Civil Engineering / İnşaat Mühendisliği
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Article Citation - WoS: 61Citation - Scopus: 60Performance of Structures in İzmir After the Samos Island Earthquake(Springer, 2022) Yakut, A.; Sucuoǧlu, H.; Binici, B.; Canbay, E.; Dönmez, C.; Ilki, A.; Ay, B.Ö.The October 30, 2020 Earthquake caused unexpectedly significant damage in İzmir considering its distance to the city. This paper evaluates the recorded ground motions, summarizes the performance of structures affected from the earthquake with emphasis on the reasons of damage. A detailed damage assessment was carried out by the Earthquake Engineering Research Center of Middle East Technical University to compile data on the damage of RC and masonry buildings. It was observed that majority of the damage was concentrated in the Bayraklı district due to its peculiar soil properties where many 7–10 story mid-rise RC buildings suffered heavy damage and collapse. The level of amplified ground motions combined with deficiencies of apparently non-code compliant buildings exacerbated the damage. The main reasons of damage were mainly attributed to the presence of soft stories, lack of proper detailing, poor construction quality, presence of heavy overhangs, and hence significant lack of code-compliance in essence. The influence of infill walls on seismic performance of deficient and inadequate buildings was clearly seen in this earthquake. This paper also discusses seismic code requirements in effect and their influence on the observed building performance. The recorded ground motions were compared with the code spectra to evaluate the performance of the buildings. The code response spectra were found to be well above the recorded ground motion spectra at the sites where significant damage was observed. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.Book Part Citation - Scopus: 3High Radiogenic Granites of Western Anatolia for Egs: a Review(CRC Press, 2023) Chandrasekharam, Dornadula; Baba, Alper; Ayzit, TolgaTurkey has made remarkable progress in the hydrothermal sector by promoting both electricity generation and direct application. In terms of power generation, this country is the fourth top country in the world. Nearly 1 billion kWh of energy is being utilized to keep 150,000 homes warm in the winter. In addition, Turkey has huge amounts of uptapped energy in its high radiogenic granites in western Anatolia, spread over a cumulative area of 6,910 km2. The radioactive heat generated by these granites varies from 5 to 13 µW/m3. These granite plutons are located over a region with high heat flow values (120 mW/m2) and the Curie temperature isotherm in this region is located at a depth varying from 6 to 12 km. The heat flow values here are 50% higher than the world average. This thermal regime concurs well with the wet granite melting curve at a heat flow of 85 mW/m2. The entire thermal regime indicates a visco-elastic lower crustal layer in this region. Thus, these granites provide excellent sites for initiating Enhanced Geothermal Systems projects in Turkey. Earlier EGS projects in France and Australia gave power estimates of 79×106 kWh of electricity from 1km3 of such granite. With ongoing development in drilling technology, the classical concept of creating a fracture network is being replaced with loop technology that reduces minor seismic risks and also the cost of power. The most important additional advantage Turkey has is the high-temperature regime at shallow depth, unlike other countries where the granites are located at depths >5km. These factors cause the cost of power to fall below 6 euro cents per kWh. Besides the power and heat, the greatest advantage is the reduction in emissions and achieving UN sustainable development goals. A conservative estimate shows that these radiogenic granites of western Anatolia are capable of generating a minimum of 546×109 kWh of power. Energy from these granites can be utilized to generate freshwater using the desalination method. Earlier studies indicate that to produce 1 m3 of desalinated water, ~16 kWh of electrical energy are needed. The cost of fresh water generated using geothermal energy sources will be <1.5 euros per 1m3. Turkey can utilize the energy from granite for water and food security in the future. © 2024 selection and editorial matter, Dornadula Chandrasekharam and Alper Baba.Book Enhanced Geothermal Systems (egs): the Future Energy-Road Ahead(CRC Press, 2023) Chandrasekharam, Dornadula; Baba, AlperPeter Meisen, Past President, Global Energy Network Institute, asked in 1997, “What if there was an existing, viable technology, that when developed to its highest potential could increase everyone’s standard of living, cut fossil fuel demand and the resultant pollution?" After 23 years of sustained effort by the global scientific community, this is becoming a reality. The technology to extract heat from granite has been revolutionized in the last few years. The classical method of creating fracture networks by hydrofracturing is being replaced by a closed-loop method