Engineering Inc - March/April 2018 - 44

A hydraulic jack system
lifts a bow-tie.

Brisk Bridge
Construction
PROJECT: NEW CHAMPLAIN BRIDGE
MONTREAL, QUEBEC, CANADA
FIRM: T.Y. LIN INTERNATIONAL
SAN FRANCISCO

O

pened to traffic in 1962,
Montreal's Champlain Bridge
crosses the St. Lawrence River
and Seaway to provide the
South Shore's primary access to and from
Montreal Island. When officials determined that the aging bridge's deterioration
was rapidly worsening, they quickly moved
into replacement mode.
Using a P3 model, Infrastructure
Canada selected the consortium Signature
on the Saint Lawrence Group to provide
a replacement bridge on an aggressive
42-month design-build schedule.
T.Y. Lin International is the lead
designer on the 3.4-kilometer bridge
now under construction, working as
the managing partner in a joint venture
with International Bridge Technologies
44

ENGINEERING INC. MARCH / APRIL 2018

and SNC-Lavalin. "It
includes the approach spans
and the 529-meter-long,
Marwan Nader
cable-stayed portion of the
bridge, which has a main
span of 240 meters. The asymmetric,
cable-stayed signature bridge features a
168-meter-high concrete tower and stay
cables in an aesthetic harp arrangement.
The three-corridor design includes two
three-lane corridors for vehicular traffic
and a two-lane transit corridor capable of
accommodating a light rail transit system.
There will also be a multiuse path for
pedestrians and bicyclists.
Montreal has six months of extremely
cold weather each year, allowing about 21
months to construct the bridge. To accommodate this constraint, designers have
used prefabricated concrete and fabricated
steel wherever possible.
"We basically looked at building the
bridge like we used to put something
together out of Lego blocks," says Marwan
Nader, T.Y. Lin International's lead
designer for the bridge. "The concept was
to make it as repetitive as possible."
The design incorporates precast pier
foundations, the top portions of which
projected above the water after installation,

the pier legs and elements
of the tower up to the first
crossbar. All use high-strength
concrete to reduce the weight
of each unit. The 70-meterwide pier caps are fabricated steel.
Using precast and prefabricated components decreased the amount of work to
be performed over the river, limited the
need for field welding and concrete placement in very cold weather. This enabled
crews to meet the demanding construction
schedule despite the harsh environment.
Additionally, using composite steel
and concrete in the approach structures
allowed for longer spans and optimized
the number of piers required. The helical ribs on the stays have been modified
to limit the amount of ice accumulation.
"The ribs still control wind and rain
vibration," Nader says. "But changing the
geometry means the falling ice pieces are
now a lot smaller, instead of being very
heavy and potentially damaging to the
traveling public."
Construction on the bridge began in
June 2015, and it is expected to open in
December 2018. The contractor for the
project is SNC-Lavalin, Dragados Canada
and Flatiron Constructors Canada.
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