The effect of resurfacing on the lateral resistance of narrow gauge low profile concrete sleepers

Poulton, Ashley (2016) The effect of resurfacing on the lateral resistance of narrow gauge low profile concrete sleepers. [USQ Project]

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Abstract

Modern railway track construction employs the process of continuously welded rail (CWR), which increases the ride quality and operational speed of the track, while reducing maintenance requirements compared to traditional jointed track. However, CWR prevents the rails from freely elongating under elevated temperatures, which consequentially 'locks' thermal stresses within the rails. This results in CWR track being susceptible to buckling when a combination of elevated rail temperatures, track misalignments, and weakened lateral sleeper resistance occurs.

Queensland Rail (QR) is currently installing low profile concrete sleepers on their narrow gauge CWR network, to replace aging timber sleepers in the Brisbane Suburban Area. A knowledge gap exists regarding the effect of track resurfacing on the lateral resistance of low profile concrete sleepers, and the consequent effect on the track’s resistance to buckling. While many investigations of this topic have been completed on foreign rail networks; the results are usually network specific due to the local sleeper geometry and ballast conditions. Additionally, the majority of these investigations were conducted on networks with track gauges wider than 1067mm, and thus their results are not directly relevant to QR. Hence due to the negative implications of track buckling, it was pertinent an investigation relevant to QR’s local track conditions was completed.

This investigation used mathematical and field testing methods to determine the lateral resistance of narrow gauge low profile concrete sleepers, before and after resurfacing. For the field testing component, a Single Sleeper Push Test (SSPT) device was developed to suit QR’s narrow gauge low profile concrete sleeper.

The lateral sleeper resistance results were applied to a classical equation to model the track’s critical buckling load, before and after resurfacing. The length and amplitude of the initial misalignment were modelled as variables to assess their sensitivity on the track’s critical buckling load. The track’s factor of safety against buckling after resurfacing was also determined.

The investigation concluded that resurfacing reduced the lateral resistance of narrow gauge low profile concrete sleepers by 24% and 14%, based on peak and limiting resistance respectively. Resurfacing was found to reduce the critical buckling load of track, constructed using 50kg/m rail, by 7.5% to 23%, and provide a factor of safety against buckling ranging from 0.9 to 14.6, depending on the span and amplitude of the initial misalignment encountered.


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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering (Honours) Major Civil Engineering project
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying
Supervisors: Alehossein, Habib
Date Deposited: 21 Jul 2017 04:12
Last Modified: 21 Jul 2017 04:12
Uncontrolled Keywords: resurfacing; lateral resistance; narrow gauge; concrete sleepers; railway track construction
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090502 Construction Engineering
URI: http://eprints.usq.edu.au/id/eprint/31460

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