001-45_127_NOV-DEC_LAYOUT_PT - Flipbook - Page 12
INTERNATIONAL PROJECTS
COWI
ALASKA, U.S. —
JUNEAU CREEK BRIDGE
COWI has completed the erection engineering behind
12—RENEW CANADA – NOVEMBER/DECEMBER 2026
launched across the canyon as a single system. At
maximum cantilever, the structure extended 440foot before reaching its next permanent support. The
solution incorporated a lightweight 180-foot launching
nose, temporary king posts and a stay system to
redistribute loads and control deflection as the bridge
advanced.
Launching all five girder lines simultaneously created a wide, indeterminate structural system, with small
differences in girder camber or roller elevation capable
of redistributing substantial loads between supports.
Survey control, staged jacking, roller adjustments and
reaction monitoring allowed the field team to check
the bridge’s behaviour against the erection analysis
throughout the launch.
Wind was also a critical consideration. Site-specific
analysis examined the effects of the surrounding terrain
and the bridge’s susceptibility to aerodynamic effects
during different stages, with wind effects ultimately
governing the design of several components and
requiring significant strengthening of plan bracing and
cross-frames.
Claus Fredriksen, Head of Department, Roads and
Major Crossings, COWI, said: “The challenge wasn’t simply getting a very large bridge across a canyon. At every
stage of the launch, the structural system changed
as the girders moved from one support condition to
another.
“We had to understand how five girder lines, the
temporary stays, launching nose, rollers and permanent
steel would behave together throughout that process,
while accounting for wind, seismic demands, camber
and the tolerances inherent in a structure of this scale.
“The result was an erection system that allowed an
exceptionally large bridge superstructure to be assembled in a controlled area and then moved across a site
where conventional construction access was extremely
difficult.”
The bridge is now progressing into its next phase
of construction, with deck work scheduled for 2027.
It forms part of the wider Sterling Highway MP 45–60
project, which will reroute approximately 15 miles of
highway and includes 14 new structures, four wildlife
under crossings and Alaska’s first wildlife overcrossing.
Credit: EXACT Technology
the launch of the Juneau Creek Bridge in Alaska,
developing an engineering solution that enabled
nearly seven million pounds of structural steel to
be moved across a steep, environmentally sensitive
canyon where conventional erection from below was
severely constrained.
The bridge is the signature structure on the Alaska
Department of Transportation and Public Facilities’
(AKDOT&PF) Sterling Highway MP 45–60 project near
Cooper Landing. The permanent structure comprises
three steel plate-girder spans, including a 440-foot
main span and two 240-foot side spans, with girders
approximately 13 feet, three inches deep.
Acting as erection engineer for the QAP/Traylor Joint
Venture, COWI developed the launch arrangement and
carried out the staged erection analysis required to
control the structural behaviour of the bridge throughout the operation.
Rather than constructing the superstructure piece
by piece over the canyon, the full-width, five-girder
steel superstructure was assembled on one side and
