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REM – Two launching gantries to build the elevated structure on the West Island

Updated July 3, 2019

Fairview Avenue:

From July 3 through 12, the road will be completely closed at night (7 p.m. – 6 a.m.); there will also be a partial closure with two-way traffic during the day in this same time period. Detours will use Saint-Jean and Saint-Charles Boulevards.


Douglas-Floreani Street:

From June 25 through July 5, Douglas B. Floreani Street will be completely closed at night. When the closures at night take place, flaggers will direct traffic flow beneath the beam.

From June 19 through July 5, there will be a partial closure with two-way traffic during the day.


Nature of the work:

The foundation work for the elevated structure, including caisson piles, columns and pierheads, was completed in certain sectors of the West Island, enabling construction of the elevated structure’s slab to begin between West Robert Bourassa Boulevard and Sainte-Anne-de-Bellevue, with the help of two launching gantries.

Both launching gantries, which total length is 105 metres, were assembled on site. This specific technology allows to raise and move extremely heavy loads, all while minimizing construction impacts. Each prefabricated segment used to form the elevated structure’s slab weighs approximately 50 tons; the launching gantries assemble them one after another to form the slab on which the REM cars will travel.

The launching gantries rests on two columns and a crane is used to move the prefabricated segments in order to assemble the span, i.e. the distance between the two columns. Once positioned, the prefabricated segments are connected using steel cables and epoxy joints. It only takes two days to assemble the span using this construction method; once a span is complete, the launching gantry is moved to the next two columns and the process is repeated.

Watch this video taken when the first prefabricated segments were raised during the week of June 3, 2019.

Traffic is allowed to flow beneath the equipment, since an engineer verifies that the prefabricated segments are properly anchored before they are raised. However, complete or partial closures must be scheduled at certain times when the segments are delivered, raised and assembled.


Anticipated impacts and mitigation measures:

Just as for any construction site, the work will generate noise, vibrations, dust, heavy truck traffic and traffic disruptions. Mitigation measures will be implemented to minimize the impacts. The REM project office and NouvLR consortium’s goal is to prevent or minimize impact on surrounding residents as much as possible and ensure safety by implementing all appropriate measures.

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1-833-rem-info (736-4636)