Construction of the U.S. Army Corps of Engineers’ $3.2-billion New Lock at the Soo project in Sault Ste. Marie, Mich., is advancing toward completion in 2030. The Corps recently awarded a $213.8-million contract option to Phase 3 contractor Kokosing Alberici Traylor LLC for construction of the lock wall monoliths. 

The project is replacing two smaller locks with one equal to the 1,200-ft-long, 110-ft-wide, 32-ft-deep Poe Lock, which is currently the only of the Soo Locks on the St. Mary's River, between Michigan and Ontario, Canada, that is capable of accommodating modern “laker” shipping vessels. The scope of the newly awarded contract option includes construction of 21 chamber monoliths for both the north and south walls of the new lock, according to Jeremy Nichols, corps project design engineer. Each of the monoliths are about 44 ft wide and 70 ft tall, and will be built by placing concrete in 5-ft-high lifts.

The Corps awarded Kokosing Alberici Traylor—a joint venture of Westerville, Ohio-based Kokosing Industrial, St. Louis-based Alberici Constructors and Evansville, Ind.-based Traylor Bros.—a $1.1-billion base contract in 2022 for the third, final and largest phase of the lock project. Awarding the contract then allowed work to proceed on early portions of the project, while additional pieces are covered in contract options awarded as funding is available.

The Corps has previously awarded three other contract options worth a combined $281.3 million. Since mobilizing in late 2022, the contractor has placed cells for upstream and downstream cofferdams, started construction of a bridge to a mid-river hydropower plant, stabilized the existing monoliths and installed a grout curtain ahead of dewatering and conducted blasting and excavation for a planned utility shaft. 

“Construction will continue over the winter season, to include hazardous waste abatement, concrete demolition, utility shaft excavation and electrical work,” said Mollie Mahoney, Corps senior project manager, in a statement. 

The Corps plans to award four more worth $320 million combined over the next two years, according to Kevin McDaniels, deputy district engineer of the Corps’ Detroit District. 

“The remaining options are required for a complete lock,” McDaniels said in a statement. 

A rendering (right) shows the placement of a planned lock beside the existing Poe Lock. The smaller MacArthur Lock sits on the opposite side of the Poe. Courtesy U.S. Army Corps of Engineers

The Soo Locks allow vessels to bypass rapids with a 21-ft elevation change as they travel along the St. Mary’s River between Lake Superior and Lake Huron. According to the Corps, about 80 million tons of commercial commodities are shipped through the locks each year. But the Poe Lock, which is the only of the existing locks on the U.S. or Canadian side of the river which can accommodate larger modern vessels, was built in the 1960s and is now older than the lifespan for which it was designed. Building a second 1,000-ft lock would take pressure off the Poe and allow for it to undergo needed rehabilitation work. 

“Each year in the last decade, we’ve had more and more repairs that are required,” Mahoney previously told ENR. 

Phase 1 involved deepening the upstream approach. Mesquite, Nev.-based Trade West Construction Inc. completed that work in 2022. Phase 2, led by another joint venture of Kokosing and Alberici, includes rehabilitating the upstream approach walls. That work is scheduled to be completed this summer.