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Yayın Seismic behavior of an ordinary RC structure exposed to corrosion(Işık Üniversitesi, 2019-01-18) Türkmen, Gizem Ceren; Karadoğan, Hüseyin Faruk; Işık Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıWithin the scope of this thesis, seismic behavior of a 15 years old, approximately ½ scale, one storey, one bay frame which has concrete made of sea sand, mild reinforcing steel, and which was exposed to outdoor conditions for 15 years that resulted in a certain amount of corrosion of reinforcement, subjected to constant axial load and displacement reversals was examined analytically and experimentally. This frame represents the building stock with insu?cient seismic details in Turkey which is built without conforming the existing design codes. Analytical part of the study consists of two approaches; distributed plasticity approach and concentrated plasticity approach. Parameters such as unit deformation and strength of materials were obtained by the axial tension and compression tests for the steel and concrete, respectively. A reference frame having same dimensions and characteristics with the corroded frame except for compressive strength of concrete, was tested 9 years ago with the same experimental procedure also takes a part of this study for comparisons. Experimental results of corroded frame were compared with analytical results which are obtained by nonlinear static time history analysis and pushover analysis. Besides, a retro?tting technique that is RC jacketing is assumed to be applied on the columns of the frame and in?uence of this technique on the seismic behavior of the frame was examined for several assumptions with static pushover analysis and the obtaining the capacity curves for each assumption, comparisons were done. Moreover, a parametric study which involves the increase in the amount of corrosion of the specimen tested, was performed to have the insight about the effect of diameter loss of reinforcement due to corrosion on the lateral load carrying capacity and deformation capacity of the structure. The experiment was ended at %3 drift ratio and bending and shear cracks were observed at the ends of columns. Structure elements underwent excessive loading which is beyond their load carrying capacity and had plastic deformation at the column ends which refers to strong beam weak column analogy. Furthermore, implementation of RC jacketing as a retro?tting technique analytically, led the plastic deformation to occur at the beam ends instead of column top end which complies with the proposal of TEC known as strong column-weak beam situation. According to the experimental and analytical studies, seismic behavior of the frame which is presented by capacity curve is modeled better with concentrated plasticity approach. Secondly, load carrying capacity, energy dissipation, cumulative energy dissipation of recently tested frame is higher than the reference frame which has lower compressive strength of concrete. Also, when comparing capacity curves,the frame has quite similar behavior when the concrete is 32 days old. Furthermore increasing corrosion rates of column reinforcements leads lower lateral load carrying capacity and ductility under lateral loading. As it is expected, it was observed that retro?tting of the columns by RC thin jacketing like 4-6 cm thickness is an e?ective and useful method to increase sectional and hence the displacement ductility and the lateral strength of the frame. Self-leveling and self-compact special concrete can be used for those thin jackets.Yayın Evaluation of the efficiency of mainline and ramp metering in highway traffic management(Işık Üniversitesi, 2020-06-16) Yaran, Güzem; Kesten, Ali Sercan; Işık Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıIn the study, the effects of the mainline and ramp control theories on the highway traffic flow are investigate. In order to eliminate to alleviate the traffic congestion problem, which has become a problem in high-population cities, the mainline and ramp controls are considered as a solution, and control networks are emphasized. Examples of applications and results in the world are given. The applicability of the methods to be used by examining the previous studies was first examined on a general model and then on a selected highway network. In the models prepared, vehicle speeds, travel times, flow (volume) concepts, and relationships between them are mentioned. In addition, general information about highway management was also provided before. Control models were examined with the Microscopic Simulation Program, the purpose and types of models applied were compared. The traffic simulation model of the region between K-8 and K-11 on the O-2 highway from Asia to Europe has been created and the effects created by the control have been examined by applying both ramp and mainline metering. Analysis results; It has been observed that the control of ramp and mainline