Center for Railway Engineering

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Browsing Center for Railway Engineering by Subject "Abaqus2Matlab"

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    Developing New Expression for Dynamic Impact Factor of Railway Bridges
    (Addis Ababa University, 2019-07) Milki, Feyissa; Abrham, Gebre (PhD)
    There is a significant demand worldwide, that is ever-increasing on understanding the dynamic performance of railway bridges. One of these demands is directed towards finding a comprehensive expression for determining the Dynamic Amplification Factor (DAF), or simply called impact factor. A bridge’s dynamic response is affected by many bridge, track and train characteristics. However, the Dynamic Amplification Factor as given by different codes is generally a function of bridge span only. In addition, there is a significant variation in the codes and no provision exists that considers other influencing parameters in combination with the bridge’s span. Therefore, the dynamic amplification factor, given it being an important parameter in the design of bridges, to this day has not found a general expression that represents its true value. Some disagreement exists among various bridge codes as well. In this research, a new Dynamic Amplification Factor expression for railway bridges is developed by performing a parametric study considering track stiffness, bridge span length, concrete compressive strength, train speed and length of transition zone. After 32 combinations of these parameters were generated using the Latin Hypercube Sampling technique, 32 bridges were modelled in ABAQUS using MATLAB. Static and Dynamic analysis were performed for these bridges, and the dynamic amplification values were determined from the displacement results of the two analysis. Finally, multivariate regression was performed to develop the best fitting Dynamic Amplification Factor expression. The developed expression is also compared with the Dynamic Amplification Factor values from codes.