Civil Engineering / İnşaat Mühendisliği

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Citation - WoS: 7
Citation - Scopus: 6
Adaptation Measures for Seawalls To Withstand Sea-Level Rise
(Elsevier, 2022-04-15) Kısacık, Doğan; Tarakçioğlu, Gülizar Özyurt; Cappietti, Lorenzo
Sea level rise necessitates adaptation measures for coastal protection structures like seawalls as changes in the design conditions will generate higher wave overtopping discharges and coastal flooding. Although increasing crest height is a common measure, the recreational function of urban seawalls limits the applicability. In this paper, performance on overtopping control of crest modifications such as storm walls, parapets, promenade, and stilling wave basin (SWB), are studied for simple and composite vertical seawalls. Two independent physical model studies from Turkey and Italy that cover a wide range of hydrodynamic conditions focusing on low relative freeboard are presented. Reduction factors that can be integrated into EurOtop prediction formulae (2018) are proposed within the experiment boundaries. The results show that a simple promenade, extending landward of a vertical seawall, provides very little reduction, whereas a seaward storm wall, under low freeboard conditions, is not effective as a similar storm wall once located on the landward edge of the promenade. Parapets decrease the overtopping further, however, the increase in relative freeboard influences the effect of parapets. Basin width and storm wall heights are important design parameters for SWB. Although the performance of different SWB configurations converges to lower reduction factors as the relative freeboard decreases, they perform better overall. Further analysis showed that the multiplication of the two individual reduction factors, one for the parapet effects and one for the promenade effects could provide an accurate representation of the composite reduction factor to determine the total effect. However, for complex geometries, it is seen that the composite reduction factors should reflect the interdependency of components when different elements with different mechanisms that change the overtopping discharge exist such as an overtopping bore on the promenade overtopping a storm wall. However, for developing future design guidelines, it is also important to consider the influence of individual components on the composite reduction factors such as the influence of storm wall height for a storm wall at the end of a promenade.
Citation - WoS: 2
Citation - Scopus: 2
Assessment of Future Water Demand in a Semiarid Region of Turkey: a Case Study of Tahtali–seferihisar Basin
(Springer, 2023-04) Karahan, S. M.; Elçi, Şebnem
Water is a vital resource for society and nature, and its scarcity has consequences in all aspects of existence. Today, issues including the inability to preserve the status of existing water resources and excessive water withdrawal are causing the amount of water to diminish day by day. Furthermore, factors such as urbanization and industrialization, population growth, water quality degradation owing to agricultural pesticides, and climate change, all have a negative impact on water supplies. A basin-based water management analysis was carried out in this study by applying the "Integrated Water Resources Management" strategy to the Tahtalı–Seferihisar sub-basin in Turkey, where water stress is expected in the future. Using the WEAP (Water Evaluation and Planning System) model, the hydrological (precipitation, flow, evaporation) data of important water resources for the basin and Izmir (Tahtalı, Seferihisar, Ürkmez, and Kavakdere Dams) were used to predict the availability of water resources in the future, and several possible scenarios for water demands/supplies were analyzed. The water budget balances projected in 2050 have been calculated by considering six different scenarios: Reference Scenario, Report Consumption Scenario, Optimistic Case Scenario, Pessimistic Case Scenario, Return Flow Scenario, and Various Forecast Scenario. The water balances that can be obtained in each scenario under various situations were computed and compared. For all considered scenarios, unmet water demand in the basin is found to be significant (157.52 hm3 in the Optimistic Case Scenario and 373.16 hm3 in the Pessimistic Case Scenario).
Citation - WoS: 85
Citation - Scopus: 124
Autonomous Electric Vehicles Can Reduce Carbon Emissions and Air Pollution in Cities
(Elsevier, 2022-11) Ercan, Tolga; Onat, Nuri C.; Keya, Nowreen; Tatari, Ömer; Eluru, Naveen; Küçükvar, Murat
Heavy dependence on personal vehicle usage made the transportation sector a major contributor to global climate change and air pollution in cities. In this study, we analyzed autonomous electric vehicles and compared their potential environmental impacts with public transportation options, carpooling, walking, cycling, and various transportation policy applications such as limiting lane-mile increases, and carbon tax. Fractional split multinomial logit and system dynamics modeling approaches are integrated to create a novel hybrid simulation model to process data from 929 metro/micropolitan areas in the U.S. for transportation mode choice behavior. The results show that the adoption of autonomous electric vehicles can reduce greenhouse gas emissions by up to 34% of the total emissions from transportation by 2050. This study has revealed that transportation-related impacts can only be reduced with a paradigm shift in the current practices of today's transportation industry, with disruptive reforms of automation, electrification, and shared transport.
