Award Description

Project Participants

Owner – Brookfield Properties, Toronto, ON Canada
Architect/Designer – WZMH Architects, Toronto, ON Canada
Structural Engineer – Halcrow Yolles Partnership, Toronto, ON Canada
General Contractor – EllisDon Corporation, Mississauga, ON Canada
Concrete Contractor – Structform, Scarborough, ON Canada
Concrete Producer – Canada Building Materials, Toronto, ON Canada
Masonry Contractor – Clifford Masonry Ltd., Scarborough, ON Canada
Landscape Architect – Envision – The Hough Group, Toronto, ON Canada
Other – Shaheen Peaker –Coffey Geotechnics Inc., Toronto, ON Canada
Other – WR Grace – Ajax, ON Canada
Other – Carpenters Local 27, Woodbridge, ON Canada
Other – Harris Rebar, Mississauga, ON Canada
Other – Ironworkers Local 721, Toronto, ON Canada
Other – LIUNA Local 506, Toronto, ON Canada
Other – Erico, Grace Construction Products, Structural/Hardrock, Joint Venture, PERI Formwork Systems Inc., Walters Structural

Brookfield Properties Corporation awarded the Bay Adelaide Centre project to contractor EllisDon in January 2006. The project, a 52 story, 1.2 million sq. ft., office complex in downtown Toronto, presented unique challenges, both logistically and schedule-wise.

Initial enabling works entailed demolishing the existing 6 story core, which was abandoned in 1992, and two 13 stories adjacent office towers extending until January, 2007. This allowed only 25 months to shovel into the ground, excavating and shoring down 60 ft. to the P4 level (5 levels below grade), back up to grade, up 52 floors, enclose and substantially complete all floors, and ready for tenant fit up in February 2009.

Rising to the challenge, the EllisDon team developed the plan to complete the work in the timeframe required.

By incorporating some of the existing foundation walls into the shoring design, and cutting into the existing operating parking garage, down through all 5 levels, working from within, the contractors were able to bring the new structure back up to ground floor by December 2007. Because they started their “Peri” corewall jumpform at the P3 level, we were already at level 6 on the structural concrete core wall when the ground floor was completed. The Peri form was a unique hydraulic self-jacking form, designed and manufactured in Germany specifically for this mutli-celled core (22 cells), which we were able to jack up 1 floor every 3 days. This required some aggressive concrete strength gains (8 MPa in 12 hours, 60 MPa in 90 days) which our supplier CBM was able to deliver. All in situ concrete strength gain testing was done in-house with maturity meters. In the course of developing the formwork logistics, contractors performed trials with self-consolidating concrete, and while this had its own issues, it was determined to be a net benefit to the project.

The core cycle required 2 – 18 ton hydraulic booms at the form platform to service rebar installation. All core work proceeded on a double shift basis. Central in the core was the main self-jacking tower crane (140 ton TG1900 diesel over hydraulic) erecting structural steel and servicing the platform on the off shift. In addition, a 28m placing boom and Schwing BP 8800 pump placed most of the core concrete and all of the slab concrete through twin 5” risers. A 90 ton service crane was dedicated to rebar prefab at ground floor level.

Once the core was rolling, over every 3 days the team brought the balance of the trades in line with the same program. Structural steel 3 floors every 9 working days (except during weather delays) curtainwall 2 floors every week, interior finishes on the same tier with appropriate lag time. The tenant fit-out dates were met and substantial completion was achieved in July 2009, with a flagship lobby that is remarkably stellar, even amongst Toronto’s many national corporate head offices.