On the use of under sleeper pads in transition zones at railway underpasses: experimental field testing

Abstract

The railway track at transition zones to bridges or to other structures usually requires considerably more interventions to maintain the same open track service quality and safety levels. Under sleeper pads (USP) have been reported to contribute to reduce degradation and frequency of maintenance operations in open ballasted tracks, and recent numerical studies have suggested its use in transition zones. In this study, the influence of using USP at transition zones to underpasses was investigated. The structural behaviour of two transitions to similar box culverts was compared. USP were added to the sleepers in one of the transitions. Track characterisation using non-destructive tests is presented and analysed. Measurements of track response from passing trains are also presented and discussed. Results indicate that USP influence the dynamic behaviour of the track, increasing its vertical flexibility and amplifying both rail displacements and sleeper accelerations.

Keywords::

• railway underpasses
• transition zones
• under sleeper pads
• field measurements
• track monitoring

Notes

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^4. Email: [email protected]

Additional information

Funding

The research presented in this article was carried out under a joint research project by LNEC and FEUP, supported by Rede Ferroviária Nacional – REFER, EPE. The financial support of Fundação para a Ciência e a Tecnologia, through the first author's Ph.D. [grant number SFRH/BD/75821/2011] is also acknowledged. Part of the work was conducted in the framework of the TC202 national committee of the Portuguese Geotechnical Society (SPG) “Transportation Geotechnics”, in association with the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE-TC202).