Crews reached a milestone this summer, launching the tallest bridge in Alaska.
The $151 million Juneau Creek Bridge is part of the $850 million — and likely rising — Cooper Landing Bypass Project (Sterling Highway Milepost 45–60 Project) that also will see the construction of about 10 mi. of new roadway, the widening of shoulders, bringing roadway curves into compliance with design speeds and adding passing lanes, pathways and new wildlife crossings.
Alaska Department of Transportation & Public Facilities photo
“This is certainly the largest and most complex project I've had the opportunity to manage,” said Jonathan Tymick, project manager for the Alaska Department of Transportation and Public Facilities (DOT&PF) told Construction Equipment Guide. “I've worked on many significant transportation projects throughout Alaska, but nothing compares to the complexity of the Cooper Landing Bypass.
“Having the opportunity to serve as both the design manager and now the construction manager has been especially rewarding because I've been able to see the project evolve from design concepts and environmental commitments into something that is actually being built in the field.”
The bridge is a critical part of the Cooper Landing bypass, which will eventually reroute 10 mi. of the Sterling Highway to improve safety and traffic flow through the area.
Alaska Department of Transportation & Public Facilities photo
Among its superlatives, the bridge will be:
• the highest crossing in the state at 285 ft.; Hurricane Gulch is about 250 ft.;
• longest single-span bridge in the state since 1982; and
• longest erected and launched bridge in the state.
Crews with contractor Quality Asphalt and Paving and Traylor Bros. Inc. Joint Venture (QAP-Traylor JV) launched the bridge across the canyon in June.
The steel girders were assembled on one side of the canyon and pushed across to the other side.
Launching is a construction method where pre-built parts of the bridge, such as the 13-ft.-tall girders on this project, are incrementally pushed across piers rather than lifted into place.
“This will likely be the longest launched bridge in North America,” according to Alaska DOT&PF.
Since the launching, construction crews have been removing the temporary launching equipment, jacking the bridge down onto its bearing pads, completing final cross-frame connections, repairing and completing metallization on portions of the steel and advancing the backwalls and wingwalls.
Alaska Department of Transportation & Public Facilities photo
“The next major piece of work is pouring the bridge deck in summer 2027,” Tymick said.
When complete, the Juneau Creek Bridge will stand approximately 250 ft. tall, stretch 928 ft. long and be 63.5 ft. wide. Construction will call for 6.75 million lbs. of structural steel, 1.12 million lbs. of reinforcing steel, 16.7 million lbs. of concrete, and more than 35,000 bolts holding it all together.
“A significant amount of temporary equipment and temporary works had to be designed specifically for the bridge launch,” Tymick said. “The bridge itself was designed not only for the loads it will experience throughout its service life, but also for some very unusual temporary loading conditions that occurred while it was being launched across the canyon.
“The contractor developed specialized launching equipment and temporary works to support, guide, jack and control the bridge during the launch. That coordination between the contractor and our Bridge Design Section was a major part of the design process.”
Work on the bypass project began in about 2019, though studies on updating the Sterling Highway have been on the books since the 1980s. The highway was built in the 1940s and '50s as a gravel road and not designed for the traffic it carries today, Alaska DOT&PF said.
“It had become increasingly congested, especially during the summer months, creating safety issues for travelers,” the agency said.
Challenges include those technically related, but the biggest hurdle stems from the state's use of an alternative procurement method, “in this case, Construction Manager/General Contractor (CM/GC), Tymick said. “... consistent funding and continuity are required for that delivery method to work as intended. That is something this project has never had. Without consistent funding and a clear plan to advance successive phases, contractor equipment has at times sat idle or been underutilized, and some equipment has even been mobilized off the project only to later be brought back.
Alaska Department of Transportation & Public Facilities photo
“So, the biggest challenge has been delivering a project of this magnitude through years of funding uncertainty while trying to maintain momentum — keeping contractors and their equipment working, progressing design, meeting environmental commitments and keeping future phases ready to advance when funding becomes available.”
In addition to the steel girder bridge spanning Juneau Creek Canyon, the bypass project features four wildlife undercrossing structures and the first wildlife overpass of a highway in Alaska.
Ninety percent of the funding for the project is anticipated to come from the Federal Highway Trust Fund, according to the Alaska DOT&PF, with the state of Alaska supplying the remaining 10 percent.
The bridge is expected to be completed in 2028, and the full bypass is expected to open in 2032.
