Civil Engineering / İnşaat Mühendisliği
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Article Citation - WoS: 10Citation - Scopus: 11Experimental Investigation of Sediment Movement as a Result of Homogeneous Earth-Fill Dam Overtopping Break Over a Simplified Urban Area(Elsevier, 2023) Taşkaya, Ebru; Bombar, Gökçen; Tayfur, GökmenWhen 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.Article Citation - WoS: 8Citation - Scopus: 13Masonry Buildings Subjected To Settlements: Half-Scale Testing, Detailed Measurements, and Insights Into Behaviour(Elsevier, 2023) Dalgıç, Korhan Deniz; Gülen, Burcu; Liu, Yiyan; Açıkgöz, Sinan; Burd, Harvey; Maraşlı, Muhammed; İlki, AlperIndustry 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.Article Citation - WoS: 112Citation - Scopus: 137Autonomous Electric Vehicles Can Reduce Carbon Emissions and Air Pollution in Cities(Elsevier, 2022) Ercan, Tolga; Onat, Nuri C.; Keya, Nowreen; Tatari, Ömer; Eluru, Naveen; Küçükvar, MuratHeavy 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.Article Citation - WoS: 8Citation - Scopus: 11Geothermal Potential of Granites: Case Study- Kaymaz and Sivrihisar (eskisehir Region) Western Anatolia(Elsevier, 2022) 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.Article Citation - WoS: 1Citation - Scopus: 1The Modified Vlasov Model on a Nonhomogeneous and Nonlinear Soil Layer(Elsevier, 2022) İşbuğa, Volkan; Çerezci, Mehmet; Aşık, M. ZülfüThis 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.Article Citation - WoS: 12Citation - Scopus: 15Optimal Design of Elastic and Elastoplastic Tuned Mass Dampers Using the Mouth Brooding Fish Algorithm for Linear and Nonlinear Structures(Elsevier, 2022) Roozbahan, Mostafa; Jahani, EhsanA 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.Article Citation - WoS: 7Citation - Scopus: 11Utilization of Membrane Separation Processes for Reclamation and Reuse of Geothermal Water in Agricultural Irrigation of Tomato Plants-Pilot Membrane Tests and Economic Analysis(Elsevier, 2022) Jarma, Yakubu A.; Karaoğlu, Aslı; Senan, Islam Rashad Ahmed; Meriç, Mehmet Kamil; Kukul, Yasemin Senem; Özçakal, Emrah; Barlas, Neriman Tuba; Çakıcı, Hakan; Baba, Alper; Kabay, NalanThe quality of irrigation water is critical for enhancing agricultural productivity. As a result, this research was carried out with the aim of treating spent geothermal water before it is used for agricultural irrigation. While doing that, cost analysis of the system was taken into consideration as well. The product water was targeted to suit irrigation water standards for tomato plants. Two commercially available pressure driven membranes (NF8040-70 as NF membrane and TM720D-400 as RO membrane) were employed for this task. A constant applied pressure of 15 bar and 60% of water recovery were kept constant during the product water production while mode of operation for the membrane system was continuous. According to Turkish Ministry of Environment and Urbanization irrigation water standards and the results obtained from this study, it was clearly seen that both NF and RO product waters meet the quality I class irrigation water standards with respect total dissolved substances (TDS), electrical conductivity (EC), concentrations of Na+ and Cl− ions. Quality 1 means that the produced water will not cause any environmental effect when employed for irrigation purpose. Nevertheless, the produced water was found not to obey the irrigation standards with respect to sodium adsorption ratio (SAR) and boron concentration (quality III class). Quality III explains that the water will cause soil infiltration problems when employed for irrigation purpose. Since most of the minerals needed for plant growth were rejected by NF and RO membranes, an appropriate mixing ratio of the product water with well water for remineralization was determined. Mixing 50 and 60% of well water with the product waters of NF (50%) and RO (40%) membranes, respectively was found to be the optimum mixing ratios to produce the requested water quality for tomato irrigation. Quality II class irrigation water which can be applied with caution was targeted in terms of SAR as well as boron concentration (2–4 and 4–6 mg/L) while determining the mixing ratios. The cost of the product water was found as 0.76 and 1.56$/m3 for NF and RO processes, respectively.Article Citation - WoS: 29Citation - Scopus: 40Geothermal Resources for Sustainable Development: a Case Study(Wiley, 2022) Baba, Alper; Chandrasekharam, DornadulaTurkey'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.Article Citation - WoS: 21Citation - Scopus: 23Soil Liquefaction-Induced Uplift of Buried Pipes in Sand-Granulated Mixture: Numerical Modeling(Elsevier, 2022) Valizadeh, Hadi; Ecemiş, NurhanThe 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.Article Citation - WoS: 8Citation - Scopus: 7Adaptation Measures for Seawalls To Withstand Sea-Level Rise(Elsevier, 2022) Kısacık, Doğan; Tarakçioğlu, Gülizar Özyurt; Cappietti, LorenzoSea 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.