It is tough to put an arm around a body of water. However, if given the chance, those involved in the construction of the Maple-Oregon Bridge in Sturgeon Bay, Wis., would prefer to deliver an encouraging embrace rather than a wrestling choke hold.
Nobody wants to fight any form of Mother Earth, which is why Lunda Construction Co. was not fooling around with the cofferdams of the new Maple-Oregon movable double-leaf rolling bascule span, No. 4 on this year’s Top 10 Bridges list.
The Sturgeon Bay turns into a sheet in winter, with usually 2 to 3 ft of ice forming on the surface. For Lunda Construction, it was a race before the region hardened, but fortunately a mild cold season allowed for relatively easy cofferdam construction.
It is not easy to put an arm around a body of government, either. Again, the Maple-Oregon team preferred a more intimate approach. The Wisconsin Department of Natural Resources (DNR) prohibits water construction from March 1 to June 30 during the fish-spawning season. Lunda Construction still had to build cofferdams, which were 15 ft 6 in. x 52 ft 6 in. in dimension, for the bascule portion of the bridge as spring approached. To stay on schedule, the contractor approached the Wisconsin DNR with a videotape showing the impact of pile driving. It was minimal, and construction was able to proceed.
The project’s ambition began gaining strength long before ground was broken on the jobsite. After a lengthy delay due to a lack of funding, money for the project suddenly appeared, and Wisconsin Gov. Tim Doyle promptly called for the bridge’s completion. That put the schedule on a two-year time frame, which translated into an eight-to-nine-month final design phase.
The fact that it was a movable bridge thickened the complexity of the engineering.
“It’s not just a fixed span; it involves interface between the structure and the machinery.” Ken Smorynski an associate with Teng & Associates, Chicago, the lead designer for the bridge, told Roads & Bridges.
Steel H piles, varying in length from 37 to 60 ft, were driven to support the 10 cast-in-place piers. Driving shoes were used because of the presence of cobbles and boulders in the Sturgeon Bay. The approach spans consist of 54-in. prestressed bulb tee girders, which support a conventional concrete deck. The superstructure, however, comes with a lightweight concrete deck instead of the traditional open-grid steel deck used for double-leaf rolling bascule bridges.
