The federal government will spend $137 million to upgrade the Commonwealth Avenue bridge, in a project that will extend the life of the bridge by at least 50 years.
Infrastructure Australia added the bridge to its list of priority projects for Australia late last year, saying the project had a "strong strategic and economic case" and would deliver a "net benefit to the economy".
The work to be completed will increase the load-bearing capacity of the bridge so it can handle current traffic and future expected volumes. Infrastructure Australia's evaluation report of the bridge found it had reached its traffic-carrying capacity more than three years ago, and problems would worsen under the weight of Canberra's growing population.
Pedestrian pathways will be widened and vehicle safety barriers will be replaced to meet current safety standards, and the bridge's superstructure will be strengthened to prevent structural damage.
The upgrade has been foreshadowed by the federal government since the 2019 budget, when research into the business case for the upgrades was funded. The push to upgrade the bridge was given an extra boost last year when it was added to Infrastructure Australia's list of nationally significant projects.
The National Capital Authority will be responsible for delivering the project.
But the funding is not part of the ACT government's second stage of light rail, which is set to cross the bridge as it runs between Civic and Woden. The decision on whether to approve stage 2A of light rail, from Civic to the start of Commonwealth Bridge, currently sits with Environment Minister Sussan Ley.
It means further work could be needed when it is time to build a light rail connection from north to south Canberra, but with the complex approvals required for the route through the Parliamentary Triangle, work on stage 2B of the project is a long way off.
ACT Liberal Senator Zed Seselja said the funding was part of an "investment bonanza" for Canberra.
"This includes $500 million for the Australian War Memorial, $115 million for the Monaro Highway, $88 million for Molonglo Bridge, $20 million for William Slim Drive and $150 million for upgrades to the Barton Highway," he said.
"This is what the Australian government's $110 billion nationwide infrastructure investment program is all about: getting Australians home sooner and safer while creating jobs and economic stimulus to lay the economic foundations for recovery following the COVID-19 pandemic."
Deputy Prime Minister Michael McCormack, who is responsible for infrastructure and transport, said the funding was a win for the capital.
"This investment ensures this important piece of infrastructure can continue to function safely for the next 50 years and beyond," Mr McCormack said.
"This investment will also back Canberra's construction workforce and economy at a critical time, with the bridge upgrade expected to create more than 700 jobs.
"We are particularly pleased the majority of construction materials to be used for the project, such as the steel and concrete, are manufactured in Australia."