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Earlier this month, M3 at M City celebrated a major milestone with a topping-off ceremony, marking the completion of concrete forming at the top of the building. Rising within the multi-phase M City project in Mississauga City Centre, the 77-storey tower designed by Arcadis for Rogers Real Estate Development and Urban Capital Property Group, is now the tallest building west of Toronto in Canada.
As construction transitions to steel girder erection for the peak, crews are also assembling the building’s massive tuned mass damper (TMD); this pendulum system will stabilize the slender structure by oscillating opposite to the tower’s movement, ensuring comfort for residents. Adam Segal, Director of Construction at Urban Capital, has provided UrbanToronto with further details on the TMD system and its installation within a three-storey void in the concrete, now awaiting the framework that will hold the TMD, prior to installation of the TMD and enclosing cladding.
A high-angle view into the crown reveals the three-storey concrete chamber, where assembly of the 705-tonne (705,000 kg, or 1,554,258.95 pounds) steel weight is underway. At the chamber’s centre, prefabricated steel elements form the damper’s core frame, while thick counterweight plates are arranged for assembly. These plates were delivered in 65 truckloads, with assembly of the system taking place over roughly two months.
Viewed head-on, this image offers a clear look at the immense steel object forming the core of M3’s TMD, where the labelled steel plates (each etched for identification and alignment) are being positioned within the three-storey concrete enclosure. Next steps include the installation of long-span beams that will suspend the damper from the crown structure above. Yellow ladders and a blue lift remain on site as crews finalize assembly before the system’s tuning phase, scheduled for January, 2026.
Looking north to M3 from Webb Drive, this image captures the current extent of M City, with M3 dominating the centre. The tower’s open cavity at its crown is visible from grade. Meanwhile, M1 and M2 (turned 90° to each other and distinguished by their accordion-like silhouettes) stand to the right, and the cranes for M4 and M5 rise to the left and right foreground, respectively.
Coming up, work is beginning on enclosing the TMD chamber, with steel framing soon to complete the west elevation before crown steel is erected. Once this uppermost structure is clad with glazing and perimeter railings, crews will install M3's BMU, or Building Maintenance Unit, and will then dismantle the external hoists, and finally disassemble the crane, signalling the end of heavy construction as the tower moves toward completion in Summer 2026. At 260.29m with 949 units, M3 stands as both Mississauga’s tallest building and the tallest in Canada outside of Toronto.
UrbanToronto will continue to follow progress on these developments, but in the meantime, you can learn more about them from our Database files, linked below. If you'd like, you can join in on the conversations in the associated Project Forum threads or leave a comment in the space provided on this page.
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UrbanToronto's research and data service, UTPro, provides comprehensive data on construction projects in the Greater Golden Horseshoe—from proposal through to completion. Other services include Instant Reports, downloadable snapshots based on location, and a daily subscription newsletter, New Development Insider, that tracks projects from initial application.
