The federal agency that is responsible for three of the bridges that cross the St. Lawrence will spend $300 million on construction this summer.

Major work to finish the deck reconstruction of the federal half of the Mercier Bridge should wrap up this year, while maintenance continues to keep the Champlain Bridge roadworthy until its replacement is completed.

Major work is also necessary on the Jacques Cartier Bridge.

The announcement comes day after the city of Montreal presented its plan for $500 million in construction projects taking place this year.

"We have to really plan all of this work to ensure that we don't cause congestion all at the same time, at the same place," said Glen Carlin, CEO of the Bridge Corp.

"We're working very closely with our partners: the Quebec Ministry of Transportation, the local cities and it just takes a lot of planning, but once it's done it's just to execute it and make sure it all falls into place as planned."

The Bridge Corporation said Thursday that it has updated its website with full descriptions of the work plans, a section where people can subscribe to get text messages or email alerts about closures and emergency work.

The Jacques Cartier and Champlain Bridge Corp. website also displays photos of traffic on all three bridges and the Melocheville Tunnel.

Mercier Bridge

This year the deck replacement on the federal section of the Mercier Bridge, the part that spans the St. Lawrence Seaway, should be completed, eight years after it began. The project is supposed to extend the life of the bridge by 75 years.

Construction work on the access ramps from the South Shore will begin on June 24 and last eight weeks.

Traffic will be reduced to one lane in each direction while the concrete decks are installed.

Champlain Bridge

The Bridge Corp. will replace 11 expansion joints, repair 6 support piers, and install 48 support trusses underneath the bridge deck, making the work on the Champlain Bridge the most costly of the three projects.

The support trusses are going to hold up the edges of the bridge because the girders in that location are weak.

Construction crews will force the full closure of the Champlain Bridge toward the South Shore the weekend of April 30, and a closure of the inbound lanes the weekend of May 7.

Four more weekend blitzes are planned for the fall.

Jacques Cartier Bridge

Two major projects are planned for the Jacques Cartier Bridge.

Over the next 18 months crews will be doing major structural repairs to reinforce the bridge that will require many closures. Most of this work will be done overnight.

Crews will also be installing a special lighting system on the bridge as preparation for Montreal's 375th anniversary.