Beauharnois Toll bridge opens across St. Lawrence

The Beauharnois Bridge, part of the last leg of Autoroute 30, opened on December 15, completing a massive highway project that started construction in 2009 but has its genesis in the 1960s. Autoroute 30 runs from Vaudreuil-Dorion to Chateauguay, bypassing Montreal via the south and providing a corridor to the Montérégie region. It is a four-lane highway that has cost a total of $1.5 billion.

Lead engineering designer for bridge and the entire 41-kilometre highway is Arup.

The $750-million Beauharnais Canal Bridge is a tolled bridge that is one of two major crossings along the route. It is a 2.5 kilometres long structure with a gradient of 3.5% that provides the necessary 38.5 metres of clearance above the shipping canal in the Seaway.

The bridge’s eastern approach and navigation bridge is a continuous steel-concrete composite box girder superstructure stretching 1,457 metres, while the western approach is 1,095 metres, constructed of typically 45-metre spans with 2-metre deep NEBT beams. The box girder deck was launched over the shipping canal, which is the main shipping route between the Atlantic and the Great Lakes.

Within the canal, the footprint of the bridge had to be minimized, both to limit the loss of fish habitat and also to minimize any head-loss in the river flow that might affect a hydro-electricity dam downstream. To achieve this, the bridge in this section has 82-metre spans with pile caps that lie above the water level.

Rather than relying on the Canadian Bridge Design Code’s more conservative approach, Arup analyzed the soil conditions in a seismic response model at each of the bridge’s foundations. The specific soil properties varied significantly along the length of the bridge, so this method resulted in a more accurate and efficient design, at a greatly reduced cost.

Arup is a partner in Societe-Nouvelle-Autoroute-30, the public-private consortium which has a 35-year contract to design, build, operate, finance and maintain the entire highway. The international consortium includes Dragados Canada, Acciona Infrastructures Canada, Aecon and Verreault.

Arup is doing project, highway engineering, bridge design, geotechnical engineering, tunnel design and commercial management.

For more information about Highway 30, see

Photography: SNA30/CJV