where fluids are not in contact with the hot granite. Supercritical CO2 is replacing water as a circulating fluid. Certainly, the future energy road is going to be led by highly radiogenic granites. While hydrothermal sources are site-specific and have their limitations, EGS can be initiated anywhere on earth. EGS is removing all such obstacles and, in the future, will provide uninterrupted electricity for all. Energy-deficient countries can have surplus electricity; water-stressed countries can have a perennial freshwater supply; and countries can become food-secure and rise above poverty levels. Countries need not depend on energy imports and can independently evolve into carbon neutral or low carbon societies. The contributions made by experts will help researchers and investors to close the energy demand and supply gap in the very near future by tapping the unlimited energy of the Earth. Opportunities available for investors in Turkey are well documented with field, geophysical, and geochemical data and information on the energy generating capacity of the granite intrusive spread over a cumulative area of 6,910 km2 in western Anatolia. With the signing of the Global Geothermal Alliance (GGA) by several countries during the December 2015 CoP 21 (Conference of Parties) summit in Paris, countries are obliged to reduce CO2 emissions by increasing the footprint of renewable energy in the primary source mix. Information provided in this book will lead the way to establishing a clean energy future for millions of people for sustainable development and help to mitigate crises arising due to food, water, and energy shortage issues. Academic and research institutes will benefit to a large extent from the expertise of the top contributors in this book. This information provided in this book will help to lay the foundation for super-hot EGS research in future. © 2024 selection and editorial matter, Dornadula Chandrasekharam and Alper Baba.Book Part Citation - Scopus: 4Application of Fuzzy Logic in Water Resources Engineering(Elsevier, 2022) Tayfur, GökmenThis chapter introduces the fundamentals of fuzzy logic (FL), fuzzy sets, and fuzzy model components such as the fuzzification, the fuzzy rule base, the fuzzy inference engine, and the defuzzification. The processes of the fuzzy model components are presented by working on the examples from the water resources engineering application problems. This chapter also discusses the merits and the shortcomings of the fuzzy modeling. Hydrological processes have inherent source of uncertainty, for which the fuzzy set theory can be an effective solution tool. © 2023 Elsevier Inc. All rights reserved.Book Part Citation - Scopus: 1Developments in Sediment Transport Modeling in Alluvial Channels(Elsevier, 2022) Tayfur, GökmenThis chapter discusses the developments in the mathematical modeling of sediment transport dynamics in alluvial channels. Starting with early experimental and empirical studies, it goes on to treating the processes in 1D, 2D, and 3D uniform sediment transport. Finally, it describes the treatment of the processes in 3D nonuniform sediment transport considering turbulence effects. While introducing the advancements in mathematical modeling of the dynamics, the chapter also discusses the outstanding issues like the treatment of the particle fall velocity, the particle velocity, and sediment transport rate function. © 2023 Elsevier Inc. All rights reserved.Book Part Citation - Scopus: 3Real-Time Flood Hydrograph Predictions Using Rating Curve and Soft Computing Methods (ga, Ann)(Elsevier, 2022) Tayfur, GökmenThis chapter introduces hydraulic and hydrologic flood routing methods in natural channels. It details hydrological flood routing methods of the Rating Curve and Muskingum. Based on the rating curve method (RCM), it presents real-time flood hydrograph predictions using the genetic algorithm (GA-based RCM) model. In addition, it presents how to make real-time flood hydrograph predictions using the artificial neural network (ANN). The chapter briefly introduces the basics of GA and details how to calibrate and validate the GA-based RCM model using measured real-time flood hydrographs. Similarly, after giving the basics of ANN, it shows how to train and test the ANN model using measured hydrographs. Real hydrograph simulations by the RCM, GA-based RCM, and ANN are presented, and merits of each model are discussed. © 2023 Elsevier Inc. All rights reserved.Conference Object Citation - WoS: 3Salihli Granitoid, Menderes Massif, Western Anatolia: a Sustainable Clean Energy Source for Mitigating Co2 Emissions(2022) Chandrasekharam, Dornadula; Ayzit, Tolga; Baba, AlperTurkey has a great opportunity to promote renewable energy, which is produced from high heat-generating granitoids using EGS (Enhanced Geothermal Systems) technology. Exploiting the energy from the radiogenic granitoid will help the country save about 32211 million kg of CO2 from gas-based electricity power plants. In addition to the hydrothermal energy sources, energy from EGS will make the country free from energy