An older, single-span steel bridge in the town of Plympton-Wyoming, on Lake Huron, had been closed for over a year due to safety issues. The bridge's concrete abutments had deteriorated and its rail system did not meet code. Town officials, and especially residents using the Uttoxeter Road crossing over Hickory Creek, were eager to have a safe and dependable replacement as soon as possible.

After considering several options, the project partners chose an AIL Dur•A•Span Aluminum Structural Plate Box Culvert option as it offered an environmentally-friendly, open-flow solution that was well suited to the site.

Lightweight and strong, AIL's Dur•A•Span has been going the distance in over 1,000 structures worldwide for many years - beating the usual heavyweight contenders like precast concrete on performance and cost. But, AIL's recent proprietary innovations in reinforcing rib technology have helped Dur•A•Span become even stronger and span even greater distances. The new Type X, Hat-Shaped Rib was perfect for this project. Dur•A•Span Box Culverts and Arches can now reach spans or 12.2 m and greater with this technology.

The Hickory Creek project represents the largest Aluminum Box Culvert ever installed, with a span of 12.013 m, a rise of 3.562 m and a length of 12.344 m. The cover depth is 600 mm to 670 mm and there is an engineered backfill envelope of 3 m on each side, up to the road grade. This solution was designed for a CL-625 Ontario Truck Live Load. AIL's economical and easy-to-install Vist-A-Wall MSE Structural Wall System (Welded Wire Wall with Cobble Stone) was used for the headwalls.

The project had encountered several delays, resulting in the footings being poured in the late fall of 2008. In response to the Town's requirement to get the new structure in place as soon as possible, assembly, placement and some of the backfilling were able to take place during the winter months. The structure was assembled adjacent to the site and then crane-lifted in one piece onto the footings. With the spring thaw, the remaining backfill, road surface and rail structures were completed.

The structure was instrumented with stress and strain gauges to help advance AIL's ongoing research and development programs. Shape monitoring, using total station and prisms mounted on the inside of the structure, was conducted throughout construction and after installation.

Ontario-based project partners were: The Town of Pympton-Wyoming; Northwest Consulting Engineers, of Ilderton; and Murray Mills Excavating and Trucking (Sarnia) Ltd. Interesting project factoid: Just 2.5 km farther upstream on Hickory Creek, is the site of AIL's first Super•Cor Box Culvert ever installed in Ontario, in 1993.