Life Extension of Aging Railway Bridges: A Case Study of the Burnett River Bridge
- Publication no: ABC-AAI402-14
- Published: 22 October 2014
The North Coast Rail Line in Queensland between Bundaberg and Gladstone has three major crossings over the Burnett, Kolan and Boyne Rivers. The bridges were constructed in the 1890s using cast iron piers and through-girder spans. Queensland Rail Network Pty Ltd identified significant deterioration in the cast iron piers and placed speed restrictions on two of the bridges. In 2009 Jacobs SKM were engaged to undertake a detailed study to determine whether it was feasible to repair and maintain the bridges in service or whether they should be replaced.The paper describes the methods adopted to establish the current load rating of the bridges, i.e. the strength capacity to withstand the maximum load applied by the QR rating vehicle. In addition, the paper describes the measures that have been recommended to prevent further deterioration of the cast iron piers and to improve the capacity of the bridge piers to withstand train braking loads. A comprehensive program of materials testing, finite element analysis, and load testing of the Burnett River Bridge was carried out and is discussed in the paper. The study recommended the adoption of an innovative system of hydraulic lock-up devices to transfer train braking loads from the more heavily loaded piers to other piers, and the application of carbon fibre wrapping to regain the pier strength that has been reduced by corrosion. These modifications will enable the bridge to remain in service for a further 25 to 30 years.