deficit and provide sustainable power, water, and food. In the present paper, we assess the power generation capacity of Salihli granitoid (SG), with an outcropping area of about 100 km2 located within the western Anatolian plateau, and describe the technology involved in harnessing the heat from these granitoids. The Anatolian Plateau is known for extension tectonics and is explained by the westward tectonic escape and subduction rollback processes. The most prominent structures of western Anatolia are E-W and ENE-WSW trending graben and horst controlled by low and high-angle oblique to dip-slip normal faults, exposing the Menderes Massif. Magmatic activity in western Anatolia is mainly related to episodic-two stage extensional regime, where the early phase is characterized mainly by calc-alkaline Early-Middle Miocene felsic lavas and pyroclastic and the latter by late Miocene-Quaternary rift-related alkaline basaltic volcanism. The plutonic activity started during 12 to 15 Ma represented by SG. The heat generation capacity of the SG varies from 5.5 to 6.7 (µW/m3), while the heat flow values over SG range from 68 to 107 HF (mW/m2). These values are much higher compared to the global average crustal values.Article Citation - WoS: 37Citation - Scopus: 35Behaviour of Buried Continuous Pipelines Crossing Strike-Slip Faults: Experimental and Numerical Study(Elsevier, 2021) Demirci, Hasan Emre; Karaman, Mustafa; Bhattacharya, SubhamoyThe paper examines the behaviour of buried continuous pipelines crossing strike-slip faults using experimental and numerical modelling. A newly developed experiment setup is presented along with the derivation of relevant scaling laws and non-dimensional terms governing global response of continuous pipelines to strike-slip faulting. Four model tests are carried out to understand the performance of the pipelines and the results are presented through the derived non-dimensional framework. Three-dimensional (3D) Finite Element (FE) model is also undertaken to simulate buried continuous pipelines crossing strike-slip faults and is calibrated against the model test results and a field case record for validation and verification. A parametric study is also carried out to better understand the parameters influencing the response of buried continuous pipelines to strike-slip faults and to also investigate the effects of pipe end conditions on their behaviour. API 5 L X70 steel pipe with 490 MPa of yield strength was used in the numerical parametric study. Two different scenarios based on fault crossing angle of the pipe (beta) were considered in the parametric study: (a) pipelines in tension and bending; (b) pipelines in compression and bending. The experimental and numerical results show that the longitudinal pipe strains under strike-slip faulting are strongly dependent on six parameters: (a) normalized fault displacements (represented by delta/D where delta is the fault displacement and D is the pipe diameter which is also an indication of soil strain in the mobilised zone); (b) ratio of pipe diameter to wall thickness (D/t); (c) fault crossing angle of the pipe (beta); (d) relative soil-pipe stiffness (kD4/EI); (e) ratio of burial depth to pipe diameter (H/D) and (f) pipe end conditions. Finally, practical implications of the study are discussed.Article A Fuzzy Logic Model To Classify Design Efficiency of Nursing Unit Floors(Yıldız Teknik Üniversitesi, 2010) Kazanasmaz, Tugce; Tayfur, GokmenThis study was conducted to determine classifications for the planimetric design efficiency of certain public hospitals by developing a fuzzy logic algorithm. Utilizing primary areas and circulation areas from nursing unit floor plans, the study employed triangular membership functions for the fuzzy subsets. The input variables of primary areas per bed and circulation areas per bed were fuzzified in this model. The relationship between input variables and output variable of design efficiency were displayed as a result of fuzzy rules. To test existing nursing unit floors, efficiency output values were obtained and efficiency classes were constructed by this model in accordance with general norms, guidelines and previous studies. The classification of efficiency resulted from the comparison of hospitals.Conference Object Upscaling Surface Flow Equations Depending Upon Data Availability at Different Scales(Springer Verlag, 2003) Tayfur, GökmenSt. Venant equations, which are used to model sheet flows, are point-scale, depth-averaged equations, requiring data on model parameters at a very fine scale. When data are available at the scale of a hillslope transect, the point equations need to be upscaled to conserve the mass and momentum at that scale, Hillslope-scale upscaled model must be developed if data are available at that scale. The performance of the three models applied to simulate flows from non-rilled surfaces revealed that the hillslope-scale upscaled model performs as good as the point-scale model though it uses far less data. The transectionally-upscaled model slightly underestimates the observed data.