The winner of an engineering excellence award and a daily time-saver for 70,000 Canberra traffic commuters, the new $30 million Kings Avenue overpass nevertheless was not completed without hair-raising setbacks.
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Woden Contractors project manager Glen Crawley has revealed that early in the project, workmen took so much care not to break crucial optic fibre cables running through the middle of the notorious Russell roundabout, which the overpass has replaced, they brought traffic to a sudden standstill when a temporary road collapsed because of rain.
Cars banked up back to Civic while Mr Crawley rang radio stations to urge people not to use Parkes Way, the main link to the city and Canberra Airport, Parliament House and Russell Defence precinct.
''We had every service provider known; Optus, Telstra, Defence, Attorney-General's, all with optic fibre networks running through the roundabout. For the first couple of months the first thing was to re-route these around the outside of the roundabout so the bridge could be built.
''Dealing with optic fibres is a big deal. You can't just cut and paste them like a copper one and you have to be very careful because if you break them, you are talking serious amounts of money. It's been known to cost $200,000 to $300,000 to fix it. All the bells go off and everyone descends on you.''
Working with limited space, contractors set them down in special corridors and a temporary road was built over the edge of the optic fibres.
''And the difficulty with those is that you can't compact the trenches like you would under a road normally because you can squash conduits and damage them,'' Mr Crawley said.
A couple of months into the project, in the middle of prolonged rain, his foreman phoned him to say the temporary road had fallen apart. Traffic was banked up back to Civic.
''And you know, it was just a disaster,'' Mr Crawley said.
''We are not talking about a piece of road, we're talking about a whole section of it and it had failed over this trench.
''Things were pretty grim.''
The National Capital Authority received the Engineers Australia (ACT division) excellence award.
The project, which untangled one of Canberra's worst traffic snarls, was also commended for its precision and quality in construction and exceptional stakeholder engagement throughout the design and delivery.
Almost completed, the overpass is still being hampered by rain.
Asphalt works will now be laid on Parkes Way and Morshead Drive from this Wednesday to Saturday.
Delays are expected at the Kings Avenue overpass during morning peak periods while the work is carried out.
