Pursuing the title of Canada’s tallest building, The One has been the most recognizable building on UrbanToronto for more months than we can count. Most of our readers could identify the exterior of the Mizrahi Developments building from virtually any angle, but even with this ubiquitous popularity, the opportunity to see the building from the inside has remained elusive, granted only through third-party drone 'flythrough' videos — until now. 

UrbanToronto was invited for a hardhat tour of the site to observe for the first time how the construction of the tower’s interior is progressing. Guided by Esteban Yanquelevech, Vice President of Construction at Mizrahi Developments, we explored the site up and down, and will be reporting on what we saw over two articles, beginning with a look at the building’s core and its sophisticated construction systems. 

East-facing view of The One from the construction entrance through the western laneway, image by Matias Bessai

The first stop on our tour was the 6th level terrace, a future outdoor amenity space which is currently being used as a staging area for various materials and equipment, and also happens to be the home of the city’s most photographed crane. 

Looking up the the south elevation of The One from the 6th floor terrace, image by Matias Bessai

On lease from construction equipment supplier Morrow, the huge crane is a luffing boom model, made by German manufacturers Liebherr. Unlike flattop or hammerhead cranes, luffing boom cranes have the ability to raise and lower their boom (the arm of the crane), minimizing the turning radius and ultimately allowing the machine to be more adaptable to the varying conditions of tight urban sites. 

The crane is positioned in a top climbing configuration, which allows the cabin and boom to be lifted by adding more sections over time as needed to the crane’s mast, a feat achieved with the help of a hydraulic system built into the crane itself. Rather than rising directly from the building’s centre, the crane is positioned to the south of the building frame, and fixed to it with a custom tie-in system pictured below. 

Close up of the crane's tower, fixed to the building with custom tie-ins, image by Matias Bessai

While standard tie-ins position the crane anywhere from 1 to 3 metres from the edge of the building, The One requires a much more significant gap to leave ample space for the protruding Automated Climbing System (ACS) used to form the floors. Constructed with a pair of massive steel I-beams, the two tie-ins currently in use are fixed to the crane via the standard square mount, and run across to the tower where they are anchored to now cured floor-plates, below where the latest forming work is taking place. 

From the 6th floor, we took the next hoist up as high as it went, to floor 13, to get a close up tour of the tower’s core. Exiting the hoist, we took the stairs up one more level, where we were able to walk into the future hallways of the 14th floor, the centre of the tower’s floor-plate, and look all the way up to the underside of the ACS, six storeys above. 

Looking up at the underside of the ACS and Gantry Crane from inside the tower's core, image by Matias Bessai

Slabs just like the 14th floor one we stood on, along with extending the elevator shafts upwards, will soon be created on every floor above us, but for now, more work is required to complete the 14th floor elevator shafts. Composed of reinforced concrete walls, the construction of the elevator shafts, following several floors below the surrounding sections of floor-plates, is a complex process that is made easier with the assistance of a gantry crane.

Pictured in the media above as a yellow beam running across the underside of the ACS, the gantry crane is a hoisting machine that has the ability to move its motorized hoist, block, and hook laterally on an XY plane. 

Elevator shafts under construction in the tower core, image by Matias Bessai

The beam can be moved up and down the perpendicular rails like a track, while the hoist itself can also move back and forth on the beam. With these specialized capabilities, the gantry crane handles the movement of heavy materials while workers continue to construct forms for the elevator shafts below. 

Gantry crane assists with movement of steel while workers construct elevator shafts, image by Matias Bessai

Some 20 +/- metres above, work is being done to complete the tower’s 20th floor. With the hotel (floors 7 to 16) and the first mechanical section (floors 17 and 18) now complete, construction is reverting back to repeating floor-plans, this time for the first section of condo levels, soon to bring the tower’s lowest residential floors to life. 

Don’t miss our next story sharing the exclusive photos and details from our hardhat tour of The One, as we take you down to the lower floors where exterior finishes are making progress. Until then, you can learn more about The One 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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UrbanToronto has a research service, UrbanToronto Pro, that provides comprehensive data on construction projects in the Greater Toronto Area—from proposal through to completion. We also offer Instant Reports, downloadable snapshots based on location, and a daily subscription newsletter, New Development Insider, that tracks projects from initial application.

Related Companies:  A&H Tuned Mass Dampers, Aercoustics Engineering Ltd, Core Architects, Doka Canada Ltd./Ltee, Live Patrol Inc., McIntosh Perry, Mizrahi Developments, NEEZO Studios, Rebar Enterprises Inc, RJC Engineers, Terraprobe Inc, The Planning Partnership, VDF Vertical, Walters Group