to obtain water depths and inlet spacings for an inlet of full capture capacity. It is found that the allowable spacing values do not constitute any major restrictions in highway setting (3 m shoulder) in terms of recommended spacing. In the local setting, however, with a maximum spread of 1.8 m, maximum allowable inlet spacing becomes a limitation in many orientations, and slope optimization under such conditions becomes crucial at times when providing the same spacing for two orientations.Öğe Experimental study of seismic torsional behavior of reinforced concrete walls(2022) Türkay, Alperen; Altun, FatihIn this paper, the seismic torsional behavior of reinforced concrete walls has been studied experimentally. Reinforced concrete walls having 7, 6, and 5 aspect ratios have been produced on a 1/2 scale. Three specimens have been produced from each aspect ratio. In addition to these specimens, a reference specimen having a 6 aspect ratio has been produced. The reference specimen test has been used for determining the loading protocol. It has been tried to determine optimum load increase by changing load increments in the reference specimen test. Thus, ten seismic torsion tests have been carried out by using these specimens. The main purpose of the tests is to experimentally investigate the pure seismic torsional behavior of reinforced concrete walls which are under axial load. Moreover, it has been aimed to investigate the effects of the aspect ratio on torsional behavior using the tests. As a result of the study; cracking and maximum torsional moments, torque-twist angle curves, torsional stiffnesses, energy consumptions, damage patterns of the reinforced concrete walls have been obtained. It is observed from the results that the reinforced concrete walls having large cross-sections have greater torsional strengths and torsional stiffnesses. The average cracking and maximum torsional moments have increased 65.7% and 45.5% as the aspect ratio increased from 5 to 7. Furthermore, a significant decrease of torsional stiffness of the reinforced concrete walls has occurred with the occurrence of torsional cracking. The average ratios of post-cracking torsional stiffness to pre-cracking torsional stiffness have been calculated as 0.0781, 0.0922, and 0.0843 for the walls with 5, 6, and 7 aspect ratios, respectively. It has been concluded to study that choosing the aspect ratio of 5 or 6 would be appropriate in terms of torsional behavior.Öğe Effects of Concrete Strength and Openings in Infill Walls on Blasting Responses of RC Buildings Subjected to TNT Explosive(2021) Altunişik, Ahmet Can; Önalan, Fatma; Sunca, FezayilThe explosions caused by terrorism and/or accidental lead to serious damage and/or collapse in structures, economic losses, and most importantly endanger public safety. The blasting loads that can be larger than design loads are generally neglected in the design stage of civil engineering structures, despite these catastrophic effects. For these reasons, especially strategically important structures such as hospitals, military buildings, and bridges should be designed considering the blasting effects. To this aim, the effects of design parameters such as concrete strength and openings in infill walls on blasting responses of reinforced concrete (RC) buildings are investigated in this study. In situ experimental tests are firstly conducted on a test specimen constructed with brick elements to verify the finite element (FE) model criteria and assumptions. The blasting experiments are performed using 40, 150, and 290 g trinitrotoluene (TNT) explosives. Then, two RC buildings are selected as application, and blasting analyses are done with numerical and empirical methods. FE models of the buildings including structural and non-structural elements are constituted in ANSYS Workbench software. The blasting analyses are carried out with ANSYS AUTODYN software using 100 kg TNT explosives. In the analyses, two different openings in infill walls and six different concrete classes are considered. The blasting pressures, displacements, absorbed and released total energies, and damage ratios are obtained and presented as comparison parameters. The results obtained from the blasting analyses are presented with graphics and tables, comparatively. The study shows that peak pressures and maximum displacements decrease by 22.50% and 32.16% with the increase in concrete strength. Also, it is observed from numerical analyses that openings in infill walls lead to a change of 8.16% in peak pressures and 13.92% in maximum displacements.Öğe Optimal sensor placements for system identification of concrete arch dams(2021) Altunişik, Ahmet Can; Sevim, Barış; Sunca, Fezayil; Okur, Fatih YeseviThis paper investigates the optimal sensor placements and capabilities of this procedure for dynamic characteristics identification of arch dams. For this purpose, a prototype arch dam is constructed in laboratory conditions. Berke arch dam located on the Ceyhan River in city of Osmaniye is one of the highest arch dam constructed in Turkey is selected for field verification. The ambient vibration tests are conducted using initial candidate sensor locations at the beginning of the study. Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification methods are used to extract experimental dynamic characteristics. Then, measurements are repeated according to optimal sensor locations of the dams. These locations are specified using the Effective Independence Method. To determine the optimal sensor locations, the target mode shape matrices which are obtained from ambient vibration tests of the selected dam with a large number of accelerometers are used. The dynamic characteristics obtained from each ambient vibrations tests are compared with each other. It is concluded that the dynamic characteristics obtained from initial measurements and those obtained from a limited number of sensors are compatible with each other. This situation indicates that optimal sensor placements determined by the Effective Independence Method are useful for dynamic characteristics identification of arch dams.Öğe Optimal Sensor Placement for Laminated Composite and Steel Cantilever Beams by the Effective Independence Method(2021) Sunca, Fezayil; Okur, Fatih Yesevi; Altunişik, Ahmet Can; Kahya, VolkanIn modal testing, the quality of vibration signals and clarity of peak points to extract the natural frequencies, corresponding mode shapes and damping ratio depend on the number and location of the sensors. High measurement costs are required for structural identification and long-term structural health monitoring in large structures, which require a high number of sensors. Therefore, the minimum number of sensors should be placed at appropriate locations on the system during experimental measurements to ensure both information of sufficient quality and cost reductions. The aim of this study is to perform cost-efficient non-destructive modal tests for a laminated composite and steel cantilever beams using an optimal sensor placement approach. Finite element models of the sample beams are constituted in ANSYS® software to determine the initial candidate set of sensor locations. Then, ambient vibration tests are conducted. Based on the experimental modal amplitudes and mode shapes, optimal sensor locations are determined using the effective independence method, and measurements are repeated. The study shows that there is good agreement between the natural frequencies and mode shapes obtained from the initial measurements and those obtained using the limited number of sensors.Öğe Modal identification and fatigue behavior of Eynel steel arch highway bridge with calibrated models(2021) Sunca, Fezayil; Ergün, Mustafa; Altunişik, Ahmet Can; Günaydın, Murat; Okur, Fatih YeseviIn this paper, modal parameters of the Eynel steel arch highway bridge are identified and the fatigue behavior of the bridge is investigated. Modal parameters were extracted from three ambient vibration tests carried out over the period since the bridge came into service. The bridge became operational in 2009, and experimental measurements were taken in 2010, 2019, and 2021. The Enhanced Frequency Domain Decomposition (EFDD) method in the frequency domain and the Stochastic Subspace Identification (SSI) method in the time domain were used. Modal parameters were compared and any differences found over time in the measurement test results were investigated. Comparison of the results shows that changes in the natural frequencies were very limited and there was no change between the mode shapes. When experimental natural frequencies were compared, the maximum difference between the first and second measurements was calculated as 2.827%. Similarly, the maximum difference between the first and third measurements was 5.587% for the second mode, and around 3% for the other modes. This result is as expected because: (i) the bridge is not subject to heavy vehicle traffic and only connects village roads; (ii) no significant earthquake occurred during this period in the region which might have caused structural damage; (iii) no corrosion was found in the structural system elements as there was no contact with the reservoir water; (iv) no settlement or sliding occurred in the ground and boundary conditions remained unchanged. Moreover, the fatigue behavior of the bridge was investigated using the stress life method and AASHTO LRFD Bridge Design Specifications. To rationalize the results against the fatigue effects, the verified finite element model was used. From the fatigue analyses, it was concluded that the fatigue life of the bridge was within safe limits.Öğe Optimizing Non-linear Granular Layer Coefficients of a Flexible Pavement for Mechanistic-Empirical Method(2021) Bostancıoğlu, MuratIn recent years, mechanistic-empirical (M-E) design methods are preferred in the design of flexible pavements instead of empirical methods using equations based on the road performance tests. However, the calibration of transfer equations that convert mechanical responses to pavement life and the definition of layer materials used in M-E methods have great importance for M-E methods. In this study, mechanical analyses of a cross-section designed with the AASHTO-93 method were performed, and service life values were calculated with different empirical transfer equations. The obtained M-E design results were compared with the results calculated with the AASHTO-93 method, and transfer equations compatible with the AASHTO-93 method were determined. Among the transfer equations examined, it was found that the rutting equation of the Asphalt Institute gave the most consistent results with the AASHTO-93 method. In the mechanical analysis of the selected cross-section, granular base and sub-base layers were defined as non-linear elastic reflecting the actual in-situ conditions. K-Ɵ model was preferred for non-linear elastic layer definition, and K1 and K2 parameters of this model were optimized.Öğe Closure to "predictions of missing wave data by recurrent neuronets" by Can Elmar Balas, Levent Koç, and Lale Balas(2006) Balas C.E.; Koç L.; Balas L.[No abstract available]
