The State Government has provided $26 million for the demolition and reconstruction of the bridges, which will be wider, longer and safer.
The Third Avenue Bridge, built in 1910, in Mt Lawley, will be torn down and reconstructed by the end of this year.
Construction of the Seventh Avenue Bridge, built in 1913, in Maylands, will start in 2014 and completed before 2015.
Main Roads project manager Anthony Morrow said concrete structures, replacing the timber bridges, would improve the safety and efficiency of the local road and rail network.
‘Up to 10,000 vehicles use Third Avenue Bridge each weekday,’ he said. ‘In the five years to December 2010, 56 crashes were reported.
‘The Seventh Avenue Bridge has also reached the end of its design life. It carries up to 3500 vehicles each weekday.’
Both bridges link Railway Parade and Whatley Crescent.
Yokine resident Valerie Butler was recently involved in an accident approaching Third Avenue Bridge when her car and a taxi collided.
Although the accident is still under investigation, she said it reinforced the need for an overhaul.
‘They are too narrow and the approaches to the Third Avenue Bridge, from both directions along Whatley Crescent, are visually obstructive due to the steep rise on the approach to the bridge coming from the city,’ Mrs Butler said.
The new bridges will be constructed on the footprints of the old bridges, but will be longer and wider to allow for expansion of the rail network, as well as increased lane widths, turning capabilities and traffic loads. The new bridge at Third Avenue will span 22m while the Seventh Avenue structure will span more than 80m.
Both will include footpaths.