Ontario Construction News staff writer
Acrow, an international bridge engineering and supply company, has announced the installation of a long-span modular steel bridge as a permanent replacement for the aging single-lane Thessalon River Bridge on Highway 638. The bridge was originally built of wood in the late 1880s.
The wider two-lane replacement bridge was provided to the Ontario Ministry of Transportation (MTO) and installed by project contractor The Miller Group.
The replacement project posed several challenges, the company says, because the road is located in a remote area – at the junction of Highway 17 and Highway 129 on the north shore of Lake Huron – and provides access for emergency vehicles. A short construction time was considered critical, with a maximum 15-day closure of the bridge permitted.
Also, the work site had an extremely limited footprint with steep slopes on both sides of the east bridge approach making it impossible to use as a temporary laydown area. Components were shipped to a nearby quarry pit to be sorted and then transported by truck to the construction site.
Because timing was so vital, a fleet of 22 trucks was used to ensure a coordinated, efficient offloading of bridging materials.
The long-span Delta bridge is 67.5 meters (221.5 feet) long and has a curb-to-curb width of 7.35 meters (24.1 feet) to accommodate two lanes of traffic, plus a cantilevered foot pathon one side.
After site preparation including earthworks, foundation, unloading and preassembly of truss panels, the old bridge was removed, and assembly of the new bridge began June 21. It was installed seven days later using a full cantilever launch, and jacked down onto its bearings, from a height of more than two meters, on June 30, opening to traffic on July 2.
“Acrow’s cost-effective Delta system provided the perfect solution to this project with extremely limited access and a tight installation timeframe,” said Betul Oliver, Acrow Canada’s business development manager, Eastern Canada. “The speed of installation avoided the need for a detour structure, and kept the project on schedule and within budget.”