Canadian Consulting Engineer

Louis-Hippolyte Lafontaine Bridge-Tunnel

One of Montreal's transportation landmarks and a vital link in the Trans-Canada Highway is the 1.8-kilometre bridge-tunnel that crosses from the Island of Montreal over the St. Lawrence River near Lon...

December 1, 2005   By Electrical consultant: RSW

One of Montreal’s transportation landmarks and a vital link in the Trans-Canada Highway is the 1.8-kilometre bridge-tunnel that crosses from the Island of Montreal over the St. Lawrence River near Longueuil. The Louis-Hippolyte Lafontaine bridge-tunnel was built by the Government of Quebec between 1963 and 1967, not only to connect Montreal to the cities of the south shore, but also to connect eastern and western Canada.

The tunnel portion of the crossing is 1.4 kilometres long, housing a six-lane highway that carries more than 110,000 vehicles per day. The tunnel is the longest underwater tunnel in Canada and consists of two tubes, a central service corridor and two ventilation towers. (Roger Nicolet, Armand Couture and Bernard Lamarre were the design engineers.)

In November 2000, Quebec’s Ministry of Transportation contracted RSW to upgrade the tunnel’s electrical systems, including doing the studies, the detailed engineering and supervision of construction.

The retrofit involved completely updating the electrical system supply to 12 kV. Two new electrical rooms to house 12.45 kV and main 600 V were built close to the tunnel’s north and south ventilation towers. An Inergen fire protection system was used in the electrical rooms. Made with a combination of nitrogen, argon and carbon dioxide, the suppression system is an environmental alternative to replace halon. Inergen lowers the oxygen content of the area to a point sufficient to sustain human life, but insufficient to support combustion. In the old electrical rooms, the existing carbon dioxide systems were restored and carbon dioxide detectors were installed to monitor and alarm any possible gas leakage.

To evacuate rainwater from the tunnel there are three pumping stations, one at each end housing 60-HP pumps, and one in the middle housing a 50-HP pump. In collaboration with Groupe Sguin-BBA, RSW modernized the pump system with programmable controllers that can collect data in real time.

Ventilation in the tunnel is assisted by 16 fans (eight fresh air fans, and eight exhaust fans) ranging from 125 HP to 200 HP. Fresh air is blown into the tunnel through the service tunnel and evacuated through the ventilation towers at each end. RSW designed a new ventilation control system. The old three-speed drives were replaced by variable frequency drives, which allowed an improvement of the power factor and reduction in operating costs.

The power supply to the lighting system and the control centre were upgraded, and RSW also supervised construction of the new power supply to the control centre. The centre, located in the north tower, has a system of 23 closed circuit surveillance cameras.

Client/Owner: Ministre des Transports du Quebec

Electrical consultant: RSW, Montreal (Joaquin Duque, ing., Sylvain Paquette, ing., Michel Paradis, Tech., Ren Paquet, Tech., Pascal Turgeon, ing.)

Controls: Groupe Seguin-BBA


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