A four-kilometre stretch of the Queensway reopened about 12 hours behind schedule, as crews replacing bridges over encountered "unforseen challenges."

The Queensway was closed between Bronson and Carling Avenue starting at 8 p.m. Thursday to allow crews to replace the bridges over the O-Train tracks and the Canadian Pacific Railway.

The work was scheduled to be completed by 6 a.m. Monday, with the road open in time for the new work week.

However, the City of Ottawa announced Sunday evening the work might take longer than expected, and the Ministry of Transportation advised the highway would still be closed Monday morning.

Drivers were asked to continue to take detours.

The rapid bridge replacements swapped out five old spans with two new ones. The bridges are going overtop the O-Train track which is also being redesigned as part of the Trillium Line expansion project. The underpass will make way for more room and a second multi-use path along the west side of the tracks.

Rapid bridge replacements along the Queensway have been used before, however they have been wheeled into place with self-propelled transporters that pick up the bridge and drive it into place. These bridges are using what what Frank Vanderlaan, area manager of highway engineering for the MTO, says is a ‘jack and slide methodology’. A first for eastern Ontario.

“In this case because the bridges were over the tracks and the tracks were quite a bit lower we would have had to backfill for the self propelled modular transporters to drive on,” says Vanderllan. “It made more sense to basically build the bridges right next to the highway and then demolish the existing bridges and then slide them in.”

The delay in reopen was what Vanderlaan called a ripple effect. Adjustments during the slide process causes slow-downs, which in turn delayed the start of re-paving until the daytime, a process that was expected to happen at night.

“Of course right now it’s very hot,” he says. “And the effect is that the asphalt takes longer to cool off so you have to wait a little longer for the next lifts is put in place so unfortunately it all takes time.”

The highway reopened in all directions at around 6 p.m. Monday.

Cleared: #Closure #Ottawa #HWY417 Eastbound lanes are reopened.

— 511Ontario (@511Ontario) July 6, 2020

The closure caused some confusion, despite being widely announced. Ontario Provincial Police said three people attempted to drive past barriers Thursday night, when the closures started.

In a tweet Monday, OPP said eight drivers had been charged with allegedly driving past barricades since construction work began.

Section of #Hwy417 remains closed for construction. #OttawaOPP have charged 8 people who insisted on driving past the barricades and signs and into the area where workers are. All received a ticket. Follow detours and exercise patience. #otttraffic @OPP_COMM_ER
^bd pic.twitter.com/qnlbffoZUg

— OPP East Region (@OPP_ER) July 6, 2020