The pieces of the immense supergirder were moved closer to their final destination early Tuesday morning. But not everyone is sure installing the superbeam is the best idea.
The engineer who designed it as well as the Quebec Order of Engineers approve of the fix, suggested by a British Columbia company that specializes in bridges.
But architect Pierre Brisset believes the supergirder is too heavy for the bridge to support. He said placing the 75-tonne beam on the edge of the roadway will put that section of the bridge off-balance, much like a heavy weight placed on one side of a see-saw.
He said if the roadway was attached to the support pillars the plan would make sense, but he points out that the road deck just sits on pillars, and relies on gravity to hold it in place.
Catherine Tremblay, the lead engineer with the Jacques-Cartier and Champlain Bridge Corporation, said Brisset is wrong, and said the bridge deck is attached to its support pillars.
She also said the bridge deck is so much heavier than the supergirder that there is no way the steel beam could affect the balance of the bridge.
Other concerns
Said Mirza, a civil engineer and professor emeritus at McGill University said he is worried about the other beams that have been deemed to be in the same state of disrepair.
“My concern is that these beams might crack at some stage, get into a state of distress and then many super beams would you place?” he asked.
He also pointed out the bridge is deteriorating as a pace that is more rapid than was anticipated because it wasn’t designed to withstand the use of salt on the roads in the winter.
He said bridges such as the Champlain are supposed last at least 75 years, and to be in such dire condition after 50 years is “a waste of taxpayers’ money.”
Closer to its new home
The 75 tonnes of steel have been kept at a storage depot on the South Shore for the past four years, prepared by bridge officials who were anticipating the type of failure that finally occurred two weeks ago, when a 2 mm crack developed in the exterior girder of the southbound side of the Champlain Bridge.
Carried on the back of several trucks, the beam components came over the Jacques Cartier Bridge and along the Ville-Marie Expressway and the 15 South to a parking area on the Montreal side of the bridge, where a line of toll booths used to sit at the bridge's entrance.
Installation possible this weekend
During the next few days the components will be joined into a single piece and, weather permitting, this weekend the massive supergirder will be laid in place, and the weakened concrete structure will be securely attached to the beam.
That project is expected to take more than 48 hours and will require closing four out of the Bridge's six lanes, although at the moment only four lanes are open to traffic.
Since the crack was first spotted two weeks ago the federal bridge authority has closed one, and then two lanes on the southbound span. At the moment it is operating two lanes in each direction, and it has eliminated the counterflow bus lane.
