001-48_126_RENEW_SEPT-OCT26_PT - Flipbook - Page 20
TRANSIT
Design principles
The architectural and urban framework for Line 5 was anchored by two overarching planning documents: the City
of Toronto’s Eglinton Connects framework and Metrolinx’s
Design Excellence principles.
As McCarthy and Mustafa explained, the vision was not
merely to build transit stops, but to establish a cohesive
urban data set that could guide the mid-rise densi昀椀cation
of Eglinton Avenue over the coming decades.
“People ask us, ‘Why did you make the station entrances
so tall in some cases?’” McCarthy noted. “It was because the
city wanted to ensure that the architecture built for the transit
line would be consistent in terms of scale and 昀椀t for the future
development that would follow... to replace the two-story
buildings and go up to 10 stories with step-backs.”
To overcome these physical constraints, the engineering
team executed two pioneering construction techniques:
TOP-DOWN CONSTRUCTION: Implemented at Forest Hill
and Chaplin Stations, top-down construction allowed the
site team to build the roof slab 昀椀rst and restore surface
tra昀케c 昀氀ow above while excavation and concrete works
continued in deep pits below.
SEQUENTIAL EXCAVATION METHOD (SEM): Deployed on
three underground stations (including Laird Station), SEM
mining allowed crews to excavate station caverns 20 to 23
metres beneath Eglinton Avenue via o昀昀-street access shafts.
Ground excavation proceeded underground “like an ant
eating at the earth” without opening the street above.
Notably, the team successfully adapted SEM for clayey and
silty soil conditions—a technique historically reserved for
solid rock formations.
Precision engineering
The single most technically demanding engineering hurdle on
the Line 5 project occurred at the
Yonge-Eglinton interchange, where
the new LRT line was routed directly beneath the active TTC Line 1
subway box.
Because Yonge-Eglinton is one of
Canada’s busiest transit hubs, the
existing Line 1 subway box had to
remain fully operational throughout excavation. The design team developed an elaborate structural underpinning
and jacking system to support the massive subway box
while tunneling beneath it.
“We had an allowable construction tolerance of just 3
millimetres—the equivalent of 昀椀ve business cards,” McCarthy explained. “We developed a system of piling needle
beams and computer-coordinated hydraulic jacks that
could automatically adjust as any microscopic movement
took place.”
Through this precision monitoring, the construction
team successfully underpinned the active subway line,
completing the critical intervention ahead of planned engineering tolerances.
“What I’m most proud of is the partnership spirit—a true partnership
enacted throughout the life of this project. Riding the line and seeing
it working as it was designed to do is a profound feeling.”
Key design pillars integrated across the line include:
PASSENGER-FIRST FUNCTIONALITY: Main station headhouses were positioned on corner lots near primary intersections to minimize transfer distances, placing entrance
doors just 10 to 15 metres from surface bus stops.
SPATIAL GENEROSITY AND NATURAL LIGHT: By moving
heavy technical and mechanical equipment rooms up
to street level rather than packing them underground,
designers created double-height cavern spaces above
underground platforms. This vertical generosity uplifts the
passenger experience, reducing the claustrophobic feel of
traditional underground subway boxes.
INTUITIVE WAYFINDING AS ARCHITECTURE: Entrance
structures feature distinctive, canted architectural forms
that act as visual urban beacons, helping transit riders
navigate to station entrances from blocks away.
ACTIVE TRANSPORTATION ENHANCEMENTS:
Recon昀椀guring surface streetscapes from narrow sidewalks
and six lanes of vehicle tra昀케c to include dedicated bike
lanes, wider pedestrian zones, and generous public realms.
Top-down construction
Building massive station caverns beneath a mature, fully
developed urban street required innovative civil engineering methods to prevent severe surface disruption and
avoid damaging historic building stocks.
“There was a lot of anxiety on the client side because we
were piling within a few metres of all these brick buildings
of an aged housing stock along the corridor,” McCarthy
recalled. “Our platform levels go from 15 metres underground to as much as almost 30 metres underground.”
20—RENEW CANADA – SEPTEMBER/OCTOBER 2026
Heritage relocation
At the western terminus at Mount Dennis, the design team
encountered a major physical impediment: Building 9 of
the historic Kodak factory complex. Standing directly in
the footprint required for the new Mount Dennis Station, bus terminal, and Maintenance and Storage Facility
(EMSF), the 99-year-old structure was a cherished community landmark.
Rather than demolishing the structure, the project team
executed one of the largest structural relocations in Canadian history.
“It was decided after many optioneering sessions to relocate the 3,500-tonne former Kodak building by about 75 metres to allow the constructors the freedom to excavate,” said
Mustafa. “They cut the foundations, lifted the building onto
rollers, moved it, and then re-established the foundations.”
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