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Superdomes

Standing on the end of the West Jetty on Nun’s Island, the two white “superdomes” are a veritable assembly line where workers can prepare the 74 transition segments, protected from the cold and the inclement weather conditions. The segments, which will provide the interface between the pier caps and pier legs, are made in Spain.

Preparatory stages before installation

Each segment is first brought to an unheated space in the plant, where work is done on the hollow steel shells in preparation for the next step, involving the addition of rebar, embedded elements and post‑tensioning ducts.

The piece is then ready for the pouring of concrete. It is transferred to what could be referred to as the “segment nursery,” a heated area of the plant that provides optimal temperature control. Setting concrete cannot withstand any substantial changes in temperature. That is why doing this type of work in the winter requires temporary facilities.

Once the concrete has been poured, the segment is moved to its next destination in the plant, where it can be rotated to optimize the concrete’s quality, notably in the anchor heads.

Finally, the steel-and-concrete component is ready to be stored outside as it awaits installation. Assembling of the segments is expected to be finished by spring 2018.

Transition segments by the numbers

• 50 segments completed
• 44 segments installed
• Weight: 100 metric tons
• Length: between 7.7 meters and 8.2 meters
• Width: 3.4 meters