Monday, May 16, 2011

Australia's Bridges: Merivale Railway Bridge across the Brisbane River in Queensland (1)

March 2011 (-27.469 deg., 153.013 deg.) Merivale Railway Bridge

Continuing upstream past the William Jolly Roadway Bridge is the Merivale Railway Bridge. It is a 2460 ft long viaduct that includes a 440 ft long steel arch over the Brisbane River. The floor beams are supported by thirty-two 94.5 mm diameter cables inclined at angles from the arch ribs. The ribs are also inclined towards each other to form a basket handle arch. The bridge was designed by Cameron McNamara Proprietary Limited and constructed by Transfield Proprietary Limited in 1979.

Railroad companies had long been trying to connect northern and southern Australia with a bridge over the Brisbane River. However, the elevation was so low at the South Brisbane Railway Station that even at maximum grade very little vertical clearance could be provided over the Brisbane River. Moreover, the many barges (at that time) on the river required a wide shipping channel. The designer chose a tied arch bridge to minimize the depth of the bottom chord while still providing a very long span. Welded steel box segments for the arch and ties were brought to the site and assembled with high strength bolts.

We'll take another look at this bridge tomorrow.
Creative Commons License
Australia's Bridges: Merivale Railway Bridge across the Brisbane River in Queensland (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

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