Citation - WoS: 1
Citation - Scopus: 1
Comparison of the Predicted and the Observed Wave Spectral Parameters During the Storms at Filyos Coasts, the Southwestern Black Sea
(Elsevier, 2022-09) Öztunalı Özbahçeci, Bergüzar; Güler, Muzaffer
In-situ wave measurement data are mainly used to validate the bulk wave parameters predicted by numerical models. Although the frequently used third-generation wave models are spectral models, determination of various spectral parameters and validation with the observed data are not common. This study covers the spectral analysis of selected storm records of a nearshore wave measurement campaign carried out at Filyos coasts with the complex bottom topography in Turkey, Southwestern Black Sea. The bulk wave and the spectral parameters are also calculated by a third-generation nearshore wave model, SWAN (Simulating Waves Nearshore), forced by the ERA5 offshore wave data, which is the newest re-analysis of the European Centre for Medium-Range Weather Forecasts (ECMWF) for the selected storms. Before using ERA5 offshore wave data, they are calibrated by the wave data of the satellite radar altimeter. In-situ measured bathymetry data are used in the SWAN model. Observed and predicted bulk wave and spectral parameters are compared, and the statistical error measures are calculated not only for the significant wave height, the peak period, and the peak wave direction but also for the three different spectral periods, three different frequency width parameters, a directional width and, a spectral peakedness parameter for the first time. Low values of statistical error measures show that the current wave predictions have a good agreement with the observed ones in terms of the significant wave height, Hs, and the peak period, Tp. However, the SWAN model predicts a slightly narrower frequency and directional spectrum with higher peaks, although the error measures are low. Moreover, SWAN can not predict the wide range of spectral shape occurrences that the observed spectra have. The development of the various spectral parameters during the storms is also investigated for the first time. It is found that the frequency and directional spreading of the observed spectra become wider and unsharpened in the late stages of the storm compared to the early stages. However, the same tendency is not observed clearly in the predicted directional spreading
Citation - WoS: 3
Citation - Scopus: 4
Destratification of Thermally Stratified Water Columns by Air Diffusers
(Elsevier, 2023) Elçi, Şebnem; Hazar, Oğuz; Bahadıroğlu, Nisa; Karakaya, Derya; Bor, Aslı
This study aims at improving the understanding in order to optimise an aeration system for artificial destratification to control cyanobacteria growth in the reservoirs. Previous applications for artificial destratification in reservoirs were based on installations based on computational methods, where neither the effect of air bubble size and configuration nor the effect of air density in the bubble plume could be investigated. This study seeks for an optimized design with the help of experimental and numerical analyses. In order to perform experimental studies, a novel water tank enabling the heating/cooling of the water column as desired and a diffuser system were manufactured. During the experimental studies, effect of bubble size, bubble slip velocity, and other parameters of air diffuser on destratification efficiency were investigated. Based on the nondimensional parameters, a new destratification efficiency formula is obtained by the Genetic Algorithm (GA) approach. Additionaly, the hydrodynamics of the water tank during the mixing process by air diffuser was simulated via 3D numerical model and validated with experimental results. The Eulerian multiphase model with the ‘degassing’ boundary condition and k-ω turbulence model are found to be suitable for the purposes of the study. Based on the error analysis of comparisons of the model and observations, the best configuration of air diffuser is proposed, and the numerical model is found to be successful in simulating the destratification of thermally stratified water columns by air diffuser.
