At the southwest corner of Yonge and Bloor in the heart of Toronto, the excavation for The One from Mizrahi Developments is growing deeper. The Foster + Partners and Core Architects-designed project will bring an 85-storey, 306-metre-tall luxury condo, retail, and hotel tower to the intersection, but long before the building takes the title of Canada's tallest building, there's complex work to be done at ground level.

Looking southeast across The One site, image by Forum contributor skycandy

Over the last few months, crews from Michael Bros Excavation have been digging to create space for the project's foundations, lower retail floor, and four-level underground garage. At the time of our last update one month ago, a concrete staging platform was in place at the south end of the site, and the pit had been dug below it to a depth of approximately two storeys. In the weeks since, crews have excavated many feet deeper, and the pit is expected to reach foundation depth in the next several weeks.

Looking west across The One site, image by Forum contributor skycandy

As the pit grows deeper, tieback installation is progressing along the below-grade caisson walls. Horizontal drilling rigs have completed two rows of tiebacks, which serve to stabilize the caisson walls by anchoring them to the surrounding earth.

Tieback drilling rig at site of The One, image by Forum contributor skycandy

At the same time, diagonal steel bracing is in use to stabilize the site's west side (another two of these braces have been added since our last update) where the tiebacks are not in use: tiebacks drilled into the ground below adjacent properties require the agreement from the property owner before they can happen. The braces eliminate the need for tiebacks, but are more complicated to build around until they can be taken out.

Diagonal steel bracing at the site's west end, image by Forum contributor skycandy

Things are set to get fairly exciting in the coming months. Once foundation level is reached, forming is expected to begin for the below-grade components, with the first above grade construction to surface late in the first quarter of 2019.

The One, image courtesy of Mizrahi Developments

Additional information and images can be found in our database file for the project, linked below. Want to get involved in the discussion? Check out the associated Forum threads, or leave a comment in the field provided at the bottom of this page.

Related Companies:  Core Architects, Foster + Partners, GFL Environmental Inc., Live Patrol Inc., Mizrahi Developments, RJC Engineers, The Planning Partnership