scenarios provides benefits compared to uncontrolled situations. Among the benefits provided; when the analysis of the basic model and mainline metering is applied, it is seen that there is an increase of 20.76% in travel times and an increase of 19.78% in vehicle speeds. Nevertheless, the implications of these control scenarios should be thoroughly investigated. Simulation results show that Ramp Metering (RM) and Mainline Metering (MM) controls can be an effective method in the management of highway-highway connections. In this regard, it is recommended that the control strategies mentioned in intensive highway-to-highway participations be tested in real life in order to increase efficiency.Yayın Analyzing the benefits and challenges of the building information modelling and life cycle assessment integration(Işık Üniversitesi, 2019-07-17) Azizoğlu, Heval Botan; Seyis, Senem; Işık Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıThe architecture, engineering and construction (AEC) industry involves the large quantities of material and energy consumption. Previous studies show that the AEC industry consumes about 40 percent of primary energy utilization and contributes up to more than half of global GHG emissions. With the aim of decreasing these negative impacts of AEC industry on the natural environment, the integrated use of advanced technological instruments has been increasing in the last decade. One of the promising technological instrument integrations is the collaborative use Building Information Modeling (BIM) and Life Cycle Assessment (LCA) which is able to decrease negative impacts of AEC industry on natural environment in an e ective and e cient manner. The objective of this MS thesis is to identify, classify and prioritize the bene ts and challenges of the integrated use of Building Information Modelling and Life Cycle Assessment in the AEC industry. In order to achieve research objectives of this thesis, a comprehensive literature review, semi-structured interviews with experts and Delphi method were performed. The interrater agreement and signi cance-level statistics were conducted for analyzing and validating the consensus among the Delphi method participants. Results of this study provide twenty-two types of bene ts and seven types of challenges for the integrated use of BIM and LCA in the AEC industry. The contributions of this thesis are a comprehensive identi cation, classi cation and prioritization of the integrated use of BIM and LCA. The results of this study may contribute to extend utilization of BIM-LCA integration in the AEC industry.Yayın An experimental and theoretical work on the seismic behavior of a reinforced concrete frame(Işık Üniversitesi, 2019-01-18) Agyemang, Christabel Akosua Sakyiwaa Osei; Karadoğan, Hüseyin Faruk; Işık Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıCorrosion of reinforcements embedded in concrete is one of the numerous causes of deterioration in reinforced concrete structures. In an earthquake prone region, corroded structures become more vulnerable to early failure within its life cycle.The major difficulty for experimental work on corrosion is related to the preparation of a naturally corroded specimens because it is time consuming hence accelerate corrosion is utilized in many researches. In this study, a 15 year old naturally corroded one storey one bay frame specimen and several standout cylindrical specimens were constructed using unseived sea sand containing seashells and to represent structures built during the rapid urbanization period in last 5 decades. The specimen was tested under reversed cyclic loads and the test results were compared to results achieved previously with no corrosion. Furthermore, a numerical analysis was conducted by existing computer programs (SAP2000 and SeismoStruct) and a pushover algorithm was adapted considering lumped plasticity to obtain the structural response of the specimen by different techniques for two theories of analysis including an algorithm for determining stability loads and period at different states of plastic deformations. All numerical results were compared with the experimental results. 15 year old frame showed moderate corrosion at the lower ends of the columns with the lateral load capacity and ultimate displacement not extremely affected by the corrosion. However, higher energy dissipation capacity was observed and with low lateral stiffness at low levels of displacement. Aside the study on corrosion on the frame specimen, this thesis developed a correlation between Poisson’s ratio and nonlinearity index ? based on the gathered empirical data on the uniaxial compression test of 15 year old cylindrical specimens.Yayın Seismic behavior of fifteen years old RC frame(Işık Üniversitesi, 2019-01-18) Ekşi, Hızır; Karadoğan, Hüseyin Faruk; Işık Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıIt is known that during the construction process of signi?cant part of RC structure stock, mild steel and