Citation - WoS: 21
Citation - Scopus: 25
Drought Assessment in the Aegean Region of Turkey
(Springer, 2022) Mersin, Denizhan; Gülmez, Ayşe; Safari, Mir Jafar Sadegh; Vaheddoost, Babak; Tayfur, Gökmen
Drought indices are commonly used to monitor the duration and severity of droughts. In this regard, the continuously changing climate regardless of its cause or effect pushes the limit of the water deficit through time and space. Izmir is a raising city in Turkey, which owns various water resources including but not limited to seashores, lakes, river streams, and groundwater aquifers. In this study, the long-term precipitation and temperature records from 14 meteorological stations between 1973 and 2020 (for 47 years) are used to investigate the drought characteristics in Buyuk Menderes, Kucuk Menderes, and Gediz basins located in the Aegean region of Turkey. For this, the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), Percent of Normal (PNI), and the so-called Discrepancy Precipitation Index (DPI) are used with consideration to 1-, 3-, 6-, and 12-month moving averages to investigate the drought patterns. Results showed that the monthly indices depict very similar results for the entire region. However, in the 1980s and 2010s droughts were more severe than the rest of the historical records. When the moving average operator is implemented in the analysis (3-, 6- and 12-month periods), neither SPI nor the SPEI showed the same results at any stations. It is illustrated that the periods of severe and normal drought have occurred in the past, yet the indices that are obtained using average values are generally within the normal limits, but extreme values (extremely arid or extremely wet) occurred occasionally. It is also concluded that although there is a similarity between the implemented indices, the DPI and PNI depict the highest resemblance.
Citation - WoS: 9
Citation - Scopus: 10
Experimental Investigation of Sediment Movement as a Result of Homogeneous Earth-Fill Dam Overtopping Break Over a Simplified Urban Area
(Elsevier, 2023-02) Taşkaya, Ebru; Bombar, Gökçen; Tayfur, Gökmen
When an earth-fill dam breaks, dam body sediment and water flow simultaneously move to downstream area causing devastation. Dam break studies in the literature have concentrated mostly on the water flow part while ignoring the sediment movement by designing the dam body as a movable metal gate. This study, however, is the first one experimentally investigating flow and sediment transport due to an earth-fill dam break by constructing the dam body from sediment. Sediment propagation as a result of homogenous earth-fill dam overtopping break was experimentally studied in a laboratory flume of 18.4 m long and 2.0 m wide, and 0.88 m in height in the Hydraulics Laboratory of Izmir Katip Celebi University, Izmir, Turkey. Downstream section right after the dam body was designed as a smooth bed and rough bed. The rough bed, resembling a simplified urban area, was created by using thirteen 10 × 10 × 10 cm sized concrete blocks. The dam body was constructed as homogenous with uniform material having D50 = 0.441 mm. The earth-fill dam body was built using the standard compression methods; each layer of sediment with a thickness of 10 cm was laid in layers, and the body was prepared with a crest width of 10 cm, a transverse base width of 200 cm, a longitudinal base width of 202 cm and height of 60 cm with upstream and downstream slopes of 1:1.6. The water level behind the dam was gradually raised until it overtopped the crest level. A pre-breach was formed at the top of the dam to trigger the break. During each dam break event, water depths were measured by three ULS-40D level meter sensors at different locations, and the final sediment bathymetry map was generated using the ULS-40D Probes at 10 × 10 cm grids. The results showed that, in both smooth and rough downstream bed cases, the dam body eventually collapsed while a great portion of it was carried away by the flood flow. The sediment spreading occurred all over the downstream area, showing significant non-uniform variation in thickness both longitudinally and transversely, especially in the simulated urban area. All the residential areas, while breaking in motion, were submerged under the muddy flow. Some blocks were almost submerged while sediment heights reached half level of some blocks at the end of the experiment. Sediment heights were higher in the urban area.
Citation - WoS: 2
Citation - Scopus: 5
Experimental Modeling of Antimony Sulfides-Rich Geothermal Deposits and Their Solubility in the Presence of Polymeric Antiscalants
(Elsevier, 2022-05) Karaburun, Emre; Sözen, Yiğit; Çiftçi, Celal; Şahin, Hasan; Baba, Alper; Akbey, Ümit; Yeşilnacar, Mehmet İrfan; Erdim, Eray; Regenspurg, Simona; Demir, Mustafa Muammer
Antimony (Sb)-rich geothermal deposits have been observed in many geothermal power plants worldwide. They occur as red-colored, sulfidic precipitates disturbing energy-harvesting by clogging the geothermal installations. In order to prevent the formation of this scale, information on its physicochemical features is needed. For this purpose, Sb-rich sulfide-based deposits were synthesized at controlled conditions in a pressurized glass reactor at geothermal conditions (135 °C and 3.5 bar). Various polymeric antiscalants with different functional groups, such as acrylic acid, sulphonic acid, and phosphonic acid groups were tested for their effect on Sb sulfide solubility. An additional computational study was performed to determine the binding energy of Sb and S atoms to these groups. The results suggest that sulfonic acid groups are the most affective. Therefore, it was concluded that these macromolecule containing sulfonic acid groups and poly (vinyl sulfonic acid) derivatives could potentially act as antiscalants for the formation of antimony sulfide.
