A $52 million rehabilitation of the St. Vital Bridge in Winnipeg demonstrates how a comprehensive approach to construction can kill two birds with one stone.
St. Vital bridge is actually two adjacent bridges side by side over the Red River. The project has grown beyond its original scope to include rehabilitation of roads adjacent to the bridge and pedestrian infrastructure work as well.
The project will see the rehabilitation of the two bridges including bridge deck replacements and superstructure work, rehabilitation of the north and south roads connected to the bridge, increased pedestrian infrastructure on the bridges, reconstruction of pedestrian tunnels and the creation of 1.4 kilometres of new pedestrian trails.
“We incorporated or tried to incorporate all that into the scope of work simultaneously,” said bridge project engineer and project manager Damir Muhurdarevic.
But it all starts with the bridge decks.
“The bridge was built in the 1960s and its last rehabilitation was in 1988,” Muhurdarevic said.
“The rehab in 1988 was led by the the project manager for the city that is now the project manager for our consulting firm on the project.”
He said the deck replacement is coming at the right time and that the old decks are in “terrible condition.”
The main infrastructure work revolves around demolishing the decks on both bridges and replacing them with wider decks to accommodate more active transportation lanes. The bridges will be widened by one metre.
The new bridge will have two lanes for traffic going each way and a three metre multi-use path and barriers separating pedestrians from traffic.
Crews are already on the ground dismantling the west bridge deck.
“Demolition stage should be complete over this month, hopefully only for a couple of weeks. It’ll be followed by building and construction of the new deck starting in the spring once the weather warms up,” he said.
The speed limit on the bridge has been reduced as a part of the project.
Originally, the project team considered making the bridge even wider to accommodate traffic standards for the posted 70 km/h speed limit but a simpler solution was found: lower the speed limit.
The south side of the bridge has a 60 km/h posted limit, the bridge is 70 km/h and the north side is 50 km/h, meaning drivers have to change their speed three times which has resulted in some frustration.
The speed reduction has already been approved by city council meaning the width of the new deck will be appropriate for a 60 km/h zone with no further widening required.
Demolition of the west deck is expected to be finished early spring with the new deck installed over the summer and into the fall. After that, the east bridge will be closed and the same process will begin.
The summer will see work done on the superstructures.
“We are replacing all the bearings except for pier five bearings, which are the fixed bearings, that are going to be cleaned up and adjusted to accommodate the new bearings and all the other piers and abutments,” Muhurdarevic said.
He said minor work will also be done on the substructures which are in “really good condition.”
All the while work will be happening to rehabilitate the north and south roads leading up to the bridge, construct new access routes as well as the construction and rehabilitation of pedestrian paths.
As part of the project, the city will be building 1.4 kilometres of new walking paths on the north and south sides of the bridge.
One of the biggest challenges is ensuring work gets done during the paving season, which lasts roughly from April until snow starts building up in November or October.
But Muhurdarevic has seen the paving season start as late as the end of May some years.
He said some other challenges with the project will be working over the Red River and ensuring all debris is appropriately contained as well as working around the strict schedule which doesn’t allow river work before June 1.
On top of the pedestrian paths, two pedestrian tunnels that cross perpendicular under the bridge will receive upgrades. One cool feature is the addition of heat tracing to keep the tunnels warm during the winter months.
“They are demolishing the tunnel floor slab down to the top layer of the rebar and then putting the heat tracing.”
He said this should help manage excessive ice build up.
“Last year, it looked like a frozen Niagara Falls because you get runoff when it warms up, especially through those inadequately sloped approaches that were very steep. Everything runs into the funnel on both sides and then of course it freezes over.”
The heat tracing will cost roughly $200,000 combined for both tunnels, he said.
All in, the project is estimated for completion in 2024.
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