aggregates coming from sea bed used before the existing code proposals and standards in Turkey. Low concrete quality, mild-nonribbed reinforcement and sea type of aggregates are some of the under design features of those structures. This study mainly focused on seismic behaviour of this type of RC frame as experimentally and analytically. Especially in humid environments, reinforcement corrosion probably occurs when the concrete quality is low and it includes aggregates coming from sea bed. The reinforcement corrosion can cause a lot of structural problems such as cracking of concrete, bond lost and decreasing of e?ective cross sectional area of rebar during the service life of RC structure. These destructive corrosion results limit the service life of existing structure stock. Depending on the degree of natural corrosion attack, the adherence between the reinforcement and concrete is adversely a?ected, the e?ective reinforcement cross section is reduced as a function of time and the cracking of the concrete cover can be seen as the main structural damages. Within the scope of this study, the ?fteen years old RC frames were tested to represent the structures which are naturally corroded and constructed before recent earthquake codes and standards. Nearly 1/3 scale one RC frames and one reference frame (15 years ago) were tested under the cyclic horizontal loads and constant axial forces in the ?Istanbul Technical University Building and Earthquake Engineering Laboratory. The seismic behavior of reinforced concrete frames has been tried to be explained by analysing the strength development, displacement capacity, ductility, lost of e?ective cross sectional area of reinforcement, sti?ness, moment-curvature relations and displacement components obtained under cyclic load procedures. The poisson ratio of ?fteen years old con?ned and uncon?ned concrete in descending branch of stress-strain diagrams was another topic for which only limited amount of literature is available. In the theoretical part of this study; non-linear pushover analysis of the structural frame was investigated using by DC2B-v2 which include distributed plasticity theory, Sap2000 and SeismoStruct that are based on concentrated plasticity theory computer programs. The outputs obtained from these programs by using theoretical models and the results of the experimental behavior are compared. There is a special purpose computer program has been developed for ?nding the buckling load parameters of a frame with and without plastic hinges. According to the experimental and analytical results; strength development, lateral and vertical displacement capacity, ductility and moment curvature relationships have been measured, evaluated and compared. The tested frame specimen did not reach its theoretical load capacity and drift level due to decrement of e?ective cross sectional area of reinforcement and decrement of adherence between the concrete and rebar. Displacement capacity of tested corroded frame was reduced visibly when compared with uncorroded reference frame. Some of the reinforcing bars of stirrups which are closer to the outer joints were ruptured at 4% story drift that indicate a loss in displacement capacity and shear capacity due to high corrosion attack on those outer stirrups reinforcements.Yayın Analytical and numerical analysis of the dissipative kundu-eckhaus equation(Işık Üniversitesi, 2019-12-02) Yurtbak, Hazal; Bayındır, Cihan; Işık Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıIt is well-known that the Kundu-Eckhaus equation (KEE) is a nonlinear equation which belongs to nonlinear Schrödinger class and it is commonly used as a model to investigate the dynamics of diverse phenomena in many areas including but are not limited to hydrodynamics, fiber and nonlinear optics, plasmas and finance. However, the effects of dissipation on the dynamics of KEE have not been investigated so far. In this thesis, in order to address this open problem we propose the dissipative Kundu-Eckhaus equation (dKEE) and perform an analytical and numerical analysis of the dKEE. With this motivation, we derive a simple monochromatic wave solution to dKEE. Then, we propose a split step Fourier method (SSFM) for the numerical solution of the dKEE and we test the stability of the SSFM using the analytical solution derived as a benchmark problem. Observing the stability and the accuracy of the scheme, we first investigate the rogue wave dynamics of the dKEE using the SSFM. More specifically, we show that modulation instability (MI) turns the monochromatic wave field into a chaotic one, thus the appearance of rogue waves become obvious. We discuss the properties and characteristics of such rogue waves. Additionally, we depict the amplitude probability distribution functions (PDFs) and discuss the effects of diffusion, Raman and dissipation coeficient as well as the MI parameters on the probability of rogue wave occurrence. Secondly, we investigate the effects of