A portion of the Queensway in Ottawa's west end will be closed overnight Saturday to allow for the replacement of the Carling Avenue eastbound bridge, in a switch so quick that officials have set up bleachers so engineering fans can watch the action.

The $11.5-million bridge replacement will take less than 24 hours, but Ottawa's main highway will be shut down starting at 6 p.m. on Saturday in the area around the Carling overpass.

It's scheduled to re-open at 11 a.m. Sunday with one lane in each direction before re-opening fully in time for Monday's commute.

Brandy Duhaime, with the Ontario Ministry of Transportation, said drivers should take their time this weekend and take alternative routes. Travellers are being encouraged to use Fallowfield Road, Richmond Road, Baseline Road or Hunt Club Road to move across the city during the closure.

Ministry of Transportation crews say they will use "rapid replacement technology" to bring the deck of the new bridge into place.

Island Park and Clyde Avenue bridges have been replaced with the same method in the past three years.

Engineer Ken Polson said the relatively new technology will allow work crews to have a smaller impact on the Queensway than would have been required in the past.

"Ten years ago it would have taken two years," he said.

The old bridge will be sliced away and carted off on a hydraulic machine. The new bridge, which was built on a staging area next to the highway, will then be rolled into place.

"There's a fabulous team behind this and many folks are calling this sexy engineering," said engineering manager Peter Makula.

The technology is attracting engineering students who are travelling to the site with their professors and the city has set up bleachers to house the crowds that have turned out during past rapid bridge replacements.

The replacement can also be viewed on a live web cam overlooking the highway at mtocarlingbridge.com