Canadian Consulting Engineer
Rescue system in waiting since 2009 deployed for Champlain BridgeTransportation Transportation Infrastructure
The federal government and its agency that looks after the Champlain Bridge in Montreal have gone into high gear after a "significant crack" was found in a girder. First discovered on November 12, the 2-mm crack lengthened and the girder's...
The federal government and its agency that looks after the Champlain Bridge in Montreal have gone into high gear after a “significant crack” was found in a girder. First discovered on November 12, the 2-mm crack lengthened and the girder’s condition deteriorated over the next two weeks. By November 22 authorities had discovered two more cracks.
The 1950s steel truss cantilever bridge crosses the St. Lawrence River from Montreal to the South Shore via Nun’s Island. It measures 6 kilometres long with its approaches and carries 160,000 vehicles daily, making it Canada’s busiest crossing.
After the problems were detected, traffic lanes on the bridge were reduced and traffic calming methods were implemented.
On November 22, Denis Lebel, the federal Minister of Infrastructure, Communities and Intergovernmental Affairs, announced that given the new developments it will be speeding up the project to build a bridge replacement so that it can go into service before 2021.
Meanwhile, Jacques Cartier and Champlain Bridges Inc. (JCCBI), the federal agency that oversees the existing bridge, has started an urgent mitigation plan to isolate the problem girder. The “Support Beam Operation” involves a system that was already designed, built and stored since 2009 in the event that such a problem would occur.
The JCCBI says that the reinforcing operation involves two stages and describes it as follows:
“Phase 1: Stabilize the situation and secure the girder.
“The first step consists of transporting to the bridge approaches the five sections of the massive steel beam, which until now has been stored near the Jacques Cartier Bridge. This beam will be assembled near the bridge and then moved using a long-load dolly onto the bridge, where two cranes will pick it up and place it just above the girder that requires reinforcement.
“The support beam will then be installed above the existing girder across its entire length and attached at the piers. Enormous steel rods anchored to the support beam will be lowered beneath the girder in order to fully support it. Once this girder has been secured, we will begin the process of reopening the traffic lanes that are currently closed.
“It should be noted that this support beam will result in the width of the open lanes being reduced. This temporary situation will only last until the second phase of the operation. The objective is to stabilize the situation as quickly as possible, secure the girder, and then launch phase 2 once traffic has been re-established.
“Phase 2: Install a permanent support structure
“Phase 2 will consist of installing steel modular grating from below, which will be attached to the span’s two pillars. This grating will also support the girder across its entire length, like the support beam installed in the first phase.
Installation of the permanent support (modular grating) will begin in spring 2014 due to the difficulties of carrying out this operation in winter conditions. Once this second phase is completed, the support beam will be removed and the full lane width will be re-established on the bridge.”
The corporation is hoping to complete the first step in mid-December to open the six lanes to traffic as soon as possible.