EVALUATION OF EXISTING RAILWAY BRIDGES FOR INCREASING SPEED OF TRAINS

Abstract

The rapid growth of semi-high-speed and high-speed (HS) railway networks in the late twentieth and early twenty-first centuries necessitated the up-gradation of existing lines and the building of new lines with higher speed to shorten the travel time. This dissertation aims to study the impact of train speed on dynamic amplification factor, vertical acceleration, and deformations of bridges under moving trains. The dissertation starts with a summarization of the existing normative standards in different regions of the world, further, it provide details of the models and various input parameters used in the study. The bridges have been considered from the Indian Railway broad gauge lines provided by Research Design and Standards Organisation (RDSO). Open web, box girder, steel composite and prestressed I-girder bridges have been used to study the effect of train speed. The Moving Load of trains is applied on models for analysis. To obtain the analytical solutions, the program has been coded in Octave to verify the numerical results extracted from the Midas Civil. Open web (truss) bridge is modelled using frame element with end releases and box girder, steel composite and prestressed I girder have been designed by beam elements. Lastly, the dissertation presents results obtained from time history analyses for different speeds and the impact of speed on various parameters crucial for the stability of the bridges and the safety and comfort of passengers.