Inspection of Rail Bridge Trestle Elements
Introduction
Sinclair Knight Metz (SKM) engaged Vertigo Specialist High Access Services on behalf of Pilbara Iron Pty Ltd (Rail Division) to undertake inspections of the trestle elements of Bridges nos. 10 and 11 on the Pannawonica to Point Lambert Railway in Western Australia.
The line forms part of the largest private rail network in the world and transports more than 55 million tonnes of iron ore annually from the inland mines.
Bridge # 10 consists of discontinuous steel girders, supported on concrete abutments & two steel trestles on concrete piers. Bridge #11 is of a similar design but features three supporting trestles & piers.
The site inspection work was conducted using Industrial Rope Access methods in November 2006.
Scope of Work
All metal trestle & concrete pier elements on the two bridges were subjected to detailed visual inspection. Corrosion, weld defects & fixing anomalies were recorded and photographs taken. The findings from the inspections were compiled into a brief report documenting the condition of the elements.
Outcome
In spite of the constraints imposed by the requirement to obtain possession of the section of rail track during inspections, the remote and isolated nature of the work site & ambient temperatures over 45°C, Vertigo successfully completed the inspections on schedule. A report was issued reviewing in detail the condition of the support elements of each bridge. This information was used by the client to determine the structural adequacy of the bridges.
This project draws on Vertigo’s experience in bridge inspection work & highlights the advantages of the rope access method, where the lightweight nature of the equipment allows for rapid deployment & derigging of the access system as well as minimising transport logistics to remote & isolated work sites.