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Tracking Stage 2 Trillium Line Rail Bridge Work

Tracking Stage 2 Trillium Line Rail Bridge Work

The Stage 2 Trillium Line South Extension project will provide a fast, efficient, affordable, accessible, and environmental commuting option for Canada’s fast-growing capital city.In addition to further stimulating the city’s development, this project will keep Ottawa’s residents, businesses, and visitors moving in multiple ways through the creation of 17 new bridges.

About the bridges:

One of the most interesting aspects of the Stage 2 project is that the entire O-Train system will be grade separated, meaning trains will travel within a dedicated guideway that crosses over or under roads, paths, and other transportation routes. In order to achieve this, 17 new bridges will be constructed and 2 bridges will be rehabilitated on the Trillium Line South Extension project that will benefit the community in multiple ways.

New pedestrian bridges will be constructed at Bayview Station, the Rideau River, and Hunt Club Road providing pedestrians and cyclists with new, convenient and safe active transportation choices.

Construction of seven rail-over-road bridges along the extension will allow the LRT to pass seamlessly over vehicular traffic. The rail bridges over Limebank and Bowesville Roads will have two tracks to enhance the operational efficiency of the line.

A new rail bridge will be constructed at Ellwood Diamond allowing VIA Rail trains to safely pass below the Trillium Line without any impacts to O-Train operations. .

Finally, a new pedestrian/wildlife bridge will be constructed at High Road between Leitrim and Bowesville Station, allowing for pedestrians and wildlife to connect the natural areas that would be otherwise divided by the alignment.

How are they built?

Crews will start by drilling caissons, which are usually solid, deep foundations constructed from reinforced concrete to support the bridge superstructure above. Caissons are an important element of the construction industry because they can be designed to distribute the load of a structure evenly to a solid and sound rock base, which provides stability to the structure. As part of the Trillium Line south extension, approximately 74 caissons will be drilled to an average depth of 30 metres. To date, 32 of the 74 caissons have been completed, using approximately 2,270 cubic metres of concrete. The TransitNEXT team is close to completing the caissons that will form the substructure for rail bridges over Leitrim Road, Lester Road and Bowesville Road as well as for the airport elevated guideway. Caisson work will soon start at Mosquito Creek and Ellwood Diamond.

Above the completed caissons, crews pour concrete columns and pier caps that ultimately support the pre-fabricated concrete girders that create the bridge deck. The girders used on the Trillium Line South Extension are approximately 40 metres long, requiring a 300-tonne-crane to hoist them into place before they are secured using concrete diaphragms.

Construction of the rail bridges over Uplands Drive, Bowesville Road and Airport Parkway has advanced to the point where concrete girders are schedule for installation in June.

Illustration showing the structural components of a bridge

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