Lower Don Bridge and Don Valley Parkway
Location: Toronto, Ontario
Client: Metrolinx
Timeframe: 2023-2026
Key Personnel: Kyle Boudreau, Marc Tarling, Claire Spearns, Simon Brown
Lower Don Enabling Works
The Ontario Line will bring 15.6 kilometres of new subway service to Toronto, making it faster and easier for people to get where they need to be each day. The line will stretch across the city, from the Ontario Science Centre in the northeast to Exhibition and Ontario Place in the southwest. The Lower Don Enabling Works are planned for where the Ontario Line will run alongside GO train operations. The early works set the groundwork for other major construction on the Ontario Line project.
Ther Lower Don Enabling Works, Package 2 (P2) was awarded to Construction Demathieu and Bard (CDB) and included the installation and relocation of subsurface utilities. These consisted namely of an existing watermain travelling North-South beneath existing and new tracks. The original design identified two (2) cofferdams constructed using secant piles, and a jet grouted base slab for soil stabilization and water piping/infiltration during construction. Similarly, jet grouting was contemplated for the permanent watermain thrust block. Due to environmental concerns with the originally contemplated jet grouting, CDB hired Harbourside Engineering to develop an alternative design.
The alternative design used a traditional concrete slab for the base of the cofferdam (tremied in the wet), in addition to using secondary king piles for the permanent watermain thrust block. Harbourside Engineering Consultants was responsible for the detailed alternative design for the cofferdam, the working and drilling platform design, the thrust block alternative design, access and railing designs, and all required Quality Verification Engineering (Structural and Geotechnical).
Harbourside Engineering was also commissioned to provide on-site Quality Verification Engineering for the installation of permanent King Piles that would later serve as permanent support for a bypass slab installed over the cofferdam following tunnel boring operations to install the new watermain.
Don Valley Parkway Trestle Erection and Demolition
Harbourside Engineering is the specialist bridge erection engineer for the Don Valley Parkway Bridge Erection. The new rail structure is an internally tied, network hanger cable arrangement arch structure. It spans over the Don Valley Parkway and the Don River immediately north of the waterfront in Toronto. The site is extremely constricted and required a portion of the construction trestle and approximately 30% of the arch and deck system to be launched over the extremely busy Don Valley Parkway in a very short weekend closure window.
Harbourside’s Scope of Work
Acted as the Construction Engineering Specialist for the project.
Development of the full means and methods planning for construction.
Full, detailed, construction phasing.
Detailed design of all temporary works including: construction trestle, temporary towers to facilitate erection, skid systems, lifting arrangements, etc.
Crane Pad, Temporary Tower Foundation, Access Road Review/Design/Retrofit.
Assessment of existing and new infrastructure (permanent foundations, marine walls, pipe vaults, buried pipes, etc).
Trestle Demolition Design.
Construction QVE (Parent Bridge Steel Superstructure, Trestle, Erection).
Development of the full geometry control plan for arch erection.
Cable specialist for cable tuning (combined load and geometry targets).
PROJECT UPDATES
FEBRUARY 2026
A weekend closure on one of Toronto’s busiest arteries (the Don Valley Parkway), our Team – ESFL, CMW, KO Constructors reached a huge milestone by launching the easternmost section of the bridge steel superstructure into its final longitudinal position. The best part, City of Toronto was able to open to traffic 7 hours ahead of schedule on a 52-hour closure.
MAY 2026
Another major milestone was achieved with the completion of the bridge arch. READ MORE