Concrete core samples extracted from the piers of the Commonwealth Avenue Bridge. Photo: NCA.
Work to strengthen the Commonwealth Avenue Bridge is expected to start this spring, now that engineers know exactly what they’re dealing with.
But expect your trips into Civic to get even slower, and trickier.
Over the past few months, the National Capital Authority (NCA) has sent divers down into Lake Burley Griffin to inspect the parts of the bridge under water, while survey teams mapped out the land above.
This included drilling a number of holes into the bridge piers to test the strength of the concrete.
“The cores are crushed in a laboratory and the results are used by structural engineers to confirm the bridge piers will be strong enough to support the load of the upgraded bridge,” the NCA said in a social media post.
So it might come as some relief to the thousands of Canberra motorists – not to mention runners, walkers and more laidback joggers – who use the bridge every day that construction is about to start.
The NCA hasn’t revealed what the engineers found in the concrete samples, but it’s enough for the green light.
The $137 million project is the first major upgrade to the bridge since it was built 60 years ago, and is needed to bring it up to modern standards.
“In this time we have seen the size and weight of everyday vehicles increase,” the NCA said in a statement.
“It is important to ensure the bridge is upgraded to accommodate these increasing vehicle sizes today and into the future.”
The National Capital Authority says the project is necessitated by the fact cars are getting heavier. Photo: NCA.
The bridge will score a higher load rating – enough to take vehicles up to 44 tonnes – while today’s narrow 2.4-metre paths on either side of the bridge will be doubled in width, “significantly improving safety for both pedestrians and cyclists”.
But for all this to happen, the bridge will need to literally be lifted off its existing piers.
“During these works, the bridge will be lifted off the existing piers and it is critical there is no additional load on the bridge during this time,” the NCA said.
“While these works are underway it is important to close the bridge to ensure the safety of both the workers and the public.”
And this comes with traffic headaches.
The project will be tackled in two stages – first the northbound span, then the southbound – with each stage expected to take about a year. One side of the bridge will remain open at all times, carrying traffic both ways, as well as pedestrians and cyclists.
Even so, the NCA is blunt: “There will be significant changes and traffic impacts”.
The project is scheduled to wrap up in 2027, and the NCA says it is working with the ACT Government to coordinate road closures around what’s already happening along Commonwealth Avenue with light-rail.