Citation - WoS: 6
Citation - Scopus: 10
Geothermal Potential of Granites: Case Study- Kaymaz and Sivrihisar (eskisehir Region) Western Anatolia
(Elsevier, 2022-08) Chandrasekharam, Dornadula; Baba, Alper; Ayzit, Tolga; Singh, Hemant K.
Radiogenic granites are gaining importance due to their ability to generate a substantial amount of electricity and support the advancement of agricultural and water sectors. In the western Anatolian region, such granites occupy a cumulative area of 6910 km2 varying from 7 to 20 μW/m3, far above the heat generated by the average continental crust of 5 μW/ m3. One cubic. The granite plutons of the Eskisehir region are amongst such granites with radioactive heat generation kilometer of such granite can generate 79 × 106 kWh of electricity. In the present case, the Eskisehir granites are capable of generating 616 million kWh of carbon-free electricity. Besides electricity, the heat from the granites can be utilized for space heating and greenhouse cultivation. This energy can also be utilized for the generation of fresh water from the sea through the desalination process. Hydrofracturing of the granites to create a fracture network connecting injection and production well is being replaced with closed-loop system that do not require knowledge about the stress pattern of the region and reduce the risk of induced micro-seismicity that was a bottleneck for developing EGS projects. Although the currently estimated cost of electricity generated from EGS projects is 9 euro cents/kWh, this cost will get reduced due to technological development in drilling technology. The Western Anatolian region has an additional advantage over the cost, since the drilling depth to capture the heat from the granites is shallow (∼3 km) which gives further benefit to the cost due to the reduction in drilling depth cost. In addition to high radiogenic granites, the presence of curie point temperature at shallow depth, high heat flow, and high geothermal gradient makes this region a warehouse of energy making Turkey energy-food and water independent in the future.
Citation - WoS: 2
Citation - Scopus: 4
Geothermal Potential of Manuguru Geothermal Field of Godavari Valley, India
(Elsevier, 2022-10) Singh, Hemant K.; Chandrasekharam, Dornadula; Minissale, A.; Raju, N. Janardhana; Baba, Alper
The Godavari geothermal field in India is one of the potential areas manifested by several geothermal waters and groundwaters. The geothermal waters of the area are near neutral (pH: 6.5–7.3) with surface temperature ranging from 30 to 55 °C while groundwaters are also near neutral (pH: 6.6–7.5) with surface temperature ranging from 24 to 28 °C. The hydrogeochemistry of the geothermal waters suggests that the geothermal waters show a Na-Ca-SO4-HCO3 to a Ca-HCO3 type and groundwaters are of the Ca-HCO3 to Na-Ca-HCO3 type while groundwaters and river waters are of the Ca-Na-SO4 types. The geothermal waters of the study area are enriched in SO42– and Cl–, due to the interaction with the pyrite-bearing Gondwana sediments and granitic gneiss basement rocks. Furthermore, enrichment of Ca2+, Mg2+ and an increased HCO3/Cl ratio in geothermal water is caused by the exchange and/or mixing process that takes place during water-rock interaction at an elevated temperature while ascending to the surface. This type of behavior of water is also observed during the water-rock interaction experiment at 100 °C. Studies on geothermal gas geochemistry suggest the deeper circulation of geothermal waters in the crust and high helium concentration as a thermal gas that can be utilized for commercial purposes. Estimated reservoir temperatures from quartz and Na-K-Ca geothermometry are in the range 110–195 °C. Therefore, the geothermal water of the study area is categorized as a moderate enthalpy geothermal system. Thermal logging in the borewell and depth range from 50 to 1000 m suggest that the geothermal gradient in the Manuguru area ranges from 22.5 to 105.5 °C/km and heat flow ranges from 83 to 388 mW/m2, which is higher than the regional condition. Therefore, 3584 MWe power can be produced by using the Organic Rankine Cycle (ORC) from the Manuguru geothermal area of Godavari valley
Citation - WoS: 26
Citation - Scopus: 35
Geothermal Resources for Sustainable Development: a Case Study
(Wiley, 2022) Baba, Alper; Chandrasekharam, Dornadula
