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Öğe Modelling Weekend Traffic With Weather Conditions Using Various Equation Type And Differential Evolution Algorithm(Scientific Research Center Ltd Belgrade, 2016) Dogan, Erdem; Akgungor, Ali Payidar; Korkmaz, ErsinIn weekends, amount of passenger car traffic is usually higher than weekday because of the activity-based traveling on some highways. Forecasting of this traffic, might help to local authorities to take safety precautions decisions on a road segments. This study aims to compose models to forecast weekend traffics using weather conditions and average weekday traffic variables. For this aim, two main models were composed: The Saturday traffic model and the Sunday traffic model. The Saturday traffic model variables are mean weekday daily traffic, maximum temperatures of Saturday and precipitations. The Sunday model is a linear model with only one variable: the predicted traffic values from the Saturday traffic model. In the modeling Saturday traffics, six-month (from January to June) data, which belongs to year 2015 and Ankara Kinkkale highway in Turkey, were used and 2014-March data were used for testing the models. The used temperatures were normalized and the precipitations data were involved as logical (0 or 1) inputs in models. To find best equation type for Saturday traffic model, four various equation forms were selected: (1) Linear, (2) polynomial-1, (3) polynomial-2, (4) multiplicative equation from. The linear and polynomial-1 have three, multiplicative has four, and polynomial -2 equation has five coefficients need to be determinate. Differential evolution algorithm was utilized to determinate best fitted values for these coefficients. Performance of the models were calculated using mean square error and coefficient of determination. The model with the polynomial-2 equation has minimum errors for the modelling stage and R-2 value is around 0.80. The model with the polynomial-2 showed the best performance on testing stage (R-2=0.96). These results show that the weekend traffic is related to weather conditions and it can be modeled convenient equation form and differential evolution algorithm.Öğe Estimation Of Car Ownership In Turkey Using Artificial Bee Colony Algorithm(Scientific Research Center Ltd Belgrade, 2016) Korkmaz, Ersin; Dogan, Erdem; Akgungor, Ali PayidarThis study proposes Artificial Bee Colony (ABC) models to estimate the number of cars in Turkey. In other words, car ownership is defined the number of cars per 1000 people. In the models development, population (P), per capita Gross Domestic Product (GDP) as dollars and fuel prices as Petrol, Diesel and Lpg were selected as model parameters. Two different ABC models were developed using the data covering from 2004 to 2015. According to fuel type, the coefficients of models were determined for each fuel type. Therefore, the sum of number of cars for each fuel type presented car ownership in Turkey. Developed models' results were statistically compared to observed values in terms of root mean square errors (RMSE), mean absolute percentage errors (MAPE) and coefficient of determination (R-2). The results of the ABC models showed that they were suitable to estimate the number of cars. To investigate the performance of ABC models for future estimations, a ten-year period from 2016 to 2025 was considered. Thus, future values of population were obtained from the projection of Turkish Statistical Institute (TSI) and the projections of other parameters, per capita GDP and fuel price, were executed according to current growth curve. The results obtained from future estimations reveal the suitability of ABC approach for determination of car ownership.Öğe Estimating The Number Of Traffic Accidents, Injuries And Fatalities In Turkey Using Adaptive Neuro-Fuzzy Inference System(Scientific Research Center Ltd Belgrade, 2016) Akgungor, Ali Payidar; Korkmaz, Ersin; Dogan, ErdemThis study proposes Adaptive Neuro-Fuzzy Inference System (ANFIS) models to estimate the number of accidents, injuries and fatalities in Turkey. In the model development, population (P) and the number of vehicles (N) are selected as model parameters. Three different ANFIS structure models are developed using the data covering from 2000 to 2014. Developed models' results are statistically compared to observed values for training and test data in terms of root mean square errors (RMSE), mean absolute percentage errors (MAPE) and coefficient of determination (R-2). The results of the ANFIS models showed that they was suitable to estimate the number of accidents, injuries and fatalities. To investigate the performance of ANFIS models for future estimations, a ten-year period from 2015 to 2024 is considered. Thus, future values of population was obtained from the projection of Turkish Statistical Institute (TSI) and the vehicle ownership rate is expected to reach 0.4 by 2024. Therefore, population and the number of vehicles are considered to reach approximately 85 and 34 million, respectively. The results obtained from future estimations reveal the suitability of ANFIS approach for road safety applications.