Design and implementation of stream bridge in kuzey Marmara highway: Alemdag stream bridge

As natural events are created in a balanced way, they do not require external factors caused by human. In other words, in a non-interfered environment, problems do not occur. However, area of natural event is limited because of increasing population and materiality of people. Occurrence of water disasters has become inevitable because of interference against even the minimal area of nature, unplanned urbanization, industrialization and careless construction as well as transportation network. As a caution for future water disasters, protection construction for water disasters should be defined with their capacities and build accordingly due to the arrangement of organization rules. This thesis includes hydrologic, hydraulic and sizing calculations of Umraniye Alemdag Stream Bridge of Northern Marmara Highway that leads to Yavuz Sultan Selim Bridge. Yavuz Sultan Selim Bridge has been formed by designing a different route that includes not only highway but also railway. Bridge that is located in North of Bosphorus connects Garipce neighborhood of Sariyer in Europe side and Poyrazkoy district of Beykoz on the Asia side. All connection highways are designed and constructed from the start, because of the chosen unique route of this bridge. In the first part, general information has been presented. Second part includes literature research about hydraulic calculations, trend analysis and curves of intensity-duration-frequency (IDF) with detailed references. In this project, hydraulic and highway engineers knowledge is required because of its concern about hydraulic and highway engineering. Third part includes detailed presentation of working area and application technics. Tthis part also includes mass flow rate design and application of hydraulic calculation techniques, IDF curves and involved trend analysis technics. Fourth part includes completion of application with the required technics and the fifth part presents conclusions. In this project, the data are provided from General Directorate of Meteorology. Measurements cover the period of 66 years between 1942 and 2007. They are obtained in Istanbul Goztepe rainfall station that has 33 meters altitude from the mean sea level. Thus, consequences are calculated by analyses, forecasts and calculation for 66 extreme precipitations. In the thesis, trend analysis has been done because one of the most current topics nowadays is climate change caused by global warming. Especially, increases have been observed on extreme values of disasters such as flood and drought. For instance, changes of IDF curves has an important role in definition of flood design mass flow rate. Thus, hydraulic engineers require enhancement of their plans and projects by considering climate change trend analysis. In the first part rainfall data trend analysis has been obtained. It is shown with Şen technic for rainfall data. It is possible to sort application steps of this simple technic. First of all, time series are separated into two equal length, previous and subsequent half temporally. Then each half of time series is sorted in descending or ascending order. Scatter diagram is obtained by putting previous half data on x-axis and subsequent half data on y-axis in Cartesian coordinate system. In the last step, it is decided that whether there is a trend in time series by observing the location of scattered data with respect to 1:1 straight line. Any trend that has possibility of occurring in time series is revealed clearly by looking at the scatter diagram as shown in the main text. According to analysis results, graphics are drawn and mathematical results are calculated by cumulative distribution functions and probability distribution functions in the second main step. These graphics are a stratum of random curves for predicted values with stable frequency. In the first step, for drawing curves, long term measurements have been obtained. Histograms have been obtained with measured data. Available probability distribution functions and cumulative probability distribution functions hav been set onto these histograms. Curves that has been obtained from probability distribution functions and cumulative probability distribution functions on the example histograms are shown in the thesis. Intensity values are obtained according to chosen frequency values. For example, intensity of rainfall values are obtained according to right tail of probability distribution function with using F=1/n formula (n is annual frequency). On the other hand, results of 1-1/n on cumulative probability distribution function and raindrop intensity are the same. There are many formulas for probability distribution function and cumulative probability distribution function. Gamma distribution function with two parameters has flexibility and skew. In this thesis, Gamma distribution has been used. In the third main step calculations are performed for design discharge. Discharge is determined according to rainfall frequencies in the basin.On the other hand, discharge capacity has been calculated by designing stream bridge that has highway on top of it. Snyder methodology of design is sufficient for computations in this thesis with the peak flow through the synthetic unit hydrograph approach. It has been deemed appropriate to use here the flow coefficient presented in the rational method for the precipitation calculation. There are few formulas and coefficient that manages Synder method. However, if rainfall-flow data for a basin are calculated then hydrograph can be drawn with some calibration. In the basin that is considered in this project physical attributes are used because there is no data of this kind. When a basins ground slope is known then there are two coefficients for Snyder peak discharge calculations. The dimensionless coefficient Cp is used to determine the peak discharge. The other coefficient, Ct, indicates how long the peak will appear after the rainfall start. In order to sum up, after the Ct and Cp have been defined, calculation of two main formulas leads to time of peak and peak discharge. It is possible to draw hydrograph if these two values are specified. Hydrograph is very important for water resources management, dam design, flood forecasting and flood risk mapping. In this thesis, however, only the peak discharge is taken into account for the determination of the flow carrying capacity of the relevant channel. The calculation step of the flow rate capacity of the duct is obtained with the classic Manning equation. On the other hand, near-realistic hydrographs can be obtained via dimensionless unit hydrograph (DUH), and DUH has been used to constitute an example in this study.