Turkey's primary energy source is fossil fuels, with a contribution of 55%. According to the International Energy Agency forecast, fossil fuels will continue to be the primary energy source for the next decade. The current CO2 emissions from fossil fuel-based energy are 400 Mt. If the present energy usage trend continues, then the emissions will cross 500 Mt by 2030. However, Turkey has large scope to mitigate climate-related issues and follow sustainable development agenda by increasing the share of geothermal energy as a primary energy source mix. The country established a strong geothermal energy program in 1984 by installing a 17 MWe geothermal power plant in Kızıldere and made tremendous progress in this field. Currently, the power generation has crossed 1665 MWe. Turkey has drawn a new road map to enhance its primary energy source mix by developing its radiogenic granites (Enhanced Geothermal Systems) for power generation and carbon dioxide capture programs. This is an emerging technology that is being recommended for Turkey. Currently, France, Australia, and the United Kingdom are surging ahead in implementing Enhanced Geothermal Systems (EGS), and France has established a pilot power plant using EGS and generating 10 MWe. The United Kingdom will be starting its 3 MWe power plant. The hydrothermal source, in combination with Enhanced Geothermal Systems, can contain the annual CO2 emissions to 500 Mt and reduce the per-capita CO2 emissions to 4.5 tons annually. One of the greatest contributions to climate mitigation and sustainable development made by the geothermal industry is the sequestration of CO2 from the Kızıldere geothermal power plant for the manufacturıng of dry ice and use CO2 from the Tuzla geothermal power plant for minimizing scaling. This dry ice technology can be extended to the cement industry to capture 18 billion CO2 being emitted annually from clinker manufacturıng units. The dry ice will be useful in combating forest fires that are common in Turkey. The article discusses the new technological developments that Turkey is adopting to mitigate climate change and achieve sustainable development goals.
Citation - WoS: 6
Citation - Scopus: 10
Impacts of Construction of Dam on the Flow Regimes and Water Quality: a Case Study From Turkey
(Springer, 2022-05) Bor, Aslı; Elçi, Şebnem
Dam construction has important positive and negative effects on the environment, including physical changes of the riverbed morphology, changes in sediment transport patterns and water quality, and the river ecosystem in general. The primary objective of this study is to present a methodology to assess the impacts of construction and operation of Çine Dam, in Aydin, Turkey, on the river flow regimes, sedimentation, and water quality of the downstream reach of Büyük Menderes River. Construction of the dam significantly reduced the sediment load from the Çine tributary to the main reach, as expected. To evaluate changes in the water quality of the Çine River, five different water quality index methods are compared before and after the dam operation: Weighted Arithmetic Index (WAI-WQI), Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), Universal Water Quality Index (UWQI), Oregon Water Quality Index (OWQI) and Aquatic Toxicity Index (ATI). ATI and CCME-WQI methods are found to be more appropriate for the 10-year water quality assessment of the river.
Citation - WoS: 11
Citation - Scopus: 18
Integrated Pressure-Driven Membrane Separation Processes for the Production of Agricultural Irrigation Water From Spent Geothermal Water
(Elsevier, 2022-02) Jarma, Yakubu Abdullahi; Karaoğlu, Aslı; Tekin, Özge; Senan, Islam Rashad Ahmed; Baba, Alper
The application of different pressure-driven membranes to treat the spent geothermal water to be used for agricultural irrigation was explored in this study. Firstly, individual performances of different commercially available nanofiltration (NF) and reverse osmosis (RO) membranes attached to a mini-pilot membrane test system were studied. For the single membrane test TR-NF and NF90 as NF membranes and TR-BWRO, Vontrone, TR-SWRO and BW30 as RO membranes were employed while combination of TR-NF with TR-BWRO, Vontrone, TR-SWRO and BW30 was employed in the integrated study (with and without pH adjustment).When performances of individual membranes were investigated, the permeate fluxes obtained it was found that there was no significant flux drop with the experimental time (4 h) in all the studies. In terms of boron removals, boron was partially removed in single membrane study as 22.7–23.6% and 30.6–56.8% by NF and RO membranes, respectively. For the integrated NF + RO membrane configuration (without pH adjustment), boron removals were in the range of 42.1–59.4% while 91.3–95.4% of boron removal was obtained in the integrated NF + RO (at elevated pH). It was found that the produced water complied with class I quality with respect to irrigation water parameters with the exception of boron and sodium adsorption ratio (SAR), while the pH of the product water in the integrated NF + RO study at elevated pH was found to be in class III. Hence, produced water will be suitable (class II) for irrigation if 30% of well water should be blended with the product water in the integrated NF + RO studies (with and without pH adjustment) as well as pH adjustment when necessary.
