Montreal’s Bonaventure Expressway coming down

The long awaited start of demolition of downtown Montreal’s largest freeway access — the Bonaventure Expressway — has finally begun, with the first phase scheduled for completion before the end of August.

The Bonaventure, constructed in 1966 during a mammoth spate of Greater Montreal highway construction to ready the city for Expo 67, was a structure of its time — an elevated six lane freeway and terminus of Autoroute 10, linking the Champlain Bridge to the central business district.

But as part of a project to celebrate the city’s 375th anniversary in 2017, Montreal has embarked on a $141.6 million project that will see the elevated expressway end sooner and morph into a nine lane, park-lined, urban boulevard which has been dubbed Montreal’s Champs Elysees.

Utility work for the project, eventually stretching north from the Lachine Canal to Notre Dame Street and renamed Robert-Bourassa Boulevard, began in 2011 and wrapped up last year.

Demolition of phase one, from the Lachine Canal to Wellington Street, started July 20. Montreal’s Groupe Bauval is the principal contractor.

The north side ramp into downtown is being demolished first with traffic rerouted on to the south side.

This summer’s work consists of taking down nine connecting sections, "from pile (pier) 22 to pile 13," said project manager Pierre Sainte-Marie of the City of Montreal, which owns that part of the freeway. The federal government owns the remaining several kilometre link to the Champlain Bridge which is also under reconstruction in preparation for an announced replacement of the Champlain Bridge.

Each section is 20 metres in length for almost 200 metres total deconstruction. Next year the remaining northbound side, along with the southbound ramp out of downtown, will come under demolition.

The freeway will be replaced by a new nine lane boulevard consisting of four northbound and five southbound lanes, set to be finished in 2017.

"We have a very strong commitment by our mayor (Denis Coderre) for the project to be completed (by that time)," Sainte-Marie said.

The crews are using two methods to take down the slabs, the bottom of which have ground clearance of five metres.

Over streets which could be damaged by falling debris they’re using hydraulic lifts, supporting two cross beams to lower the slab to the ground, where it’s then broken up and the debris trucked away. There are two lifts per beam.

"It comes down as a big platform," Sainte-Marie said.

In other areas, excavator claws are simply tearing up the roadway in place, with the debris falling to the ground and then removed.

Along with the demolition is the construction of a new northbound ramp that will provide future access to a widened urban boulevard.

Will the new boulevard handle all the expressway traffic?

"We did all sorts of mathematical modelling to make sure that this could accommodate current traffic," said Sainte-Marie.

"And we’re satisfied that it will."

This includes dedicated bus lanes to support 1,000 buses each way linking downtown with the city’s southshore suburbs.

"There’s a lot of transit use," he said.

"There are more people in the buses than in the cars in that corridor."

Were there challenges?

"There were lots of challenges," Sainte-Marie said. He noted the close proximity to the main Canadian National Railway viaduct and the handling of the train tracks running parallel into nearby Central Station.

On the east side there are office buildings and one residential complex.

"And of course we met with everyone and we took into consideration their needs and so on and for now things are going well," the official said.