Browsing by Author "Gezahegne, Samuel"

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    Approximate and Grillage Analogy Methods of Analysis of Rc T- And Box Girder Bridges - Comparative Study
    (Addis Ababa University, 2016-04) Gezahegne, Samuel; Adamu, Asnake (PhD)
    Bridges are one part of the Road Infrastructures which needs care during design stages, among which include analysis. The most common Bridge superstructures forms widely used are RC T- and Box Girder types. To analyze such forms the most widely used method of analysis is Approximate Method based on Distribution Factor concept. This method is preferred due to its simplicity for use. This method has limitation for not considering stiffness of components sufficiently and effect of provision of diaphragm on load distribution; these parameters have great impact on load distribution between Girders. The result of this method is also considered conservative as compared to more refined method of analysis. In this study, the result obtained by this method and refined method of analysis (Grillage Analogy Method) are investigated. Using these methods, RC T- and Box Girder superstructures are analyzed, considering different Traffic lanes and span length. This task involves examining the maximum Bending Moment and Shear Force using the two numerical models. Furthermore, the effect of Diaphragm on load distribution is also investigated. This study provided useful information about the variation of Bending Moment, Shear Force with respect to change in Traffic Lanes, Span Length and arrangement of Diaphragm. It is concluded that the results obtained from Grillage analogy method are smaller than approximate method, except for shear force of Interior Girder of T-Girder Bridge, which gives slightly higher result where, the percentage differences varies from case to case. For all other cases considered, approximate method gives conservative values. In addition, since approximate method does not consider effect of diaphragm, provision of more number of diaphragms has effect on load distribution is observed for T-Girder than Box Girder in Grillage Analogy method. Key words: T-Girder; Box Girder; Approximate Method (Distribution Factor Method); Grillage Analogy Method; Flexural Moment of Inertia; Torsional Moment of Inertia; Bending Moment; Shear Force; Vehicular Live Load; Traffic Lanes; Span Length