RAILWAY TRACK AND BRIDGE INTERACTION UNDER SEISMIC EXCITATION

Abstract

With the growing population and economy, it is very important that our transportation system should be upgraded in terms of speed and serviceability criteria. Railways are one of the major transportation means that most of us choose for long journeys. For high speed trains, the general requirement is continuous welded rails and grade separated viaducts, for their smooth operation. These continuous welded rails restrain free movement of bridge/viaduct causing additional stresses in tracks and bridges which are non-negligible. This phenomenon is known as TBI (track-bridge interaction). This dissertation delves into the complexities of track-bridge interaction, aiming to enhance our understanding of the phenomena involved. The dynamic behavior of the bridge with track and without track is studied under free vibrations, and effect of the TBI on seismic response of a railway bridge is explored. The dissertation initiates with a comprehensive review of the existing literature concerning track-bridge interaction, with a focus on identifying pivotal factors that shape the behavior of both track and bridge components, as well as their mutual interaction. To fulfill this objective, a pre-designed bridge of 3 spans each of 90 m length simply supported over the piers, situated in Rishikesh is selected for the study due to the notable fluctuations in temperature experienced in this region. Employing theoretical analyses and numerical simulations, the dissertation delves into multiple facets of this interaction over the chosen bridge. It scrutinizes dynamic responses, exploring how varying conditions impact the behavior of the system. Additionally, it examines the influence of temperature fluctuations on rail stresses and pier moments, investigates the distribution of loads across the rails and its effect on stresses, and analyzes relative displacements induced by braking and seismic forces. Through these investigations, the dissertation aims to provide a complete understanding of the intricate dynamics inherent in track-bridge interaction, shedding light on key phenomena that underpin the performance and resilience of railway infrastructure. The conclusion of the study is that the continuous welded rail can not be used over the selected bridge span is large and the rail stresses exceeds the specified limits of the UIC (2001)