Citation - WoS: 1
Citation - Scopus: 1
A Magnetically Driven Elastic Rod Type Bi-Directional Swimmer at Stokes Flow
(Springer, 2022-04) Özdemir, İzzet
In this paper, a flexible rod type micro-swimmer is proposed which achieves swimming direction reversal on the fly by forming a chiral helix-like geometry through external magnetic excitation. Furthermore an accompanying low Reynolds number flow-structure interaction analysis framework is developed which effectively combines a geometrically non-linear shear deformable beam model with regularized Stokeslet method in a monolithic implicit solution algorithm. This framework is used to investigate the basic characteristics of the proposed micro-swimmer in terms of dimensionless groups reflecting the interplay between different forces involved.
Citation - WoS: 6
Citation - Scopus: 11
Masonry Buildings Subjected To Settlements: Half-Scale Testing, Detailed Measurements, and Insights Into Behaviour
(Elsevier, 2023-03) Dalgıç, Korhan Deniz; Gülen, Burcu; Liu, Yiyan; Açıkgöz, Sinan; Burd, Harvey; Maraşlı, Muhammed; İlki, Alper
Industry procedures to assess the risk of settlement-induced damage to masonry buildings ignore key aspects of the problem, such as the influences of building weight, façade openings, and floor structures. Experimental data are needed to characterise the influence of these aspects on damage. This paper describes tests on three brick masonry half-scale building models subjected to settlements. The use of scaling rules in choosing the model materials and kentledge, the settlement apparatus, and the cross-validation of displacement and strain measurements are presented. Comparative evaluation of building responses show that: (i) the distribution of building weight and the resulting in-situ stresses play a key role in determining compliance to settlements, (ii) openings make the structure vulnerable to cracking and (iii) floor slabs stiffen and strengthen the building and prevent the formation of damage in the upper floors, leading to a concentration of damage at the ground storey.
Citation - WoS: 1
Citation - Scopus: 1
The Modified Vlasov Model on a Nonhomogeneous and Nonlinear Soil Layer
(Elsevier, 2022-06) İşbuğa, Volkan; Çerezci, Mehmet; Aşık, M. Zülfü
This study presents a novel approach to account for the soil nonlinearity of nonhomogeneous soil deposits in foundation deflection analyses in the context of a modified Vlasov foundation model. We present an extension of the previously proposed formulation by developing a new formulation employing an improved algorithm that takes the modulus degradation curves at varying strain levels into account in an iterative manner. This new model, which takes the nonlinear soil behavior into account, was first verified against a linear elastic soil model given in the literature to ensure that the new model algorithm can capture the original solution when the soil behavior is assumed to be linear elastic. Later, the experimental data reported in the literature for a specific type of dense and loose sands were used in the example analyses. Example problems were considered for different cases, which presented (i) how the model captures nonlinear behavior and (ii) the significant effect of the nonlinear soil behavior. The result of the new model was also compared with the finite element model results, assuming elastoplastic soil. The results obtained from both models match well, especially for the maximum deflection value, provided that laterally constrained sections underneath the foundation are used.
Citation - WoS: 11
Citation - Scopus: 13
Optimal Design of Elastic and Elastoplastic Tuned Mass Dampers Using the Mouth Brooding Fish Algorithm for Linear and Nonlinear Structures
(Elsevier, 2022) Roozbahan, Mostafa; Jahani, Ehsan
A tuned mass damper (TMD) is a vibration control system used to reduce the structural responses to earthquakes and extreme wind loads. The performance of a TMD depends on its parameters, such as mass, damping coefficient, and stiffness. Therefore, several methods have been proposed to optimize the parameters of TMDs. This paper proposes a new method for optimizing TMDs' parameters using the Mouth Brooding Fish (MBF) algorithm based on white noise excitations. The effectiveness of TMDs optimized using the proposed method and other methods in reducing the maximum displacement of a ten-story linear structure was compared. The results indicated that the proposed method could effectively find the optimum parameters of the TMD. The efficacy of elastic and elastoplastic TMDs optimized using the proposed method in the responses of linear and nonlinear 10-story structures was also investigated. According to the results, the optimal elastic TMD more effectively reduced the maximum displacement of linear and nonlinear structures than the optimal elastoplastic TMD. Besides, elastic and elastoplastic TMDs exhibited higher efficiency in reducing the maximum displacement of the linear structure than the nonlinear structure.
