Jetty: The jetty allows the dismantling of structural elements of the bridge in areas on the shore where the use of barges is not possible due to the shallow water.
Pier: The pier of a bridge, or the “leg”, is an intermediate support supporting the deck of the structure.
Footing: A footing of a bridge, or the “foot”, is the base that takes up the loads of the bridge.
Abutment: The abutment of a bridge is the part located on the shore intended to support the weight of a deck.
Deck: The deck of a bridge is a load-bearing structure that supports the loads of road traffic.
Span: The span of a bridge is the part between two piers or between a pier and an abutment.
Pier cap: The pier cap of a bridge is the upper part of a pier when the deck rests on it by means of one or more supports.
Section 5 : St. Lawrence River
Lowering of the spans – Removal of the 30th and last span
The mega catamaran barge, also called the “River Giant,” helped our crews lift and deconstruct the spans in the marine sector while protecting the St. Lawrence River, will be dismantled in the coming weeks.
Removal of piers and footings
The deconstruction teams have begun work to remove the piers and footings using specialized barge-mounted excavators. The barges will be used as a work space and will help the teams take concrete debris toward the quay berth of the Île des Sœurs jetty.
Work on the river will continue until summer 2023. To date, 32 piers and 12 footings have been deconstructed between Île des Soeurs and the St. Lawrence Seaway. (Update May 2022)
Deconstruction steps: piers
The piers are deconstructed from top to bottom using hydraulic percussion hammers installed on the excavators.
Two barges are needed to deconstruct a pier.
The barges are attached together to recover the debris.
The debris is recycled at authorized recycling centres.
It takes about 10 days to deconstruct each pier.
Deconstruction steps: footings
Two barges assembled into an “L” shape surround the footings, which are retained with sheet piles.
Once the sheet piles are in place, excavators with GPS positioning systems extract the footing from the bed of the St. Lawrence River.
The space in the river bed left by the removed footing is restored with stone fill, and the sheet piles are removed.
It takes about 20 days to remove each footing.
Construction of the temporary jetty
Nouvel Horizon Saint-Laurent (NHSL) is partially removing the jetty on the Île des Soeurs side, in the section adjacent to the Estacade entrance to recover materials that are no longer needed.
These materials will be used to complete the seaway dike jetty to reduce the need to bring new materials from quarries, which will decrease trucking in the network surrounding the project and lower greenhouse gases.
Also, when the jetty is removed, NHSL will begin the deconstruction of the three footings located under the jetty.
Section 6 : Seaway
Deconstruction of the cantilever section
The deconstruction of the cantilever of the east span (on the Brossard side) has begun and will continue until December 2022.
207 steel components to be cut and lowered
Approximately 207 steel components remain to be cut and lowered with a crane onto the jetty from the cantilever section of the bridge’s east span (Brossard side).
Steel reinforcements and two temporary support systems have been installed above and below the existing structure so that it can be cut into two sections and deconstructed from the centre toward the piers. This work will continue until fall 2022.
The 5 steps of a lifting operation:
To lift a component from the bridge, engineers have to identify and calculate the weight to be lifted.
Once the weight is determined, cutting lines are painted onto the component.
The component is attached to a crane, and crews on the bridge deck cut the steel into pieces.
Finally, the component is lowered and placed on the jetty by the crane.
The materials are sent to authorized recycling centres.
On average, about ten lifting operations can be done per day depending on the weather.