With 30 million vehicles crossing over it every year, the Honoré Mercier bridge is one of Canada’s busiest. And with at least one person inside each vehicle, the total number of people who annually traverse the bridge is comparable to Canada’s entire population of 34 million and change.
Named after Quebec’s ninth premiere, the Honoré Mercier bridge spans the St. Lawrence River between LaSalle on Montreal Island and the Mohawk Territory of Kahnawake on the south shore. It consists of two structures: 1) upstream, which was built in the 1930’s and carries traffic westbound towards the south shore, 2) downstream, which was built in the 1960’s and carries traffic eastbound towards Montreal.
The original bridge celebrated its 75th anniversary in 2009; the same year it began the largest bridge rehabilitation project in Canada’s history. The purpose of the project is to replace the old bridge deck with new pre-fabricated concrete deck panels designed to last 75 years. This process is more efficient and prevents extended lane closures.
The panels are the same kind that were used to replace the bridge deck on Montreal’s Jacques-Cartier Bridge in 2001, as well as several other notable bridges throughout North America, including Lion’s Gate in Vancouver, Halifax Suspension Bridge in Halifax, Laviolette Bridge in Trois-Rivières, George Washington Bridge in New York and Golden Gate Bridge in San Francisco.
The Honoré Mercier bridge project marked a significant milestone in August following a seven-week “blitz” on the federal section of the bridge between piers 14 and 27. During the blitz construction crews of 80 to 100 worked 20 hours per day, closing two lanes out of four, and finished $10 million in repairs. Major works completed included 193 concrete slabs, 15 expansion joints, 666 bearing devices, more than 3,400 metres of post-tension slabs, 3,988 square metres of waterproofing membrane, 550 metres of paving and road markings, and 125 square metres of concrete surface for the new strip.
BUILDING BRIDGES
This project is the first of its kind, as it represents a three-way agreement between the governments of Canada and Quebec and the Mohawk Council of Kahnawake. The federal section of the bridge is located in the Mohawk territory of Kahnawake, and The Jacques Cartier and Champlain Bridges Inc. is overseeing that part of the project. Repairs to the provincial section of the bridge, from Maline Island across the St. Lawrence, are being done as a separate project by the Ministère des Transports du Québec.
Pascal Villeneuve, program director for The Jacques Cartier and Champlain Bridges Inc., says due to the joint-ownership of the bridge, the project involves collaborating with many different authorities—First Nations band council members, provincial and municipal police and politicians, and transportation bodies, to name a few. “We work very closely with all those members, and we work together, and it’s going very well,” he says.
Repairing the federal section is being done in two contracts: Contract A and B, which create approximately 1,000 direct and indirect jobs annually. “Due to the particularities that we are working over Mohawk land, we have to use local personnel and workers,” explains Villeneuve.
Contract A, which involved reinforcing the steel structure of the bridge and replacing the concrete decks on access ramps 2, 3 and 4, was completed in 2011. Contract B breaks down into three parts. The first part is the “island” section of the bridge (between piers 14 and 27). Deck replacements on this section began in 2013 on one side of the bridge structure and crews will complete the other side later this year.
Concrete slabs used for the island part of the project were 8.8 metres long and 3.7 metres wide (including a jersey barrier). They were made at a shop in Drummondville, Que. then transported to a spot underneath the bridge where crews used a 650-ton crane to replace the old deck with the new slabs.
THE HOMESTRETCH
So far, completing Contract A and the first part of Contract B has cost around $165 million. When all is said and done, the total cost of the overall project will likely come in around $200-million, says Villeneuve.
Replacing the bridge deck for part two (the “seaway” section from piers 27 to 28) and part three (the “mixed” section from piers 28 to 32) of Contract B is expected to be finished by 2017.
Repairs on the two remaining sections also involves replacing the bridge deck, and the bulk of the work will take place during the summer blitz periods when there is less traffic. In the fall and winter months, work will shifts to things like ditch digging, prep work and steel reinforcement, since the new pre-fabricated concrete slabs are heavier than the ones they are replacing.
When it comes to sizing the slabs, accuracy is of the utmost importance. Working on such a busy bridge, with such limited time, there is no room for error, says Villeneuve.
That’s why 3D imaging will be used to make sure the pre-fabricated slabs are the precise size. “Once we are in a blitz period, it is not time to make corrections on the slabs,” Villeneuve emphasizes.
The size of the slabs for the second and third part of Contract B will differ than those used on the island portion, he adds. “Once we are on the seaway they will be a little bit smaller because you don’t have enough space to go and work underneath the steel structure,” he says. “When we go to the mixed section, where there is a merge, the slabs will be heavier and bigger. Not flat, but angular to fit the merge. This will be another challenge.”
Nonetheless, Villeneuve says crews will continue to optimize their work periods in order to lessen traffic interruptions on the bridge. And he is hopeful that the project may even wrap up in 2016—one year earlier than expected. “We are trying to do as much work as we can in the shortest period we can,” he says. When asked for his thoughts on what it is like to work on such a significant project, which when complete will have spanned nearly a decade, Villeneuve, speaking on behalf of the entire team at The Jacques Cartier and Champlain Bridges Inc., says, “It has been a great experience for us.”