Citation - WoS: 3
Citation - Scopus: 3
A Quality Assessment of Public Water Fountains and Relation To Human Health: a Case Study From Yozgat, Turkey
(John Wiley and Sons Inc., 2019-11) İritaş, Servet Birgin; Türksoy, Vugar Ali; Deniz, Serdar; Koçoğlu, Serhat; Kırat, Güllü; Demirkesen, Ali Can; Baba, Alper
Public fountains are very common and everyday people appreciate the benefits a water fountain can bring. However, consumption of public fountain water in some country has decreased because of growing concerns that constituents in fountain water may have adverse effects on health. A few studies have examined the safety of public fountains, proposing only limited evidence of fountain-related health issues in Turkey. Most of these public fountains are sourced from natural springs in Turkey. In this study, a 177 fountain water and 32 rock samples were analysed for source and quality of water. The geology of the region has the direct impact on the quality of the public fountain water. The results indicate that the level of some elements exceeded the limit values determined by WHO and US.EPA. The most striking high values were observed for iron (Fe), nickel (Ni), aluminum (Al), arsenic (As) and bromine (Br) concentrations.
Citation - WoS: 2
Citation - Scopus: 3
Site Assessment of Surface Texture and Skid Resistance by Varying the Grit Parameters of an Sma
(American Society of Civil Engineers (ASCE), 2022-09) Gökalp, İslam; Uz, Volkan Emre; Saltan, Mehmet; Tepe, Mehtap
For the sale operation of vehicles, pavement should provide adequate skid resistance, which can be achieved by using high polishing-resistant aggregate in wearing courses. However, supplying high-quality aggregate is not always feasible due to high transportation costs. For this reason, a method called gritting was adapted to meet the Highway Technical Specification (HTS) of Turkey in 2013. According to the method, for certain parts of the country, the wearing course can be constructed with local aggregates that have minimum polished stone value (PSV) of 40 (PSV >= 40), but, in this case, the surface must be covered with a high polishing-resistant aggregate (PSV >= 50), after the rollers' first pass. The objective of this study was to improve the present gritting method by investigating the effect of grit parameters on pavement performance under real traffic conditions. In this regard, during its construction, the wearing course of 0-51 Highway was gritted with different aggregate types (slags and natural), sizes (1-3; 1-5 mm), spreading amount (1.5; 2; 2.5 kg/m(2)), and spreading time (before and after the first pass of a roller) on eight test sections. Then, the macrotexture and skid resistance performance of these sections were evaluated under real traffic and environmental conditions for longer than 4 years. Changes in surface texture and skid resistance with respect to traffic were determined for each section. The results showed that higher skid resistance values were obtained at the sections gritted with metallurgical slags. Additionally, the sections gritted with 1-5 mm aggregates had better skid resistance than those gritted with 1-3 mm, while the change in mean texture depths were not very significant.
Citation - WoS: 16
Citation - Scopus: 23
Soil Liquefaction-Induced Uplift of Buried Pipes in Sand-Granulated Mixture: Numerical Modeling
(Elsevier, 2022-03) Valizadeh, Hadi; Ecemiş, Nurhan
The significant uplift of buried pipes observed during recent earthquakes has showed the need for further research in remediation methods for soil liquefaction. Sand-granulated rubber mixture is reported as a new soil improvement method that can be applied as a liquefaction mitigation filling material around buried pipe. In this study, the effects of pipe size, burial depth, and shaking intensity on the pipe uplift and the liquefaction potential of the sand-tire derived granulated rubber mixture placed around the buried pipes were investigated using numerical models. First, the result of 1-g shaking table tests was used for the verification of the numerical analysis. Comparing the numerical results and the experimental measurements showed that the numerical simulation using the UBCSAND constitutive model could accurately estimate the liquefaction-induced uplift of the buried pipes as well as the related failure. Then, a parametric study was conducted to investigate the effects of the pipe diameter, the pipe depth, and the value of the acceleration on pipe uplift and liquefaction potential when the SGR mixture was placed as filling material. Eventually, an analytical formula was proposed to estimate the liquefaction-induced uplift of buried pipes, and the soil failure mode was categorized according to the pipe's burial depth ratio.