Öğe Experimental and Analytical Investigation of Lateral-Torsional Buckling of RC Beams with Geometric Imperfections(Trans Tech Publications Ltd, 2014) Lee, Jong-Han; Kalkan, IlkerThe design of reinforced concrete beams has usually focused on the ultimate flexural capacity and disregarded the lateral stability of the beams. However, the development of high-strength concrete and the implementation of new construction techniques increase the use of longer and deeper concrete beams, which makes the lateral instability a primary concern of failure in concrete bridges. In particular, the lateral stability should be more taken into consideration in the construction and erection phases due to inadequate lateral supports. Thus, an experimental study was carried out to evaluate the lateral torsional buckling of reinforced concrete beams with initial geometric imperfections. The lateral flexural and torsional rigidity expressions, which could account for the flexural, torsional, and shrinkage cracking of concrete, the contribution of longitudinal and shear reinforcement, and the nonlinearity of materials, were proposed for rectangular reinforced concrete beams. Finally, this study proposed an analytical formula to estimate the buckling loads of initially imperfect reinforced concrete beams. The estimates of the study showed close agreement with the experimental values.Öğe Stabilization of clays using liquid enzymes(Crc Press-Taylor & Francis Group, 2009) Yılmaz, Yüksel; Güngör, Ahmet Gürkan; Avşar, CahitThe potential of three different liquid enzymes to stabilize CL and CH type of soils is evaluated. The evaluation involved the determination of the geotechnical properties of clay soils in their natural state as well as when mixed with three different liquid enzymes, separately. The parameters tested included the particle size distribution, Atterberg limits, compaction characteristics (optimum moisture content and maximum dry unit weight) under standard Proctor compaction energy effort, swell percentage and California bearing ratio (CBR). All tests of the treated samples were repeated after 1-day, 7-day and 28-day curing periods. Results showed that the geotechnical parameters of clay soils are improved very little by the addition of liquid enzymes; plasticity and optimum moisture content were reduced around 5% to 10%, maximum dry unit weight is reduced as negligible as 1%. But, swell percentages and CBR values are increased by 5% to 350% and 5% to 70% depending on the curing period and type of soil treated, respectively. These results imply that although liquid enzymes provide some beneficial effects in CBR values, it is unlikely to be a substitute for CH type of soil as swell percentage increased dramatically.Öğe Investigation of the effect of a polypropylene fiber material on the shear strength and CBR characteristics of high plasticity Ankara clay(Crc Press-Taylor & Francis Group, 2009) Mollamahmutoğlu, Murat; Yılmaz, YükselNowadays, many soil improvement methods have evolved with different materials used. In this study, a series of laboratory tests are carried out to investigate the effect of a polypropylene fiber material on the shear strength and California Bearing Capacity (CBR) characteristics of high plasticity Ankara clay. First, geotechnical properties of Ankara clay are presented. Then, results of unconfined compressive strength, triaxial strength (CU type) and CBR tests conducted on the various polypropylene fiber/clay mixtures (0.1%, 0.2%, 0.3% and 0.4% by dry weight) are given. Samples were compacted at optimum moisture contents and maximum dry unit weights obtained from the standard Proctor compaction effort. Standard Proctor compaction tests and CBR tests revealed that percentage of 19 mm length F type polypropylene fiber did not influence much the optimum moisture content, maximum dry unit weight and CBR values. Unconfined compression tests showed that inclusion of fiber content increased the axial strain at failure. Moreover, consolidated-undrained (CU) triaxial test results exhibited that due to inclusion of 19 mm length F type polypropylene fiber, the cohesion intercept decreased slightly but the internal angle of friction increased considerably.
