Design and monitoring of well-performing bridge transitions

This paper presents a review of railroad track transition designs that have performed well, e.g., ballasted bridge decks, hot-mixed asphalt (HMA) sublayer, and concrete wing walls parallel to the track, to guide future design and maintenance of bridge transitions instead of installing a concept and monitoring its performance. Using noninvasive monitoring techniques, e.g., miniature accelerometers, the performance of the two railroad track transitions has been measured and evaluated. The results show well-performing track exhibits tie accelerations of 5g or less with little difference between: (1) the bridge deck, approach embankment, and open track, (2) concrete and wood ties, and (3) clayey or silty subgrades. The measured transient vertical tie displacements are negligible, which verifies the observed good track support. The results from these two sites are being used as a control for comparison with poorly-performing bridge transitions, track defects, e.g. broken ties, rail-fastener gaps, fouled ballast, broken rail, and to verify the success of remedial measures.