11/03/2012 17:31 EDT | Updated 01/23/2014 18:58 EST

Northbound Louis-H. La Fontaine tunnel closed for repairs

Montreal drivers are facing major disruptions on some roads this weekend, as construction crews do scheduled demolition work on the northbound lanes of the Louis-Hippolyte-La Fontaine tunnel and at the intersection of Upper Lachine Road and St-Jacques Street.

Construction crews are removing the last of the so-called paralumes — the concrete slats at the entrance and exit of the tunnel that act as light shades.

In the southbound direction, only two lanes of the tunnel will be operating until the tunnel's scheduled reopening at 5 a.m. Monday.

The paralumes were demolished on the southbound side of the tunnel in December 2011, after corrosion was found on the beams supporting them.

That same design proved treacherous in July 2011, when a 25-tonne paralume collapsed in the Viger Tunnel of the Ville-Marie expressway. No one was injured, but traffic was disrupted for more than a week while emergency repairs were undertaken.

In Oct. 2011, Quebec's transportation ministry removed the remaining 134 paralumes from the Ville-Marie tunnel after engineers found the shades and the beams that hold them to be in serious disrepair.

This weekend will mark the completion of the paralume demolition on the Louis-Hippolyte-La Fontaine tunnel. Paralumes in the Dorval tunnel and the Ville-Marie tunnel will eventually need to be removed as well, according to Transport Quebec spokeswoman Caroline Larose.

Detour on St-Jacques Street

In Montreal's west end, the overpass at St-Jacques Street and Upper Lachine Road is being demolished.

That overpass is one of a dozen key pieces of road infrastructure deemed to be in critical condition in a City of Montreal report released in Sept. 2011.

The overpass dates back to 1958.

Traffic headed west on St-Jacques Street between Belgrave and Hingston avenues will be rerouted for the duration of that repair work.

Montreal's public transit is also doing its part to help detour traffic during the repairs. The STM has added capacity on its yellow line, and the city of Longueuil has provided free parking close to the metro for people travelling downtown.