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While Metrolinx's Toronto crews continue to chip away at the various transit expansion projects underway, the company’s Mississauga portfolio is also advancing. Last week, the Hurontario-Main LRT, to be named after the late Mississauga Mayor Hazel McCallion upon opening, took another significant step forward last week with the successful installation of a new underpass for the future 18 km light rail line.
The primary challenge for the project since it began construction has been conceiving a strategy to lay tracks on a route that is already heavily developed with existing transportation infrastructure. The route intersects with a number of major regional highways like the QEW and the 401, as well as transit systems like GO Transit’s Lakeshore West line, so figuring out a way to build around these pieces of infrastructure without causing significant disruption is one of the keys to project’s success.
The primary approach to this problem was demonstrated in November of last year, when the construction crew deployed the innovative push box system to create a new underpass below the QEW. The system's name is quite literal; the ground beneath the highway was excavated and a hollow concrete box was simultaneously pushed into that excavated opening, providing structural support for the highway while also allowing for a new underpass beneath. And all of this was accomplished in just 55 hours.
Just last week, the crew executed a similar procedure, creating a new underpass at Port Credit Station a few kilometres to the south, but this time there was an added layer of complexity; the underpass they were creating was be below the tracks of the Lakeshore West GO line, and with 33,000 riders relying on the line every day, the work was required to proceed without causing any service interruptions. The only way to accomplish this was by employing the Italian-designed Verona System, crafted by Pertucco Box Jacking Systems.
Representing the first deployment of this system in all of Canada, the Verona System provides temporary structural support for train tracks to allow service to continue while work is carried out below. In this instance, the system was composed of a series of robust steel members (blue), installed parallel to the tracks and spanning the entire width of the excavation area, which passes below perpendicularly. Resting on piles on either side of the opening, these steel members support a grid of smaller steel pieces that add another layer of support to the tracks.
With the Verona System in place, the crew was able to proceed with the installation of the next push box, sliding the 6,000-tonne concrete mass into place beneath the Lakeshore West tracks. A time-lapse of the excavation and push can be seen in the video below.
With this technical operation now complete, workers will be able to move forward with the expansion of the existing Port Credit GO Station, which will be the southern terminus of the Hurontario-Main Line, and a new high-traffic transit hub connecting the western GTA to Downtown Toronto. The project is targeting completion in 2024.
UrbanToronto will continue to follow progress on this development, but in the meantime, you can learn more about it from our Database file, linked below. If you'd like, you can join in on the conversation in the associated Project Forum thread or leave a comment in the space provided on this page.
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