dissipation on the self-localized solitons of the KEE. For this purpose, we propose a Petviashvili method (PM) to obtain the self-localized solitons of the KEE and analyze the effects of dissipation by time stepping of these solitons using the SSFM proposed for dKEE. It is known that, KEE admits stable single, two and N-soliton solutions for the no potential case. It has been recently found that, under the effect of photorefractive and saturable potentials, such solitons of the KEE become unstable. We show that the dissipation parameter can be used to stabilize the single, two and three solitons of the KEE which do not satisfy the necessary Vakhitov-Kolokolov condition for the soliton stability. With this aim, we present the power graphs as functions of soliton eigenvalue and as well as time. Additionally, we depict the soliton shapes for various times to show that they are preserved for time scales long enough for many engineering purposes.We comment on our findings and discuss the applicability and uses of our results. Additionally, we suggest possible directions for the near future research activities.Yayın Evaluation of acceleration characteristics on operational eco - driving(Işık Üniversitesi, 2020-06-16) Yıldıran, Çağlar Latif; Kesten, Ali Sercan; Işık Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıGreenhouse gasses is a main thread for global warming and there are several strategies that reducing GHG gasses especially in developing countries as using alternative fuel types, dealing with the congestion, maintaining the steady traffic flow, dealing with the maintenances of vehicle, managing desired speed and the acceleration rates and so on. Eco-Driving is indicating any implementations which enables driving more economic and ecologic style. One of the main concepts of eco-driving is configuring driving behaviour to reduce consumption and emissions. In this thesis, impact of driver's behaviour tried to be investigated by using an instantaneous emission modelling to obtain minimum acceleration deceleration rate in generically created urban network.Yayın Impact of traffic incident duration and road characteristics on traffic flow performance(Işık Üniversitesi, 2020-06-16) Alan, Ali Rıza; Kesten, Ali Sercan; Işık Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıNon-recurrent events that occur in any part of the highway such as accident, vehicle breakdown,fire, scattering of substances like load, fuel oil etc. on the road which disrupt the traffic flow are defined as traffic incidents. Traffic Incident Management is the planned and coordinated utilization of all human and institutional resources in order to reduce the negative effects of these incidents and to ensure the safety of the drivers, pedestrians, all other victims and response teams. Incidents generally causes congestion and yields in increased travel time which imposes costs to road users, either economic loss or reduced quality of life and mobility. This thesis presents the recent literature review on the traffic incident management theory and practice along with the traffic incident simulation models. The thesis study is comprised of two parts; a data collection and analysis and a simulation experiment phase. Firstly, Traffic incident data from Istanbul Metropolitan Area is collected and analyzed. Secondly, a microscopic traffic simulation model was developed to simulate different types of incidents and traffic demand and also various geometric characteristics of highway. The analyses are performed taking total travel time, queue length and the speed as performance measures. Lastly, to evaluate and compare the performance of the cases, statistical tests are applied. The results show that there is a linear relationship between the incident duration and the average flow speed. The increase in incident duration causes the decrease in average speed up to 11.8% for overall traffic flow and up to 29.6% for the traffic flow of the post-incident process. The longest average queue length is observed in incidents in the middle lane. The shortest average queue length is observed in incidents in the right lane. In incidents in the middle lane, queue length increases up to 34.6% compared to the incidents in the right lane for overall traffic flow. In cases where the number of vehicles per lane is the same, the increase in the number of lanes causes a decrease in average speed up to 6.4% for the traffic flow of the post-incident process. According to the results of the applied statistical tests, when overall simulation periods are analyzed, statistically different results are seen only in incident duration, vehicle input, and lane width changes. When post-incident processes are analyzed, statistically different results are seen only in incident duration and lane width changes. The results of this thesis could be used by the traffic control authorities to reduce incident duration, congestion, secondary incidents, and the associated human and economic losses.
